IBM System Networking RackSwitch™ G8124/G8124-E

Application Guide
For IBM Networking OS™ 7.11
Note: Before using this information and the product it supports, read the general information in the Safety information and
Environmental Notices and User Guide documents on the IBM Documentation CD and the Warranty Information document that comes
with the product.

First Edition (November 2014)

© Copyright IBM Corporation 2014
US Government Users Restricted Rights – Use, duplication or disclosure restricted by GSA ADP Schedule Contract
with IBM Corp.
Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Who Should Use This Guide . . . . . . . . . . . . . . . . . . . . 15
What You’ll Find in This Guide . . . . . . . . . . . . . . . . . . . 15
Additional References. . . . . . . . . . . . . . . . . . . . . . . 17
Typographic Conventions . . . . . . . . . . . . . . . . . . . . . 18
How to Get Help . . . . . . . . . . . . . . . . . . . . . . . . . 19

Part 1: Getting Started . . . . . . . . . . . . . . . . . . . . . . 21

Chapter 1. Switch Administration . . . . . . . . . . . . . . . . . 23

Administration Interfaces . . . . . . . . . . . . . . . . . . . . . 23
Industry Standard Command Line Interface. . . . . . . . . . . . . 23
Browser-Based Interface . . . . . . . . . . . . . . . . . . . . 23
Establishing a Connection . . . . . . . . . . . . . . . . . . . . . 24
Using the Switch Management Ports . . . . . . . . . . . . . . . 24
Using the Switch Data Ports. . . . . . . . . . . . . . . . . . . 25
Using Telnet . . . . . . . . . . . . . . . . . . . . . . . . . 26
Using Secure Shell . . . . . . . . . . . . . . . . . . . . . . 27
Using a Web Browser . . . . . . . . . . . . . . . . . . . . . 29
Using Simple Network Management Protocol . . . . . . . . . . . . 31
BOOTP/DHCP Client IP Address Services. . . . . . . . . . . . . . . 32
Global BOOTP Relay Agent Configuration . . . . . . . . . . . . . 32
Domain-Specific BOOTP Relay Agent Configuration . . . . . . . . . 33
DHCP Option 82 . . . . . . . . . . . . . . . . . . . . . . . 33
DHCP Snooping . . . . . . . . . . . . . . . . . . . . . . . 34
Switch Login Levels . . . . . . . . . . . . . . . . . . . . . . . 34
Setup vs. the Command Line . . . . . . . . . . . . . . . . . . . . 35
Idle Disconnect . . . . . . . . . . . . . . . . . . . . . . . . . 35
Boot Strict Mode . . . . . . . . . . . . . . . . . . . . . . . . . 36
Acceptable Cipher Suites . . . . . . . . . . . . . . . . . . . . 39
Configuring Strict Mode . . . . . . . . . . . . . . . . . . . . 40
SSL/TLS Version Limitation . . . . . . . . . . . . . . . . . . . 40
Limitations . . . . . . . . . . . . . . . . . . . . . . . . . 40

Chapter 2. Initial Setup . . . . . . . . . . . . . . . . . . . . . . 41

Information Needed for Setup. . . . . . . . . . . . . . . . . . . . 41
Default Setup Options. . . . . . . . . . . . . . . . . . . . . . . 42
Stopping and Restarting Setup Manually . . . . . . . . . . . . . . . 43
Setup Part 1: Basic System Configuration . . . . . . . . . . . . . . . 43
Setup Part 2: Port Configuration . . . . . . . . . . . . . . . . . . . 45
Setup Part 3: VLANs . . . . . . . . . . . . . . . . . . . . . . . 46
Setup Part 4: IP Configuration . . . . . . . . . . . . . . . . . . . 47
IP Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . 47
Default Gateways . . . . . . . . . . . . . . . . . . . . . . . 48
IP Routing. . . . . . . . . . . . . . . . . . . . . . . . . . 48
Setup Part 5: Final Steps . . . . . . . . . . . . . . . . . . . . . 49
Optional Setup for Telnet Support . . . . . . . . . . . . . . . . . . 50
Loopback Interfaces . . . . . . . . . . . . . . . . . . . . . . . 50
Using Loopback Interfaces for Source IP Addresses . . . . . . . . . 50
Loopback Interface Limitation . . . . . . . . . . . . . . . . . . 51

© Copyright IBM Corp. 2014 3

 Chapter 3. Switch Software Management . . . . . . . . . . . . . . 53
Loading New Software to Your Switch . . . . . . . . . . . . . . . . 54
Loading Software via the ISCLI . . . . . . . . . . . . . . . . . 54
Loading Software via BBI . . . . . . . . . . . . . . . . . . . 55
The Boot Management Menu . . . . . . . . . . . . . . . . . . . 56

Part 2: Securing the Switch . . . . . . . . . . . . . . . . . . . 59

Chapter 4. Securing Administration . . . . . . . . . . . . . . . . 61

Secure Shell and Secure Copy . . . . . . . . . . . . . . . . . . . 62
Configuring SSH/SCP Features on the Switch . . . . . . . . . . . 62
Configuring the SCP Administrator Password. . . . . . . . . . . . 63
Using SSH and SCP Client Commands . . . . . . . . . . . . . . 63
SSH and SCP Encryption of Management Messages . . . . . . . . 65
Generating RSA Host Key for SSH Access . . . . . . . . . . . . 65
SSH/SCP Integration with Radius Authentication . . . . . . . . . . 65
SSH/SCP Integration with TACACS+ Authentication . . . . . . . . . 65
End User Access Control . . . . . . . . . . . . . . . . . . . . . 66
Considerations for Configuring End User Accounts . . . . . . . . . 66
Strong Passwords . . . . . . . . . . . . . . . . . . . . . . 66
User Access Control . . . . . . . . . . . . . . . . . . . . . 67
Listing Current Users . . . . . . . . . . . . . . . . . . . . . 68
Logging into an End User Account . . . . . . . . . . . . . . . . 68
Password Fix-Up Mode . . . . . . . . . . . . . . . . . . . . 68

Chapter 5. Authentication & Authorization Protocols . . . . . . . . . 69

RADIUS Authentication and Authorization. . . . . . . . . . . . . . . 69
How RADIUS Authentication Works . . . . . . . . . . . . . . . 69
Configuring RADIUS on the Switch . . . . . . . . . . . . . . . . 70
RADIUS Authentication Features in IBM N/OS . . . . . . . . . . . 71
Switch User Accounts . . . . . . . . . . . . . . . . . . . . . 71
RADIUS Attributes for IBM N/OS User Privileges . . . . . . . . . . 72
TACACS+ Authentication . . . . . . . . . . . . . . . . . . . . . 73
How TACACS+ Authentication Works. . . . . . . . . . . . . . . 73
TACACS+ Authentication Features in IBM N/OS . . . . . . . . . . 74
Command Authorization and Logging . . . . . . . . . . . . . . . 75
Configuring TACACS+ Authentication on the Switch . . . . . . . . . 76
LDAP Authentication and Authorization. . . . . . . . . . . . . . . . 77

Chapter 6. Access Control Lists. . . . . . . . . . . . . . . . . . 79

Summary of Packet Classifiers . . . . . . . . . . . . . . . . . . . 80
Summary of ACL Actions . . . . . . . . . . . . . . . . . . . . . 81
Assigning Individual ACLs to a Port . . . . . . . . . . . . . . . . . 82
ACL Order of Precedence . . . . . . . . . . . . . . . . . . . . . 82
ACL Metering and Re-Marking . . . . . . . . . . . . . . . . . . . 82
ACL Port Mirroring . . . . . . . . . . . . . . . . . . . . . . . . 84
Viewing ACL Statistics . . . . . . . . . . . . . . . . . . . . . . 84
ACL Logging . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Enabling ACL Logging. . . . . . . . . . . . . . . . . . . . . 85
Logged Information . . . . . . . . . . . . . . . . . . . . . . 85
Rate Limiting Behavior . . . . . . . . . . . . . . . . . . . . 86
Log Interval . . . . . . . . . . . . . . . . . . . . . . . . . 86
ACL Logging Limitations . . . . . . . . . . . . . . . . . . . . 86

4 RackSwitch G8124: Application Guide

 ACL Configuration Examples . . . . . . . . . . . . . . . . . . . . 87
VLAN Maps. . . . . . . . . . . . . . . . . . . . . . . . . . . 89
VLAN Classification . . . . . . . . . . . . . . . . . . . . . . . 90
Using Storm Control Filters. . . . . . . . . . . . . . . . . . . . . 92

Part 3: Switch Basics . . . . . . . . . . . . . . . . . . . . . . 93

Chapter 7. VLANs . . . . . . . . . . . . . . . . . . . . . . . . 95
VLANs Overview. . . . . . . . . . . . . . . . . . . . . . . . . 96
VLANs and Port VLAN ID Numbers . . . . . . . . . . . . . . . . . 96
VLAN Numbers . . . . . . . . . . . . . . . . . . . . . . . 96
PVID/Native VLAN Numbers . . . . . . . . . . . . . . . . . . 97
VLAN Tagging/Trunk Mode . . . . . . . . . . . . . . . . . . . . 98
VLAN Topologies and Design Considerations . . . . . . . . . . . . . 102
Multiple VLANs with Tagging/Trunk Mode Adapters . . . . . . . . . 102
VLAN Configuration Example . . . . . . . . . . . . . . . . . . 104
Private VLANs . . . . . . . . . . . . . . . . . . . . . . . . . 105
Private VLAN Ports . . . . . . . . . . . . . . . . . . . . . . 105
Configuration Guidelines . . . . . . . . . . . . . . . . . . . . 106
Configuration Example . . . . . . . . . . . . . . . . . . . . . 106

Chapter 8. Ports and Trunking . . . . . . . . . . . . . . . . . . 109

Trunking Overview . . . . . . . . . . . . . . . . . . . . . . . . 110
Static Trunks . . . . . . . . . . . . . . . . . . . . . . . . . . 111
Static Trunk Requirements . . . . . . . . . . . . . . . . . . . 111
Static Trunk Group Configuration Rules . . . . . . . . . . . . . . 111
Configuring a Static Port Trunk . . . . . . . . . . . . . . . . . 112
Link Aggregation Control Protocol . . . . . . . . . . . . . . . . . . 114
Static LACP Trunks . . . . . . . . . . . . . . . . . . . . . . 115
LACP Port Modes. . . . . . . . . . . . . . . . . . . . . . . 115
LACP Individual . . . . . . . . . . . . . . . . . . . . . . . 116
LACP Minimum Links Option . . . . . . . . . . . . . . . . . . 116
Configuring LACP. . . . . . . . . . . . . . . . . . . . . . . 117
Configurable Trunk Hash Algorithm . . . . . . . . . . . . . . . . . 118

Chapter 9. Spanning Tree Protocols . . . . . . . . . . . . . . . . 119

Spanning Tree Protocol Modes . . . . . . . . . . . . . . . . . . . 119
Global STP Control . . . . . . . . . . . . . . . . . . . . . . . . 120
PVRST Mode . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Port States . . . . . . . . . . . . . . . . . . . . . . . . . 121
Bridge Protocol Data Units . . . . . . . . . . . . . . . . . . . 121
Simple STP Configuration . . . . . . . . . . . . . . . . . . . 123
Per-VLAN Spanning Tree Groups . . . . . . . . . . . . . . . . 125
Using Multiple STGs to Eliminate False Loops . . . . . . . . . . 125
VLANs and STG Assignment. . . . . . . . . . . . . . . . . 126
Manually Assigning STGs . . . . . . . . . . . . . . . . . . 127
Guidelines for Creating VLANs . . . . . . . . . . . . . . . . 127
Rules for VLAN Tagged/Trunk Mode Ports . . . . . . . . . . . 127
Adding and Removing Ports from STGs . . . . . . . . . . . . 128
The Switch-Centric Model . . . . . . . . . . . . . . . . . . 129
Configuring Multiple STGs . . . . . . . . . . . . . . . . . . . 130

© Copyright IBM Corp. 2014 Contents 5

 Rapid Spanning Tree Protocol . . . . . . . . . . . . . . . . . . . 132
Port States . . . . . . . . . . . . . . . . . . . . . . . . . 132
RSTP Configuration Guidelines . . . . . . . . . . . . . . . . . 132
RSTP Configuration Example . . . . . . . . . . . . . . . . . . 133
Multiple Spanning Tree Protocol . . . . . . . . . . . . . . . . . . 134
MSTP Region . . . . . . . . . . . . . . . . . . . . . . . . 134
Common Internal Spanning Tree . . . . . . . . . . . . . . . . 134
MSTP Configuration Guidelines . . . . . . . . . . . . . . . . . 135
MSTP Configuration Examples . . . . . . . . . . . . . . . . . 135
Port Type and Link Type . . . . . . . . . . . . . . . . . . . . . 138
Edge/Portfast Port . . . . . . . . . . . . . . . . . . . . . . 138
Link Type . . . . . . . . . . . . . . . . . . . . . . . . . . 138

Chapter 10. Virtual Link Aggregation Groups . . . . . . . . . . . . 139

VLAG Capacities . . . . . . . . . . . . . . . . . . . . . . . . 141
VLAGs versus Port Trunks . . . . . . . . . . . . . . . . . . . . 142
Configuring VLAGs . . . . . . . . . . . . . . . . . . . . . . . 143
Basic VLAG Configuration . . . . . . . . . . . . . . . . . . . 144
VLAG Configuration - VLANs Mapped to MSTI . . . . . . . . . 146
Configuring Health Check . . . . . . . . . . . . . . . . . . 149
VLAGs with VRRP . . . . . . . . . . . . . . . . . . . . . . 150
Configuring VLAGs in Multiple Layers. . . . . . . . . . . . . . . 155
VLAG with PIM . . . . . . . . . . . . . . . . . . . . . . . . . 158
Traffic Forwarding . . . . . . . . . . . . . . . . . . . . . . 158
Health Check . . . . . . . . . . . . . . . . . . . . . . . . 159

Chapter 11. Quality of Service . . . . . . . . . . . . . . . . . . 161

QoS Overview . . . . . . . . . . . . . . . . . . . . . . . . . 162
Using ACL Filters . . . . . . . . . . . . . . . . . . . . . . . . 163
Summary of ACL Actions . . . . . . . . . . . . . . . . . . . 163
ACL Metering and Re-Marking . . . . . . . . . . . . . . . . . 164
Using DSCP Values to Provide QoS . . . . . . . . . . . . . . . . . 166
Differentiated Services Concepts . . . . . . . . . . . . . . . . 166
Per Hop Behavior . . . . . . . . . . . . . . . . . . . . . . 167
QoS Levels . . . . . . . . . . . . . . . . . . . . . . . . . 168
DSCP Re-Marking and Mapping . . . . . . . . . . . . . . . . . 168
DSCP Re-Marking Configuration Examples . . . . . . . . . . . . 169
Using 802.1p Priority to Provide QoS . . . . . . . . . . . . . . . . 171
Queuing and Scheduling . . . . . . . . . . . . . . . . . . . . . 172

Part 4: Advanced Switching Features . . . . . . . . . . . . . . . 173

Chapter 12. Deployment Profiles . . . . . . . . . . . . . . . . . 175

Available Profiles . . . . . . . . . . . . . . . . . . . . . . . . 176
Selecting Profiles . . . . . . . . . . . . . . . . . . . . . . . . 177
Automatic Configuration Changes . . . . . . . . . . . . . . . . . . 178

Chapter 13. Virtualization . . . . . . . . . . . . . . . . . . . . 179

6 RackSwitch G8124: Application Guide

 Chapter 14. Virtual NICs . . . . . . . . . . . . . . . . . . . . . 181
Defining Server Ports . . . . . . . . . . . . . . . . . . . . . . . 182
Enabling the vNIC Feature . . . . . . . . . . . . . . . . . . . . . 182
vNIC IDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
vNIC IDs on the Switch . . . . . . . . . . . . . . . . . . . . 182
vNIC Interface Names on the Server . . . . . . . . . . . . . . . 183
vNIC Bandwidth Metering . . . . . . . . . . . . . . . . . . . . . 184
vNIC Groups . . . . . . . . . . . . . . . . . . . . . . . . . . 185
vNIC Teaming Failover . . . . . . . . . . . . . . . . . . . . . . 187
vNIC Configuration Example . . . . . . . . . . . . . . . . . . . . 189
Basic vNIC Configuration . . . . . . . . . . . . . . . . . . . . 189
vNICs for iSCSI on Emulex Endeavor 2 . . . . . . . . . . . . . . 192

Chapter 15. VMready . . . . . . . . . . . . . . . . . . . . . . 193

VE Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . 194
Defining Server Ports . . . . . . . . . . . . . . . . . . . . . . . 194
VM Group Types. . . . . . . . . . . . . . . . . . . . . . . . . 194
Local VM Groups . . . . . . . . . . . . . . . . . . . . . . . . 195
Distributed VM Groups . . . . . . . . . . . . . . . . . . . . . . 197
VM Profiles . . . . . . . . . . . . . . . . . . . . . . . . . 197
Initializing a Distributed VM Group . . . . . . . . . . . . . . . . 198
Assigning Members . . . . . . . . . . . . . . . . . . . . . . 198
Synchronizing the Configuration . . . . . . . . . . . . . . . . . 199
Removing Member VEs . . . . . . . . . . . . . . . . . . . . 199
VMcheck . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
Virtual Distributed Switch . . . . . . . . . . . . . . . . . . . . . 202
Prerequisites . . . . . . . . . . . . . . . . . . . . . . . . 202
Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . 202
Migrating to vDS . . . . . . . . . . . . . . . . . . . . . . . 203
Virtualization Management Servers . . . . . . . . . . . . . . . . . 204
Assigning a vCenter . . . . . . . . . . . . . . . . . . . . . . 204
vCenter Scans . . . . . . . . . . . . . . . . . . . . . . . . 205
Deleting the vCenter. . . . . . . . . . . . . . . . . . . . . . 205
Exporting Profiles . . . . . . . . . . . . . . . . . . . . . . . 206
VMware Operational Commands . . . . . . . . . . . . . . . . . 206
Pre-Provisioning VEs . . . . . . . . . . . . . . . . . . . . . . . 207
VLAN Maps. . . . . . . . . . . . . . . . . . . . . . . . . . . 208
VM Policy Bandwidth Control . . . . . . . . . . . . . . . . . . . . 209
VM Policy Bandwidth Control Commands . . . . . . . . . . . . . 209
Bandwidth Policies vs. Bandwidth Shaping . . . . . . . . . . . . . 210
VMready Information Displays . . . . . . . . . . . . . . . . . . . 211
VMready Configuration Example . . . . . . . . . . . . . . . . . . 215

Chapter 16. FCoE and CEE . . . . . . . . . . . . . . . . . . . . 217

Fibre Channel over Ethernet . . . . . . . . . . . . . . . . . . . . 218
The FCoE Topology . . . . . . . . . . . . . . . . . . . . . . 218
FCoE Requirements. . . . . . . . . . . . . . . . . . . . . . 219
Port Trunking . . . . . . . . . . . . . . . . . . . . . . . . 220
Converged Enhanced Ethernet . . . . . . . . . . . . . . . . . . . 221
Turning CEE On or Off . . . . . . . . . . . . . . . . . . . . . 221
Effects on Link Layer Discovery Protocol. . . . . . . . . . . . . . 221
Effects on 802.1p Quality of Service . . . . . . . . . . . . . . . 222
Effects on Flow Control . . . . . . . . . . . . . . . . . . . . 223

© Copyright IBM Corp. 2014 Contents 7

 FCoE Initialization Protocol Snooping . . . . . . . . . . . . . . . . 224
Global FIP Snooping Settings . . . . . . . . . . . . . . . . . . 224
FIP Snooping for Specific Ports . . . . . . . . . . . . . . . . . 225
Port FCF and ENode Detection . . . . . . . . . . . . . . . . . 225
FCoE Connection Timeout . . . . . . . . . . . . . . . . . . . 225
FCoE ACL Rules . . . . . . . . . . . . . . . . . . . . . . . 226
FCoE VLANs . . . . . . . . . . . . . . . . . . . . . . . . 226
Viewing FIP Snooping Information . . . . . . . . . . . . . . . . 227
Operational Commands . . . . . . . . . . . . . . . . . . . . 227
FIP Snooping Configuration . . . . . . . . . . . . . . . . . . 228
Priority-Based Flow Control . . . . . . . . . . . . . . . . . . . . 229
Global Configuration . . . . . . . . . . . . . . . . . . . . . 230
PFC Configuration Example . . . . . . . . . . . . . . . . . . 231
Enhanced Transmission Selection. . . . . . . . . . . . . . . . . . 232
802.1p Priority Values . . . . . . . . . . . . . . . . . . . . . 232
Priority Groups . . . . . . . . . . . . . . . . . . . . . . . 233
PGID . . . . . . . . . . . . . . . . . . . . . . . . . . 233
Assigning Priority Values to a Priority Group . . . . . . . . . . 234
Deleting a Priority Group . . . . . . . . . . . . . . . . . . 234
Allocating Bandwidth. . . . . . . . . . . . . . . . . . . . 235
Configuring ETS . . . . . . . . . . . . . . . . . . . . . . . 236
Data Center Bridging Capability Exchange . . . . . . . . . . . . . . 239
DCBX Settings . . . . . . . . . . . . . . . . . . . . . . . 240
Configuring DCBX . . . . . . . . . . . . . . . . . . . . . . 242

Part 5: IP Routing. . . . . . . . . . . . . . . . . . . . . . . . 243

Chapter 17. Basic IP Routing . . . . . . . . . . . . . . . . . . . 245

IP Routing Benefits . . . . . . . . . . . . . . . . . . . . . . . 246
Routing Between IP Subnets . . . . . . . . . . . . . . . . . . . . 246
Example of Subnet Routing . . . . . . . . . . . . . . . . . . . . 247
Using VLANs to Segregate Broadcast Domains . . . . . . . . . . . 248
Configuration Example . . . . . . . . . . . . . . . . . . . . 248
ECMP Static Routes . . . . . . . . . . . . . . . . . . . . . . . 251
ECMP Route Hashing . . . . . . . . . . . . . . . . . . . . . 251
Configuring ECMP Static Routes . . . . . . . . . . . . . . . . 252
Dynamic Host Configuration Protocol . . . . . . . . . . . . . . . . 253

Chapter 18. Routed Ports . . . . . . . . . . . . . . . . . . . . 255

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 255
Configuring a Routed Port . . . . . . . . . . . . . . . . . . . . . 257
Configuring OSPF on Routed Ports . . . . . . . . . . . . . . . 257
Configuring RIP on Routed Ports . . . . . . . . . . . . . . . . 258
Configuring PIM on Routed Ports . . . . . . . . . . . . . . . . 259
Configuring BGP on Routed Ports . . . . . . . . . . . . . . . . 260
Configuring IGMP on Routed Ports . . . . . . . . . . . . . . . . 260
Limitations . . . . . . . . . . . . . . . . . . . . . . . . . . . 261

Chapter 19. Internet Protocol Version 6 . . . . . . . . . . . . . . 263

IPv6 Limitations . . . . . . . . . . . . . . . . . . . . . . . . . 263
IPv6 Address Format . . . . . . . . . . . . . . . . . . . . . . . 264
IPv6 Address Types . . . . . . . . . . . . . . . . . . . . . . . 265
IPv6 Address Autoconfiguration. . . . . . . . . . . . . . . . . . . 266

8 RackSwitch G8124: Application Guide

 IPv6 Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . 267
Neighbor Discovery . . . . . . . . . . . . . . . . . . . . . . . 268
Supported Applications . . . . . . . . . . . . . . . . . . . . . . 270
Configuration Guidelines . . . . . . . . . . . . . . . . . . . . . 271
IPv6 Configuration Examples . . . . . . . . . . . . . . . . . . . . 272

Chapter 20. IPsec with IPv6 . . . . . . . . . . . . . . . . . . . . 273

IPsec Protocols . . . . . . . . . . . . . . . . . . . . . . . . . 274
Using IPsec with the RackSwitch G8124 . . . . . . . . . . . . . . . 275
Setting up Authentication . . . . . . . . . . . . . . . . . . . . 275
Creating an IKEv2 Proposal . . . . . . . . . . . . . . . . . 276
Importing an IKEv2 Digital Certificate . . . . . . . . . . . . . 276
Generating an IKEv2 Digital Certificate . . . . . . . . . . . . . 277
Enabling IKEv2 Preshared Key Authentication . . . . . . . . . . 277
Setting Up a Key Policy . . . . . . . . . . . . . . . . . . . . 278
Using a Manual Key Policy . . . . . . . . . . . . . . . . . . . 279
Using a Dynamic Key Policy . . . . . . . . . . . . . . . . . . 281

Chapter 21. Routing Information Protocol . . . . . . . . . . . . . . 283

Distance Vector Protocol . . . . . . . . . . . . . . . . . . . . . 283
Stability . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283
Routing Updates . . . . . . . . . . . . . . . . . . . . . . . . . 284
RIPv1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
RIPv2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284
RIPv2 in RIPv1 Compatibility Mode . . . . . . . . . . . . . . . . . 284
RIP Features . . . . . . . . . . . . . . . . . . . . . . . . . . 285
RIP Configuration Example . . . . . . . . . . . . . . . . . . . . 286

Chapter 22. Internet Group Management Protocol . . . . . . . . . . 289

IGMP Terms . . . . . . . . . . . . . . . . . . . . . . . . . . 290
How IGMP Works . . . . . . . . . . . . . . . . . . . . . . . . 291
IGMP Capacity and Default Values . . . . . . . . . . . . . . . . . 292
IGMP Snooping . . . . . . . . . . . . . . . . . . . . . . . . . 293
IGMP Querier . . . . . . . . . . . . . . . . . . . . . . . . 293
IGMP Groups . . . . . . . . . . . . . . . . . . . . . . . . 294
IGMPv3 Snooping . . . . . . . . . . . . . . . . . . . . . . 294
IGMP Snooping Configuration Guidelines . . . . . . . . . . . . . 295
IGMP Snooping Configuration Example . . . . . . . . . . . . . . 296
Advanced Configuration Example: IGMP Snooping. . . . . . . . . . 297
Prerequisites . . . . . . . . . . . . . . . . . . . . . . . 298
Configuration . . . . . . . . . . . . . . . . . . . . . . . 298
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . 301
Additional IGMP Features . . . . . . . . . . . . . . . . . . . . . 304
FastLeave. . . . . . . . . . . . . . . . . . . . . . . . . . 304
IGMP Filtering . . . . . . . . . . . . . . . . . . . . . . . . 304
Static Multicast Router . . . . . . . . . . . . . . . . . . . . . 305

© Copyright IBM Corp. 2014 Contents 9

 Chapter 23. Multicast Listener Discovery . . . . . . . . . . . . . . 307
MLD Terms . . . . . . . . . . . . . . . . . . . . . . . . . . 308
How MLD Works . . . . . . . . . . . . . . . . . . . . . . . . 309
MLD Querier . . . . . . . . . . . . . . . . . . . . . . . . 310
Dynamic Mrouters . . . . . . . . . . . . . . . . . . . . . . 310
MLD Capacity and Default Values . . . . . . . . . . . . . . . . . . 311
Configuring MLD . . . . . . . . . . . . . . . . . . . . . . . . 312

Chapter 24. Border Gateway Protocol . . . . . . . . . . . . . . . 313

Internal Routing Versus External Routing . . . . . . . . . . . . . . . 313
Route Reflector . . . . . . . . . . . . . . . . . . . . . . . 314
Forming BGP Peer Routers . . . . . . . . . . . . . . . . . . . . 317
Static Peers . . . . . . . . . . . . . . . . . . . . . . . . . 317
Dynamic Peers . . . . . . . . . . . . . . . . . . . . . . . 318
Loopback Interfaces . . . . . . . . . . . . . . . . . . . . . . . 319
What is a Route Map? . . . . . . . . . . . . . . . . . . . . . . 319
Incoming and Outgoing Route Maps . . . . . . . . . . . . . . . 320
Precedence . . . . . . . . . . . . . . . . . . . . . . . . . 321
Configuration Overview . . . . . . . . . . . . . . . . . . . . 321
Aggregating Routes . . . . . . . . . . . . . . . . . . . . . . . 323
Redistributing Routes. . . . . . . . . . . . . . . . . . . . . . . 323
BGP Communities . . . . . . . . . . . . . . . . . . . . . . . . 324
BGP Attributes . . . . . . . . . . . . . . . . . . . . . . . . . 325
Selecting Route Paths in BGP . . . . . . . . . . . . . . . . . . . 327
BGP Failover Configuration . . . . . . . . . . . . . . . . . . . . 328
Default Redistribution and Route Aggregation Example . . . . . . . . . 330

Chapter 25. OSPF. . . . . . . . . . . . . . . . . . . . . . . . 333

OSPFv2 Overview . . . . . . . . . . . . . . . . . . . . . . . . 334
Types of OSPF Areas . . . . . . . . . . . . . . . . . . . . . 334
Types of OSPF Routing Devices. . . . . . . . . . . . . . . . . 335
Neighbors and Adjacencies. . . . . . . . . . . . . . . . . . . 336
The Link-State Database. . . . . . . . . . . . . . . . . . . . 336
The Shortest Path First Tree . . . . . . . . . . . . . . . . . . 337
Internal Versus External Routing. . . . . . . . . . . . . . . . . 337
OSPFv2 Implementation in IBM N/OS . . . . . . . . . . . . . . . . 338
Configurable Parameters . . . . . . . . . . . . . . . . . . . 338
Defining Areas . . . . . . . . . . . . . . . . . . . . . . . . 339
Assigning the Area Index . . . . . . . . . . . . . . . . . . 339
Using the Area ID to Assign the OSPF Area Number . . . . . . . 340
Attaching an Area to a Network . . . . . . . . . . . . . . . 340
Interface Cost . . . . . . . . . . . . . . . . . . . . . . . . 341
Electing the Designated Router and Backup . . . . . . . . . . . . 341
Summarizing Routes . . . . . . . . . . . . . . . . . . . . . 341
Default Routes. . . . . . . . . . . . . . . . . . . . . . . . 342
Virtual Links . . . . . . . . . . . . . . . . . . . . . . . . . 342
Router ID . . . . . . . . . . . . . . . . . . . . . . . . . . 343
Authentication . . . . . . . . . . . . . . . . . . . . . . . . 344
Configuring Plain Text OSPF Passwords . . . . . . . . . . . . 344
Configuring MD5 Authentication . . . . . . . . . . . . . . . 345
Host Routes for Load Balancing . . . . . . . . . . . . . . . . . 346
Loopback Interfaces in OSPF . . . . . . . . . . . . . . . . . . 346
OSPF Features Not Supported in This Release . . . . . . . . . . . 346

10 RackSwitch G8124: Application Guide

 OSPFv2 Configuration Examples . . . . . . . . . . . . . . . . . . 347
Example 1: Simple OSPF Domain . . . . . . . . . . . . . . . . 348
Example 2: Virtual Links . . . . . . . . . . . . . . . . . . . . 350
Example 3: Summarizing Routes . . . . . . . . . . . . . . . . . 354
Verifying OSPF Configuration . . . . . . . . . . . . . . . . . . 355
OSPFv3 Implementation in IBM N/OS . . . . . . . . . . . . . . . . 356
OSPFv3 Differences from OSPFv2 . . . . . . . . . . . . . . . . 356
OSPFv3 Requires IPv6 Interfaces . . . . . . . . . . . . . . . 356
OSPFv3 Uses Independent Command Paths . . . . . . . . . . 356
OSPFv3 Identifies Neighbors by Router ID . . . . . . . . . . . 357
Other Internal Improvements . . . . . . . . . . . . . . . . . 357
OSPFv3 Limitations . . . . . . . . . . . . . . . . . . . . . . 357
OSPFv3 Configuration Example . . . . . . . . . . . . . . . . . 357

Chapter 26. Protocol Independent Multicast . . . . . . . . . . . . . 361

PIM Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 362
Supported PIM Modes and Features . . . . . . . . . . . . . . . . . 363
Basic PIM Settings . . . . . . . . . . . . . . . . . . . . . . . . 364
Globally Enabling or Disabling the PIM Feature . . . . . . . . . . . 364
Defining a PIM Network Component . . . . . . . . . . . . . . . 364
Defining an IP Interface for PIM Use . . . . . . . . . . . . . . . 364
PIM Neighbor Filters. . . . . . . . . . . . . . . . . . . . . . 365
Additional Sparse Mode Settings . . . . . . . . . . . . . . . . . . 366
Specifying the Rendezvous Point. . . . . . . . . . . . . . . . . 366
Influencing the Designated Router Selection . . . . . . . . . . . . 367
Specifying a Bootstrap Router . . . . . . . . . . . . . . . . . . 367
Configuring a Loopback Interface . . . . . . . . . . . . . . . . 367
Using PIM with Other Features . . . . . . . . . . . . . . . . . . . 369
PIM Configuration Examples . . . . . . . . . . . . . . . . . . . . 370

Part 6: High Availability Fundamentals . . . . . . . . . . . . . . . 373

Chapter 27. Basic Redundancy . . . . . . . . . . . . . . . . . . 375

Trunking for Link Redundancy . . . . . . . . . . . . . . . . . . . 376
Virtual Link Aggregation . . . . . . . . . . . . . . . . . . . . . . 376
Hot Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377
Forward Delay . . . . . . . . . . . . . . . . . . . . . . . . 377
Preemption . . . . . . . . . . . . . . . . . . . . . . . . . 377
FDB Update . . . . . . . . . . . . . . . . . . . . . . . . . 377
Configuration Guidelines . . . . . . . . . . . . . . . . . . . . 377
Configuring Hot Links . . . . . . . . . . . . . . . . . . . . . 378

Chapter 28. Layer 2 Failover . . . . . . . . . . . . . . . . . . . 379

Monitoring Trunk Links . . . . . . . . . . . . . . . . . . . . . . 379
Setting the Failover Limit . . . . . . . . . . . . . . . . . . . . . 379
Manually Monitoring Port Links . . . . . . . . . . . . . . . . . . . 380
L2 Failover with Other Features . . . . . . . . . . . . . . . . . . . 381
LACP . . . . . . . . . . . . . . . . . . . . . . . . . . . 381
Spanning Tree Protocol . . . . . . . . . . . . . . . . . . . . 381
Configuration Guidelines . . . . . . . . . . . . . . . . . . . . . 382
Configuring Layer 2 Failover . . . . . . . . . . . . . . . . . . . . 382

© Copyright IBM Corp. 2014 Contents 11

 Chapter 29. Virtual Router Redundancy Protocol . . . . . . . . . . 383
VRRP Overview . . . . . . . . . . . . . . . . . . . . . . . . . 384
VRRP Components . . . . . . . . . . . . . . . . . . . . . . 384
VRRP Operation . . . . . . . . . . . . . . . . . . . . . . . 385
Selecting the Master VRRP Router . . . . . . . . . . . . . . . . 386
Failover Methods . . . . . . . . . . . . . . . . . . . . . . . . 387
Active-Active Redundancy . . . . . . . . . . . . . . . . . . . 387
Virtual Router Group . . . . . . . . . . . . . . . . . . . . . 387
IBM N/OS Extensions to VRRP . . . . . . . . . . . . . . . . . . . 388
Virtual Router Deployment Considerations . . . . . . . . . . . . . . 389
High Availability Configurations . . . . . . . . . . . . . . . . . . . 390
VRRP High-Availability Using Multiple VIRs . . . . . . . . . . . . 390
VRRP High-Availability Using VLAGs . . . . . . . . . . . . . . . 394

Part 7: Network Management . . . . . . . . . . . . . . . . . . . 395

Chapter 30. Link Layer Discovery Protocol . . . . . . . . . . . . . 397

LLDP Overview . . . . . . . . . . . . . . . . . . . . . . . . . 398
Enabling or Disabling LLDP . . . . . . . . . . . . . . . . . . . . 399
Global LLDP Setting . . . . . . . . . . . . . . . . . . . . . 399
Transmit and Receive Control . . . . . . . . . . . . . . . . . . 399
LLDP Transmit Features . . . . . . . . . . . . . . . . . . . . . 400
Scheduled Interval . . . . . . . . . . . . . . . . . . . . . . 400
Minimum Interval . . . . . . . . . . . . . . . . . . . . . . . 400
Time-to-Live for Transmitted Information . . . . . . . . . . . . . 401
Trap Notifications . . . . . . . . . . . . . . . . . . . . . . 401
Changing the LLDP Transmit State. . . . . . . . . . . . . . . . 402
Types of Information Transmitted . . . . . . . . . . . . . . . . 402
LLDP Receive Features. . . . . . . . . . . . . . . . . . . . . . 404
Types of Information Received . . . . . . . . . . . . . . . . . 404
Viewing Remote Device Information . . . . . . . . . . . . . . . 404
Time-to-Live for Received Information . . . . . . . . . . . . . . 406
LLDP Example Configuration. . . . . . . . . . . . . . . . . . . . 407

Chapter 31. Simple Network Management Protocol. . . . . . . . . . 409

SNMP Version 1 & Version 2. . . . . . . . . . . . . . . . . . . . 409
SNMP Version 3 . . . . . . . . . . . . . . . . . . . . . . . . 410
Configuring SNMP Trap Hosts . . . . . . . . . . . . . . . . . . . 412
SNMP MIBs . . . . . . . . . . . . . . . . . . . . . . . . . . 415
Switch Images and Configuration Files . . . . . . . . . . . . . . . . 421
Loading a New Switch Image . . . . . . . . . . . . . . . . . . 422
Loading a Saved Switch Configuration . . . . . . . . . . . . . . 422
Saving the Switch Configuration . . . . . . . . . . . . . . . . . 423
Saving a Switch Dump . . . . . . . . . . . . . . . . . . . . 423

Chapter 32. NETCONF . . . . . . . . . . . . . . . . . . . . . . 425

NETCONF Overview . . . . . . . . . . . . . . . . . . . . . . . 426
XML Requirements . . . . . . . . . . . . . . . . . . . . . . . 427
Installing the NETCONF Client . . . . . . . . . . . . . . . . . . . 428
Using Juniper Perl Client . . . . . . . . . . . . . . . . . . . . . 430
Establishing a NETCONF Session . . . . . . . . . . . . . . . . . 431
NETCONF Operations . . . . . . . . . . . . . . . . . . . . . . 433

12 RackSwitch G8124: Application Guide

 Protocol Operations Examples . . . . . . . . . . . . . . . . . . . 434
<get-config> . . . . . . . . . . . . . . . . . . . . . . . . . 434
<edit-config>. . . . . . . . . . . . . . . . . . . . . . . . . 435
<copy-config> . . . . . . . . . . . . . . . . . . . . . . . . 437
<delete-config>. . . . . . . . . . . . . . . . . . . . . . . . 438
<lock> . . . . . . . . . . . . . . . . . . . . . . . . . . . 438
<unlock> . . . . . . . . . . . . . . . . . . . . . . . . . . 439
<get> . . . . . . . . . . . . . . . . . . . . . . . . . . . 440
<close-session> . . . . . . . . . . . . . . . . . . . . . . . 441
<kill-session> . . . . . . . . . . . . . . . . . . . . . . . . 441
<get-configuration> . . . . . . . . . . . . . . . . . . . . . . 442
<get-interface-information> . . . . . . . . . . . . . . . . . . . 443

Part 8: Monitoring . . . . . . . . . . . . . . . . . . . . . . . . 447

Chapter 33. Remote Monitoring . . . . . . . . . . . . . . . . . . 449

RMON Overview . . . . . . . . . . . . . . . . . . . . . . . . . 449
RMON Group 1—Statistics . . . . . . . . . . . . . . . . . . . . . 450
RMON Group 2—History . . . . . . . . . . . . . . . . . . . . . 451
History MIB Object ID . . . . . . . . . . . . . . . . . . . . . 451
Configuring RMON History . . . . . . . . . . . . . . . . . . . 451
RMON Group 3—Alarms . . . . . . . . . . . . . . . . . . . . . 452
Alarm MIB objects . . . . . . . . . . . . . . . . . . . . . . 452
Configuring RMON Alarms . . . . . . . . . . . . . . . . . . . 452
RMON Group 9—Events . . . . . . . . . . . . . . . . . . . . . 453

Chapter 34. sFlow . . . . . . . . . . . . . . . . . . . . . . . . 455

sFlow Statistical Counters . . . . . . . . . . . . . . . . . . . . . 455
sFlow Network Sampling . . . . . . . . . . . . . . . . . . . . . 455
sFlow Example Configuration . . . . . . . . . . . . . . . . . . . . 456

Chapter 35. Port Mirroring . . . . . . . . . . . . . . . . . . . . 457

Part 9: Appendices . . . . . . . . . . . . . . . . . . . . . . . 459

Appendix A. Getting help and technical assistance . . . . . . . . . . 461

Before you call . . . . . . . . . . . . . . . . . . . . . . . . . 461
Using the documentation . . . . . . . . . . . . . . . . . . . . . 461
Getting help and information on the World Wide Web . . . . . . . . . . 462
Software service and support . . . . . . . . . . . . . . . . . . . . 462
Hardware service and support . . . . . . . . . . . . . . . . . . . 462
IBM Taiwan product service . . . . . . . . . . . . . . . . . . . . 462

Appendix B. Notices . . . . . . . . . . . . . . . . . . . . . . . 463

Trademarks. . . . . . . . . . . . . . . . . . . . . . . . . . . 464
Important Notes . . . . . . . . . . . . . . . . . . . . . . . . . 465
Particulate contamination . . . . . . . . . . . . . . . . . . . . . 466
Documentation format . . . . . . . . . . . . . . . . . . . . . . 467

© Copyright IBM Corp. 2014 Contents 13

 Electronic emission notices . . . . . . . . . . . . . . . . . . . . 468
Federal Communications Commission (FCC) statement . . . . . . . 468
Industry Canada Class A emission compliance statement . . . . . . . 468
Avis de conformité à la réglementation d'Industrie Canada . . . . . . 468
Australia and New Zealand Class A statement . . . . . . . . . . . 468
European Union EMC Directive conformance statement . . . . . . . 469
Germany Class A statement . . . . . . . . . . . . . . . . . . 470
Japan VCCI Class A statement . . . . . . . . . . . . . . . . . 471
Korea Communications Commission (KCC) statement . . . . . . . . 471
Russia Electromagnetic Interference (EMI) Class A statement . . . . . 471
People’s Republic of China Class A electronic emission statement . . . 471
Taiwan Class A compliance statement . . . . . . . . . . . . . . 471

14 RackSwitch G8124: Application Guide

Preface
This Application Guide describes how to configure and use the IBM
Networking OS 7.11 software on the RackSwitch G8124/G8124 (collectively
referred to as G8124 throughout this document). For documentation on installing the
switch physically, see the Installation Guide for your G8124.

Who Should Use This Guide

This guide is intended for network installers and system administrators engaged in
configuring and maintaining a network. The administrator should be familiar with
Ethernet concepts, IP addressing, Spanning Tree Protocol, and SNMP configuration
parameters.

What You’ll Find in This Guide

This guide will help you plan, implement, and administer IBM N/OS software. Where
possible, each section provides feature overviews, usage examples, and
configuration instructions. The following material is included:

Part 1: Getting Started

This material is intended to help those new to N/OS products with the basics of
switch management. This part includes the following chapters:
• Chapter 1, “Switch Administration,” describes how to access the G8124 to
configure the switch and view switch information and statistics. This chapter
discusses a variety of manual administration interfaces, including local
management via the switch console, and remote administration via Telnet, a web
browser, or via SNMP.
• Chapter 2, “Initial Setup,” describes how to use the built-in Setup utility to perform
first-time configuration of the switch.
• Chapter 3, “Switch Software Management,” describes how to update the N/OS
software operating on the switch.

Part 2: Securing the Switch

• Chapter 4, “Securing Administration,” describes methods for using Secure Shell
for administration connections, and configuring end-user access control.
• Chapter 5, “Authentication & Authorization Protocols,” describes different secure
administration for remote administrators. This includes using Remote
Authentication Dial-in User Service (RADIUS), as well as TACACS+ and LDAP.
• Chapter 6, “Access Control Lists,” describes how to use filters to permit or deny
specific types of traffic, based on a variety of source, destination, and packet
attributes.

Part 3: Switch Basics

• Chapter 7, “VLANs,” describes how to configure Virtual Local Area Networks
(VLANs) for creating separate network segments, including how to use VLAN
tagging for devices that use multiple VLANs. This chapter also describes
Protocol-based VLANs, and Private VLANs.
• Chapter 8, “Ports and Trunking,” describes how to group multiple physical ports
together to aggregate the bandwidth between large-scale network devices.

© Copyright IBM Corp. 2014 15

 • Chapter 9, “Spanning Tree Protocols,” discusses how Spanning Tree Protocol
(STP) configures the network so that the switch selects the most efficient path
when multiple paths exist. Covers Rapid Spanning Tree Protocol (RSTP),
Per-VLAN Rapid Spanning Tree (PVRST), and Multiple Spanning Tree Protocol
(MSTP).
• Chapter 10, “Virtual Link Aggregation Groups,” describes using Virtual Link
Aggregation Groups (VLAG) to form trunks spanning multiple VLAG-capable
aggregator switches.
• Chapter 11, “Quality of Service,” discusses Quality of Service (QoS) features,
including IP filtering using Access Control Lists (ACLs), Differentiated Services,
and IEEE 802.1p priority values.

Part 4: Advanced Switching Features

• Chapter 12, “Deployment Profiles,” describes how the G8124 can operate in
different modes for different deployment scenarios, adjusting switch capacity
levels to optimize performance for different types of networks.
• Chapter 13, “Virtualization,” provides an overview of allocating resources based
on the logical needs of the data center, rather than on the strict, physical nature of
components.
• Chapter 14, “Virtual NICs,” discusses using virtual NIC (vNIC) technology to divide
NICs into multiple logical, independent instances.
• Chapter 15, “VMready,” discusses virtual machine (VM) support on the G8124.
• Chapter 16, “FCoE and CEE,” discusses using various Converged Enhanced
Ethernet (CEE) features such as Priority-based Flow Control (PFC), Enhanced
Transmission Selection (ETS), and FIP Snooping for solutions such as Fibre
Channel over Ethernet (FCoE).

Part 5: IP Routing
• Chapter 17, “Basic IP Routing,” describes how to configure the G8124 for IP
routing using IP subnets, BOOTP, and DHCP Relay.
• Chapter 18, “Routed Ports describes how to configure a switch port to forward
Layer 3 traffic.
• Chapter 19, “Internet Protocol Version 6,” describes how to configure the G8124
for IPv6 host management.
• Chapter 20, “IPsec with IPv6,” describes how to configure Internet Protocol
Security (IPsec) for securing IP communications by authenticating and encrypting
IP packets, with emphasis on Internet Key Exchange version 2, and
authentication/confidentiality for OSPFv3.
• Chapter 21, “Routing Information Protocol,” describes how the N/OS software
implements standard Routing Information Protocol (RIP) for exchanging TCP/IP
route information with other routers.
• Chapter 22, “Internet Group Management Protocol,” describes how the N/OS
software implements IGMP Snooping or IGMP Relay to conserve bandwidth in a
multicast-switching environment.
• Chapter 23, “Multicast Listener Discovery,” describes how Multicast Listener
Discovery (MLD) is used with IPv6 to support host users requests for multicast
data for a multicast group.
• Chapter 24, “Border Gateway Protocol,” describes Border Gateway Protocol
(BGP) concepts and features supported in N/OS.

16 RackSwitch G8124: Application Guide

 • Chapter 25, “OSPF,” describes key Open Shortest Path First (OSPF) concepts
and their implemented in N/OS, and provides examples of how to configure your
switch for OSPF support.
• Chapter 26, “Protocol Independent Multicast,” describes how multicast routing can
be efficiently accomplished using the Protocol Independent Multicast (PIM)
feature.

Part 6: High Availability Fundamentals

• Chapter 27, “Basic Redundancy,” describes how the G8124 supports redundancy
through trunking, and hotlinks.
• Chapter 28, “Layer 2 Failover,” describes how the G8124 supports
high-availability network topologies using Layer 2 Failover.
• Chapter 29, “Virtual Router Redundancy Protocol,” describes how the G8124
supports high-availability network topologies using Virtual Router Redundancy
Protocol (VRRP).

Part 7: Network Management

• Chapter 30, “Link Layer Discovery Protocol,” describes how Link Layer Discovery
Protocol helps neighboring network devices learn about each others’ ports and
capabilities.
• Chapter 31, “Simple Network Management Protocol,” describes how to configure
the switch for management through an SNMP client.
• Chapter 32, “NETCONF,” describes how to manage the G8124 using the Network
Configuration Protocol (NETCONF), a mechanism based on the Extensible
Markup Language (XML).

Part 8: Monitoring
• Chapter 33, “Remote Monitoring,” describes how to configure the RMON agent on
the switch, so that the switch can exchange network monitoring data.
• Chapter 34, “sFlow, described how to use the embedded sFlow agent for
sampling network traffic and providing continuous monitoring information to a
central sFlow analyzer.
• Chapter 35, “Port Mirroring,” discusses tools how copy selected port traffic to a
monitor port for network analysis.

Part 9: Appendices
• Appendix A, “Glossary,” describes common terms and concepts used throughout
this guide.

Additional References
Additional information about installing and configuring the G8124 is available in the
following guides:
• RackSwitch G8124 Installation Guide
• IBM Networking OS 7.11 ISCLI Reference Guide
• IBM Networking OS 7.11 BBI Quick Guide

© Copyright IBM Corp. 2014 Preface 17

Typographic Conventions
The following table describes the typographic styles used in this book.
Table 1. Typographic Conventions

Typeface or Meaning Example

Symbol

ABC123 This type is used for names of View the readme.txt file.
commands, files, and directories
used within the text.

It also depicts on-screen computer Main#

output and prompts.

ABC123 This bold type appears in Main# sys

command examples. It shows text
that must be typed in exactly as
shown.

<ABC123> This italicized type appears in To establish a Telnet session,

command examples as a enter:
parameter placeholder. Replace host# telnet <IP
the indicated text with the address>
appropriate real name or value
when using the command. Do not
type the brackets.

This also shows book titles, Read your User’s Guide

special terms, or words to be thoroughly.
emphasized.

[ ] Command items shown inside host# ls [-a]

brackets are optional and can be
used or excluded as the situation
demands. Do not type the
brackets.

| The vertical bar ( | ) is used in host# set left|right

command examples to separate
choices where multiple options
exist. Select only one of the listed
options. Do not type the vertical
bar.

AaBbCc123 This block type depicts menus, Click the Save button.
buttons, and other controls that
appear in Web browsers and other
graphical interfaces.

18 RackSwitch G8124: Application Guide

How to Get Help
If you need help, service, or technical assistance, visit our web site at the following
address:
http://www.ibm.com/support

The warranty card received with your product provides details for contacting a
customer support representative. If you are unable to locate this information, please
contact your reseller. Before you call, prepare the following information:
• Serial number of the switch unit
• Software release version number
• Brief description of the problem and the steps you have already taken
• Technical support dump information (# show tech-support)

© Copyright IBM Corp. 2014 Preface 19

20 RackSwitch G8124: Application Guide
Part 1: Getting Started

© Copyright IBM Corp. 2014 21

22 RackSwitch G8124: Application Guide
Chapter 1. Switch Administration
Your RackSwitch G8124 (G8124) is ready to perform basic switching functions right
out of the box. Some of the more advanced features, however, require some
administrative configuration before they can be used effectively.

The extensive IBM Networking OS switching software included in the G8124

provides a variety of options for accessing the switch to perform configuration, and
to view switch information and statistics.

This chapter discusses the various methods that can be used to administer the
switch.

Administration Interfaces
IBM N/OS provides a variety of user-interfaces for administration. These interfaces
vary in character and in the methods used to access them: some are text-based,
and some are graphical; some are available by default, and some require
configuration; some can be accessed by local connection to the switch, and others
are accessed remotely using various client applications. For example,
administration can be performed using any of the following:
• A built-in, text-based command-line interface and menu system for access via
serial-port connection or an optional Telnet or SSH session
• The built-in Browser-Based Interface (BBI) available using a standard
web-browser
• SNMP support for access through network management software such as IBM
Director or HP OpenView

The specific interface chosen for an administrative session depends on user

preferences, as well as the switch configuration and the available client tools.

In all cases, administration requires that the switch hardware is properly installed
and turned on. (see the RackSwitch G8124 Installation Guide).

Industry Standard Command Line Interface

The Industry Standard Command Line Interface (ISCLI) provides a simple, direct
method for switch administration. Using a basic terminal, you can issue commands
that allow you to view detailed information and statistics about the switch, and to
perform any necessary configuration and switch software maintenance.

You can establish a connection to the ISCLI in any of the following ways:
• Serial connection via the serial port on the G8124 (this option is always avail-
able)
• Telnet connection over the network
• SSH connection over the network

Browser-Based Interface
The Browser-based Interface (BBI) provides access to the common configuration,
management and operation features of the G8124 through your Web browser.

For more information, refer to the BBI Quick Guide.

© Copyright IBM Corp. 2014 23

Establishing a Connection
The factory default settings permit initial switch administration through only the
built-in serial port. All other forms of access require additional switch configuration
before they can be used.

Remote access using the network requires the accessing terminal to have a valid,
routable connection to the switch interface. The client IP address may be configured
manually, or an IPv4 address can be provided automatically through the switch
using a service such as DHCP or BOOTP relay (see “BOOTP/DHCP Client IP
Address Services” on page 32), or an IPv6 address can be obtained using IPv6
stateless address configuration.
Note: Throughout this manual, IP address is used in places where either an IPv4
or IPv6 address is allowed. IPv4 addresses are entered in dotted-decimal
notation (for example, 10.10.10.1), while IPv6 addresses are entered in
hexadecimal notation (for example, 2001:db8:85a3::8a2e:370:7334). In
places where only one type of address is allowed, IPv4 address or IPv6
address is specified.

Using the Switch Management Ports

To manage the switch through the management ports, you must configure an IP
interface for each management interface. Configure the IPv4 address/mask and
default gateway address:
1. Log on to the switch.
2. Enter Global Configuration mode.

RS G8124> enable
RS G8124# configure terminal

3. Configure a management IP address and mask.

The switch reserves four management interfaces:
– Using IPv4:

RS G8124(config)# interface ip [127|128]

RS G8124(config-ip-if)# ip address <management interface IPv4 address>
RS G8124(config-ip-if)# ip netmask <IPv4 subnet mask>
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit

• IF 127 supports IPv4 management port A and uses IPv4 default gateway 3.
• IF 128 supports IPv4 management port B and uses IPv4 default gateway 4.
– Using IPv6:

RS G8124(config)# interface ip [125|126]

RS G8124(config-ip-if)# ipv6 address <management interface IPv6 address>
RS G8124(config-ip-if)# ipv6 prefixlen <IPv6 prefix length>
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit

• IF 125 supports IPv6 management port A and uses IPv6 default gateway 3.
• IF 126 supports IPv6 management port B and uses IPv6 default gateway 4.

24 RackSwitch G8124: Application Guide

 4. Configure the appropriate default gateway.
– If using IPv4, IPv4 gateway 3 is required for IF 127, and IPv4 gateway 4 is
required for IF 128.

RS G8124(config)# ip gateway [3|4] address <default gateway IPv4 address>

RS G8124(config)# ip gateway [3|4] enable

– If using IPv6, IPv6 gateway 3 is required for IF 125, and IPv4 gateway 4 is
required for IF 126.

RS G8124(config)# ip gateway6 [3|4] address <default gateway IPv6 address>

RS G8124(config)# ip gateway6 [3|4] enable

Once you configure a management IP address for your switch, you can connect to a
management port and use the Telnet program from an external management station
to access and control the switch. The management port provides out-of-band
management.

Using the Switch Data Ports

You also can configure in-band management through any of the switch data ports.
To allow in-band management, use the following procedure:
1. Log on to the switch.
2. Enter IP interface mode.

RS G8124> enable
RS G8124# configure terminal
RS G8124(config)# interface ip <IP interface number>

Note: Interface 125 through 128 are reserved for out-of-band management (see
“Using the Switch Management Ports” on page 24).
3. Configure the management IP interface/mask.
– Using IPv4:

RS G8124(config-ip-if)# ip address <management interface IPv4 address>

RS G8124(config-ip-if)# ip netmask <IPv4 subnet mask>

– Using IPv6:

RS G8124(config-ip-if)# ipv6 address <management interface IPv6 address>

RS G8124(config-ip-if)# ipv6 prefixlen <IPv6 prefix length>

4. Configure the VLAN, and enable the interface.

RS G8124(config-ip-if)# vlan 1
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit

© Copyright IBM Corp. 2014 Chapter 1: Switch Administration 25

 5. Configure the default gateway.
– If using IPv4:

RS G8124(config)# ip gateway <gateway number> address <IPv4 address>

RS G8124(config)# ip gateway <gateway number> enable

– If using IPv6:

RS G8124(config)# ip gateway6 <gateway number> address <IPv6 address>

RS G8124(config)# ip gateway6 <gateway number> enable

Note: IPv4 gateway 1 and 2, and IPv6 gateway 1, are used for in-band data
networks. IPv4 and IPv6 gateways 3 and 4 are reserved for out-of-band
management ports (see “Using the Switch Management Ports” on page 24).

Once you configure the IP address and have a network connection, you can use the
Telnet program from an external management station to access and control the
switch. Once the default gateway is enabled, the management station and your
switch do not need to be on the same IP subnet.

The G8124 supports a menu-based command-line interface (CLI) as well as an

industry standard command-line interface (ISCLI) that you can use to configure and
control the switch over the network using the Telnet program. You can use the CLI or
ISCLI to perform many basic network management functions. In addition, you can
configure the switch for management using an SNMP-based network management
system or a Web browser.

For more information, see the documents listed in “Additional References” on

page 17.

Using Telnet
A Telnet connection offers the convenience of accessing the switch from a
workstation connected to the network. Telnet access provides the same options for
user and administrator access as those available through the console port.

By default, Telnet access is enabled. Use the following commands to disable or

re-enable Telnet access:

RS G8124(config)# [no] access telnet enable

Once the switch is configured with an IP address and gateway, you can use Telnet
to access switch administration from any workstation connected to the management
network.

To establish a Telnet connection with the switch, run the Telnet program on your
workstation and issue the following Telnet command:

telnet <switch IPv4 or IPv6 address>

You will then be prompted to enter a password as explained “Switch Login Levels”
on page 34.

Two attempts are allowed to log in to the switch. After the second unsuccessful
attempt, the Telnet client is disconnected via TCP session closure.

26 RackSwitch G8124: Application Guide

Using Secure Shell
Although a remote network administrator can manage the configuration of a G8124
via Telnet, this method does not provide a secure connection. The Secure Shell
(SSH) protocol enables you to securely log into another device over a network to
execute commands remotely. As a secure alternative to using Telnet to manage
switch configuration, SSH ensures that all data sent over the network is encrypted
and secure.

The switch can do only one session of key/cipher generation at a time. Thus, a
SSH/SCP client will not be able to login if the switch is doing key generation at that
time. Similarly, the system will fail to do the key generation if a SSH/SCP client is
logging in at that time.

The supported SSH encryption and authentication methods are:

• Server Host Authentication: Client RSA-authenticates the switch when starting
each connection
• Key Exchange: ecdh-sha2-nistp521, ecdh-sha2-nistp384, ecdh-sha2-nistp256,
ecdh-sha2-nistp224, ecdh-sha2-nistp192, rsa2048-sha256, rsa1024-sha1,
diffie-hellman-group-exchange-sha256, diffie-hellman-group-exchange-sha1,
diffie-hellman-group14-sha1, diffie-hellman-group1-sha1
• Encryption: aes128-ctr, aes128-cbc, rijndael128-cbc, blowfish-cbc,3des-cbc,
arcfour256, arcfour128, arcfour
• MAC: hmac-sha1, hmac-sha1-96, hmac-md5, hmac-md5-96
• User Authentication: Local password authentication, public key authentication,
RADIUS, TACACS+

IBM Networking OS implements the SSH version 2.0 standard and is confirmed to
work with SSH version 2.0-compliant clients such as the following:
• OpenSSH_5.4p1 for Linux
• Secure CRT Version 5.0.2 (build 1021)
• Putty SSH release 0.60

Using SSH with Password Authentication

By default, the SSH feature is disabled. Once the IP parameters are configured and
the SSH service is enabled, you can access the command line interface using an
SSH connection.

To establish an SSH connection with the switch, run the SSH program on your
workstation by issuing the SSH command, followed by the switch IPv4 or IPv6
address:

# ssh <switch IP address>

You will then be prompted to enter a password as explained “Switch Login Levels”
on page 34.

© Copyright IBM Corp. 2014 Chapter 1: Switch Administration 27

 Using SSH with Public Key Authentication

SSH can also be used for switch authentication based on asymmetric cryptography.
Public encryption keys can be uploaded on the switch and used to authenticate
incoming login attempts based on the clients’ private encryption key pairs. After a
predefined number of failed public key login attempts, the switch reverts to
password-based authentication.

To set up public key authentication:

1. Enable SSH:

RS G8124(config)# ssh enable

2. Import the public key file using SFTP or TFTP for the admin user account::

RS G8124(config)# copy {sftp|tftp} public-key

Port type ["DATA"/"MGT"]: mgt
Address or name of remote host: 9.43.101.151
Source file name: 11.key
Username of the public key: admin
Confirm download operation (y/n) ? y

Note: When prompted to input a username, a valid user account name must be
entered. If no username is entered, the key is stored on the switch, and can be
assigned to a user account later.
Note: A user account can have up to 100 public keys set up on the switch.
3. Configure a maximum number of 3 failed public key authentication attempts
before the system reverts to password-based authentication:

RS G8124(config)# ssh maxauthattempts 3

Once the public key is configured on the switch, the client can use SSH to login from
a system where the private key pair is set up:

# ssh <switch IP address>

28 RackSwitch G8124: Application Guide

Using a Web Browser
The switch provides a Browser-Based Interface (BBI) for accessing the common
configuration, management, and operation features of the G8124 through your Web
browser.

By default, BBI access via HTTP is enabled on the switch.

You can also access the BBI directly from an open Web browser window. Enter the
URL using the IP address of the switch interface (for example, http://<IPv4 or
IPv6 address>).

Configuring HTTP Access to the BBI

By default, BBI access via HTTP is enabled on the switch.

To disable or re-enable HTTP access to the switch BBI, use the following
commands:

RS G8124(config)# access http enable (Enable HTTP access)

-or-
RS G8124(config)# no access http enable (Disable HTTP access)

The default HTTP web server port to access the BBI is port 80. However, you can
change the default Web server port with the following command:

RS G8124(config)# access http port <TCP port number>

To access the BBI from a workstation, open a Web browser window and type in the
URL using the IP address of the switch interface (for example, http://<IPv4 or
IPv6 address>).

Configuring HTTPS Access to the BBI

The BBI can also be accessed via a secure HTTPS connection over management
and data ports.
1. Enable HTTPS.
By default, BBI access via HTTPS is disabled on the switch. To enable BBI
Access via HTTPS, use the following command:

RS G8124(config)# access https enable

2. Set the HTTPS server port number (optional).

To change the HTTPS Web server port number from the default port 443, use
the following command:

RS G8124(config)# access https port <x>

© Copyright IBM Corp. 2014 Chapter 1: Switch Administration 29

 3. Generate the HTTPS certificate.
Accessing the BBI via HTTPS requires that you generate a certificate to be used
during the key exchange. A default certificate is created the first time HTTPS is
enabled, but you can create a new certificate defining the information you want
to be used in the various fields.

RS G8124(config)# access https generate-certificate

Country Name (2 letter code) [US]:
State or Province Name (full name) [CA]:
Locality Name (eg, city) [Santa Clara]:
Organization Name (eg, company) [IBM Networking Operating System]:
Organizational Unit Name (eg, section) [Network Engineering]:
Common Name (eg, YOUR name) [host’s IP address]:
Email (eg, email address) [info@IBM.com]:
Confirm generating certificate? [y/n]: y
Generating certificate. Please wait (approx 30 seconds)
restarting SSL agent

4. Save the HTTPS certificate.

The certificate is valid only until the switch is rebooted. To save the certificate so
it is retained beyond reboot or power cycles, use the following command:

RS G8124(config)# access https save-certificate

When a client (such as a web browser) connects to the switch, the client is asked to
accept the certificate and verify that the fields match what is expected. Once BBI
access is granted to the client, the BBI can be used as described in the IBM
Networking OS 7.11 BBI Quick Guide.

Browser-Based Interface Summary

The BBI is organized at a high level as follows:

Context buttons—These buttons allow you to select the type of action you wish to
perform. The Configuration button provides access to the configuration elements for
the entire switch. The Statistics button provides access to the switch statistics and
state information. The Dashboard button allows you to display the settings and
operating status of a variety of switch features.

Navigation Window—This window provides a menu of switch features and functions:

• System—this provides access to the configuration elements for the entire switch.
• Switch Ports—Configure each of the physical ports on the switch.
• Port-Based Port Mirroring—Configure port mirroring behavior.
• Layer 2—Configure Layer 2 features for the switch.
• RMON Menu—Configure Remote Monitoring features for the switch.
• Layer 3—Configure Layer 3 features for the switch.
• QoS—Configure Quality of Service features for the switch.
• Access Control—Configure Access Control Lists to filter IP packets.
• CEE—Configure Converged Enhanced Ethernet (CEE).
• FCoE—Configure FibreChannel over Ethernet (FCoE).
• Virtualization—Configure vNICs and VMready for virtual machines (VMs).

For information on using the BBI, refer to the IBM Networking OS 7.11 BBI Quick Guide.

30 RackSwitch G8124: Application Guide

Using Simple Network Management Protocol
N/OS provides Simple Network Management Protocol (SNMP) version 1, version 2,
and version 3 support for access through any network management software, such
as IBM Director or HP-OpenView.
Note: SNMP read and write functions are enabled by default. For best security
practices, if SNMP is not needed for your network, it is recommended that
you disable these functions prior to connecting the switch to the network.

To access the SNMP agent on the G8124, the read and write community strings on
the SNMP manager must be configured to match those on the switch. The default
read community string on the switch is public and the default write community
string is private.

The read and write community strings on the switch can be configured using the
following commands:

RS G8124(config)# snmp-server read-community <1-32 characters>

-and-
RS G8124(config)# snmp-server write-community <1-32 characters>

The SNMP manager must be able to reach any one of the IP interfaces on the
switch.

For the SNMP manager to receive the SNMPv1 traps sent out by the SNMP agent
on the switch, configure the trap host on the switch with the following commands:

RS G8124(config)# snmp-server trap-source <trap source IP interface>

RS G8124(config)# snmp-server host <IPv4 address> <trap host community string>

To restrict SNMP access to specific IPv4 subnets, use the following commands:

RS G8124(config)# access management-network <IPv4 address> <subnet mask> snmp-ro

-and-
RS G8124(config)# access management-network <IPv4 address> <subnet mask> snmp-rw

For IPv6 networks, use:

RS G8124(config)# access management-network6 <IPv6 address> <IPv6 prefix length> snmp-ro

-and-
RS G8124(config)# access management-network6 <IPv6 address> <IPv6 prefix length> snmp-rw

Note: Subnets allowed for SNMP read-only access must not overlap with subnets
allowed for SNMP read-write access.

For more information on SNMP usage and configuration, see “Simple Network
Management Protocol” on page 409.

© Copyright IBM Corp. 2014 Chapter 1: Switch Administration 31

BOOTP/DHCP Client IP Address Services
For remote switch administration, the client terminal device must have a valid IP
address on the same network as a switch interface. The IP address on the client
device may be configured manually, or obtained automatically using IPv6 stateless
address configuration, or an IPv4 address may obtained automatically via BOOTP
or DHCP relay as discussed in the next section.

The G8124 can function as a relay agent for Bootstrap Protocol (BOOTP) or DHCP.
This allows clients to be assigned an IPv4 address for a finite lease period,
reassigning freed addresses later to other clients.

Acting as a relay agent, the switch can forward a client’s IPv4 address request to up
to five BOOTP/DHCP servers. In addition to the five global BOOTP/DHCP servers,
up to five domain-specific BOOTP/DHCP servers can be configured for each of up
to 10 VLANs.

When a switch receives a BOOTP/DHCP request from a client seeking an IPv4

address, the switch acts as a proxy for the client. The request is forwarded as a
UDP Unicast MAC layer message to the BOOTP/DHCP servers configured for the
client’s VLAN, or to the global BOOTP/DHCP servers if no domain-specific
BOOTP/DHCP servers are configured for the client’s VLAN. The servers respond to
the switch with a Unicast reply that contains the IPv4 default gateway and the IPv4
address for the client. The switch then forwards this reply back to the client.

DHCP is described in RFC 2131, and the DHCP relay agent supported on the
G8124 is described in RFC 1542. DHCP uses UDP as its transport protocol. The
client sends messages to the server on port 67 and the server sends messages to
the client on port 68.

BOOTP and DHCP relay are collectively configured using the BOOTP commands
and menus on the G8124.

Global BOOTP Relay Agent Configuration

To enable the G8124 to be a BOOTP (or DHCP) forwarder, enable the BOOTP relay
feature, configure up to four global BOOTP server IPv4 addresses on the switch,
and enable BOOTP relay on the interface(s) on which the client requests are
expected.

Generally, it is best to configure BOOTP for the switch IP interface that is closest to
the client, so that the BOOTP server knows from which IPv4 subnet the newly
allocated IPv4 address will come.

32 RackSwitch G8124: Application Guide

 In the G8124 implementation, there are no primary or secondary BOOTP servers.
The client request is forwarded to all the global BOOTP servers configured on the
switch (if no domain-specific servers are configured). The use of multiple servers
provides failover redundancy. However, no health checking is supported.
1. Use the following commands to configure global BOOTP relay servers:

RS G8124(config)# ip bootp-relay enable

RS G8124(config)# ip bootp-relay server <1-5> address <IPv4 address>

2. Enable BOOTP relay on the appropriate IP interfaces.

BOOTP/DHCP Relay functionality may be assigned on a per-interface basis
using the following commands:

RS G8124(config)# interface ip <interface number>

RS G8124(config-ip-if)# relay
RS G8124(config-ip-if)# exit

Domain-Specific BOOTP Relay Agent Configuration

Use the following commands to configure up to five domain-specific BOOTP relay
agents for each of up to 10 VLANs:

RS G8124(config)# ip bootp-relay bcast-domain <1-10> vlan <VLAN number>

RS G8124(config)# ip bootp-relay bcast-domain <1-10> server <1-5> address <IPv4 address>
RS G8124(config)# ip bootp-relay bcast-domain <1-10> enable

As with global relay agent servers, domain-specific BOOTP/DHCP functionality may

be assigned on a per-interface basis (see Step 2 in page 33).

DHCP Option 82
DHCP Option 82 provides a mechanism for generating IP addresses based on the
client device’s location in the network. When you enable the DHCP relay agent
option on the switch, it inserts the relay agent information option 82 in the packet,
and sends a unicast BOOTP request packet to the DHCP server. The DHCP server
uses the option 82 field to assign an IP address, and sends the packet, with the
original option 82 field included, back to the relay agent. DHCP relay agent strips off
the option 82 field in the packet and sends the packet to the DHCP client.

Configuration of this feature is optional. The feature helps resolve several issues
where untrusted hosts access the network. See RFC 3046 for details.

Given below are the commands to configure DHCP Option 82:

RS G8124(config)# ip bootp-relay information enable (Enable Option 82)

RS G8124(config)# ip bootp-relay enable (Enable DHCP relay)
RS G8124(config)# ip bootp-relay server <1-5> address <IP address>

© Copyright IBM Corp. 2014 Chapter 1: Switch Administration 33

DHCP Snooping
DHCP snooping provides security by filtering untrusted DHCP packets and by
building and maintaining a DHCP snooping binding table. This feature is applicable
only to IPv4.

An untrusted interface is a port that is configured to receive packets from outside the
network or firewall. A trusted interface receives packets only from within the
network. By default, all DHCP ports are untrusted.

The DHCP snooping binding table contains the MAC address, IP address, lease
time, binding type, VLAN number, and port number that correspond to the local
untrusted interface on the switch; it does not contain information regarding hosts
interconnected with a trusted interface.

By default, DHCP snooping is disabled on all VLANs. You can enable DHCP
snooping on one or more VLANs. You must enable DHCP snooping globally. To
enable this feature, enter the commands below:

RS G8124(config)# ip dhcp snooping vlan <vlan number(s)>

RS G8124(config)# ip dhcp snooping

Following is an example of DHCP snooping configuration, where the DHCP server

and client are in VLAN 100, and the server connects using port 24.

RS G8124(config)# ip dhcp snooping vlan 100

RS G8124(config)# ip dhcp snooping
RS G8124(config)# interface port 24
RS G8124(config-if)# ip dhcp snooping trust (Optional; Set port as trusted)
RS G8124(config-if)# ip dhcp snooping information option-insert
(Optional; add DHCP option 82)
RS G8124(config-if)# ip dhcp snooping limit rate 100
(Optional; Set DHCP packet rate)

Switch Login Levels

To enable better switch management and user accountability, three levels or classes
of user access have been implemented on the G8124. Levels of access to CLI, Web
management functions, and screens increase as needed to perform various switch
management tasks. Conceptually, access classes are defined as follows:
• User interaction with the switch is completely passive—nothing can be changed
on the G8124. Users may display information that has no security or privacy
implications, such as switch statistics and current operational state information.
• Operators can only effect temporary changes on the G8124. These changes will
be lost when the switch is rebooted/reset. Operators have access to the switch
management features used for daily switch operations. Because any changes an
operator makes are undone by a reset of the switch, operators cannot severely
impact switch operation.
• Administrators are the only ones that may make permanent changes to the
switch configuration—changes that are persistent across a reboot/reset of the
switch. Administrators can access switch functions to configure and troubleshoot
problems on the G8124. Because administrators can also make temporary
(operator-level) changes as well, they must be aware of the interactions between
temporary and permanent changes.

34 RackSwitch G8124: Application Guide

 Access to switch functions is controlled through the use of unique user names and
passwords. Once you are connected to the switch via console, remote Telnet, or
SSH, you are prompted to enter a password. The default user names/password for
each access level are listed in the following table.
Note: It is recommended that you change default switch passwords after initial
configuration and as regularly as required under your network security
policies.

Table 2. User Access Levels - Default Settings

User Password Description and Tasks Performed Status

Account

user user The User has no direct responsibility for Disabled

switch management. He or she can view all
switch status information and statistics, but
cannot make any configuration changes to
the switch.

oper oper The Operator manages all functions of the Disabled

switch. The Operator can reset ports, except
the management ports.

admin admin The superuser Administrator has complete Enabled

access to all menus, information, and
configuration commands on the G8124,
including the ability to change both the user
and administrator passwords.

Note: Access to each user level (except admin account) can be disabled by setting
the password to an empty value. To disable admin account, use no access
user administrator-enable command. Admin account can be disabled
only if there is at least one user account enabled and configured with
administrator privilege.

Setup vs. the Command Line

Once the administrator password is verified, you are given complete access to the
switch. If the switch is still set to its factory default configuration, the system will ask
whether you wish to run Setup (see “Initial Setup” on page 41”), a utility designed to
help you through the first-time configuration process. If the switch has already been
configured, the command line is displayed instead.

Idle Disconnect
By default, the switch will disconnect your Telnet session after 10 minutes of
inactivity. This function is controlled by the idle timeout parameter, which can be set
from 0 to 60 minutes, where 0 means the session will never timeout.

Use the following command to set the idle timeout value:

RS G8124(config)# system idle <0-60>

© Copyright IBM Corp. 2014 Chapter 1: Switch Administration 35

Boot Strict Mode
The implementations specified in this section are compliant with National Institute of
Standards and Technology (NIST) Special Publication (SP) 800-131A.

The RackSwitch G8124 can operate in two boot modes:

• Compatibility mode (default): This is the default switch boot mode. This mode
may use algorithms and key lengths that may not be allowed/acceptable by NIST
SP 800-131A specification. This mode is useful in maintaining compatibility with
previous releases and in environments that have lesser data security
requirements.
• Strict mode: Encryption algorithms, protocols, and key lengths in strict mode are
compliant with NIST SP 800-131A specification.

When in boot strict mode, the switch uses Secure Sockets Layer (SSL)/Transport
Layer Security (TLS) 1.2 protocols to ensure confidentiality of the data to and from
the switch.

Before enabling strict mode, ensure the following:

• The software version on all connected switches is IBM N/OS 7.11.
• The supported protocol versions and cryptographic cipher suites between
clients and servers are compatible. For example: if using SSH to connect to the
switch, ensure that the SSH client supports SSHv2 and a strong cipher suite
that is compliant with the NIST standard.
• Compliant Web server certificate is installed on the switch, if using BBI.
• A new self-signed certificate is generated for the switch
(RS G8124(config)# access https generate-certificate). The
new certificate is generated using 2048-bit RSA key and SHA-256 digest.
• Protocols that are not NIST SP 800-131A compliant must be disabled or not
used.
• Only SSHv2 or higher is used.
• The current configuration, if any, is saved in a location external to the switch.
When the switch reboots, both the startup and running configuration are lost.
• Only protocols/algorithms compliant with NIST SP 800-131A specification are
used/enabled on the switch. Please see the NIST SP 800-131A publication for
details. The following table lists the acceptable protocols and algorithms:
Table 3. Acceptable Protocols and Algorithms
Protocol/Function Strict Mode Algorithm Compatibility Mode Algorithm
BGP BGP does not comply with NIST SP Acceptable
800-131A specification. When in strict
mode, BGP is disabled. However, it can
be enabled, if required.
Certificate RSA-2048 RSA 2048
Generation SHA-256 SHA 256
Certificate RSA 2048 or higher RSA
Acceptance SHA 224 or higher SHA, SHA2
HTTPS TLS 1.2 only TLS 1.0, 1.1, 1.2
See “Acceptable Cipher Suites” on See “Acceptable Cipher Suites” on
page 39; page 39;

36 RackSwitch G8124: Application Guide

 Table 3. Acceptable Protocols and Algorithms (continued)
Protocol/Function Strict Mode Algorithm Compatibility Mode Algorithm
IKE
Key Exchange DH Group 24 DH group 1, 2, 5, 14, 24
Encryption 3DES, AES-128-CBC 3DES, AES-128-CBC
Integrity HMAC-SHA1 HMAC-SHA1, HMAC-MD5
IPSec
AH HMAC-SHA1 HMAC-SHA1, HMAC-MD5
ESP 3DES, AES-128-CBC, HMAC-SHA1 3DES, AES-128-CBC,
HMAC-SHA1, HMAC-MD5
LDAP LDAP does not comply with NIST SP Acceptable
800-131A specification. When in strict
mode, LDAP is disabled. However, it
can be enabled, if required.
OSPF OSPF does not comply with NIST SP Acceptable
800-131A specification. When in strict
mode, OSPF is disabled. However, it
can be enabled, if required.
RADIUS RADIUS does not comply with NIST Acceptable
SP 800-131A specification. When in
strict mode, RADIUS is disabled. How-
ever, it can be enabled, if required.
Random Number NIST SP 800-90A AES CTR DRBG NIST SP 800-90A AES CTR DRBG
Generator
Secure NTP Secure NTP does not comply with Acceptable
NIST SP 800-131A specification.
When in strict mode, secure NTP is dis-
abled. However, it can be enabled, if
required.
SLP SHA-256 or higher
RSA/DSA 2048 or higher
SNMP SNMPv3 only SNMPv1, SNMPv2, SNMPv3
AES-128-CFB-128/SHA1 DES/MD5,
AES-128-CFB-128/SHA1
Note: Following algorithms are accept-
able if you choose to support old
SNMPv3 factory default users:
AES-128-CFB/SHA1
DES/MD5
AES-128-CFB-128/SHA1

© Copyright IBM Corp. 2014 Chapter 1: Switch Administration 37

 Table 3. Acceptable Protocols and Algorithms (continued)
Protocol/Function Strict Mode Algorithm Compatibility Mode Algorithm
SSH/SFTP
Host Key SSH-RSA SSH-RSA
Key Exchange ECDH-SHA2-NISTP521 ECDH-SHA2-NISTP521
ECDH-SHA2-NISTP384 ECDH-SHA2-NISTP384
ECDH-SHA2-NISTP256 ECDH-SHA2-NISTP256
ECDH-SHA2-NISTP224 ECDH-SHA2-NISTP224
RSA2048-SHA256 ECDH-SHA2-NISTP192
DIFFIE-HELL- RSA2048-SHA256
MAN-GROUP-EXCHANGE-SHA256 RSA1024-SHA1
DIFFIE-HELL- DIFFIE-HELL-
MAN-GROUP-EXCHANGE-SHA1 MAN-GROUP-EXCHANGE-SHA
256
DIFFIE-HELL-
MAN-GROUP-EXCHANGE-SHA
1
DIFFIE-HELL-
MAN-GROUP14-SHA1
DIFFIE-HELL-
MAN-GROUP1-SHA1
Encryption AES128-CTR AES128-CTR
AES128-CBC AES128-CBC
3DES-CBC RIJNDAEL128-CBC
BLOWFISH-CBC
3DES-CBC
ARCFOUR256
ARCFOUR128
ARCFOUR
MAC HMAC-SHA1 HMAC-SHA1
HMAC-SHA1-96 HMAC-SHA1-96
HMAC-MD5
HMAC-MD5-96
TACACS+ TACACS+ does not comply with NIST Acceptable
SP 800-131A specification. When in
strict mode, TACACS+ is disabled.
However, it can be enabled, if required.

38 RackSwitch G8124: Application Guide

Acceptable Cipher Suites
The following cipher suites are acceptable (listed in the order of preference) when
the RackSwitch G8124 is in compatibility mode:
Table 4. List of Acceptable Cipher Suites in Compatibility Mode
Cipher ID Key Authentication Encryption MAC Cipher Name
Exchange
0xC027 ECDHE RSA AES_128_CBC SHA256 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
0xC013 ECDHE RSA AES_128_CBC SHA1 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
0xC012 ECDHE RSA 3DES SHA1 SSL_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA
0xC011 ECDHE RSA RC4 SHA1 SSL_ECDHE_RSA_WITH_RC4_128_SHA
0x002F RSA RSA AES_128_CBC SHA1 TLS_RSA_WITH_AES_128_CBC_SHA
0x003C RSA RSA AES_128_CBC SHA256 TLS_RSA_WITH_AES_128_CBC_SHA256
0x0005 RSA RSA RC4 SHA1 SSL_RSA_WITH_RC4_128_SHA
0x000A RSA RSA 3DES SHA1 SSL_RSA_WITH_3DES_EDE_CBC_SHA
0x0033 DHE RSA AES-128_CBC SHA1 TLS_DHE_RSA_WITH_AES_128_CBC_SHA
0x0067 DHE RSA AES_128_CBC SHA256 TLS_DHE_RSA_WITH_AES_128_CBC_SHA256
0x0016 DHE RSA 3DES SHA1 SSL_DHE_RSA_WITH_3DES_EDE_CBC_SHA

The following cipher suites are acceptable (listed in the order of preference) when
the RackSwitch G8124 is in strict mode:
Table 5. List of Acceptable Cipher Suites in Strict Mode
Cipher ID Key Authentication Encryption MAC Cipher Name
Exchange
0xC027 ECDHE RSA AES_128_CBC SHA256 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256
0xC013 ECDHE RSA AES_128_CBC SHA1 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA
0xC012 ECDHE RSA 3DES SHA1 SSL_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA
0x0033 DHE RSA AES-128_CBC SHA1 TLS_DHE_RSA_WITH_AES_128_CBC_SHA
0x0067 DHE RSA AES_128_CBC SHA256 TLS_DHE_RSA_WITH_AES_128_CBC_SHA256
0x0016 DHE RSA 3DES SHA1 SSL_DHE_RSA_WITH_3DES_EDE_CBC_SHA
0x002F RSA RSA AES_128_CBC SHA1 TLS_RSA_WITH_AES_128_CBC_SHA
0x003C RSA RSA AES_128_CBC SHA256 TLS_RSA_WITH_AES_128_CBC_SHA256
0x000A RSA RSA 3DES SHA1 SSL_RSA_WITH_3DES_EDE_CBC_SHA

© Copyright IBM Corp. 2014 Chapter 1: Switch Administration 39

Configuring Strict Mode
To change the switch mode to boot strict mode, use the following command:

RS G8124(config)# [no] boot strict enable

When strict mode is enabled, you will see the following message:

Warning, security strict mode limits the cryptographic algorithms used by secure
protocols on this switch. Please see the documentation for full details, and verify
that peer devices support acceptable algorithms before enabling this mode. The mode
change will take effect after reloading the switch and the configuration will be
wiped during the reload. System will enter security strict mode with default factory
configuration at next boot up.

Do you want SNMPV3 support old default users in strict mode (y/n)?

For SNMPv3 default users, see “SNMP Version 3” on page 410.

When strict mode is disabled, the following message is displayed:

Warning, disabling security strict mode. The mode change will take effect after
reloading the switch.

You must reboot the switch for the boot strict mode enable/disable to take effect.

SSL/TLS Version Limitation

Each of the following successive encryption protocol versions provide more security
and less compatibility: SSLv3, TLS1.0, TLS1.1, TLS1.2. When negotiating the
encryption protocol during the SSL handshake, the switch will accept, by default, the
latest (and most secure) protocol version supported by the client equipment. To
enforce a minimal level of security acceptable for the connections, use the following
command:

RS G8124(config)# ssl minimum-version {ssl|tls10|tls11|tls12}

Limitations
In IBM N/OS 7.11, consider the following limitation/restrictions if you need to operate
the switch in boot strict mode:
• Power ITEs and High-Availability features do not comply with NIST SP 800-131A
specification.
• The G8124 will not discover Platform agents/Common agents that are not in
strict mode.
• Web browsers that do not use TLS 1.2 cannot be used.
• Limited functions of the switch managing Windows will be available.

40 RackSwitch G8124: Application Guide

Chapter 2. Initial Setup
To help with the initial process of configuring your switch, the IBM Networking OS
software includes a Setup utility. The Setup utility prompts you step-by-step to enter
all the necessary information for basic configuration of the switch.

Setup can be activated manually from the command line interface any time after
login.

Information Needed for Setup

Setup requests the following information:
• Basic system information
– Date & time
– Whether to use Spanning Tree Group or not
• Optional configuration for each port
– Speed, duplex, flow control, and negotiation mode (as appropriate)
– Whether to use VLAN trunk mode/tagging or not (as appropriate)
• Optional configuration for each VLAN
– Name of VLAN
– Which ports are included in the VLAN
• Optional configuration of IP parameters
– IP address/mask and VLAN for each IP interface
– IP addresses for default gateway
– Whether IP forwarding is enabled or not

© Copyright IBM Corp. 2014 41

Default Setup Options
The Setup prompt appears automatically whenever you login as the system
administrator under the factory default settings.
1. Connect to the switch.
After connecting, the login prompt appears.

Enter Password:

2. Enter admin as the default administrator password.

If the factory default configuration is detected, the system prompts:

RackSwitch G8124
18:44:05 Wed Jan 3, 2009

The switch is booted with factory default configuration.

To ease the configuration of the switch, a "Set Up" facility which
will prompt you with those configuration items that are essential to the
operation of the switch is provided.
Would you like to run "Set Up" to configure the switch? [y/n]:

Note: If the default admin login is unsuccessful, or if the administrator Main Menu
appears instead, the system configuration has probably been changed from
the factory default settings. If desired, return the switch to its factory default
configuration.
3. Enter y to begin the initial configuration of the switch, or n to bypass the Setup
facility.

Default IP Address - Management Interface

To facilitate switch boot up, the in-band and out-of-band management interfaces are
configured with factory default IP addresses. These are as follows:
• VLAN 1/ Interface 1: 192.168.49.50/24
• Out-of-band Management Port A: 192.168.50.50/24
• Out-of-band Management Port B: 192.168.51.50/24

If you configure static IP addresses or if DHCP/BOOTP addresses are assigned to

these interfaces, the factory default IP addresses will not be applied. By default,
DHCP and BOOTP are enabled on the management interfaces.

If you add interface 1 to another VLAN and do not configure any IP address, the
factory default IP address will be automatically assigned to the interface.

We recommend that you disable the factory default IP address configuration after
the switch boot up and configuration is complete. Use the following command:

RS G8124(config)# no system default-ip [data|mgta|mgtb]

42 RackSwitch G8124: Application Guide

Stopping and Restarting Setup Manually
Stopping Setup
To abort the Setup utility, press <Ctrl-C> during any Setup question. When you abort
Setup, the system will prompt:

Would you like to run from top again? [y/n]

Enter n to abort Setup, or y to restart the Setup program at the beginning.

Restarting Setup
You can restart the Setup utility manually at any time by entering the following
command at the administrator prompt:

RS G8124(config)# setup

Setup Part 1: Basic System Configuration

When Setup is started, the system prompts:

"Set Up" will walk you through the configuration of

System Date and Time, Spanning Tree, Port Speed/Mode,
VLANs, and IP interfaces. [type Ctrl-C to abort "Set Up"]

1. Enter y if you will be configuring VLANs. Otherwise enter n.

If you decide not to configure VLANs during this session, you can configure them
later using the configuration menus, or by restarting the Setup facility. For more
information on configuring VLANs, see the IBM Networking OS Application
Guide.
Next, the Setup utility prompts you to input basic system information.
2. Enter the year of the current date at the prompt:

System Date:
Enter year [2009]:

Enter the four-digits that represent the year. To keep the current year, press
<Enter>.
3. Enter the month of the current system date at the prompt:

System Date:
Enter month [1]:

Enter the month as a number from 1 to 12. To keep the current month, press
<Enter>.

© Copyright IBM Corp. 2014 Chapter 2: Initial Setup 43

 4. Enter the day of the current date at the prompt:

Enter day [3]:

Enter the date as a number from 1 to 31. To keep the current day, press <Enter>.
The system displays the date and time settings:

System clock set to 18:55:36 Wed Jan 28, 2009.

5. Enter the hour of the current system time at the prompt:

System Time:
Enter hour in 24-hour format [18]:

Enter the hour as a number from 00 to 23. To keep the current hour, press
<Enter>.
6. Enter the minute of the current time at the prompt:

Enter minutes [55]:

Enter the minute as a number from 00 to 59. To keep the current minute, press
<Enter>.
7. Enter the seconds of the current time at the prompt:

Enter seconds [37]:

Enter the seconds as a number from 00 to 59. To keep the current second, press
<Enter>. The system then displays the date and time settings:

System clock set to 8:55:36 Wed Jan 28, 2009.

8. Turn Spanning Tree Protocol on or off at the prompt:

Spanning Tree:
Current Spanning Tree Group 1 setting: ON
Turn Spanning Tree Group 1 OFF? [y/n]

Enter y to turn off Spanning Tree, or enter n to leave Spanning Tree on.

44 RackSwitch G8124: Application Guide

Setup Part 2: Port Configuration
Note: When configuring port options for your switch, some prompts and options
may be different.
1. Select whether you will configure VLANs and VLAN trunk mode/tagging for
ports:

Port Config:
Will you configure VLANs and VLAN Tagging/Trunk-Mode for ports? [y/n]

If you wish to change settings for VLANs, enter y, or enter n to skip VLAN
configuration.
Note: The sample screens that appear in this document might differ slightly from
the screens displayed by your system. Screen content varies based on the
firmware versions and options that are installed.
2. Select the port to configure, or skip port configuration at the prompt:
If you wish to change settings for individual ports, enter the number of the port
you wish to configure. To skip port configuration, press <Enter> without
specifying any port and go to “Setup Part 3: VLANs” on page 46.
3. Configure Gigabit Ethernet port flow parameters.
The system prompts:

Gig Link Configuration:

Port Flow Control:
Current Port EXT1 flow control setting: both
Enter new value ["rx"/"tx"/"both"/"none"]:

Enter rx to enable receive flow control, tx for transmit flow control, both to
enable both, or none to turn flow control off for the port. To keep the current
setting, press <Enter>.
4. Configure Gigabit Ethernet port autonegotiation mode.
If you selected a port that has a Gigabit Ethernet connector, the system prompts:

Port Auto Negotiation:

Current Port EXT1 autonegotiation: on
Enter new value ["on"/"off"]:

Enter on to enable port autonegotiation, off to disable it, or press <Enter> to

keep the current setting.
5. If configuring VLANs, enable or disable VLAN trunk mode/tagging for the port.
If you have selected to configure VLANs back in Part 1, the system prompts:

Port VLAN tagging/trunk mode config (tagged/trunk mode port can be a member of
multiple VLANs)
Current VLAN tagging/trunk mode support: disabled
Enter new VLAN tagging/trunk mode support [d/e]:

Enter d to disable VLAN trunk mode/tagging for the port or enter e to enable
VLAN tagging for the port. To keep the current setting, press <Enter>.

© Copyright IBM Corp. 2014 Chapter 2: Initial Setup 45

 6. The system prompts you to configure the next port:

Enter port (1-24, MGTA, MGTB):

When you are through configuring ports, press <Enter> without specifying any port.
Otherwise, repeat the steps in this section.

Setup Part 3: VLANs

If you chose to skip VLANs configuration back in Part 2, skip to “Setup Part 4: IP
Configuration” on page 47.
1. Select the VLAN to configure, or skip VLAN configuration at the prompt:

VLAN Config:
Enter VLAN number from 2 to 4094, NULL at end:

If you wish to change settings for individual VLANs, enter the number of the
VLAN you wish to configure. To skip VLAN configuration, press <Enter> without
typing a VLAN number and go to “Setup Part 4: IP Configuration” on page 47.
2. Enter the new VLAN name at the prompt:

Current VLAN name: VLAN 2

Enter new VLAN name:

Entering a new VLAN name is optional. To use the pending new VLAN name,
press <Enter>.
3. Enter the VLAN port numbers:

Define Ports in VLAN:

Current VLAN 2: empty
Enter ports one per line, NULL at end:

Enter each port, by port number or port alias, and confirm placement of the port
into this VLAN. When you are finished adding ports to this VLAN, press <Enter>
without specifying any port.
4. Configure Spanning Tree Group membership for the VLAN:

Spanning Tree Group membership:

Enter new Spanning Tree Group index [1-127]:

5. The system prompts you to configure the next VLAN:

VLAN Config:
Enter VLAN number from 2 to 4094, NULL at end:

Repeat the steps in this section until all VLANs have been configured. When all
VLANs have been configured, press <Enter> without specifying any VLAN.

46 RackSwitch G8124: Application Guide

Setup Part 4: IP Configuration
The system prompts for IPv4 parameters.

Although the switch supports both IPv4 and IPv6 networks, the Setup utility permits
only IPv4 configuration. For IPv6 configuration, see “Internet Protocol Version 6” on
page 263|.

IP Interfaces
IP interfaces are used for defining the networks to which the switch belongs.

Up to 128 IP interfaces can be configured on the RackSwitch G8124 (G8124). The

IP address assigned to each IP interface provides the switch with an IP presence on
your network. No two IP interfaces can be on the same IP network. The interfaces
can be used for connecting to the switch for remote configuration, and for routing
between subnets and VLANs (if used).
Note: Two interfaces are reserved for IPv4 management: interface 127 (MGTA)
and 128 (MGTB). If the IPv6 feature is enabled, two additional interfaces are
reserved to IPv6 management: interface 125 (MGTA) and 126 (MGTB).
1. Select the IP interface to configure, or skip interface configuration at the
prompt:

IP Config:

IP interfaces:
Enter interface number: (1-128)

If you wish to configure individual IP interfaces, enter the number of the IP

interface you wish to configure. To skip IP interface configuration, press <Enter>
without typing an interface number and go to “Default Gateways” on page 48.
2. For the specified IP interface, enter the IP address in IPv4 dotted decimal
notation:

Current IP address: 0.0.0.0

Enter new IP address:

To keep the current setting, press <Enter>.

3. At the prompt, enter the IPv4 subnet mask in dotted decimal notation:

Current subnet mask: 0.0.0.0

Enter new subnet mask:

To keep the current setting, press <Enter>.If configuring VLANs, specify a VLAN
for the interface.
This prompt appears if you selected to configure VLANs back in Part 1:

Current VLAN: 1
Enter new VLAN [1-4094]:

Enter the number for the VLAN to which the interface belongs, or press <Enter>
without specifying a VLAN number to accept the current setting.

© Copyright IBM Corp. 2014 Chapter 2: Initial Setup 47

 4. At the prompt, enter y to enable the IP interface, or n to leave it disabled:

Enable IP interface? [y/n]

5. The system prompts you to configure another interface:

Enter interface number: (1-128)

Repeat the steps in this section until all IP interfaces have been configured. When
all interfaces have been configured, press <Enter> without specifying any interface
number.

Default Gateways
To set up a default gateway:
1. At the prompt, select an IP default gateway for configuration, or skip default
gateway configuration:

IP default gateways:
Enter default gateway number: (1-4)

Enter the number for the IP default gateway to be configured. To skip default
gateway configuration, press <Enter> without typing a gateway number and go
to “IP Routing” on page 48.
2. At the prompt, enter the IPv4 address for the selected default gateway:

Current IP address: 0.0.0.0

Enter new IP address:

Enter the IPv4 address in dotted decimal notation, or press <Enter> without
specifying an address to accept the current setting.
3. At the prompt, enter y to enable the default gateway, or n to leave it disabled:

Enable default gateway? [y/n]

4. The system prompts you to configure another default gateway:

Enter default gateway number: (1-4)

Repeat the steps in this section until all default gateways have been configured.
When all default gateways have been configured, press <Enter> without specifying
any number.

IP Routing
When IP interfaces are configured for the various IP subnets attached to your
switch, IP routing between them can be performed entirely within the switch. This
eliminates the need to send inter-subnet communication to an external router
device. Routing on more complex networks, where subnets may not have a direct
presence on the G8124, can be accomplished through configuring static routes or
by letting the switch learn routes dynamically.

48 RackSwitch G8124: Application Guide

 This part of the Setup program prompts you to configure the various routing
parameters.

At the prompt, enable or disable forwarding for IP Routing:

Enable IP forwarding? [y/n]

Enter y to enable IP forwarding. To disable IP forwarding, enter n. To keep the

current setting, press <Enter>.

Setup Part 5: Final Steps

1. When prompted, decide whether to restart Setup or continue:

Would you like to run from top again? [y/n]

Enter y to restart the Setup utility from the beginning, or n to continue.

2. When prompted, decide whether you wish to review the configuration changes:

Review the changes made? [y/n]

Enter y to review the changes made during this session of the Setup utility. Enter
n to continue without reviewing the changes. We recommend that you review the
changes.
3. Next, decide whether to apply the changes at the prompt:

Apply the changes? [y/n]

Enter y to apply the changes, or n to continue without applying. Changes are

normally applied.
4. At the prompt, decide whether to make the changes permanent:

Save changes to flash? [y/n]

Enter y to save the changes to flash. Enter n to continue without saving the
changes. Changes are normally saved at this point.
5. If you do not apply or save the changes, the system prompts whether to abort
them:

Abort all changes? [y/n]

Enter y to discard the changes. Enter n to return to the “Apply the

changes?” prompt.
Note: After initial configuration is complete, it is recommended that you change the
default passwords.

© Copyright IBM Corp. 2014 Chapter 2: Initial Setup 49

Optional Setup for Telnet Support
Note: This step is optional. Perform this procedure only if you are planning on
connecting to the G8124 through a remote Telnet connection.

Telnet is enabled by default. To change the setting, use the following command:

RS G8124(config)# no access telnet

Loopback Interfaces
A loopback interface provides an IP address, but is not otherwise associated with a
physical port or network entity. Essentially, it is a virtual interface that is perceived as
being “always available” for higher-layer protocols to use and advertise to the
network, regardless of other connectivity.

Loopback interfaces improve switch access, increase reliability, security, and

provide greater flexibility in Layer 3 network designs. They can be used for many
different purposes, but are most commonly for management IP addresses, router
IDs for various protocols, and persistent peer IDs for neighbor relationships.

In IBM N/OS 7.11, loopback interfaces have been expanded for use with routing
protocols such as OSPF, PIM, and BGP. Loopback interfaces can also be specified
as the source IP address for syslog, SNMP, RADIUS, TACACS+, NTP, and router
IDs.

Loopback interfaces must be configured before they can be used in other features.
Up to five loopback interfaces are currently supported. They can be configured
using the following commands:

RS G8124(config)# interface loopback <1-5>

RS G8124(config-ip-loopback)# [no] ip address <IPv4 address> <mask> enable
RS G8124(config-ip-loopback)# exit

Using Loopback Interfaces for Source IP Addresses

The switch can use loopback interfaces to set the source IP addresses for a variety
of protocols. This assists in server security, as the server for each protocol can be
configured to accept protocol packets only from the expected loopback address
block. It may also make is easier to locate or process protocol information, since
packets have the source IP address of the loopback interface, rather than numerous
egress interfaces.

Configured loopback interfaces can be applied to the following protocols:

• Syslogs
RS G8124(config)# logging source-interface loopback <1-5>

• SNMP traps
RS G8124(config)# snmp-server trap-source loopback <1-5>

• RADIUS
RS G8124(config)# ip radius source-interface loopback <1-5>

50 RackSwitch G8124: Application Guide

 • TACACS+
RS G8124(config)# ip tacacs source-interface loopback <1-5>

• NTP
RS G8124(config)# ntp source loopback <1-5>

Loopback Interface Limitation

• ARP is not supported. Loopback interfaces will ignore ARP requests.
• Loopback interfaces cannot be assigned to a VLAN.

© Copyright IBM Corp. 2014 Chapter 2: Initial Setup 51

52 RackSwitch G8124: Application Guide
Chapter 3. Switch Software Management
The switch software image is the executable code running on the G8124. A version
of the image comes pre-installed on the device. As new versions of the image are
released, you can upgrade the software running on your switch. To get the latest
version of software supported for your G8124, go to the following website:

http://www.ibm.com/support/

To determine the software version currently used on the switch, use the following
switch command:

RS G8124# show boot

The typical upgrade process for the software image consists of the following steps:
• Load a new software image and boot image onto an FTP, SFTP or TFTP server
on your network.
• Transfer the new images to your switch.
• Specify the new software image as the one which will be loaded into switch
memory the next time a switch reset occurs.
• Reset the switch.

For instructions on the typical upgrade process using the IBM N/OS ISCLI, or BBI,
see “Loading New Software to Your Switch” on page 54.

CAUTION:
Although the typical upgrade process is all that is necessary in most cases,
upgrading from (or reverting to) some versions of IBM Networking OS
requires special steps prior to or after the software installation process.
Please be sure to follow all applicable instructions in the release notes
document for the specific software release to ensure that your switch
continues to operate as expected after installing new software.

© Copyright IBM Corp. 2014 53

Loading New Software to Your Switch
The G8124 can store up to two different switch software images (called image1 and
image2) as well as special boot software (called boot). When you load new
software, you must specify where it is placed: either into image1, image2, or boot.

For example, if your active image is currently loaded into image1, you would
probably load the new image software into image2. This lets you test the new
software and reload the original active image (stored in image1), if needed.

CAUTION:
When you upgrade the switch software image, always load the new boot
image and the new software image before you reset the switch. If you do not
load a new boot image, your switch might not boot properly (To recover, see
“Recovering from a Failed Upgrade” on page 56).

To load a new software image to your switch, you will need the following:
• The image and boot software loaded on an FTP, SFTP or TFTP server on your
network.

Note: Be sure to download both the new boot file and the new image file.

• The hostname or IP address of the FTP, SFTP or TFTP server

Note: The DNS parameters must be configured if specifying hostnames.

• The name of the new software image or boot file

When the software requirements are met, use one of the following procedures to
download the new software to your switch. You can use the ISCLI, or the BBI to
download and activate new software.

Loading Software via the ISCLI

1. In Privileged EXEC mode, enter the following command:

Router# copy {tftp|ftp|sftp} {image1|image2|boot-image}

2. Enter the hostname or IP address of the FTP, SFTP or TFTP server.

Address or name of remote host: <name or IP address>

3. Enter the name of the new software file on the server.

Source file name: <filename>

The exact form of the name will vary by server. However, the file location is
normally relative to the FTP, SFTP or TFTP directory (for example, tftpboot).
4. If required by the FTP, SFTP or TFTP server, enter the appropriate username
and password.
5. The switch will prompt you to confirm your request.
Once confirmed, the software will begin loading into the switch.

54 RackSwitch G8124: Application Guide

 6. When loading is complete, use the following commands to enter Global
Configuration mode to select which software image (image1 or image2) you
want to run in switch memory for the next reboot:

Router# configure terminal

Router(config)# boot image {image1|image2}

The system will then verify which image is set to be loaded at the next reset:

Next boot will use switch software image1 instead of image2.

7. Reboot the switch to run the new software:

Router(config)# reload

The system prompts you to confirm your request. Once confirmed, the switch will
reboot to use the new software.

Loading Software via BBI

You can use the Browser-Based Interface to load software onto the G8124. The
software image to load can reside in one of the following locations:
• FTP server
• TFTP server
• SFTP server
• Local computer
After you log onto the BBI, perform the following steps to load a software image:
1. Click the Configure context tab in the toolbar.
2. In the Navigation Window, select System > Config/Image Control.

The Switch Image and Configuration Management page appears.

3. If you are loading software from your computer (HTTP client), skip this step and
go to the next. Otherwise, if you are loading software from an FTP, SFTP, or
TFTP server, enter the server’s information in the FTP, SFTP, or TFTP Settings
section.
4. In the Image Settings section, select the image version you want to replace
(Image for Transfer).
– If you are loading software from an FTP, SFTP, or TFTP server, enter the file
name and click Get Image.
– If you are loading software from your computer, click Browse.
In the File Upload Dialog, select the file and click OK. Then click Download
via Browser.
Once the image has loaded, the page refreshes to show the new software.

© Copyright IBM Corp. 2014 Chapter 3: Switch Software Management 55

The Boot Management Menu
The Boot Management menu allows you to switch the software image, reset the
switch to factory defaults, or to recover from a failed software download.

You can interrupt the boot process and enter the Boot Management menu from the
serial console port. When the system displays Memory Test, press <Shift B>. The
Boot Management menu appears.

Resetting the System ...

Memory Test ................................

Boot Management Menu

1 - Change booting image
2 - Change configuration block
3 - Xmodem download
4 - Display image versions
5 - Exit

Please choose your menu option: 1

Current boot image is 1. Enter image to boot: 1 or 2: 2
Booting from image 2

The Boot Management menu allows you to perform the following actions:
• To change the booting image, press 1 and follow the screen prompts.
• To change the configuration block, press 2, and follow the screen prompts.
• To perform an Xmodem download, press 3 and follow the screen prompts.
• To exit the Boot Management menu, press 4. The booting process continues.

Recovering from a Failed Upgrade

Use the following procedure to recover from a failed software upgrade.

1. Connect a PC to the serial port of the switch.
2. Open a terminal emulator program that supports XModem Download (for
example, HyperTerminal, CRT, PuTTY) and select the following serial port
characteristics:
– Speed: 9600 bps
– Data Bits: 8
– Stop Bits: 1
– Parity: None
– Flow Control: None
3. Boot the switch and access the Boot Management menu by pressing <Shift B>
while the Memory Test is in progress and the dots are being displayed.
4. Select 3 for Xmodem download. When you see the following message,
change the Serial Port characteristics to 115200 bps:

## Switch baudrate to 115200 bps and press ENTER ...

5. Press <Enter> to set the system into download accept mode. When the
readiness meter displays (a series of “C” characters), start XModem on your
terminal emulator.

56 RackSwitch G8124: Application Guide

 6. Select the Boot Image to download. The XModem initiates the file transfer.
When the download is complete, a message similar to the following is
displayed:

yzModem - CRC mode, 62494(SOH)/0(STX)/0(CAN) packets, 6 retries

Extracting images ... Do *NOT* power cycle the switch.

**** VMLINUX ****

Un-Protected 10 sectors

Erasing Flash............. done

Writing to Flash.............done

Protected 10 sectors

**** RAMDISK ****

Un-Protected 44 sectors

Erasing Flash............................................... done

Writing to Flash...............................................done

Protected 44 sectors

**** BOOT CODE ****

Un-Protected 8 sectors

Erasing Flash........... done

Writing to Flash...........done

Protected 8 sectors

7. When you see the following message, change the Serial Port characteristics to
9600 bps:

## Switch baudrate to 9600 bps and press ESC ...

8. Press the Escape key (<Esc>) to re-display the Boot Management menu.
9. Select 3 to start a new XModem Download. When you see the following
message, change the Serial Port characteristics to 115200 bps:

## Switch baudrate to 115200 bps and press ENTER ...

10. Press <Enter> to continue the download.

© Copyright IBM Corp. 2014 Chapter 3: Switch Software Management 57

 11. Select the OS Image to download. The XModem initiates the file transfer. When
the download is complete, a message similar to the following is displayed:

yzModem - CRC mode, 27186(SOH)/0(STX)/0(CAN) packets, 6 retries

Extracting images ... Do *NOT* power cycle the switch.

**** Switch OS ****

Please choose the Switch OS Image to upgrade [1|2|n] :

12. Select the image number to load the new image (1 or 2). It is recommended
that you select 1. A message similar to the following is displayed:

Switch OS Image 1 ...

Un-Protected 27 sectors

Erasing Flash.............................. done

Writing to Flash..............................done

Protected 27 sectors

13. When you see the following message, change the Serial Port characteristics to
9600 bps:

## Switch baudrate to 9600 bps and press ESC ...

14. Press the Escape key (<Esc>) to re-display the Boot Management menu.
15. Select 4 to exit and boot the new image.

58 RackSwitch G8124: Application Guide

Part 2: Securing the
Switch

© Copyright IBM Corp. 2014 59

60 RackSwitch G8124: Application Guide
Chapter 4. Securing Administration
Secure switch management is needed for environments that perform significant
management functions across the Internet. Common functions for secured
management are described in the following sections:
• “Secure Shell and Secure Copy” on page 62
• “End User Access Control” on page 66
Note: SNMP read and write functions are enabled by default. For best security
practices, if SNMP is not needed for your network, it is recommended that
you disable these functions prior to connecting the switch to the network
(see “Using Simple Network Management Protocol” on page 31).

© Copyright IBM Corp. 2014 61

Secure Shell and Secure Copy
Because using Telnet does not provide a secure connection for managing a G8124,
Secure Shell (SSH) and Secure Copy (SCP) features have been included for G8124
management. SSH and SCP use secure tunnels to encrypt and secure messages
between a remote administrator and the switch.

SSH is a protocol that enables remote administrators to log securely into the G8124
over a network to execute management commands.

SCP is typically used to copy files securely from one machine to another. SCP uses
SSH for encryption of data on the network. On a G8124, SCP is used to download
and upload the switch configuration via secure channels.

Although SSH and SCP are disabled by default, enabling and using these features
provides the following benefits:
• Identifying the administrator using Name/Password
• Authentication of remote administrators
• Authorization of remote administrators
• Determining the permitted actions and customizing service for individual admin-
istrators
• Encryption of management messages
• Encrypting messages between the remote administrator and switch
• Secure copy support

IBM Networking OS implements the SSH version 2.0 standard and is confirmed to
work with SSH version 2.0-compliant clients such as the following:
• OpenSSH_5.4p1 for Linux
• Secure CRT Version 5.0.2 (build 1021)
• Putty SSH release 0.60

Configuring SSH/SCP Features on the Switch

SSH and SCP features are disabled by default. To change the SSH/SCP settings,
using the following procedures.
Note: To use SCP, you must first enable SSH.

To Enable or Disable the SSH Feature

Begin a Telnet session from the console port and enter the following command:

RS G8124(config)# [no] ssh enable

To Enable or Disable SCP Apply and Save

Enter the following command from the switch CLI to enable the SCP
putcfg_apply and putcfg_apply_save commands:

RS G8124(config)# [no] ssh scp-enable

62 RackSwitch G8124: Application Guide

Configuring the SCP Administrator Password
To configure the SCP-only administrator password, enter the following command
(the default password is admin):

RS G8124(config)# [no] ssh scp-password

Changing SCP-only Administrator password; validation required...
Enter current administrator password: <password>
Enter new SCP-only administrator password: <new password>
Re-enter new SCP-only administrator password: <new password>
New SCP-only administrator password accepted.

Using SSH and SCP Client Commands

This section shows the format for using some client commands. The following
examples use 205.178.15.157 as the IP address of a sample switch.

To Log In to the Switch

Syntax:

>> ssh [-4|-6] <switch IP address>

-or-
>> ssh [-4|-6] <login name>@<switch IP address>

Note: The -4 option (the default) specifies that an IPv4 switch address will be
used. The -6 option specifies IPv6.

Example:

>> ssh scpadmin@205.178.15.157

To Copy the Switch Configuration File to the SCP Host

Syntax:

>> scp [-4|-6] <username>@<switch IP address>:getcfg <local filename>

Example:

>> scp scpadmin@205.178.15.157:getcfg ad4.cfg

To Load a Switch Configuration File from the SCP Host

Syntax:

>> scp [-4|-6] <local filename> <username>@<switch IP address>:putcfg

Example:

>> scp ad4.cfg scpadmin@205.178.15.157:putcfg

© Copyright IBM Corp. 2014 Chapter 4: Securing Administration 63

 To Apply and Save the Configuration

When loading a configuration file to the switch, the apply and save commands are
still required for the configuration commands to take effect. The apply and save
commands may be entered manually on the switch, or by using SCP commands.

Syntax:

>> scp [-4|-6] <local filename> <username>@<switch IP address>:putcfg_apply

>> scp [-4|-6] <local filename> <username>@<switch IP address>:putcfg_apply_save

Example:

>> scp ad4.cfg scpadmin@205.178.15.157:putcfg_apply

>> scp ad4.cfg scpadmin@205.178.15.157:putcfg_apply_save

• The CLI diff command is automatically executed at the end of putcfg to notify
the remote client of the difference between the new and the current
configurations.
• putcfg_apply runs the apply command after the putcfg is done.
• putcfg_apply_save saves the new configuration to the flash after
putcfg_apply is done.
• The putcfg_apply and putcfg_apply_save commands are provided
because extra apply and save commands are usually required after a putcfg;
however, an SCP session is not in an interactive mode.

To Copy the Switch Image and Boot Files to the SCP Host

Syntax:

>> scp [-4|-6] <username>@<switch IP address>:getimg1 <local filename>

>> scp [-4|-6] <username>@<switch IP address>:getimg2 <local filename>
>> scp [-4|-6] <username>@<switch IP address>:getboot <local filename>

Example:

>> scp scpadmin@205.178.15.157:getimg1 6.1.0_os.img

To Load Switch Configuration Files from the SCP Host

Syntax:

>> scp [-4|-6] <local filename> <username>@<switch IP address>:putimg1

>> scp [-4|-6] <local filename> <username>@<switch IP address>:putimg2
>> scp [-4|-6] <local filename> <username>@<switch IP address>:putboot

Example:

>> scp 6.1.0_os.img scpadmin@205.178.15.157:putimg1

64 RackSwitch G8124: Application Guide

SSH and SCP Encryption of Management Messages
The following encryption and authentication methods are supported for SSH and
SCP:
• Server Host Authentication:Client RSA authenticates the switch at the
beginning of every connection
• Key Exchange: RSA
• Encryption: 3DES-CBC, DES
• User Authentication: Local password authentication, RADIUS

Generating RSA Host Key for SSH Access

To support the SSH host feature, an RSA host key is required. The host key is 2048
bits and is used to identify the G8124.

To configure RSA host key, first connect to the G8124 through the console port
(commands are not available via external Telnet connection), and enter the
following command to generate it manually.

RS G8124(config)# ssh generate-host-key

When the switch reboots, it will retrieve the host key from the FLASH memory.
Note: The switch will perform only one session of key/cipher generation at a time.
Thus, an SSH/SCP client will not be able to log in if the switch is performing
key generation at that time. Also, key generation will fail if an SSH/SCP client
is logging in at that time.

SSH/SCP Integration with Radius Authentication

SSH/SCP is integrated with RADIUS authentication. After the RADIUS server is
enabled on the switch, all subsequent SSH authentication requests will be
redirected to the specified RADIUS servers for authentication. The redirection is
transparent to the SSH clients.

SSH/SCP Integration with TACACS+ Authentication

SSH/SCP is integrated with TACACS+ authentication. After the TACACS+ server is
enabled on the switch, all subsequent SSH authentication requests will be
redirected to the specified TACACS+ servers for authentication. The redirection is
transparent to the SSH clients.

© Copyright IBM Corp. 2014 Chapter 4: Securing Administration 65

End User Access Control
IBM N/OS allows an administrator to define end user accounts that permit end users
to perform operation tasks via the switch CLI commands. Once end user accounts
are configured and enabled, the switch requires username/password
authentication.

For example, an administrator can assign a user, who can then log into the switch
and perform operational commands (effective only until the next switch reboot).

Considerations for Configuring End User Accounts

Note the following considerations when you configure end user accounts:
• A maximum of 20 user IDs are supported on the switch.
• N/OS supports end user support for console, Telnet, BBI, and SSHv2 access to
the switch.
• If RADIUS authentication is used, the user password on the Radius server will
override the user password on the G8124. Also note that the password change
command only modifies only the user password on the switch and has no effect
on the user password on the Radius server. Radius authentication and user
password cannot be used concurrently to access the switch.
• Passwords for end users can be up to 128 characters in length for TACACS,
RADIUS, Telnet, SSH, Console, and Web access.

Strong Passwords
The administrator can require use of Strong Passwords for users to access the
G8124. Strong Passwords enhance security because they make password
guessing more difficult.

The following rules apply when Strong Passwords are enabled:

• Minimum length: 8 characters; maximum length: 64 characters
• Must contain at least one uppercase alphabet
• Must contain at least one lowercase alphabet
• Must contain at least one number
• Must contain at least one special character:
Supported special characters: ! “ # % & ‘ ( ) ; < = >> ? [\] * + , - . / : ^ _ { | } ~
• Cannot be same as the username
• No consecutive four characters can be the same as in the old password

When strong password is enabled, users can still access the switch using the old
password but will be advised to change to a strong password at log-in.

Strong password requirement can be enabled using the following command:

RS G8124(config)# access user strong-password enable

The administrator can choose the number of days allowed before each password
expires. When a strong password expires, the user is allowed to log in one last time
(last time) to change the password. A warning provides advance notice for users to
change the password.

66 RackSwitch G8124: Application Guide

User Access Control
The end-user access control commands allow you to configure end-user accounts.

Setting up User IDs

Up to 20 user IDs can be configured. Use the following commands to define any
user name and set the user password at the resulting prompts:

RS G8124(config)# access user 1 name <1-64 characters>

RS G8124(config)# access user 1 password

Changing user1 password; validation required:

Enter current admin password: <current administrator password>
Enter new user1 password: <new user password>
Re-enter new user1 password: <new user password>
New user1 password accepted.

Defining a User’s Access Level

The end user is by default assigned to the user access level (also known as class of
service, or COS). COS for all user accounts have global access to all resources
except for User COS, which has access to view only resources that the user owns.
For more information, see Table 6 on page 71.

To change the user’s level, select one of the following options:

RS G8124(config)# access user 1 level {user|operator|administrator}

Validating a User’s Configuration

RS G8124# show access user uid 1

Enabling or Disabling a User

An end user account must be enabled before the switch recognizes and permits
login under the account. Once enabled, the switch requires any user to enter both
username and password.

RS G8124(config)# [no] access user 1 enable

Locking Accounts

To protect the switch from unauthorized access, the account lockout feature can be
enabled. By default, account lockout is disabled. To enable this feature, ensure the
strong password feature is enabled (See “Strong Passwords” on page 66). Then
use the following command:
RS G8124(config)# access user strong-password lockout

After multiple failed login attempts, the switch locks the user account if lockout has
been enabled on the switch.

© Copyright IBM Corp. 2014 Chapter 4: Securing Administration 67

 Re-enabling Locked Accounts

The administrator can re-enable a locked account by reloading the switch or by

using the following command:
RS G8124(config)# access user strong-password clear local user lockout username
<user name>

However, the above command cannot be used to re-enable an account disabled by

the administrator.

To re-enable all locked accounts, use the following command:

RS G8124(config)# access user strong-password clear local user lockout all

Listing Current Users

The following command displays defined user accounts and whether or not each
user is currently logged into the switch.

RS G8124# show access user

Usernames:
user - Enabled - offline
oper - Disabled - offline
admin - Always Enabled - online 1 session

Current User ID table:

1: name jane , ena, cos user , password valid, online 1 session
2: name john , ena, cos user , password valid, online 2 sessions

Logging into an End User Account

Once an end user account is configured and enabled, the user can login to the
switch using the username/password combination. The level of switch access is
determined by the COS established for the end user account.

Password Fix-Up Mode

Password Fix-Up Mode enables admin user account recovery if administrator
access is lost. A user must connect to the switch over the serial console and log in
using the “ForgetMe!” password. This enables the admin account if disabled and a
new administrator password can be entered.

To disable the Password Fix-Up functionality, use the following command:

RS G8124(config)# no access user password-recovery

68 RackSwitch G8124: Application Guide

Chapter 5. Authentication & Authorization Protocols
Secure switch management is needed for environments that perform significant
management functions across the Internet. The following are some of the functions
for secured IPv4 management and device access:
• “RADIUS Authentication and Authorization” on page 69
• “TACACS+ Authentication” on page 73
• “LDAP Authentication and Authorization” on page 77
Note: IBM Networking OS 7.11 does not support IPv6 for RADIUS, TACACS+ or
LDAP.

RADIUS Authentication and Authorization

IBM N/OS supports the RADIUS (Remote Authentication Dial-in User Service)
method to authenticate and authorize remote administrators for managing the
switch. This method is based on a client/server model. The Remote Access Server
(RAS)—the switch—is a client to the back-end database server. A remote user (the
remote administrator) interacts only with the RAS, not the back-end server and
database.

RADIUS authentication consists of the following components:

• A protocol with a frame format that utilizes UDP over IP (based on RFC 2138
and 2866)
• A centralized server that stores all the user authorization information
• A client: in this case, the switch

The G8124—acting as the RADIUS client—communicates to the RADIUS server to

authenticate and authorize a remote administrator using the protocol definitions
specified in RFC 2138 and 2866. Transactions between the client and the RADIUS
server are authenticated using a shared key that is not sent over the network. In
addition, the remote administrator passwords are sent encrypted between the
RADIUS client (the switch) and the back-end RADIUS server.

How RADIUS Authentication Works

The RADIUS authentication process follows these steps:
1. A remote administrator connects to the switch and provides a user name and
password.
2. Using Authentication/Authorization protocol, the switch sends request to
authentication server.
3. The authentication server checks the request against the user ID database.
4. Using RADIUS protocol, the authentication server instructs the switch to grant
or deny administrative access.

© Copyright IBM Corp. 2014 69

Configuring RADIUS on the Switch
Use the following procedure to configure Radius authentication on your switch.
1. Configure the IPv4 addresses of the Primary and Secondary RADIUS servers,
and enable RADIUS authentication.

RS G8124(config)# radius-server primary-host 10.10.1.1

RS G8124(config)# radius-server secondary-host 10.10.1.2
RS G8124(config)# radius-server enable

Note: You can use a configured loopback address as the source address so the
RADIUS server accepts requests only from the expected loopback address
block. Use the following command to specify the loopback interface:
RS G8124(config)# ip radius source-interface loopback <1-5>
2. Configure the RADIUS secret.

RS G8124(config)# radius-server primary-host 10.10.1.1 key <1-32 character secret>

RS G8124(config)# radius-server secondary-host 10.10.1.2 key <1-32 character secret>

3. If desired, you may change the default UDP port number used to listen to
RADIUS.
The well-known port for RADIUS is 1812.

RS G8124(config)# radius-server port <UDP port number>

4. Configure the number retry attempts for contacting the RADIUS server, and the
timeout period.

RS G8124(config)# radius-server retransmit 3

RS G8124(config)# radius-server timeout 5

70 RackSwitch G8124: Application Guide

RADIUS Authentication Features in IBM N/OS
N/OS supports the following RADIUS authentication features:
• Supports RADIUS client on the switch, based on the protocol definitions in RFC
2138 and RFC 2866.
• Allows RADIUS secret password up to 32 bytes and less than 16 octets.
• Supports secondary authentication server so that when the primary
authentication server is unreachable, the switch can send client authentication
requests to the secondary authentication server. Use the following command to
show the currently active RADIUS authentication server:

RS G8124# show radius-server

• Supports user-configurable RADIUS server retry and time-out values:

– Time-out value = 1-10 seconds
– Retries = 1-3
The switch will time out if it does not receive a response from the RADIUS server
in 1-3 retries. The switch will also automatically retry connecting to the RADIUS
server before it declares the server down.
• Supports user-configurable RADIUS application port. The default is UDP port
1645. UDP port 1812, based on RFC 2138, is also supported.
• Allows network administrator to define privileges for one or more specific users to
access the switch at the RADIUS user database.

Switch User Accounts

The user accounts listed in Table 6 can be defined in the RADIUS server dictionary
file.
Table 6. User Access Levels

User Account Description and Tasks Performed Password

User The User has no direct responsibility for switch user

management. They can view all switch status
information and statistics but cannot make any
configuration changes to the switch.

Operator The Operator manages all functions of the switch. oper

The Operator can reset ports, except the
management port.

Administrator The super-user Administrator has complete access admin

to all commands, information, and configuration
commands on the switch, including the ability to
change both the user and administrator passwords.

© Copyright IBM Corp. 2014 Chapter 5: Authentication & Authorization Protocols 71

RADIUS Attributes for IBM N/OS User Privileges
When the user logs in, the switch authenticates his/her level of access by sending
the RADIUS access request, that is, the client authentication request, to the
RADIUS authentication server.

If the remote user is successfully authenticated by the authentication server, the

switch will verify the privileges of the remote user and authorize the appropriate
access. The administrator has two options: to allow backdoor access via Telnet,
SSH, HTTP, or HTTPS; to allow secure backdoor access via Telnet, SSH, or BBI.
Backdoor and secure backdoor provides access to the switch when the RADIUS
servers cannot be reached.

The default G8124 setting for backdoor and secure backdoor access is disabled.
Backdoor and secure backdoor access is always enabled on the console port.

Irrespective of backdoor/secure backdoor being enabled or not, you can always

access the switch via the console port by using noradius as radius username. You
can then enter the username and password configured on the switch. If you are
trying to connect via SSH/Telnet/HTTP/HTTPS (not console port), there are two
possibilities:
• Backdoor is enabled: The switch acts like it is connecting via console.
• Secure backdoor is enabled: You must enter the username: noradius. The switch
checks if RADIUS server is reachable. If it is reachable, then you must
authenticate via remote authentication server. Only if RADIUS server is not
reachable, you will be prompted for local user/password to be authenticated
against these local credentials.

All user privileges, other than those assigned to the Administrator, have to be
defined in the RADIUS dictionary. RADIUS attribute 6 which is built into all RADIUS
servers defines the administrator. The file name of the dictionary is RADIUS
vendor-dependent. The following RADIUS attributes are defined for G8124 user
privileges levels:
Table 7. IBM N/OS-proprietary Attributes for RADIUS

User Name/Access User-Service-Type Value

User Vendor-supplied 255

Operator Vendor-supplied 252

Admin Vendor-supplied 6

72 RackSwitch G8124: Application Guide

TACACS+ Authentication
N/OS supports authentication and authorization with networks using the Cisco
Systems TACACS+ protocol. The G8124 functions as the Network Access Server
(NAS) by interacting with the remote client and initiating authentication and
authorization sessions with the TACACS+ access server. The remote user is
defined as someone requiring management access to the G8124 either through a
data port or management port.

TACACS+ offers the following advantages over RADIUS:

• TACACS+ uses TCP-based connection-oriented transport; whereas RADIUS is
UDP-based. TCP offers a connection-oriented transport, while UDP offers
best-effort delivery. RADIUS requires additional programmable variables such as
re-transmit attempts and time-outs to compensate for best-effort transport, but it
lacks the level of built-in support that a TCP transport offers.
• TACACS+ offers full packet encryption whereas RADIUS offers password-only
encryption in authentication requests.
• TACACS+ separates authentication, authorization and accounting.

How TACACS+ Authentication Works

TACACS+ works much in the same way as RADIUS authentication as described on
page 69.
1. Remote administrator connects to the switch and provides user name and
password.
2. Using Authentication/Authorization protocol, the switch sends request to
authentication server.
3. Authentication server checks the request against the user ID database.
4. Using TACACS+ protocol, the authentication server instructs the switch to
grant or deny administrative access.

During a session, if additional authorization checking is needed, the switch checks

with a TACACS+ server to determine if the user is granted permission to use a
particular command.

© Copyright IBM Corp. 2014 Chapter 5: Authentication & Authorization Protocols 73

TACACS+ Authentication Features in IBM N/OS
Authentication is the action of determining the identity of a user, and is generally
done when the user first attempts to log in to a device or gain access to its services.
N/OS supports ASCII inbound login to the device. PAP, CHAP and ARAP login
methods, TACACS+ change password requests, and one-time password
authentication are not supported.

Authorization

Authorization is the action of determining a user’s privileges on the device, and

usually takes place after authentication.

The default mapping between TACACS+ authorization levels and N/OS

management access levels is shown in Table 8. The authorization levels must be
defined on the TACACS+ server.
Table 8. Default TACACS+ Authorization Levels

N/OS User Access Level TACACS+ level

user 0

oper 3

admin 6

Alternate mapping between TACACS+ authorization levels and N/OS management

access levels is shown in Table 9. Use the following command to set the alternate
TACACS+ authorization levels.

RS G8124(config)# tacacs-server privilege-mapping

Table 9. Alternate TACACS+ Authorization Levels

N/OS User Access Level TACACS+ level

user 0-1

oper 6-8

admin 14 - 15

If the remote user is successfully authenticated by the authentication server, the

switch verifies the privileges of the remote user and authorizes the appropriate
access. The administrator has an option to allow secure backdoor access via
Telnet/SSH. Secure backdoor provides switch access when the TACACS+ servers
cannot be reached. You always can access the switch via the console port, by using
notacacs and the administrator password, whether secure backdoor is enabled or
not.
Note: To obtain the TACACS+ backdoor password for your G8124, contact
Technical Support.

74 RackSwitch G8124: Application Guide

 Accounting

Accounting is the action of recording a user's activities on the device for the
purposes of billing and/or security. It follows the authentication and authorization
actions. If the authentication and authorization is not performed via TACACS+, there
are no TACACS+ accounting messages sent out.

You can use TACACS+ to record and track software login access, configuration
changes, and interactive commands.

The G8124 supports the following TACACS+ accounting attributes:

• protocol (console/Telnet/SSH/HTTP/HTTPS)
• start_time
• stop_time
• elapsed_time
• disc_cause
Note: When using the Browser-Based Interface, the TACACS+ Accounting Stop
records are sent only if the Logout button on the browser is clicked.

Command Authorization and Logging

When TACACS+ Command Authorization is enabled, N/OS configuration
commands are sent to the TACACS+ server for authorization. Use the following
command to enable TACACS+ Command Authorization:

RS G8124(config)# tacacs-server command-authorization

When TACACS+ Command Logging is enabled, N/OS configuration commands are

logged on the TACACS+ server. Use the following command to enable TACACS+
Command Logging:

RS G8124(config)# tacacs-server command-logging

The following examples illustrate the format of N/OS commands sent to the
TACACS+ server:

authorization request, cmd=shell, cmd-arg=interface ip

accounting request, cmd=shell, cmd-arg=interface ip
authorization request, cmd=shell, cmd-arg=enable
accounting request, cmd=shell, cmd-arg=enable

© Copyright IBM Corp. 2014 Chapter 5: Authentication & Authorization Protocols 75

Configuring TACACS+ Authentication on the Switch
1. Configure the IPv4 addresses of the Primary and Secondary TACACS+
servers, and enable TACACS authentication. Specify the interface port
(optional).

RS G8124(config)# tacacs-server primary-host 10.10.1.1

RS G8124(config)# tacacs-server primary-host mgtb-port
RS G8124(config)# tacacs-server secondary-host 10.10.1.2
RS G8124(config)# tacacs-server secondary-host data-port
RS G8124(config)# tacacs-server enable

Note: You can use a configured loopback address as the source address so the
TACACS+ server accepts requests only from the expected loopback
address block. Use the following command to specify the loopback interface:
RS G8124(config)# ip tacacs source-interface loopback <1-5>
2. Configure the TACACS+ secret and second secret.

RS G8124(config)# tacacs-server primary-host 10.10.1.1 key <1-32 character secret>

RS G8124(config)# tacacs-server secondary-host 10.10.1.2 key <1-32 character secret>

3. If desired, you may change the default TCP port number used to listen to
TACACS+.
The well-known port for TACACS+ is 49.

RS G8124(config)# tacacs-server port <TCP port number>

4. Configure the number of retry attempts, and the timeout period.

RS G8124(config)# tacacs-server retransmit 3

RS G8124(config)# tacacs-server timeout 5

76 RackSwitch G8124: Application Guide

LDAP Authentication and Authorization
N/OS supports the LDAP (Lightweight Directory Access Protocol) method to
authenticate and authorize remote administrators to manage the switch. LDAP is
based on a client/server model. The switch acts as a client to the LDAP server. A
remote user (the remote administrator) interacts only with the switch, not the
back-end server and database.

LDAP authentication consists of the following components:

• A protocol with a frame format that utilizes TCP over IP
• A centralized server that stores all the user authorization information
• A client: in this case, the switch

Each entry in the LDAP server is referenced by its Distinguished Name (DN). The
DN consists of the user-account name concatenated with the LDAP domain name.
If the user-account name is John, the following is an example DN:
uid=John,ou=people,dc=domain,dc=com

Configuring the LDAP Server

G8124 user groups and user accounts must reside within the same domain. On the
LDAP server, configure the domain to include G8124 user groups and user
accounts, as follows:
• User Accounts:
Use the uid attribute to define each individual user account. If a custom attribute
is used to define individual users, it must also be configured on the switch.
• User Groups:
Use the members attribute in the groupOfNames object class to create the user
groups. The first word of the common name for each user group must be equal
to the user group names defined in the G8124, as follows:
– admin
– oper
– user

Configuring LDAP Authentication on the Switch

1. Turn LDAP authentication on, then configure the IPv4 addresses of the Primary
and Secondary LDAP servers. Specify the interface port (optional).

>> # ldap-server enable

>> # ldap-server primary-host 10.10.1.1 mgta-port
>> # ldap-server secondary-host 10.10.1.2 data-port

2. Configure the domain name.

>> # ldap-server domain <ou=people,dc=my-domain,dc=com>

3. You may change the default TCP port number used to listen to LDAP (optional).
The well-known port for LDAP is 389.

>> # ldap-server port <1-65000>

© Copyright IBM Corp. 2014 Chapter 5: Authentication & Authorization Protocols 77

 4. Configure the number of retry attempts for contacting the LDAP server, and the
timeout period.

>> # ldap-server retransmit 3

>> # ldap-server timeout 10

5. You may change the default LDAP attribute (uid) or add a custom attribute. For
instance, Microsoft’s Active Directory requires the cn attribute.

>> # ldap-server attribute nameì <128 alpha-numeric characters>

78 RackSwitch G8124: Application Guide

Chapter 6. Access Control Lists
Access Control Lists (ACLs) are filters that permit or deny traffic for security
purposes. They can also be used with QoS to classify and segment traffic to provide
different levels of service to different traffic types. Each filter defines the conditions
that must match for inclusion in the filter, and also the actions that are performed
when a match is made.
IBM Networking OS 7.11 supports the following ACLs:
• IPv4 ACLs
Up to 127 ACLs are supported for networks that use IPv4 addressing. IPv4 ACLs
are configured using the following ISCLI command path:

RS G8124(config)# access-control list <IPv4 ACL number> ?

• IPv6 ACLs
Up to 128 ACLs are supported for networks that use IPv6 addressing. IPv6 ACLs
are configured using the following ISCLI command path:

RS G8124(config)# access-control list6 <IPv6 ACL number> ?

• VLAN Maps (VMaps)

Up to 127 VLAN Maps are supported for attaching filters to VLANs rather than
ports. See “VLAN Maps” on page 89 for details.
Note: The stated ACL capacity reflects the Default deployment mode. ACL support
may differ under some deployments modes. In modes where ACLs are not
supported, ACL configuration menus and commands are not available. See
“Deployment Profiles” on page 175 for details.

© Copyright IBM Corp. 2014 79

Summary of Packet Classifiers
ACLs allow you to classify packets according to a variety of content in the packet
header (such as the source address, destination address, source port number,
destination port number, and others). Once classified, packet flows can be identified
for more processing.
IPv4 ACLs, IPv6 ACLs, and VMaps allow you to classify packets based on the
following packet attributes:
• Ethernet header options (for IPv4 ACLs and VMaps only)
– Source MAC address
– Destination MAC address
– VLAN number and mask
– Ethernet type (ARP, IP, IPv6, MPLS, RARP, etc.)
– Ethernet Priority (the IEEE 802.1p Priority)
• IPv4 header options (for IPv4 ACLs and VMaps only)
– Source IPv4 address and subnet mask
– Destination IPv4 address and subnet mask
– Type of Service value
– IP protocol number or name as shown in Table 10:
Table 10. Well-Known Protocol Types

Number Protocol Name

1 icmp
2 igmp
6 tcp
17 udp
89 ospf
112 vrrp

• IPv6 header options (for IPv6 ACLs only)

– Source IPv6 address and prefix length
– Destination IPv6 address and prefix length
– Next Header value
– Flow Label value
– Traffic Class value

80 RackSwitch G8124: Application Guide

 • TCP/UDP header options (for all ACLs)
– TCP/UDP application source port and mask as shown in Table 11
– TCP/UDP application destination port as shown in Table 11
Table 11. Well-Known Application Ports

TCP/UDP TCP/UDP TCP/UDP

Port Application Port Application Port Application

20 ftp-data 79 finger 179 bgp

21 ftp 80 http 194 irc
22 ssh 109 pop2 220 imap3
23 telnet 110 pop3 389 ldap
25 smtp 111 sunrpc 443 https
37 time 119 nntp 520 rip
42 name 123 ntp 554 rtsp
43 whois 143 imap 1645/1812 Radius
53 domain 144 news 1813 Radius
69 tftp 161 snmp 1985 Accounting
70 gopher 162 snmptrap hsrp

– TCP/UDP flag value as shown in Table 12

Table 12. Well-Known TCP flag values

Flag Value

URG 0x0020
ACK 0x0010
PSH 0x0008
RST 0x0004
SYN 0x0002
FIN 0x0001

• Packet format (for IPv4 ACLs and VMaps only)

– Ethernet format (eth2, SNAP, LLC)
– Ethernet tagging format
– IP format (IPv4, IPv6)

Summary of ACL Actions

Once classified using ACLs, the identified packet flows can be processed differently.
For each ACL, an action can be assigned. The action determines how the switch
treats packets that match the classifiers assigned to the ACL. G8124 ACL actions
include the following:
• Pass or Drop the packet
• Re-mark the packet with a new DiffServ Code Point (DSCP)
• Re-mark the 802.1p field
• Set the COS queue
• Change ingress VLAN classification
Note: ACLs act only upon ingress traffic on a port, not egress traffic.

© Copyright IBM Corp. 2014 Chapter 6: Access Control Lists 81

Assigning Individual ACLs to a Port
Once you configure an ACL, you must assign the ACL to the appropriate ports.
Each port can accept multiple ACLs, and each ACL can be applied for multiple
ports. ACLs can be assigned individually.

To assign an individual ACLs to a port, use the following IP Interface Mode

commands:

RS G8124(config)# interface port <port>

RS G8124(config-if)# access-control list <IPv4 ACL number>
RS G8124(config-if)# access-control list6 <IPv6 ACL number>

When multiple ACLs are assigned to a port, higher-priority ACLs are considered
first, and their action takes precedence over lower-priority ACLs. ACL order of
precedence is discussed in the next section.

ACL Order of Precedence

When multiple ACLs are assigned to a port, they are evaluated in numeric
sequence, based on the ACL number. Lower-numbered ACLs take precedence
over higher-numbered ACLs. For example, ACL 1 (if assigned to the port) is
evaluated first and has top priority.

If multiple ACLs match the port traffic, only the action of the one with the lowest ACL
number is applied. The others are ignored.

If no assigned ACL matches the port traffic, no ACL action is applied.

ACL Metering and Re-Marking

You can define a profile for the aggregate traffic flowing through the G8124 by
configuring a QoS meter (if desired) and assigning ACLs to ports.
Note: When you add ACLs to a port, make sure they are ordered correctly in terms
of precedence (see “ACL Order of Precedence” on page 82).

Actions taken by an ACL are called In-Profile actions. You can configure additional
In-Profile and Out-of-Profile actions on a port. Data traffic can be metered, and
re-marked to ensure that the traffic flow provides certain levels of service in terms of
bandwidth for different types of network traffic.

82 RackSwitch G8124: Application Guide

 Metering

QoS metering provides different levels of service to data streams through

user-configurable parameters. A meter is used to measure the traffic stream against
a traffic profile which you create. Thus, creating meters yields In-Profile and
Out-of-Profile traffic for each ACL, as follows:
• In-ProfileIf there is no meter configured or if the packet conforms to the meter,
the packet is classified as In-Profile.
• Out-of-ProfileIf a meter is configured and the packet does not conform to the
meter (exceeds the committed rate or maximum burst rate of the meter), the
packet is classified as Out-of-Profile.
Note: Metering is not supported for IPv6 ACLs. All traffic matching an IPv6 ACL is
considered in-profile for re-marking purposes.

Using meters, you set a Committed Rate in Kbps (in multiples of 64 Mbps). All traffic
within this Committed Rate is In-Profile. Additionally, you can set a Maximum Burst
Size that specifies an allowed data burst larger than the Committed Rate for a brief
period. These parameters define the In-Profile traffic.

Meters keep the sorted packets within certain parameters. You can configure a
meter on an ACL, and perform actions on metered traffic, such as packet
re-marking.

Re-Marking

Re-marking allows for the treatment of packets to be reset based on new network
specifications or desired levels of service. You can configure the ACL to re-mark a
packet as follows:
• Change the DSCP value of a packet, used to specify the service level that traffic
receives.
• Change the 802.1p priority of a packet.

© Copyright IBM Corp. 2014 Chapter 6: Access Control Lists 83

ACL Port Mirroring
For IPv4 ACLs and VMaps, packets that match the filter can be mirrored to another
switch port for network diagnosis and monitoring.

The source port for the mirrored packets cannot be a portchannel, but may be a
member of a portchannel.

The destination port to which packets are mirrored must be a physical port.

The action (permit, drop, etc.) of the ACL or VMap must be configured before
assigning it to a port.

Use the following commands to add mirroring to an ACL:

• For IPv4 ACLs:

RS G8124(config)# access-control list <ACL number> mirror port <destination port>

The ACL must be also assigned to it target ports as usual (see “Assigning
Individual ACLs to a Port” on page 82).
• For VMaps (see “VLAN Maps” on page 89):

RS G8124(config)# access-control vmap <VMap number> mirror port <monitor destination

port>

See the configuration example on page 90.

Viewing ACL Statistics

ACL statistics display how many packets have “hit” (matched) each ACL. Use ACL
statistics to check filter performance or to debug the ACL filter configuration.

You must enable statistics for each ACL that you wish to monitor:

RS G8124(config)# access-control list <ACL number> statistics

84 RackSwitch G8124: Application Guide

ACL Logging
ACLs are generally used to enhance port security. Traffic that matches the
characteristics (source addresses, destination addresses, packet type, etc.)
specified by the ACLs on specific ports is subject to the actions (chiefly permit or
deny) defined by those ACLs. Although switch statistics show the number of times
particular ACLs are matched, the ACL logging feature can provide additional insight
into actual traffic patterns on the switch, providing packet details in the system log
for network debugging or security purposes.

Enabling ACL Logging

By default, ACL logging is disabled. Enable or disable ACL logging on a per-ACL
basis as follows:

RS G8124(config)# [no] access-control list <IPv4 ACL number> log

RS G8124(config)# [no] access-control list6 <IPv6 ACL number> log

Logged Information
When ACL logging is enabled on any particular ACL, the switch will collect
information about packets that match the ACL. The information collected depends
on the ACL type:
• For IP-based ACLs, information is collected regarding
– Source IP address
– Destination IP address
– TCP/UDP port number
– ACL action
– Number of packets logged
For example:
Sep 27 4:20:28 DUT3 NOTICE ACL-LOG: %IP ACCESS LOG: list
ACL-IP-12-IN denied tcp 1.1.1.1 (0) -> 200.0.1.2 (0), 150
packets.
• For MAC-based ACLs, information is collected regarding
– Source MAC address
– Source IP address
– Destination IP address
– TCP/UDP port number
– ACL action
– Number of packets logged
For example:
Sep 27 4:25:38 DUT3 NOTICE ACL-LOG: %MAC ACCESS LOG: list
ACL-MAC-12-IN permitted tcp 1.1.1.2 (0) (12,
00:ff:d7:66:74:62) -> 200.0.1.2 (0) (00:18:73:ee:a7:c6), 32
packets.

© Copyright IBM Corp. 2014 Chapter 6: Access Control Lists 85

Rate Limiting Behavior
Because ACL logging can be CPU-intensive, logging is rate-limited. By default, the
switch will log only 10 matching packets per second. This pool is shared by all
log-enabled ACLs. The global rate limit can be changed as follows:

RS G8124(config)# access-control log rate-limit <1-1000>

Where the limit is specified in packets per second.

Log Interval
For each log-enabled ACL, the first packet that matches the ACL initiates an
immediate message in the system log. Beyond that, additional matches are subject
to the log interval. By default, the switch will buffer ACL log messages for a period of
300 seconds. At the end of that interval, all messages in the buffer are written to the
system log. The global interval value can be changed as follows:

RS G8124(config)# access-control log interval <5-600>

Where the interval rate is specified in seconds.

In any given interval, packets that have identical log information are condensed into
a single message. However, the packet count shown in the ACL log message
represents only the logged messages, which due to rate-limiting, may be
significantly less than the number of packets actually matched by the ACL.

Also, the switch is limited to 64 different ACL log messages in any interval. Once the
threshold is reached, the oldest message will be discarded in favor of the new
message, and an overflow message will be added to the system log.

ACL Logging Limitations

• When ACL logging is enabled, the ACL action for setting packet priority levels (to
a value other than 1) is not supported. For instance, the following configuration is
invalid:

RS G8124(config)# access-control list 1 action set-priority 2

• ACL logging reserves packet queue 1 for internal use. Features that allow
remapping packet queues (such as QoS CPU rate limit) may not behave as
expected if other packet flows are reconfigured to use queue 1.

86 RackSwitch G8124: Application Guide

ACL Configuration Examples
ACL Example 1

Use this configuration to block traffic to a specific host. All traffic that ingresses on
port 1 is denied if it is destined for the host at IP address 100.10.1.1
1. Configure an Access Control List.

RS G8124(config)# access-control list 1 ipv4 destination-ip-address 100.10.1.1

RS G8124(config)# access-control list 1 action deny

2. Add ACL 1 to port 1.

RS G8124(config)# interface port 1

RS G8124(config-if)# access-control list 1
RS G8124(config-if)# exit

ACL Example 2

Use this configuration to block traffic from a network destined for a specific host
address. All traffic that ingresses in port 2 with source IP from class 100.10.1.0/24
and destination IP 200.20.2.2 is denied.
1. Configure an Access Control List.

RS G8124(config)# access-control list 2 ipv4 source-ip-address 100.10.1.0

255.255.255.0
RS G8124(config)# access-control list 2 ipv4 destination-ip-address 200.20.2.2
255.255.255.255
RS G8124(config)# access-control list 2 action deny

2. Add ACL 2 to port 2.

RS G8124(config)# interface port 2

RS G8124(config-if)# access-control list 2
RS G8124(config-if)# exit

ACL Example 3

Use this configuration to block traffic from a specific IPv6 source address. All traffic
that ingresses in port 2 with source IP from class 2001:0:0:5:0:0:0:2/128 is denied.
1. Configure an Access Control List.

RS G8124(config)# access-control list6 3 ipv6 source-address 2001:0:0:5:0:0:0:2

128
RS G8124(config)# access-control list6 3 action deny

2. Add ACL 2 to port 2.

RS G8124(config)# interface port 2

RS G8124(config-if)# access-control list6 3
RS G8124(config-if)# exit

© Copyright IBM Corp. 2014 Chapter 6: Access Control Lists 87

 ACL Example 4

Use this configuration to deny all ARP packets that ingress a port.
1. Configure an Access Control List.

RS G8124(config)# access-control list 2 ethernet ethernet-type arp

RS G8124(config)# access-control list 2 action deny

2. Add ACL 2 to port EXT2.

RS G8124(config)# interface port 2

RS G8124(config-if)# access-control list 2
RS G8124(config-if)# exit

ACL Example 5

Use the following configuration to permit access to hosts with destination MAC
address that matches 11:05:00:10:00:00 FF:F5:FF:FF:FF:FF and deny access to all
other hosts.
1. Configure Access Control Lists.

RS G8124(config)# access-control list 30 ethernet destination-mac-address

11:05:00:10:00:00 FF:F5:FF:FF:FF:FF
RS G8124(config)# access-control list 30 action permit
RS G8124(config)# access-control list 100 ethernet destination-mac-address
00:00:00:00:00:00 00:00:00:00:00:00
RS G8124(config)# access-control list 100 action deny

2. Add ACLs to a port.

RS G8124(config)# interface port 2

RS G8124(config-if)# access-control list 30
RS G8124(config-if)# access-control list 100
RS G8124(config-if)# exit

88 RackSwitch G8124: Application Guide

VLAN Maps
A VLAN map (VMap) is an ACL that can be assigned to a VLAN or VM group rather
than to a switch port as with IPv4 ACLs. This is particularly useful in a virtualized
environment where traffic filtering and metering policies must follow virtual
machines (VMs) as they migrate between hypervisors.
Note: VLAN maps for VM groups are not supported simultaneously on the same
ports as vNICs (see “Virtual NICs” on page 181).

The G8124 supports up to 127 VMaps when the switch is operating in the default
deployment mode (see “Deployment Profiles” on page 175). VMap menus and
commands are not available in the Routing deployment mode.

Individual VMap filters are configured in the same fashion as IPv4 ACLs, except that
VLANs cannot be specified as a filtering criteria (unnecessary, since the VMap are
assigned to a specific VLAN or associated with a VM group VLAN).

VMaps are configured using the following ISCLI configuration command path:

RS G8124(config)# access-control vmap <VMap ID> ?

action Set filter action
ethernet Ethernet header options
ipv4 IP version 4 header options
meter ACL metering configuration
mirror Mirror options
packet-format Set to filter specific packet format types
re-mark ACL re-mark configuration
statistics Enable access control list statistics
tcp-udp TCP and UDP filtering options

Once a VMap filter is created, it can be assigned or removed using the following
configuration commands:
• For regular VLAN, use config-vlan mode:

RS G8124(config)# vlan <VLAN ID>

RS G8124(config-vlan)# [no] vmap <VMap ID> [serverports| non-serverports]

• For a VM group (see “VM Group Types” on page 194), use the global
configuration mode:

RS G8124(config)# [no] virt vmgroup <ID> vmap <VMap ID>

[serverports|non-serverports]

Note: Each VMap can be assigned to only one VLAN or VM group. However, each
VLAN or VM group may have multiple VMaps assigned to it.

When the optional serverports or non-serverports parameter is specified,

the action to add or remove the VMap is applied for either the switch server ports
(serverports) or uplink ports (non-serverports). If omitted, the operation will
be applied to all ports in the associated VLAN or VM group.

© Copyright IBM Corp. 2014 Chapter 6: Access Control Lists 89

 VMap Example

In this example, EtherType 2 traffic from VLAN 3 server ports is mirrored to a

network monitor on port 4.

RS G8124(config)# access-control vmap 21 packet-format ethernet ethernet-type2

RS G8124(config)# access-control vmap 21 mirror port 4
RS G8124(config)# access-control vmap 21 action permit
RS G8124(config)# vlan 3
RS G8124(config-vlan)# vmap 21 serverports

VLAN Classification
Packets received on ports may belong to multiple VLANs or may be untagged.
VLAN classification using ACLs allows you to assign a new VLAN to such packets
that can be flooded to a monitor port. These packets, when sent out from the
monitor port, can be identified by their source ports.

The ingress and monitor ports must belong to the new VLAN. Tagging must be
enabled on these ports.
Note: When you assign a new VLAN to the ingress packets, the packets will be
forwarded based on the new VLAN.

By default, VLAN classification is disabled.

Example

Consider the following example in which packets from ingress port 1 are assigned to
VLAN 100. Packets are flooded to monitor port 20.
1. Create a new VLAN. Add ingress and monitor ports to the VLAN:

RS G8124(config)# vlan 100

VLAN number 100 with name "VLAN 100" created.

RS G8124(config-vlan)# no shutdown
RS G8124(config-vlan)# exit

2. Create an ACL to assign the new VLAN to packets received on ingress port:

RS G8124(config)# access-control list 1 action change-vlan 100

Note: You can add filters, such as source IP address, to the ACL.
3. Enable tagging on ingress and monitor ports:

RS G8124(config)# interface port 1,20

RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 100
RS G8124(config-if)# exit

90 RackSwitch G8124: Application Guide

 4. Apply the ACL to the ingress port:

RS G8124(config)# interface port 1

RS G8124(config-if)# access-control list 1

Note: When you apply VLAN classification, VMAP, and IPv4 ACL at the same time,
IPv4 ACL takes precedence over VMAP.
Note: When you apply VLAN classification, VMAP, and IPv6 ACL at the same time,
VMAP ACL takes precedence over IPv6 ACL.

Restrictions
VLAN classification is primarily useful for monitoring packets. When you enable this
feature, the switch considers only the new VLAN. The switch does not learn the
original VLAN. We recommend that you use this feature only if the switch does not
need to process regular switching and bidirectional traffic.

© Copyright IBM Corp. 2014 Chapter 6: Access Control Lists 91

Using Storm Control Filters
Excessive transmission of broadcast or multicast traffic can result in a network
storm. A network storm can overwhelm your network with constant broadcast or
multicast traffic, and degrade network performance. Common symptoms of a
network storm are denial-of-service (DoS) attacks, slow network response times,
and network operations timing out.

The G8124 provides filters that can limit the number of the following packet types
transmitted by switch ports:
• Broadcast packets
• Multicast packets
• Unknown unicast packets (destination lookup failure)

Unicast packets whose destination MAC address is not in the Forwarding Database
are unknown unicasts. When an unknown unicast is encountered, the switch
handles it like a broadcast packet and floods it to all other ports in the VLAN
(broadcast domain). A high rate of unknown unicast traffic can have the same
negative effects as a broadcast storm.

Configuring Storm Control

Configure broadcast filters on each port that requires broadcast storm control. Set a
threshold that defines the total number of broadcast packets transmitted
(100-10000), in packets per second. When the threshold is reached, no more
packets of the specified type are transmitted.

Up to nine storm filters can be configured on the G8124.

To filter broadcast packets on a port, use the following commands:

RS G8124(config)# interface port 1

RS G8124(config-if)# storm-control broadcast level pps <packets per second>

To filter multicast packets on a port, use the following commands:

RS G8124(config-if)# storm-control multicast level pps <packets per second>

To filter unknown unicast packets on a port, use the following commands:

RS G8124(config-if)# storm-control unicast level pps <packets per second>

RS G8124(config-if)# exit

92 RackSwitch G8124: Application Guide

Part 3: Switch Basics
This section discusses basic switching functions:
• VLANs
• Port Trunking
• Spanning Tree Protocols (Spanning Tree Groups, Rapid Spanning Tree Protocol,
and Multiple Spanning Tree Protocol)
• Virtual Link Aggregation Groups
• Quality of Service

© Copyright IBM Corp. 2014 93

94 RackSwitch G8124: Application Guide
Chapter 7. VLANs
This chapter describes network design and topology considerations for using Virtual
Local Area Networks (VLANs). VLANs commonly are used to split up groups of
network users into manageable broadcast domains, to create logical segmentation
of workgroups, and to enforce security policies among logical segments. The
following topics are discussed in this chapter:
• “VLANs and Port VLAN ID Numbers” on page 96
• “VLAN Tagging/Trunk Mode” on page 98
• “VLAN Topologies and Design Considerations” on page 102
This section discusses how you can connect users and segments to a host that
supports many logical segments or subnets by using the flexibility of the multiple
VLAN system.
• “Private VLANs” on page 105
Note: VLANs can be configured from the Command Line Interface (see “VLAN
Configuration” as well as “Port Configuration” in the Command Reference).

© Copyright IBM Corp. 2014 95

VLANs Overview
Setting up virtual LANs (VLANs) is a way to segment networks to increase network
flexibility without changing the physical network topology. With network
segmentation, each switch port connects to a segment that is a single broadcast
domain. When a switch port is configured to be a member of a VLAN, it is added to
a group of ports (workgroup) that belong to one broadcast domain.

Ports are grouped into broadcast domains by assigning them to the same VLAN.
Frames received in one VLAN can only be forwarded within that VLAN, and
multicast, broadcast, and unknown unicast frames are flooded only to ports in the
same VLAN.

The RackSwitch G8124 (G8124) supports jumbo frames with a Maximum

Transmission Unit (MTU) of 9,216 bytes. Within each frame, 18 bytes are reserved
for the Ethernet header and CRC trailer. The remaining space in the frame (up to
9,198 bytes) comprise the packet, which includes the payload of up to 9,000 bytes
and any additional overhead, such as 802.1q or VLAN tags. Jumbo frame support is
automatic: it is enabled by default, requires no manual configuration, and cannot be
manually disabled.

VLANs and Port VLAN ID Numbers

VLAN Numbers
The G8124 supports up to 4095 VLANs per switch. Each can be identified with any
number between 1 and 4094. VLAN 1 is the default VLAN for the data ports. VLAN
4095 is used by the management network, which includes the management ports.

Use the following command to view VLAN information:

RS G8124# show vlan

VLAN Name Status Ports

---- ------------------------ ------ -------------------------
1 Default VLAN ena
2 VLAN 2 dis empty
4095 Mgmt VLAN ena MGMTA MGMTB

96 RackSwitch G8124: Application Guide

PVID/Native VLAN Numbers
Each port in the switch has a configurable default VLAN number, known as its PVID.
By default, the PVID for all non-management ports is set to 1, which correlates to
the default VLAN ID. The PVID for each port can be configured to any VLAN
number between 1 and 4094.

Use the following command to view PVIDs:

RS G8124# show interface information

(or)
RS G8124# show interface trunk

Alias Port Tag RMON Lrn Fld PVID DESCRIPTION VLAN(s)

Trk NVLAN
------- ---- --- ---- --- --- ----- -------------- -------------------------------
1 1 n d e e 1 1
2 2 n d e e 1 1
3 3 n d e e 1 1
4 4 n d e e 1 1
... ... ...
24 24 n d e e 24 24
MGTA 25 n d e e 4095 4095
MGTB 26 n d e e 4095 4095

* = PVID/Native-VLAN is tagged.
Trk = Trunk mode
NVLAN = Native-VLAN

Use the following command to set the port PVID/Native VLAN:

Access Mode Port

RS G8124(config)# interface port <port number>

RS G8124(config-if)# switchport access vlan <VLAN ID>

For Trunk Mode Port

RS G8124(config)# interface port <port number>

RS G8124(config-if)# switchport trunk native vlan <VLAN ID>

Each port on the switch can belong to one or more VLANs, and each VLAN can
have any number of switch ports in its membership. Any port that belongs to multiple
VLANs, however, must have VLAN tagging/trunk mode enabled (see “VLAN
Tagging/Trunk Mode” on page 98).

© Copyright IBM Corp. 2014 Chapter 7: VLANs 97

VLAN Tagging/Trunk Mode
IBM Networking OS software supports 802.1Q VLAN tagging, providing
standards-based VLAN support for Ethernet systems.

Tagging places the VLAN identifier in the frame header of a packet, allowing each
port to belong to multiple VLANs. When you add a port to multiple VLANs, you also
must enable tagging on that port.

Since tagging fundamentally changes the format of frames transmitted on a tagged

port, you must carefully plan network designs to prevent tagged frames from being
transmitted to devices that do not support 802.1Q VLAN tags, or devices where
tagging is not enabled.

Important terms used with the 802.1Q tagging feature are:

• VLAN identifier (VID)—the 12-bit portion of the VLAN tag in the frame header
that identifies an explicit VLAN.
• Port VLAN identifier (PVID)—a classification mechanism that associates a port
with a specific VLAN. For example, a port with a PVID of 3 (PVID =3) assigns all
untagged frames received on this port to VLAN 3. Any untagged frames received
by the switch are classified with the PVID of the receiving port.
• Tagged frame—a frame that carries VLAN tagging information in the header.
This VLAN tagging information is a 32-bit field (VLAN tag) in the frame header
that identifies the frame as belonging to a specific VLAN. Untagged frames are
marked (tagged) with this classification as they leave the switch through a port
that is configured as a tagged port.
• Untagged frame— a frame that does not carry any VLAN tagging information in
the frame header.
• Untagged member—a port that has been configured as an untagged member of
a specific VLAN. When an untagged frame exits the switch through an untagged
member port, the frame header remains unchanged. When a tagged frame exits
the switch through an untagged member port, the tag is stripped and the tagged
frame is changed to an untagged frame.
• Tagged member—a port that has been configured as a tagged member of a
specific VLAN. When an untagged frame exits the switch through a tagged
member port, the frame header is modified to include the 32-bit tag associated
with the PVID. When a tagged frame exits the switch through a tagged member
port, the frame header remains unchanged (original VID remains).
Note: If a 802.1Q tagged frame is received by a port that has VLAN-tagging
disabled and the port VLAN ID (PVID) is different than the VLAN ID of the
packet, then the frame is dropped at the ingress port.

98 RackSwitch G8124: Application Guide

 Figure 1. Default VLAN settings

802.1Q Switch

VLAN 1

Port 1 Port 2 Port 3 Port 4 Port 5 Port 6 Port 7 ...

PVID = 1

DA CRC
SA
Incoming Outgoing Data
untagged Data untagged packet
packet (unchanged) SA
CRC DA

Key
By default:
All ports are assigned PVID = 1
All ports are untagged members of VLAN 1
BS45010A

Note: The port numbers specified in these illustrations may not directly correspond
to the physical port configuration of your switch model.

When a VLAN is configured, ports are added as members of the VLAN, and the
ports are defined as either tagged or untagged (see Figure 2 through Figure 5).

The default configuration settings for the G8124 has all ports set as untagged
members of VLAN 1 with all ports configured as PVID = 1. In the default
configuration example shown in Figure 1, all incoming packets are assigned to
VLAN 1 by the default port VLAN identifier (PVID =1).

Figure 2 through Figure 5 illustrate generic examples of VLAN tagging. In Figure 2,

untagged incoming packets are assigned directly to VLAN 2 (PVID = 2). Port 5 is
configured as a tagged member of VLAN 2, and port 7 is configured as an untagged
member of VLAN 2.
Note: The port assignments in the following figures are not meant to match the
G8124.
Figure 2. Port-based VLAN assignment

PVID = 2 Port 1 Port 2 Port 3 Tagged member

of VLAN 2
Untagged packet
Port 4

Port 5

CRC Data SA DA 802.1Q Switch

Before Port 6 Port 7 Port 8

Untagged member
of VLAN 2

© Copyright IBM Corp. 2014 Chapter 7: VLANs 99

 As shown in Figure 3, the untagged packet is marked (tagged) as it leaves the
switch through port 5, which is configured as a tagged member of VLAN 2. The
untagged packet remains unchanged as it leaves the switch through port 7, which is
configured as an untagged member of VLAN 2.
Figure 3. 802.1Q tagging (after port-based VLAN assignment)

PVID = 2 Tagged member

Port 1 Port 2 Port 3 of VLAN 2

Port 4

Port 5
802.1Q Switch CRC* Data Tag SA DA

(*Recalculated)
Port 6 Port 7 Port 8

Untagged memeber 8100 Priority CFI VID = 2

CRC
of VLAN 2
16 bits 3 bits 1 bits 12 bits
Data
After
SA
Outgoing
untagged packet Key
DA
(unchanged) Priority - User_priority
CFI - Canonical format indicator
VID - VLAN identifier
BS45012A

In Figure 4, tagged incoming packets are assigned directly to VLAN 2 because of

the tag assignment in the packet. Port 5 is configured as a tagged member of VLAN
2, and port 7 is configured as an untagged member of VLAN 2.
Figure 4. 802.1Q tag assignment

PVID = 2 Port 1 Port 2 Port 3 Tagged member

of VLAN 2
Tagged packet Port 5
Port 4

CRC Data Tag SA DA 802.1Q Switch

Before
Port 6 Port 7 Port 8

Untagged member
of VLAN 2
BS45013A

As shown in Figure 5, the tagged packet remains unchanged as it leaves the switch
through port 5, which is configured as a tagged member of VLAN 2. However, the
tagged packet is stripped (untagged) as it leaves the switch through port 7, which is
configured as an untagged member of VLAN 2.

100 RackSwitch G8124: Application Guide

 Figure 5. 802.1Q tagging (after 802.1Q tag assignment)

PVID = 2 Tagged member

Port 1 Port 2 Port 3
of VLAN 2

Port 4

Port 5
802.1Q Switch CRC Data Tag SA DA

Port 6 Port 7 Port 8

Untagged member CRC* (*Recalculated) 8100 Priority CFI VID = 2

of VLAN 2
16 bits 3 bits 1 bit 12 bits
Data

Outgoing After
SA untagged packet
changed Key
DA (tag removed)
Priority - User_priority
CFI - Canonical format indicator
VID - VLAN identifier
BS45014A

© Copyright IBM Corp. 2014 Chapter 7: VLANs 101

VLAN Topologies and Design Considerations
Note the following when working with VLAN topologies:
• By default, the G8124 software is configured so that tagging/trunk mode is
disabled on all ports.
• By default, the G8124 software is configured so that all data ports are members
of VLAN 1.
• By default, the IBM N/OS software is configured so that the management ports
(MGTA and MGTB) are members of VLAN 4095 (the management VLAN).
• STG 128 is reserved for switch management.
• When using Spanning Tree, STG 2-128 may contain only one VLAN unless
Multiple Spanning-Tree Protocol (MSTP) mode is used. With MSTP mode, STG
1 to 32 can include multiple VLANs.
• All ports involved in both trunking and port mirroring must have the same VLAN
configuration. If a port is on a trunk with a mirroring port, the VLAN configuration
cannot be changed. For more information trunk groups, see “Ports and Trunking”
on page 109 and “Port Mirroring” on page 457.

Multiple VLANs with Tagging/Trunk Mode Adapters

Figure 6 illustrates a network topology described in Note: on page 103 and the
configuration example on page page 104.
Figure 6. Multiple VLANs with VLAN-Tagged Gigabit Adapters

Enterprise Enterprise
Routing Switch Routing Switch

Server 1 Server 2 Server 3 Server 4 Server 5

VLAN 1 VLAN 1 VLAN 2 VLAN 3 VLAN 1, 2

The features of this VLAN are described in the following table.

102 RackSwitch G8124: Application Guide

 Table 13. Multiple VLANs Example

Component Description

G8124 switch This switch is configured with three VLANs that represent three
different IP subnets. Five ports are connected downstream to
servers. Two ports are connected upstream to routing switches.
Uplink ports are members of all three VLANs, with VLAN
tagging/trunk mode enabled.

Server 1 This server is a member of VLAN 1 and has presence in only

one IP subnet. The associated switch port is only a member of
VLAN 1, so tagging/trunk mode is disabled.

Server 2 This server is a member of VLAN 1 and has presence in only

one IP subnet. The associated switch port is only a member of
VLAN 1, so tagging/trunk mode is disabled.

Server 3 This server belongs to VLAN 2, and it is logically in the same IP

subnet as Server 5. The associated switch port has
tagging/trunk mode disabled.

Server 4 A member of VLAN 3, this server can communicate only with

other servers via a router. The associated switch port has
tagging/trunk mode disabled.

Server 5 A member of VLAN 1 and VLAN 2, this server can

communicate only with Server 1, Server 2, and Server 3. The
associated switch port has tagging/trunk mode enabled.

Enterprise These switches must have all three VLANs (VLAN 1, 2, 3)

Routing configured. They can communicate with Server 1, Server 2,
switches and Server 5 via VLAN 1. They can communicate with Server 3
and Server 5 via VLAN 2. They can communicate with Server 4
via VLAN 3. Tagging/trunk mode on switch ports is enabled.

Note: VLAN tagging/trunk mode is required only on ports that are connected to
other switches or on ports that connect to tag-capable end-stations, such as
servers with VLAN-tagging/trunk mode adapters.

© Copyright IBM Corp. 2014 Chapter 7: VLANs 103

VLAN Configuration Example
Use the following procedure to configure the example network shown in Figure 6 on
page 102.
1. Enable VLAN tagging/trunk mode on server ports that support multiple VLANs.

RS G8124(config)# interface port 5

RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# exit

2. Enable tagging/trunk mode on uplink ports that support multiple VLANs.

RS G8124(config)# interface port 19

RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# exit
RS G8124(config)# interface port 20
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# exit

3. Configure server ports that belong to a single VLAN.

RS G8124(config)# interface port 4

RS G8124(config-if)# switchport access vlan 2
RS G8124(config-if)# exit

By default, all ports are members of VLAN 1, so configure only those ports that
belong to other VLANs.

104 RackSwitch G8124: Application Guide

Private VLANs
Private VLANs provide Layer 2 isolation between the ports within the same
broadcast domain. Private VLANs can control traffic within a VLAN domain, and
provide port-based security for host servers.

Use Private VLANs to partition a VLAN domain into sub-domains. Each sub-domain
is comprised of one primary VLAN and one or more secondary VLANs, as follows:
• Primary VLAN—carries unidirectional traffic downstream from promiscuous
ports. Each Private VLAN configuration has only one primary VLAN. All ports in
the Private VLAN are members of the primary VLAN.
• Secondary VLAN—Secondary VLANs are internal to a private VLAN domain,
and are defined as follows:
– Isolated VLAN—carries unidirectional traffic upstream from the host servers
toward ports in the primary VLAN and the gateway. Each Private VLAN
configuration can contain only one isolated VLAN.
– Community VLAN—carries upstream traffic from ports in the community
VLAN to other ports in the same community, and to ports in the primary
VLAN and the gateway. Each Private VLAN configuration can contain
multiple community VLANs.

After you define the primary VLAN and one or more secondary VLANs, you map the
secondary VLAN(s) to the primary VLAN.

Private VLAN Ports

Private VLAN ports are defined as follows:
• Promiscuous—A promiscuous port is a port that belongs to the primary VLAN.
The promiscuous port can communicate with all the interfaces, including ports
in the secondary VLANs (Isolated VLAN and Community VLANs). Each promis-
cuous port can belong to only one Private VLAN.
• Isolated—An isolated port is a host port that belongs to an isolated VLAN. Each
isolated port has complete layer 2 separation from other ports within the same
private VLAN (including other isolated ports), except for the promiscuous ports.
– Traffic sent to an isolated port is blocked by the Private VLAN, except the
traffic from promiscuous ports.
– Traffic received from an isolated port is forwarded only to promiscuous ports.
• Community—A community port is a host port that belongs to a community
VLAN. Community ports can communicate with other ports in the same commu-
nity VLAN, and with promiscuous ports. These interfaces are isolated at layer 2
from all other interfaces in other communities and from isolated ports within the
Private VLAN.

© Copyright IBM Corp. 2014 Chapter 7: VLANs 105

Configuration Guidelines
The following guidelines apply when configuring Private VLANs:
• Management VLANs cannot be Private VLANs. Management ports cannot be
members of a Private VLAN.
• The default VLAN 1 cannot be a Private VLAN.
• IGMP Snooping must be disabled on Private VLANs.
• All VLANs that comprise the Private VLAN must belong to the same Spanning
Tree Group.
• A secondary port’s (isolated port and community port) PVID/Native VLAN must
match its corresponding secondary VLAN ID.
• Ports in a secondary VLAN cannot be members of other VLANs.

Configuration Example
Follow this procedure to configure a Private VLAN.
1. Select a VLAN and define the Private VLAN type as primary.

RS G8124(config)# vlan 700

RS G8124(config-vlan)# private-vlan primary
RS G8124(config-vlan)# exit

2. Configure a promiscuous port for VLAN 700.

RS G8124(config)# interface port 1

RS G8124(config-if)# switchport mode private-vlan promiscuous
RS G8124(config-if)# switchport private-vlan mapping 700
RS G8124(config-if)# exit

3. Configure two secondary VLANs: isolated VLAN and community VLAN.

RS G8124(config)# vlan 701

RS G8124(config-vlan)# private-vlan isolated
RS G8124(config-vlan)# exit
RS G8124(config)# vlan 702
RS G8124(config-vlan)# private-vlan community
RS G8124(config-vlan)# exit

4. Map secondary VLANs to primary VLAN.

RS G8124(config)# vlan 700-702

RS G8124(config-vlan)# stg 1
RS G8124(config-vlan)# exit
RS G8124(config)# vlan 700
RS G8124(config-vlan)# private-vlan association 701,702
RS G8124(config-vlan)# exit

106 RackSwitch G8124: Application Guide

 5. Configure host ports for secondary VLANs.

RS G8124(config)# interface port 2

RS G8124(config-if)# switchport mode private-vlan host
RS G8124(config-if)# switchport private-vlan association 700 701
RS G8124(config-if)# exit

RS G8124(config)# interface port 3

RS G8124(config-if)# switchport mode private-vlan host
RS G8124(config-if)# switchport private-vlan association 700 702
RS G8124(config-if)# exit

6. Verify the configuration.

RS G8124(config)# show vlan private-vlan

Private-VLAN Type Mapped-To Status Ports

------------ --------- ---------- ---------- -----------------
700 primary 701,702 ena 1
701 isolated 700 ena 2
702 community 700 ena 3

© Copyright IBM Corp. 2014 Chapter 7: VLANs 107

108 RackSwitch G8124: Application Guide
Chapter 8. Ports and Trunking
Trunk groups can provide super-bandwidth, multi-link connections between the
RackSwitch G8124 (G8124) and other trunk-capable devices. A trunk group is a
group of ports that act together, combining their bandwidth to create a single, larger
virtual link. This chapter provides configuration background and examples for
trunking multiple ports together:
• “Trunking Overview” on page 110”
• “Configuring a Static Port Trunk” on page 112
• “Configurable Trunk Hash Algorithm” on page 118
• “Link Aggregation Control Protocol” on page 114

© Copyright IBM Corp. 2014 109

Trunking Overview
When using port trunk groups between two switches, as shown in Figure 7, you can
create a virtual link between the switches, operating with combined throughput
levels that depends on how many physical ports are included.

The G8124 supports two trunk types: static trunk groups (portchannel), and dynamic
LACP trunk groups. You may configure up to 24 trunk groups on the switch, with
both types (static and LACP) sharing the same pool. Of the available configuration
slots, any or all may be used for LACP trunks, though only up to 12 may used for
static trunks. In addition, although up to a total of 24 trunks may be configured and
enabled, only a maximum of 16 may be operational at any given time.

For example, if you configure and enable 12 static trunks (the maximum), up to 4
LACP trunks may also be configured and enabled, for a total of 16 operational
trunks. If more than 16 trunks are enabled at any given time, once the switch
establishes the 16th trunk group, any additional trunks are automatically placed in a
non-operational state. In this scenario, there is no administrative means to ensure
which 16 trunks are selected for operation.
Figure 7. Port Trunk Group

Switch 1 Switch 2

Aggregate
Port Trunk

Trunk groups are also useful for connecting a G8124 to third-party devices that
support link aggregation, such as Cisco routers and switches with EtherChannel
technology (not ISL trunking technology) and Sun's Quad Fast Ethernet Adapter.
Trunk Group technology is compatible with these devices when they are configured
manually.

Trunk traffic is statistically distributed among the ports in a trunk group, based on a
variety of configurable options.

Also, since each trunk group is comprised of multiple physical links, the trunk group
is inherently fault tolerant. As long as one connection between the switches is
available, the trunk remains active and statistical load balancing is maintained
whenever a port in a trunk group is lost or returned to service.

110 RackSwitch G8124: Application Guide

Static Trunks
Static Trunk Requirements
When you create and enable a static trunk, the trunk members (switch ports) take
on certain settings necessary for correct operation of the trunking feature.

Before you configure your trunk, you must consider these settings, along with
specific configuration rules, as follows:
1. Read the configuration rules provided in the section, “Static Trunk Group
Configuration Rules” on page 111.
2. Determine which switch ports (up to 12) are to become trunk members (the
specific ports making up the trunk).
3. Ensure that the chosen switch ports are set to enabled. Trunk member ports
must have the same VLAN and Spanning Tree configuration.
4. Consider how the existing Spanning Tree will react to the new trunk
configuration. See Chapter 9, “Spanning Tree Protocols,” for Spanning Tree
Group configuration guidelines.
5. Consider how existing VLANs will be affected by the addition of a trunk.

Static Trunk Group Configuration Rules

The trunking feature operates according to specific configuration rules. When
creating trunks, consider the following rules that determine how a trunk group reacts
in any network topology:
• All trunks must originate from one logical device, and lead to one logical desti-
nation device. Usually, a trunk connects two physical devices together with mul-
tiple links. However, in some networks, a single logical device may include
multiple physical devices or when using VLAGs (see “Virtual Link Aggregation
Groups” on page 139). In such cases, links in a trunk are allowed to connect to
multiple physical devices because they act as one logical device.
• Any physical switch port can belong to only one trunk group.
• Trunking from third-party devices must comply with Cisco® EtherChannel® tech-
nology.
• All ports in a trunk must have the same link configuration (speed, duplex, flow
control), the same VLAN properties, and the same Spanning Tree, storm control,
and ACL configuration. It is recommended that the ports in a trunk be members
of the same VLAN.
• Each trunk inherits its port configuration (speed, flow control, tagging) from the
first member port. As additional ports are added to the trunk, their settings must
be changed to match the trunk configuration.
• When a port leaves a trunk, its configuration parameters are retained.
• You cannot configure a trunk member as a monitor port in a port-mirroring con-
figuration.
• Trunks cannot be monitored by a monitor port; however, trunk members can be
monitored.

© Copyright IBM Corp. 2014 Chapter 8: Ports and Trunking 111

Configuring a Static Port Trunk
In the following example, three ports are trunked between two switches.
Figure 8. Port Trunk Group Configuration Example

Trunk 3 Trunk Group 3 combines

2 9 16 Ports 2, 9, and 16

1 11 18 Trunk Group 1 combines

Trunk 1 Ports 1, 11, and 18

Prior to configuring each switch in this example, you must connect to the
appropriate switches as the administrator.
Note: For details about accessing and using any of the commands described in
this example, see the RackSwitch G8124 ISCLI Reference.
1. Follow these steps on the G8124:
a. Define a trunk group.

RS G8124(config)# portchannel 3 port 2,9,16

RS G8124(config)# portchannel 3 enable

b. Verify the configuration.

# show portchannel information

Examine the resulting information. If any settings are incorrect, make

appropriate changes.
2. Repeat the process on the other switch.

RS G8124(config)# portchannel 1 port 1,11,18

RS G8124(config)# portchannel 1 enable

3. Connect the switch ports that will be members in the trunk group.
Trunk group 3 (on the G8124) is now connected to trunk group 1 (on the other
switch).
Note: In this example, two G8124 switches are used. If a third-party device support-
ing link aggregation is used (such as Cisco routers and switches with Ether-
Channel technology or Sun's Quad Fast Ethernet Adapter), trunk groups on
the third-party device must be configured manually. Connection problems
could arise when using automatic trunk group negotiation on the third-party
device.

112 RackSwitch G8124: Application Guide

 4. Examine the trunking information on each switch.

# show portchannel information

PortChannel 3: Enabled
Protocol—Static
port state:
2: STG 1 forwarding
9: STG 1 forwarding
16: STG 1 forwarding

Information about each port in each configured trunk group is displayed. Make
sure that trunk groups consist of the expected ports and that each port is in the
expected state.

The following restrictions apply:

• Any physical switch port can belong to only one trunk group.
• Up to 12 ports can belong to the same trunk group.
• All ports in static trunks must be have the same link configuration (speed, duplex,
flow control).
• Trunking from third-party devices must comply with Cisco® EtherChannel®
technology.

© Copyright IBM Corp. 2014 Chapter 8: Ports and Trunking 113

Link Aggregation Control Protocol
Link Aggregation Control Protocol (LACP) is an IEEE 802.3ad standard for grouping
several physical ports into one logical port (known as a dynamic trunk group or Link
Aggregation group) with any device that supports the standard. Please refer to IEEE
802.3ad-2002 for a full description of the standard.

The 802.3ad standard allows standard Ethernet links to form a single Layer 2 link
using the Link Aggregation Control Protocol (LACP). Link aggregation is a method
of grouping physical link segments of the same media type and speed in full duplex,
and treating them as if they were part of a single, logical link segment. If a link in a
LACP trunk group fails, traffic is reassigned dynamically to the remaining link(s) of
the dynamic trunk group.
Note: LACP implementation in the IBM Networking OS does not support the Churn
machine, an option used to detect if the port is operable within a bounded
time period between the actor and the partner. Only the Marker Responder is
implemented, and there is no marker protocol generator.

A port’s Link Aggregation Identifier (LAG ID) determines how the port can be
aggregated. The Link Aggregation ID (LAG ID) is constructed mainly from the
partner switch’s system ID and the port’s admin key, as follows:
• System ID: an integer value based on the partner switch’s MAC address and the
system priority assigned in the CLI.
• Admin key: a port’s Admin key is an integer value (1-65535) that you can
configure in the CLI. Each switch port that participates in the same LACP trunk
group must have the same admin key value. The Admin key is local significant,
which means the partner switch does not need to use the same Admin key value.

For example, consider two switches, an Actor (the G8124) and a Partner (another
switch), as shown in Table 14.
Table 14. Actor vs. Partner LACP configuration

Actor Switch Partner Switch

Port 7 (admin key = 100) Port 1 (admin key = 50) Primary trunk group

Port 8 (admin key = 100) Port 2 (admin key = 50) Primary trunk group

Port 9 (admin key = 100) Port 3 (admin key = 70) Secondary trunk group

Port 10 (admin key = 100) Port 4 (admin key = 70) Secondary trunk group

In the configuration shown in Table 14, Actor switch ports 7 and 8 aggregate to form
an LACP trunk group with Partner switch ports 1 and 2. Only ports with the same
LAG ID are aggregated in the trunk group. Actor switch ports 9 and 10 are not
aggregated in the same trunk group, because although they have the same admin
key on the Actor switch, their LAG IDs are different (due to a different Partner switch
admin key configuration). Instead, they form a secondary trunk group with Partner
switch ports 3 and 4.

LACP automatically determines which member links can be aggregated and then
aggregates them. It provides for the controlled addition and removal of physical links
for the link aggregation.

114 RackSwitch G8124: Application Guide

Static LACP Trunks
To prevent switch ports with the same admin key from forming multiple trunk groups,
you can configure the LACP trunk as static. In a static LACP trunk, ports with the
same admin key, but with different LAG IDs, compete to get aggregated in a trunk
group. The LAG ID for the trunk group is decided based on the first port that is
aggregated in the group. Ports with this LAG ID get aggregated and the other ports
are placed in suspended mode. As per the configuration shown in Table 14 on
page 114, if port 7 gets aggregated first, then the LAG ID of port 7 would be the LAG
ID of the trunk. Port 8 will join the trunk while ports 9 and 10 would be placed in
suspended mode. When in suspended mode, a port transmits only LACP data units
(LACPDUs) and discards all other traffic.

A port may also be placed in suspended mode for the following reasons:
• When LACP is configured on the port but it stops receiving LACPDUs from the
partner switch.
• When the port has a different LAG ID because of the partner switch MAC or port
LACP key being different. For example: when a switch is connected to two
partners.

Static LACP trunks are configured by associating the LACP admin key to a
portchannel ID within a dedicated LACP portchannel group range:

RS G8124(config)# portchannel <13-36> lacp key <adminkey of the LAG>

LACP Port Modes

Each port on the switch can have one of the following LACP modes.
• off (default)
The user can configure this port in to a regular static trunk group.
• active
The port is capable of forming an LACP trunk. This port sends LACPDU packets
to partner system ports.
• passive
The port is capable of forming an LACP trunk. This port only responds to the
LACPDU packets sent from an LACP active port.

Each active LACP port transmits LACP data units (LACPDUs), while each passive
LACP port listens for LACPDUs. During LACP negotiation, the admin key is
exchanged. The LACP trunk group is enabled as long as the information matches at
both ends of the link. If the admin key value changes for a port at either end of the
link, that port’s association with the LACP trunk group is lost.

When the system is initialized, all ports by default are in LACP off mode and are
assigned unique admin keys. To make a group of ports aggregatable, you assign
them all the same admin key. You must set the port’s LACP mode to active to
activate LACP negotiation. You can set other port’s LACP mode to passive, to
reduce the amount of LACPDU traffic at the initial trunk-forming stage.

Use the following command to check whether the ports are trunked:

RS G8124 # show lacp information

© Copyright IBM Corp. 2014 Chapter 8: Ports and Trunking 115

LACP Individual
Ports with LACP enabled (active or passive) are prevented by default from forming
individual links if they cannot join an LACP trunk group. To override this behavior,
use the following commands:

RS G8124(config) # interface port <port no. or range>

RS G8124(config-if) # no lacp suspend-individual

This allows the selected ports to be treated as normal link-up ports, which may
forward data traffic according to STP, Hot Links or other applications, if they do not
receive any LACPDUs.

To configure the LACP individual setting for all the ports in a static LACP trunk, use
the following commands:

RS G8124(config)# interface portchannel lacp <adminkey of the LAG>

RS G8124(config-PortChannel)# [no] lacp suspend-individual

LACP Minimum Links Option

For dynamic trunks that require a guaranteed amount of bandwidth in order to be
considered useful, you can specify the minimum number of links for the trunk. If the
specified minimum number of ports is not available, the trunk link will not be
established. If an active LACP trunk loses one or more component links, the trunk
will be placed in the down state if the number of links falls to less than the specified
minimum. By default, the minimum number of links is 1, meaning that LACP trunks
will remain operational as long as at least one link is available.

The LACP minimum links setting can be configured as follows:

• Via interface configuration mode:

RS G8124(config)# interface port <port number or range>

RS G8124(config-if)# port-channel min-links <minimum links>
RS G8124(config-if)# exit

• Or via portchannel configuration mode:

RS G8124(config)# interface portchannel lacp <LACP key>

RS G8124(config-PortChannel)# port-channel min-links <minimum links>
RS G8124(config-if)# exit

116 RackSwitch G8124: Application Guide

Configuring LACP
Use the following procedure to configure LACP for ports 7, 8, 9 and 10 to participate
in link aggregation.
1. Configure port parameters. All ports that participate in the LACP trunk group
must have the same settings, including VLAN membership.
2. Select the port range and define the admin key. Only ports with the same admin
key can form an LACP trunk group.

RS G8124(config)# interface port 7-10

RS G8124(config-if)# lacp key 100

3. Set the LACP mode.

RS G8124(config-if)# lacp mode active

4. Optionally allow member ports to individually participate in normal data traffic if

no LACPDUs are received.

RS G8124(config-if)# no lacp suspend-individual

RS G8124(config-if)# exit

5. Set the link aggregation as static, by associating it with trunk ID 13:

RS G8124(config)# portchannel 13 lacp key 100

© Copyright IBM Corp. 2014 Chapter 8: Ports and Trunking 117

Configurable Trunk Hash Algorithm
Traffic in a trunk group is statistically distributed among member ports using a hash
process where various address and attribute bits from each transmitted frame are
recombined to specify the particular trunk port the frame will use.

The switch can be configured to use a variety of hashing options. To achieve the
most even traffic distribution, select options that exhibit a wide range of values for
your particular network. Avoid hashing on information that is not usually present in
the expected traffic, or which does not vary.

The G8124 supports the following hashing options:

• Layer 2 source MAC address

RS G8124(config)# portchannel hash source-mac-address

• Layer 2 destination MAC address

RS G8124(config)# portchannel hash destination-mac-address

• Layer 2 source and destination MAC address

RS G8124(config)# portchannel hash source-destination-mac

• Layer 3 IPv4/IPv6 source IP address

RS G8124(config)# portchannel hash source-ip-address

• Layer 3 IPv4/IPv6 destination IP address

RS G8124(config)# portchannel hash destination-ip-address

• Layer 3 source and destination IPv4/IPv6 address (the default)

RS G8124(config)# portchannel hash source-destination-ip

Note: Layer 3 hashing options (source IP address and destination IP address)

enabled either for port trunk hashing or for ECMP route hashing
(ip route ecmphash) apply to both the trunking and ECMP features (the
enabled settings are cumulative). If trunk hashing behavior is not as
expected, disable any unwanted options set in ECMP route hashing.
Likewise, if ECMP route hashing behavior is not as expected, disable any
unwanted options enabled in trunk hashing.

118 RackSwitch G8124: Application Guide

Chapter 9. Spanning Tree Protocols
When multiple paths exist between two points on a network, Spanning Tree Protocol
(STP), or one of its enhanced variants, can prevent broadcast loops and ensure that
the RackSwitch G8124 (G8124) uses only the most efficient network path.

This chapter covers the following topics:

• “Spanning Tree Protocol Modes” on page 119
• “Global STP Control” on page 120
• “PVRST Mode” on page 120
• “Rapid Spanning Tree Protocol” on page 132
• “Multiple Spanning Tree Protocol” on page 134
• “Port Type and Link Type” on page 138

Spanning Tree Protocol Modes

IBM Networking OS 7.11 supports the following STP modes:
• Rapid Spanning Tree Protocol (RSTP)
IEEE 802.1D (2004) RSTP allows devices to detect and eliminate logical loops
in a bridged or switched network. When multiple paths exist, STP configures the
network so that only the most efficient path is used. If that path fails, STP
automatically configures the best alternative active path on the network to
sustain network operations. RSTP is an enhanced version of IEEE 802.1D
(1998) STP, providing more rapid convergence of the Spanning Tree network
path states on STG 1.
See “Rapid Spanning Tree Protocol” on page 132 for details.
• Per-VLAN Rapid Spanning Tree (PVRST)
PVRST mode is based on RSTP to provide rapid Spanning Tree convergence,
but supports instances of Spanning Tree, allowing one STG per VLAN. PVRST
mode is compatible with Cisco R-PVST/R-PVST+ mode.
PVRST is the default Spanning Tree mode on the G8124. See “PVRST Mode”
on page 120 for details.
• Multiple Spanning Tree Protocol (MSTP)
IEEE 802.1Q (2003) MSTP provides both rapid convergence and load balancing
in a VLAN environment. MSTP allows multiple STGs, with multiple VLANs in
each.
See “Multiple Spanning Tree Protocol” on page 134 for details.

© Copyright IBM Corp. 2014 119

Global STP Control
By default, the Spanning Tree feature is globally enabled on the switch, and is set
for PVRST mode. Spanning Tree (and thus any currently configured STP mode) can
be globally disabled using the following command:

RS G8124(config)# spanning-tree mode disable

Spanning Tree can be re-enabled by specifying the STP mode:

RS G8124(config)# spanning-tree mode {pvrst|rstp|mst}

where the command options represent the following modes:

• rstp: RSTP mode
• pvrst: PVRST mode
• mst: MSTP mode

PVRST Mode
Note: Per-VLAN Rapid Spanning Tree (PVRST) is enabled by default on the
G8124.

Using STP, network devices detect and eliminate logical loops in a bridged or
switched network. When multiple paths exist, Spanning Tree configures the network
so that a switch uses only the most efficient path. If that path fails, Spanning Tree
automatically sets up another active path on the network to sustain network
operations.

N/OS PVRST mode is based on IEEE 802.1w RSTP. Like RSTP, PVRST mode
provides rapid Spanning Tree convergence. However, PVRST mode is enhanced
for multiple instances of Spanning Tree. In PVRST mode, each VLAN may be
automatically or manually assigned to one of 127 available STGs. Each STG acts
as an independent, simultaneous instance of STP. PVRST uses IEEE 802.1Q
tagging to differentiate STP BPDUs and is compatible with Cisco R-PVST/R-PVST+
modes.

The relationship between ports, trunk groups, VLANs, and Spanning Trees is shown
in Table 15.
Table 15. Ports, Trunk Groups, and VLANs

Switch Element Belongs To

Port Trunk group or one or more VLANs

Trunk group One or more VLANs

VLAN (non-default) • PVRST: One VLAN per STG

• RSTP: All VLANs are in STG 1
• MSTP: Multiple VLANs per STG

120 RackSwitch G8124: Application Guide

Port States
The port state controls the forwarding and learning processes of Spanning Tree. In
PVRST, the port state has been consolidated to the following: discarding,
learning, and forwarding.

Due to the sequence involved in these STP states, considerable delays may occur
while paths are being resolved. To mitigate delays, ports defined as edge ports
(“Port Type and Link Type” on page 138) may bypass the discarding and
learning states, and enter directly into the forwarding state.

Bridge Protocol Data Units

To create a Spanning Tree, the switch generates a configuration Bridge Protocol
Data Unit (BPDU), which it then forwards out of its ports. All switches in the Layer 2
network participating in the Spanning Tree gather information about other switches
in the network through an exchange of BPDUs.

A bridge sends BPDU packets at a configurable regular interval (2 seconds by

default). The BPDU is used to establish a path, much like a hello packet in IP
routing. BPDUs contain information about the transmitting bridge and its ports,
including bridge MAC addresses, bridge priority, port priority, and path cost. If the
ports are in trunk mode/tagged, each port sends out a special BPDU containing the
tagged information.

The generic action of a switch on receiving a BPDU is to compare the received

BPDU to its own BPDU that it will transmit. If the priority of the received BPDU is
better than its own priority, it will replace its BPDU with the received BPDU. Then,
the switch adds its own bridge ID number and increments the path cost of the
BPDU. The switch uses this information to block any necessary ports.
Note: If STP is globally disabled, BPDUs from external devices will transit the
switch transparently. If STP is globally enabled, for ports where STP is
turned off, inbound BPDUs will instead be discarded.

Determining the Path for Forwarding BPDUs

When determining which port to use for forwarding and which port to block, the
G8124 uses information in the BPDU, including each bridge ID. A technique based
on the “lowest root cost” is then computed to determine the most efficient path for
forwarding.

Bridge Priority

The bridge priority parameter controls which bridge on the network is the STG root
bridge. To make one switch become the root bridge, configure the bridge priority lower
than all other switches and bridges on your network. The lower the value, the higher
the bridge priority. Use the following command to configure the bridge priority:

RS G8124(config)# spanning-tree stp <STG number or range> bridge priority <0-65535>

© Copyright IBM Corp. 2014 Chapter 9: Spanning Tree Protocols 121

 Port Priority

The port priority helps determine which bridge port becomes the root port or the
designated port. The case for the root port is when two switches are connected using
a minimum of two links with the same path-cost. The case for the designated port is in
a network topology that has multiple bridge ports with the same path-cost connected
to a single segment, the port with the lowest port priority becomes the designated port
for the segment. Use the following command to configure the port priority:

RS G8124(config-if)# spanning-tree stp <STG number or range> priority <port priority>

where priority value is a number from 0 to 240, in increments of 16 (such as 0, 16,

32, and so on). If the specified priority value is not evenly divisible by 16, the value
will be automatically rounded down to the nearest valid increment whenever
manually changed in the configuration, or whenever a configuration file from a
release prior to N/OS 6.5 is loaded.

Root Guard

The root guard feature provides a way to enforce the root bridge placement in the
network. It keeps a new device from becoming root and thereby forcing STP
re-convergence. If a root-guard enabled port detects a root device, that port will be
placed in a blocked state.

You can configure the root guard at the port level using the following commands:

RS G8124(config)# interface port <port number>

RS G8124(config-if)# spanning-tree guard root

The default state is “none”, i.e. disabled.

Loop Guard

In general, STP resolves redundant network topologies into loop-free topologies.

The loop guard feature performs additional checking to detect loops that might not
be found using Spanning Tree. STP loop guard ensures that a non-designated port
does not become a designated port.

To globally enable loop guard, enter the following command:

RS G8124(config)# spanning-tree loopguard

Note: The global loop guard command will be effective on a port only if the
port-level loop guard command is set to default as shown below:
RS G8124(config)# interface port <port number>
RS G8124(config-if)# no spanning-tree guard

To enable loop guard at the port level, enter the following command:

RS G8124(config)# interface port <port number>

RS G8124(config-if)# spanning-tree guard loop

The default state is “none”, i.e. disabled.

122 RackSwitch G8124: Application Guide

 Port Path Cost

The port path cost assigns lower values to high-bandwidth ports, such as 10 Gigabit
Ethernet, to encourage their use. The objective is to use the fastest links so that the
route with the lowest cost is chosen. A value of 0 (the default) indicates that the
default cost will be computed for an auto-negotiated link or trunk speed.

Use the following command to modify the port path cost:

RS G8124(config)# interface port <port number>

RS G8124(config-if)# spanning-tree stp <STG number or range> path-cost <path cost value>
RS G8124(config-if)# exit

The port path cost can be a value from 1 to 200000000. Specify 0 for automatic path
cost.

Simple STP Configuration

Figure 9 depicts a simple topology using a switch-to-switch link between two G8124
1 and 2.
Figure 9. Spanning Tree Blocking a Switch-to-Switch Link

Enterprise
Routing
Switches

Switch 1 x Switch 2
STP
Blocks Link

Server Server Server Server

To prevent a network loop among the switches, STP must block one of the links
between them. In this case, it is desired that STP block the link between the IBM
switches, and not one of the G8124 uplinks or the Enterprise switch trunk.

During operation, if one G8124 experiences an uplink failure, STP will activate the
IBM switch-to-switch link so that server traffic on the affected G8124 may pass
through to the active uplink on the other G8124, as shown in Figure 10.

© Copyright IBM Corp. 2014 Chapter 9: Spanning Tree Protocols 123

 Figure 10. Spanning Tree Restoring the Switch-to-Switch Link

Enterprise
Routing Uplink
Switches Failure

Switch 1 Switch 2
STP
Restores Link

Server Server Server Server

In this example, port 10 on each G8124 is used for the switch-to-switch link. To
ensure that the G8124 switch-to-switch link is blocked during normal operation, the
port path cost is set to a higher value than other paths in the network. To configure
the port path cost on the switch-to-switch links in this example, use the following
commands on each G8124.
RS G8124(config)# interface port 10
RS G8124(config-if)# spanning-tree stp 1 path-cost 60000
RS G8124(config-if)# exit

124 RackSwitch G8124: Application Guide

Per-VLAN Spanning Tree Groups
PVRST mode supports a maximum of 127 STGs, with each STG acting as an
independent, simultaneous instance of STP.

Multiple STGs provide multiple data paths which can be used for load-balancing and
redundancy. To enable load balancing between two G8124s using multiple STGs,
configure each path with a different VLAN and then assign each VLAN to a separate
STG. Since each STG is independent, they each send their own IEEE 802.1Q
tagged Bridge Protocol Data Units (BPDUs).

Each STG behaves as a bridge group and forms a loop-free topology. The default
STG 1 may contain multiple VLANs (typically until they can be assigned to another
STG). STGs 2-127 may contain only one VLAN each.

Using Multiple STGs to Eliminate False Loops

Figure 11 shows a simple example of why multiple STGs are needed. In the figure,
two ports on a G8124 are connected to two ports on an application switch. Each of
the links is configured for a different VLAN, preventing a network loop. However, in
the first network, since a single instance of Spanning Tree is running on all the ports
of the G8124, a physical loop is assumed to exist, and one of the VLANs is blocked,
impacting connectivity even though no actual loop exists.
Figure 11. Using Multiple Instances of Spanning Tree Group

Switch 1 Switch 2
VLAN 30
VLAN 1

STG 1 STG 2
False x
Loop VLAN 1 VLAN 30
is active is active

Application Switch Application Switch

With a single Spanning Tree, Using multiple STGs,

one link becomes blocked. both links may be active.

In the second network, the problem of improper link blocking is resolved when the
VLANs are placed into different Spanning Tree Groups (STGs). Since each STG
has its own independent instance of Spanning Tree, each STG is responsible only
for the loops within its own VLAN. This eliminates the false loop, and allows both
VLANs to forward packets between the switches at the same time.

© Copyright IBM Corp. 2014 Chapter 9: Spanning Tree Protocols 125

 VLANs and STG Assignment
In PVRST mode, up to 128 STGs are supported. Ports cannot be added directly to
an STG. Instead, ports must be added as members of a VLAN, and the VLAN must
then be assigned to the STG.

STG 1 is the default STG. Although VLANs can be added to or deleted from default
STG 1, the STG itself cannot be deleted from the system. By default, STG 1 is
enabled and includes VLAN 1, which by default includes all switch ports (except for
management VLANs and management ports).

STG 128 is reserved for switch management. By default, STG 128 is disabled, but
includes management VLAN 4095 and the management ports (MGMT-A and
MGMT-B).

By default, all other STGs (STG 2 through 127) are enabled, though they initially
include no member VLANs. VLANs must be assigned to STGs. By default, this is
done automatically using VLAN Automatic STG Assignment (VASA), though it can
also be done manually (see “Manually Assigning STGs” on page 127.

When VASA is enabled (as by default), each time a new VLAN is configured, the
switch will automatically assign that new VLAN to its own STG. Conversely, when a
VLAN is deleted, if its STG is not associated with any other VLAN, the STG is
returned to the available pool.

The specific STG number to which the VLAN is assigned is based on the VLAN
number itself. For low VLAN numbers (1 through 127), the switch will attempt to
assign the VLAN to its matching STG number. For higher numbered VLANs, the
STG assignment is based on a simple modulus calculation; the attempted STG
number will “wrap around,” starting back at the top of STG list each time the end of
the list is reached. However, if the attempted STG is already in use, the switch will
select the next available STG. If an empty STG is not available when creating a new
VLAN, the VLAN is automatically assigned to default STG 1.

If ports are tagged, each tagged port sends out a special BPDU containing the
tagged information. Also, when a tagged port belongs to more than one STG, the
egress BPDUs are tagged to distinguish the BPDUs of one STG from those of
another STG.

VASA is enabled by default, but can be disabled or re-enabled using the following
commands:

RS G8124(config)# [no] spanning-tree stg-auto

If VASA is disabled, when you create a new VLAN, that VLAN automatically belongs
to default STG 1. To place the VLAN in a different STG, assign it manually.

VASA applies only to PVRST mode and is ignored in RSTP and MSTP modes.

126 RackSwitch G8124: Application Guide

 Manually Assigning STGs
The administrator may manually assign VLANs to specific STGs, whether or not
VASA is enabled.
1. If no VLANs exist (other than default VLAN 1), see “Guidelines for Creating
VLANs” on page 127 for information about creating VLANs and assigning ports
to them.
2. Assign the VLAN to an STG using one of the following methods:
– From the global configuration mode:

RS G8124(config)# spanning-tree stp <STG numbers> vlan <VLANs>

– Or from within the VLAN configuration mode:

RS G8124(config)# vlan <VLAN numbers>

RS G8124(config-vlan)# stg <STG number>
RS G8124(config-vlan)# exit

When a VLAN is assigned to a new STG, the VLAN is automatically removed from
its prior STG.
Note: For proper operation with switches that use Cisco PVST+, it is
recommended that you create a separate STG for each VLAN.

Guidelines for Creating VLANs

Follow these guidelines when creating VLANs:
• When you create a new VLAN, if VASA is enabled (the default), that VLAN is
automatically assigned its own STG. If VASA is disabled, the VLAN automatically
belongs to STG 1, the default STG. To place the VLAN in a different STG, see
“Manually Assigning STGs” on page 127. The VLAN is automatically removed
from its old STG before being placed into the new STG.
• Each VLANs must be contained within a single STG; a VLAN cannot span
multiple STGs. By confining VLANs within a single STG, you avoid problems with
Spanning Tree blocking ports and causing a loss of connectivity within the VLAN.
When a VLAN spans multiple switches, it is recommended that the VLAN remain
within the same STG (be assigned the same STG ID) across all the switches.
• If ports are tagged, all trunked ports can belong to multiple STGs.
• A port cannot be directly added to an STG. The port must first be added to a
VLAN, and that VLAN added to the desired STG.

Rules for VLAN Tagged/Trunk Mode Ports

The following rules apply to VLAN tagged ports:
• Tagged/trunk mode ports can belong to more than one STG, but
untagged/access mode ports can belong to only one STG.
• When a tagged/trunk mode port belongs to more than one STG, the egress
BPDUs are tagged to distinguish the BPDUs of one STG from those of another
STG.

© Copyright IBM Corp. 2014 Chapter 9: Spanning Tree Protocols 127

 Adding and Removing Ports from STGs
The following rules apply when you add ports to or remove ports from STGs:
• When you add a port to a VLAN that belongs to an STG, the port is also added to
that STG. However, if the port you are adding is an untagged port and is already
a member of another STG, that port will be removed from its current STG and
added to the new STG. An untagged port cannot belong to more than one STG.
For example: Assume that VLAN 1 belongs to STG 1, and that port 1 is
untagged and does not belong to any STG. When you add port 1 to VLAN 1, port
1 will automatically become part of STG 1.
However, if port 5 is untagged and is a member of VLAN 3 in STG 2, then adding
port 5 to VLAN 1 in STG 1 will change the port PVID from 3 to 1:

"Port 5 is an UNTAGGED/Access Mode port and its PVID/Native-VLAN changed from 3

to 1.

• When you remove a port from VLAN that belongs to an STG, that port will also be
removed from the STG. However, if that port belongs to another VLAN in the
same STG, the port remains in the STG.
As an example, assume that port 2 belongs to only VLAN 2, and that VLAN 2
belongs to STG 2. When you remove port 2 from VLAN 2, the port is moved to
default VLAN 1 and is removed from STG 2.
However, if port 2 belongs to both VLAN 1 and VLAN 2, and both VLANs belong
to STG 2, removing port 2 from VLAN 2 does not remove port 2 from STG 2,
because the port is still a member of VLAN 1, which is still a member of STG 2.
• An STG cannot be deleted, only disabled. If you disable the STG while it still
contains VLAN members, Spanning Tree will be off on all ports belonging to that
VLAN.

The relationship between port, trunk groups, VLANs, and Spanning Trees is shown
in Table 15 on page 120.

128 RackSwitch G8124: Application Guide

 The Switch-Centric Model
PVRST is switch-centric: STGs are enforced only on the switch where they are
configured. PVRST allows only one VLAN per STG, except for the default STG 1 to
which multiple VLANs can be assigned. The STG ID is not transmitted in the
Spanning Tree BPDU. Each Spanning Tree decision is based entirely on the
configuration of the particular switch.

For example, in Figure 12, each switch is responsible for the proper configuration of
its own ports, VLANs, and STGs. Switch A identifies its own port 17 as part of VLAN
2 on STG 2, and the Switch B identifies its own port 8 as part of VLAN 2 on STG 2.
Figure 12. Implementing Multiple Spanning Tree Groups

Chassis Application
Switch A Switch B

STG 2
17 8
VLAN 2
18 2 1

STG 3
VLAN 3 STG 1
VLAN 1
8 2 1
1 8

Application Application
Switch C Switch D

The VLAN participation for each Spanning Tree Group in Figure 12 on page 129 is
as follows:
• VLAN 1 Participation
Assuming Switch B to be the root bridge, Switch B transmits the BPDU for STG
1 on ports 1 and 2. Switch C receives the BPDU on port 2, and Switch D receives
the BPDU on port 1. Because there is a network loop between the switches in
VLAN 1, either Switch D will block port 8 or Switch C will block port 1, depending
on the information provided in the BPDU.
• VLAN 2 Participation
Switch B, the root bridge, generates a BPDU for STG 2 from port 8. Switch A
receives this BPDU on port 17, which is assigned to VLAN 2, STG 2. Because
switch B has no additional ports participating in STG 2, this BPDU is not
forwarded to any additional ports and Switch B remains the designated root.
• VLAN 3 Participation
For VLAN 3, Switch A or Switch C may be the root bridge. If Switch A is the root
bridge for VLAN 3, STG 3, then Switch A transmits the BPDU from port 18.
Switch C receives this BPDU on port 8 and is identified as participating in VLAN
3, STG 3. Since Switch C has no additional ports participating in STG 3, this
BPDU is not forwarded to any additional ports and Switch A remains the
designated root.

© Copyright IBM Corp. 2014 Chapter 9: Spanning Tree Protocols 129

Configuring Multiple STGs
This configuration shows how to configure the three instances of STGs on the
switches A, B, C, and D illustrated in Figure 12 on page 129.

Because VASA is enabled by default, each new VLAN is automatically assigned its
own STG.
1. Set the Spanning Tree mode on each switch to PVRST.

RS G8124(config)# spanning-tree mode pvrst

Note: PVRST is the default mode on the G8124. This step is not required unless
the STP mode has been previously changed, and is shown here merely as
an example of manual configuration.
2. Configure the following on Switch A:
Enable VLAN 2 and VLAN 3.

RS G8124(config)# vlan 2
RS G8124(config-vlan)# exit
RS G8124(config)# vlan 3
RS G8124(config-vlan)# exit

If VASA is disabled, enter the following commands:

RS G8124(config)# spanning-tree stp 2 vlan 2
RS G8124(config)# spanning-tree stp 3 vlan 3

Add port 17 to VLAN 2, port 18 to VLAN 3.

RS G8124(config)# interface port 17

RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 2
RS G8124(config-if)# exit

RS G8124(config)# interface port 18

RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 3
RS G8124(config-if)# exit

VLAN 2 and VLAN 3 are removed from STG 1.

Note: In PVRST mode, each instance of STG is enabled by default.

130 RackSwitch G8124: Application Guide

 3. Configure the following on Switch B:
Add port 8 to VLAN 2. Ports 1 and 2 are by default in VLAN 1 assigned to STG 1.

RS G8124(config)# vlan 2
RS G8124(config-vlan)# exit
RS G8124(config)# interface port 8
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 2
RS G8124(config-if)# exit

If VASA is disabled, enter the following command:

RS G8124(config)# spanning-tree stp 2 vlan 2

VLAN 2 is automatically removed from STG 1. By default VLAN 1 remains in

STG 1.
4. Configure the following on application switch C:
Add port 8 to VLAN 3. Ports 1 and 2 are by default in VLAN 1 assigned to STG 1.

RS G8124(config)# vlan 3
RS G8124(config-vlan)# exit
RS G8124(config)# interface port 8
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 3
RS G8124(config-if)# exit

If VASA is disabled, enter the following command:

RS G8124(config)# spanning-tree stp 3 vlan 3

VLAN 3 is automatically removed from STG 1. By default VLAN 1 remains in

STG 1.
5. Switch D does not require any special configuration for multiple Spanning
Trees. Switch D uses default STG 1 only.

© Copyright IBM Corp. 2014 Chapter 9: Spanning Tree Protocols 131

Rapid Spanning Tree Protocol
RSTP provides rapid convergence of the Spanning Tree and provides the fast
re-configuration critical for networks carrying delay-sensitive traffic such as voice
and video. RSTP significantly reduces the time to reconfigure the active topology of
the network when changes occur to the physical topology or its configuration
parameters. RSTP reduces the bridged-LAN topology to a single Spanning Tree.

RSTP was originally defined in IEEE 802.1w (2001) and was later incorporated into
IEEE 802.1D (2004), superseding the original STP standard.

RSTP parameters apply only to Spanning Tree Group (STG) 1. The PVRST mode
STGs 2-128 are not used when the switch is placed in RSTP mode.

RSTP is compatible with devices that run IEEE 802.1D (1998) Spanning Tree
Protocol. If the switch detects IEEE 802.1D (1998) BPDUs, it responds with IEEE
802.1D (1998)-compatible data units. RSTP is not compatible with Per-VLAN Rapid
Spanning Tree (PVRST) protocol.

Port States
RSTP port state controls are the same as for PVRST: discarding, learning,
and forwarding.

Due to the sequence involved in these STP states, considerable delays may occur
while paths are being resolved. To mitigate delays, ports defined as edge/portfast
ports (“Port Type and Link Type” on page 138) may bypass the discarding and
learning states, and enter directly into the forwarding state.

RSTP Configuration Guidelines

This section provides important information about configuring RSTP. When RSTP is
turned on, the following occurs:
• STP parameters apply only to STG 1.
• Only STG 1 is available. All other STGs are turned off.
• All VLANs, including management VLANs, are moved to STG 1.

132 RackSwitch G8124: Application Guide

RSTP Configuration Example
This section provides steps to configure RSTP.
1. Configure port and VLAN membership on the switch.
2. Set the Spanning Tree mode to Rapid Spanning Tree.
RS G8124(config)# spanning-tree mode rstp

3. Configure RSTP parameters.

RS G8124(config)# spanning-tree stp 1 bridge priority 8192
RS G8124(config)# spanning-tree stp 1 bridge hello-time 5
RS G8124(config)# spanning-tree stp 1 bridge forward-delay 20
RS G8124(config)# spanning-tree stp 1 bridge maximum-age 30
RS G8124(config)# no spanning-tree stp 1 enable

4. Configure port parameters:

RS G8124(config)# interface port 3
RS G8124(config-if)# spanning-tree stp 1 priority 240
RS G8124(config-if)# spanning-tree stp 1 path-cost 500
RS G8124(config-if)# no spanning-tree stp 1 enable
RS G8124(config-if)# exit

© Copyright IBM Corp. 2014 Chapter 9: Spanning Tree Protocols 133

Multiple Spanning Tree Protocol
Multiple Spanning Tree Protocol (MSTP) extends Rapid Spanning Tree Protocol
(RSTP), allowing multiple Spanning Tree Groups (STGs) which may each include
multiple VLANs. MSTP was originally defined in IEEE 802.1s (2002) and was later
included in IEEE 802.1Q (2003).

In MSTP mode, the G8124 supports up to 32 instances of Spanning Tree,

corresponding to STGs 1-32, with each STG acting as an independent,
simultaneous instance of RSTP.

MSTP allows frames assigned to different VLANs to follow separate paths, with
each path based on an independent Spanning Tree instance. This approach
provides multiple forwarding paths for data traffic, thereby enabling load-balancing,
and reducing the number of Spanning Tree instances required to support a large
number of VLANs.

Due to Spanning Tree’s sequence of discarding, learning, and forwarding, lengthy

delays may occur while paths are being resolved. Ports defined as edge/portfast
ports (“Port Type and Link Type” on page 138) bypass the Discarding and Learning
states, and enter directly into the Forwarding state.
Note: In MSTP mode, Spanning Tree for the management ports is turned off by
default.

MSTP Region
A group of interconnected bridges that share the same attributes is called an MST
region. Each bridge within the region must share the following attributes:
• Alphanumeric name
• Revision number
• VLAN-to STG mapping scheme

MSTP provides rapid re-configuration, scalability and control due to the support of
regions, and multiple Spanning-Tree instances support within each region.

Common Internal Spanning Tree

The Common Internal Spanning Tree (CIST) or MST0 provides a common form of
Spanning Tree Protocol, with one Spanning-Tree instance that can be used
throughout the MSTP region. CIST allows the switch to interoperate with legacy
equipment, including devices that run IEEE 802.1D (1998) STP.

CIST allows the MSTP region to act as a virtual bridge to other bridges outside of
the region, and provides a single Spanning-Tree instance to interact with them.

CIST port configuration includes Hello time, path-cost, and interface priority. These
parameters do not affect Spanning Tree Groups 1-32. They apply only when the
CIST is used.

134 RackSwitch G8124: Application Guide

MSTP Configuration Guidelines
This section provides important information about configuring Multiple Spanning
Tree Groups:
• When MSTP is turned on, the switch moves VLAN 1 and VLANs 33-128 to the
CIST. When MSTP is turned off, the switch moves VLAN 1 and VLANs 33-128
from the CIST to STG 1.
• When you enable MSTP, you must configure the Region Name. A default
revision number of 1 is configured automatically.
• Each bridge in the region must have the same name, revision number, and VLAN
mapping.

MSTP Configuration Examples

Example 1

This section provides steps to configure MSTP on the G8124.

1. Configure port and VLAN membership on the switch.
2. Configure Multiple Spanning Tree region parameters, and set the mode to
MSTP.

RS G8124(config)# spanning-tree mst configuration (Enter MST configuration mode)

RS G8124(config-mst)# name <name> (Define the Region name)
RS G8124(config-mst)# revision <0 – 65535> (Define the Region revision number)
RS G8124(config-mst)# exit
RS G8124(config)# spanning-tree mode mst (Set mode to Multiple Spanning Trees)

3. Map VLANs to MSTP instances:

RS G8124(config)# spanning-tree mst configuration (Enter MST configuration mode)

RS G8124(config-mst)# instance <instance ID> vlan <vlan number or range>

© Copyright IBM Corp. 2014 Chapter 9: Spanning Tree Protocols 135

 Example 2

This configuration shows how to configure MSTP Groups on the switch, as shown in
Figure 12.
Figure 13. Implementing Multiple Spanning Tree Groups

Enterprise Enterprise
Routing Switch Routing Switch
MSTP Group 1 MSTP Group 2
Root Root

Passing VLAN 1 Blocking VLAN 1

Blocking VLAN 2 Passing VLAN 2

Server 1 Server 2 Server 3 Server 4

VLAN 1 VLAN 1 VLAN 2 VLAN 2

This example shows how multiple Spanning Trees can provide redundancy without
wasting any uplink ports. In this example, the server ports are split between two
separate VLANs. Both VLANs belong to two different MSTP groups. The Spanning
Tree priority values are configured so that each routing switch is the root for a
different MSTP instance. All of the uplinks are active, with each uplink port backing
up the other.
1. Configure port membership and define the STGs for VLAN 1. Enable tagging
on uplink ports that share VLANs. Port 19 and port 20 connect to the Enterprise
Routing switches.

RS G8124(config)# interface port 19, 20

RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# exit

2. Configure MSTP: Spanning Tree mode, region name, and version.

RS G8124(config)# spanning-tree mst configuration

RS G8124(config-mst)# name MyRegion (Define the Region name)
RS G8124(config-mst)# revision 100 (Define the Revision level)
RS G8124(config-mst)# exit
RS G8124(config)# spanning-tree mode mst (Set mode to Multiple Spanning Trees)

136 RackSwitch G8124: Application Guide

 3. Map VLANs to MSTP instances:

RS G8124(config)# spanning-tree mst configuration

RS G8124(config-mst)# instance 1 vlan 1
RS G8124(config-mst)# instance 2 vlan 2

4. Configure port membership and define the STGs for VLAN 2. Add server
ports 3, 4, and 5 to VLAN 2. Add uplink ports 19 and 20 to VLAN 2. Assign
VLAN 2 to STG 2.
RS G8124(config)# interface port 3,4,5,19,20
RS G8124(config-if)# switchport access vlan 2
RS G8124(config-if)# exit

Note: Each STG is enabled by default.

© Copyright IBM Corp. 2014 Chapter 9: Spanning Tree Protocols 137

Port Type and Link Type
Edge/Portfast Port
A port that does not connect to a bridge is called an edge port. Since edge ports are
assumed to be connected to non-STP devices (such as directly to hosts or servers),
they are placed in the forwarding state as soon as the link is up.

Edge ports send BPDUs to upstream STP devices like normal STP ports, but do not
receive BPDUs. If a port with edge enabled does receive a BPDU, it immediately
begins working as a normal (non-edge) port, and participates fully in Spanning Tree.

Use the following commands to define or clear a port as an edge port:

RS G8124(config)# interface port <port>
RS G8124(config-if)# [no] spanning-tree portfast
RS G8124(config-if)# exit

Link Type
The link type determines how the port behaves in regard to Rapid Spanning Tree.
Use the following commands to define the link type for the port:
RS G8124(config)# interface port <port>
RS G8124(config-if)# [no] spanning-tree link-type <type>
RS G8124(config-if)# exit

where type corresponds to the duplex mode of the port, as follows:

• p2p A full-duplex link to another device (point-to-point)
• shared A half-duplex link is a shared segment and can contain more than
one device.
• auto The switch dynamically configures the link type.
Note: Any STP port in full-duplex mode can be manually configured as a shared
port when connected to a non-STP-aware shared device (such as a typical
Layer 2 switch) used to interconnect multiple STP-aware devices.

138 RackSwitch G8124: Application Guide

Chapter 10. Virtual Link Aggregation Groups
In many data center environments, downstream servers or switches connect to
upstream devices which consolidate traffic. For example, see Figure 14.
Figure 14. Typical Data Center Switching Layers with STP vs. VLAG

ISL
Aggregation VLAG
Layer Peers

STP blocks Links remain

implicit loops VLAGs
active
Access
Layer

Servers

As shown in the example, a switch in the access layer may be connected to more
than one switch in the aggregation layer to provide for network redundancy.
Typically, Spanning Tree Protocol (RSTP, PVRST, or MSTP—see “Spanning Tree
Protocols” on page 119) is used to prevent broadcast loops, blocking redundant
uplink paths. This has the unwanted consequence of reducing the available
bandwidth between the layers by as much as 50%. In addition, STP may be slow to
resolve topology changes that occur during a link failure, and can result in
considerable MAC address flooding.

Using Virtual Link Aggregation Groups (VLAGs), the redundant uplinks remain
active, utilizing all available bandwidth.

Two switches are paired into VLAG peers, and act as a single virtual entity for the
purpose of establishing a multi-port trunk. Ports from both peers can be grouped
into a VLAG and connected to the same LAG-capable target device. From the
perspective of the target device, the ports connected to the VLAG peers appear to
be a single trunk connecting to a single logical device. The target device uses the
configured Tier ID to identify the VLAG peers as this single logical device. It is
important that you use a unique Tier ID for each VLAG pair you configure. The
VLAG-capable switches synchronize their logical view of the access layer port
structure and internally prevent implicit loops. The VLAG topology also responds
more quickly to link failure and does not result in unnecessary MAC flooding.

VLAGs are also useful in multi-layer environments for both uplink and downlink
redundancy to any regular LAG-capable device. For example:

© Copyright IBM Corp. 2014 139

 Figure 15. VLAG Application with Multiple Layers

Layer 2/3 Border LACP-capable

Routers
Trunk Trunk
VLAG 5 VLAG 6
Layer 2 Region ISL
with multiple levels VLAG
Peers C

VLAG 3 Trunk
VLAG 3 VLAG 4

ISL ISL
VLAG VLAG
Peers A Peers B
VLAG 1 VLAG 2
Trunk Trunk
LACP-capable
Switch
LACP-capable
Server
Servers

Wherever ports from both peered switches are trunked to another device, the
trunked ports must be configured as a VLAG. For example, VLAGs 1 and 3 must be
configured for both VLAG Peer A switches. VLAGs 2 and 4 must be configured for
both VLAG Peer B switches.VLAGs 3, 5, and 6 must be configured on both VLAG
Peer C switches. Other devices connecting to the VLAG peers are configured using
regular static or dynamic trunks.
Note: Do not configure a VLAG for connecting only one switch in the peer set to
another device or peer set. For instance, in VLAG Peer C, a regular trunk is
employed for the downlink connection to VLAG Peer B because only one of
the VLAG Peer C switches is involved.

140 RackSwitch G8124: Application Guide

 In addition, when used with VRRP, VLAGs can provide seamless active-active
failover for network links. For example
Figure 16. VLAG Application with VRRP:

VLAG
ISL Peers
VRRP VRRP
VLAG
Master Backup

Server Active
Traffic Flows

VLAG Capacities
Servers or switches that connect to the VLAG peers using a multi-port VLAG are
considered VLAG clients. VLAG clients are not required to be VLAG-capable. The
ports participating in the VLAG are configured as regular port trunks on the VLAG
client end.

On the VLAG peers, the VLAGs are configured similarly to regular port trunks, using
many of the same features and rules. See “Ports and Trunking” on page 109 for
general information concerning all port trunks.

Each VLAG begins as a regular port trunk on each VLAG-peer switch. The VLAG
may be either a static trunk group (portchannel) or dynamic LACP trunk group, and
consumes one slot from the overall port trunk capacity pool. The trunk type must
match that used on VLAG client devices. Additional configuration is then required to
implement the VLAG on both VLAG peer switches.

You may configure up to 12 trunk groups on the switch, with all types (regular or
VLAG, static or LACP) sharing the same pool.

The maximum number of configurable VLAG instances is as follows:

• With STP off: Maximum of 15 VLAG instances
• With STP on:
– PVRST/MSTP with one VLAG instance per VLAN/STG: Maximum of 15
VLAG instances
– PVRST/MSTP with one VLAG instance belonging to multiple
VLANs/STGs: Maximum of 10 VLAG instances

Each trunk type can contain up to 12 member ports, depending on the port type and
availability.

© Copyright IBM Corp. 2014 Chapter 10: Virtual Link Aggregation Groups 141
VLAGs versus Port Trunks
Though similar to regular port trunks in many regards, VLAGs differ from regular
port trunks in a number of important ways:
• A VLAG can consist of multiple ports on two VLAG peers, which are connected to
one logical client device such as a server, switch, or another VLAG device.
• The participating ports on the client device are configured as a regular port trunk.
• The VLAG peers must be the same model, and run the same software version.
• VLAG peers require a dedicated inter-switch link (ISL) for synchronization. The
ports used to create the ISL must have the following properties:
– ISL ports must have VLAN tagging turned on.
– ISL ports must be configured for all VLAG VLANs.
– ISL ports must be placed into a regular port trunk group (dynamic or static).
– A minimum of two ports on each switch are recommended for ISL use.
• Dynamic routing protocols, such as OSPF, cannot terminate on VLAGs.
• Routing over VLAGs is not supported. However, IP forwarding between subnets
served by VLAGs can be accomplished using VRRP.
• VLAGs are configured using additional commands.
• It is recommended that end-devices connected to VLAG switches use NICs with
dual-homing. This increases traffic efficiency, reduces ISL load, and provides
faster link failover.

142 RackSwitch G8124: Application Guide

Configuring VLAGs
When configuring VLAG or making changes to your VLAG configuration, consider
the following VLAG behavior:
• When adding a static Mrouter on VLAG links, ensure that you also add it on the
ISL link to avoid VLAG link failure. If the VLAG link fails, traffic cannot be
recovered through the ISL. Also ensure you add the same static entry on the
peer VLAG switch for VLAG ports.
• If you have enabled VLAG on the switch, and you need to change the STP mode,
ensure that you first disable VLAG and then change the STP mode.
• When VLAG is enabled, you may see two root ports on the secondary VLAG
switch. One of these will be the actual root port for the secondary VLAG switch
and the other will be a root port synced with the primary VLAG switch.
• The LACP key used must be unique for each VLAG in the entire topology.
• The STG to VLAN mapping on both VLAG peers must be identical.

The following parameters must be identically configured on the VLAG ports of both
the VLAG peers:
• VLANs
• Native VLAN tagging
• Native VLAN/PVID
• STP mode
• BPDU Guard setting
• STP port setting
• MAC aging timers
• Static MAC entries
• ACL configuration parameters
• QoS configuration parameters

© Copyright IBM Corp. 2014 Chapter 10: Virtual Link Aggregation Groups 143
Basic VLAG Configuration
Figure 17 shows an example configuration where two VLAG peers are used for
aggregating traffic from downstream devices.
Figure 17. Basic VLAGs

ISL
VLAG Peer 1 1 2 VLAG Peer 2
Mgmt IP: 10.10.10.1/24 2 3 Mgmt IP: 10.10.10.2/24
8 9
LACP 200 7 8

VLAG 1 VLAG 2
LACP 1000 LACP 2000
VLAN 100 VLAN 100

Client Switch Client Switch

In this example, each client switch is connected to both VLAG peers. On each client
switch, the ports connecting to the VLAG peers are configured as a dynamic LACP
port trunk. The VLAG peer switches share a dedicated ISL for synchronizing VLAG
information. On the individual VLAG peers, each port leading to a specific client
switch (and part of the client switch’s port trunk) is configured as a VLAG.

In the following example configuration, only the configuration for VLAG 1 on VLAG
Peer 1 is shown. VLAG Peer 2 and all other VLAGs are configured in a similar
fashion.

Configure the ISL

Before changing the STP mode to MSTP, ensure you have the same region name,
revision and VLAN to STG mapping on both VLAG switches.

The ISL connecting the VLAG peers is shared by all their VLAGs. The ISL needs to
be configured only once on each VLAG peer.
1. Configure STP if required. Use PVRST or MSTP mode only:

RS G8124(config)# spanning-tree mode pvrst

2. Configure the ISL ports and place them into a port trunk group:

RS G8124(config)# interface port 1-2

RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# lacp key 200
RS G8124(config-if)# exit
RS G8124(config)# vlag isl adminkey 200

144 RackSwitch G8124: Application Guide

 Note: In this case, a dynamic trunk group is shown. A static trunk (portchannel)
could be configured instead.
3. Configure VLAG Tier ID. This is used to identify the VLAG switch in a multi-tier
environment.

RS G8124(config)# vlag tier-id 10

4. Configure the ISL for the VLAG peer.

Make sure you configure the VLAG peer (VLAG Peer 2) using the same ISL
trunk type (dynamic or static), the same VLAN for VLAG and VLAG ISL ports,
and the same STP mode and tier ID used on VLAG Peer 1.
5. Enable VLAG globally.

RS G8124(config)# vlag enable

Configure the VLAG

1. Configure the VLAN for VLAG 1. Make sure members include the ISL and
VLAG 1 ports.

RS G8124(config)# vlan 100

RS G8124(config-vlan)# exit
RS G8124(config)# interface port 1-2,8
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 100
RS G8124(config-if)# exit

Note: In MSTP mode, VLANs are automatically mapped to CIST.

2. Place the VLAG 1 port(s) in a port trunk group:

RS G8124(config)# interface port 8

RS G8124(config-if)# lacp mode active
RS G8124(config-if)# lacp key 1000
RS G8124(config-if)# exit

3. Assign the trunk to the VLAG:

RS G8124(config)# vlag adminkey 1000 enable

4. Continue by configuring all required VLAGs on VLAG Peer 1, and then repeat
the configuration for VLAG Peer 2.
For each corresponding VLAG on the peer, the port trunk type (dynamic or
static), VLAN, and STP mode and ID must be the same as on VLAG Peer 1.
5. Verify the completed configuration:

# show vlag information

© Copyright IBM Corp. 2014 Chapter 10: Virtual Link Aggregation Groups 145
 VLAG Configuration - VLANs Mapped to MSTI
Follow the steps below to configure VLAG in environments where the VLANs are
mapped to Multiple Spanning Tree Instance (MSTI).

Configure the ISL

Before changing the STP mode to MSTP, ensure you have the same region name,
revision and VLAN to STG mapping on both VLAG switches.

The ISL connecting the VLAG peers is shared by all their VLAGs. The ISL needs to
be configured only once on each VLAG peer.
1. Configure STP:

RS G8124(config)# spanning-tree mode mst

2. Configure the ISL ports and place them into a port trunk group:

RS G8124(config)# interface port 1-2

RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# lacp key 200
RS G8124(config-if)# exit
RS G8124(config)# vlag isl adminkey 200

Note: In this case, a dynamic trunk group is shown. A static trunk (portchannel)
could be configured instead.
3. Configure VLAG Tier ID and enable VLAG globally. This is used to identify the
VLAG switch in a multi-tier environment.

RS G8124(config)# vlag tier-id 10

4. Configure the ISL for the VLAG peer.

Make sure you configure the VLAG peer (VLAG Peer 2) using the same ISL
trunk type (dynamic or static), the same VLAN for VLAG and VLAG ISL ports,
and the same STP mode and tier ID used on VLAG Peer 1.
5. Enable VLAG.

RS G8124(config)# vlag enable

146 RackSwitch G8124: Application Guide

 Configure the VLAG
1. Configure the VLAN for VLAG 1.

RS G8124(config)# vlan 100

RS G8124(config-vlan)# exit

Note: The VLAN is automatically mapped to CIST.

2. Shutdown ISL ports and VLAG ports. This ensures that traffic passes through
to other switches.

RS G8124(config)# interface port 1-2,8

RS G8124(config-if)# shutdown

3. Map the VLAN to an MSTI.

RS G8124(config)# spanning-tree mst configuration

RS G8124(config-mst)# instance 1 vlan 100

4. Disable VLAG.

RS G8124(config)# no vlag enable

5. Add VLAG ports to the VLAN.

RS G8124(config)# interface port 1-2,8

RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 100
RS G8124(config-if)# exit

6. Place the VLAG 1 port(s) in a port trunk group:

RS G8124(config)# interface port 8

RS G8124(config-if)# lacp mode active
RS G8124(config-if)# lacp key 1000
RS G8124(config-if)# exit

7. Assign the trunk to the VLAG:

RS G8124(config)# vlag adminkey 1000 enable

8. Continue by configuring all required VLAGs on VLAG Peer 1, and then follow
the steps below for configuring VLAG Peer 2.
9. Configure the VLAN for VLAG 2.

RS G8124(config)# vlan 100

RS G8124(config-vlan)# exit

Note: The VLAN is automatically mapped to CIST.

© Copyright IBM Corp. 2014 Chapter 10: Virtual Link Aggregation Groups 147
 10. Map the VLAN to an MSTI.

RS G8124(config)# spanning-tree mst configuration

RS G8124(config-mst)# instance 1 vlan 100

Note: At this point, traffic may be momentarily disrupted due to STP

recalculation.
11. Disable VLAG.

RS G8124(config)# no vlag enable

Note: At this point, traffic may be momentarily disrupted due to STP

recalculation.
12. Add VLAG ports to the VLAN.

RS G8124(config)# interface port 1-2,8

RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 100
RS G8124(config-if)# exit

13. Enable VLAG.

RS G8124(config)# vlag enable

Note: At this point, traffic may be momentarily disrupted due to STP

recalculation.
On VLAG Peer 1:
14. Enable ISL ports and VLAG ports:

RS G8124(config)# interface port 1-2,8

RS G8124(config-if)# no shutdown

On VLAG Peer2:
15. Place the VLAG 2 port(s) in a port trunk group:

RS G8124(config)# interface port 8

RS G8124(config-if)# lacp mode active
RS G8124(config-if)# lacp key 1000
RS G8124(config-if)# exit

16. Assign the trunk to the VLAG:

RS G8124(config)# vlag adminkey 1000 enable

17. Enable VLAG globally.

RS G8124(config)# vlag enable

18. Verify the completed configuration:

RS G8124# show vlag information

148 RackSwitch G8124: Application Guide

 Configuring Health Check
We strongly recommend that you configure the G8124 to check the health status of
its VLAG peer. Although the operational status of the VLAG peer is generally
determined via the ISL connection, configuring a network health check provides an
alternate means to check peer status in case the ISL links fail. Use an independent
link between the VLAG switches to configure health check.
Note: Configuring health check on an ISL VLAN interface or on a VLAG data port
may impact the accuracy of the health check status.
1. Configure a management interface for the switch.

Note: If the switch does not have a dedicated management interface, configure a
VLAN for the health check interface. The health check interface can be
configured with an IPv4 address:

RS G8124(config)# interface ip 128

RS G8124(config-ip-if)# ip address 10.10.10.1 255.255.255.0
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit

Note: Configure a similar interface on VLAG Peer 2. For example, use IP address
10.10.10.2.
2. Specify the IPv4 or IPv6 address of the VLAG Peer:

RS G8124(config)# vlag hlthchk peer-ip 10.10.10.2

Note: For VLAG Peer 2, the management interface would be configured as

10.10.10.2, and the health check would be configured for 10.10.10.1,
pointing back to VLAG Peer 1.

VLAG supports either IPv4 or IPv6 health check addresses at one time. Configuring
an IPv4 health check address, will set any IPv6 health check address in the VLAG to
0, and vice-versa.

One can still configure an IPv6 health check address in a profile that doesn’t support
IPv6.

The local health check IP address cannot be configured manually. It is automatically

configured within the same subnetwork as the peer’s VLAG health check IP
address.

© Copyright IBM Corp. 2014 Chapter 10: Virtual Link Aggregation Groups 149
VLAGs with VRRP
Note: In a multi-layer environment, configure VRRP separately for each layer. We
recommend that you configure VRRP only on the tier with uplinks. See
“Configuring VLAGs in Multiple Layers” on page 155.

VRRP (see “Virtual Router Redundancy Protocol” on page 383) can be used in
conjunction with VLAGs and LACP-capable devices to provide seamless
redundancy.
Figure 18. Active-Active Configuration using VRRP and VLAGs

VRRP Master
VLAG Peer 1 Server 1
Layer 3
Router VIR: 10.0.1.100 VLAG 1
10.0.1.1
1 10

11
2 Server 2
4 5 12 VLAG 2
Internet ISL 10.0.1.2
4 5 10
1 11 VLAG 3
Server 3
12
2
Layer 3 VRRP Backup 10.0.1.3
Router
VLAG Peer 2
VIR: 10.0.1.100 Network 10.0.1.0/24

Task 1: Configure VLAG Peer 1

Note: Before enabling VLAG, you must configure the VLAG tier ID and ISL
portchannel.
1. Configure VLAG tier ID

RS G8124(config)# vlag tier-id 10

2. Configure appropriate routing.

RS G8124(config)# router ospf

RS G8124(config-router-ospf)# area 1 area-id 0.0.0.1
RS G8124(config-router-ospf)# enable
RS G8124(config-router-ospf)# exit

Although OSPF is used in this example, static routing could also be deployed.
For more information, see “OSPF” on page 333 or “Basic IP Routing” on
page 245.
3. Configure a server-facing interface.

RS G8124(config)# interface ip 3
RS G8124(config-ip-if)# ip address 10.0.1.10 255.255.255.0
RS G8124(config-ip-if)# vlan 100
RS G8124(config-ip-if)# exit

150 RackSwitch G8124: Application Guide

 4. Turn on VRRP and configure the Virtual Interface Router.

RS G8124(config)# router vrrp

RS G8124(config-vrrp)# enable
RS G8124(config-vrrp)# virtual-router 1 virtual-router-id 1
RS G8124(config-vrrp)# virtual-router 1 interface 3
RS G8124(config-vrrp)# virtual-router 1 address 10.0.1.100
RS G8124(config-vrrp)# virtual-router 1 enable

5. Set the priority of Virtual Router 1 to 101, so that it becomes the Master.

RS G8124(config-vrrp)# virtual-router 1 priority 101

RS G8124(config-vrrp)# exit

6. Configure the ISL ports and place them into a port trunk group:

RS G8124(config)# interface port 4-5

RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# lacp key 2000
RS G8124(config-if)# exit

Note: In this case, a dynamic trunk group is shown. A static trunk (portchannel)
could be configured instead.
7. Configure the upstream ports.

RS G8124(config)# interface port 1

RS G8124(config-if)# switchport access vlan 10
RS G8124(config-if)# exit
RS G8124(config)# interface port 2
RS G8124(config-if)# switchport access vlan 20
RS G8124(config-if)# exit

8. Configure the server ports.

RS G8124(config)# interface port 10

RS G8124(config-if)# switchport access vlan 100
RS G8124(config-if)# exit
RS G8124(config)# interface port 11
RS G8124(config-if)# switchport access vlan 100
RS G8124(config-if)# exit
RS G8124(config)# interface port 12
RS G8124(config-if)# switchport access vlan 100
RS G8124(config-if)# exit

© Copyright IBM Corp. 2014 Chapter 10: Virtual Link Aggregation Groups 151
 9. Configure all VLANs including VLANs for the VLAGs.

RS G8124(config)# vlan 10
RS G8124(config-vlan)# exit

RS G8124(config)# vlan 20
RS G8124(config-vlan)# exit

RS G8124(config)# vlan 100

RS G8124(config-vlan)# exit
RS G8124(config)# interface port 4-5
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 100
RS G8124(config-if)# exit

10. Configure Internet-facing interfaces.

RS G8124(config)# interface ip 1
RS G8124(config-ip-if)# ip address 172.1.1.10 255.255.255.0
RS G8124(config-ip-if)# vlan 10
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# ip ospf area 1
RS G8124(config-ip-if)# ip ospf enable
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 2
RS G8124(config-ip-if)# ip address 172.1.3.10 255.255.255.0
RS G8124(config-ip-if)# vlan 20
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# ip ospf area 1
RS G8124(config-ip-if)# ip ospf enable
RS G8124(config-ip-if)# exit

11. Place the VLAG port(s) in their port trunk groups.

RS G8124(config)# interface port 10

RS G8124(config-if)# lacp mode active
RS G8124(config-if)# lacp key 1000
RS G8124(config-if)# exit
RS G8124(config)# interface port 11
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# lacp key 1100
RS G8124(config-if)# exit
RS G8124(config)# interface port 12
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# lacp key 1200
RS G8124(config-if)# exit

12. Assign the trunks to the VLAGs:

RS G8124(config)# vlag adminkey 1000 enable

RS G8124(config)# vlag adminkey 1100 enable
RS G8124(config)# vlag adminkey 1200 enable

13. Globally enable VLAG

RS G8124(config)# vlag enable

14. Verify the completed configuration:

# show vlag information

152 RackSwitch G8124: Application Guide

 Task 2: Configure VLAG Peer 2

The VLAG peer (VLAG Peer 2) must be configured using the same ISL trunk type
(dynamic or static), the same VLAN for VLAG and VLAG ISL ports, and the same
STP mode and Tier ID used on VLAG Switch 1.

For each corresponding VLAG on the peer, the port trunk type (dynamic or static),
VLAN, and STP mode and ID must be the same as on VLAG Switch 1.
1. Configure VLAG tier ID and enable VLAG globally.

RS G8124(config)# vlag tier-id 10

RS G8124(config)# vlag enable

2. Configure appropriate routing.

RS G8124(config)# router ospf

RS G8124(config-router-ospf)# area 1 area-id 0.0.0.1
RS G8124(config-router-ospf)# enable
RS G8124(config-router-ospf)# exit

Although OSPF is used in this example, static routing could also be deployed.
3. Configure a server-facing interface.

RS G8124(config)# interface ip 3
RS G8124(config-ip-if)# ip address 10.0.1.11 255.255.255.0
RS G8124(config-ip-if)# vlan 100
RS G8124(config-ip-if)# exit

4. Turn on VRRP and configure the Virtual Interface Router.

RS G8124(config)# router vrrp

RS G8124(config-vrrp)# enable
RS G8124(config-vrrp)# virtual-router 1 virtual-router-id 1
RS G8124(config-vrrp)# virtual-router 1 interface 3
RS G8124(config-vrrp)# virtual-router 1 address 10.0.1.100
RS G8124(config-vrrp)# virtual-router 1 enable

5. Configure the ISL ports and place them into a port trunk group:

RS G8124(config)# interface port 4-5

RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# lacp key 2000
RS G8124(config-if)# exit

6. Configure the upstream ports.

RS G8124(config)# interface port 1

RS G8124(config-if)# switchport access vlan 30
RS G8124(config-if)# exit
RS G8124(config)# interface port 2
RS G8124(config-if)# switchport access vlan 40
RS G8124(config-if)# exit

© Copyright IBM Corp. 2014 Chapter 10: Virtual Link Aggregation Groups 153
 7. Configure the server ports.

RS G8124(config)# interface port 10

RS G8124(config-if)# switchport access vlan 100
RS G8124(config-if)# exit
RS G8124(config)# interface port 11
RS G8124(config-if)# switchport access vlan 100
RS G8124(config-if)# exit
RS G8124(config)# interface port 12
RS G8124(config-if)# switchport access vlan 100
RS G8124(config-if)# exit

8. Configure all VLANs including VLANs for the VLAGs.

RS G8124(config)# vlan 30
RS G8124(config-vlan)# exit

RS G8124(config)# vlan 40
RS G8124(config-vlan)# exit

RS G8124(config)# vlan 100

RS G8124(config-vlan)# exit
RS G8124(config)# interface port 4-5
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 100
RS G8124(config-if)# exit

9. Configure Internet-facing interfaces.

RS G8124(config)# interface ip 1
RS G8124(config-ip-if)# ip address 172.1.2.11 255.255.255.0
RS G8124(config-ip-if)# vlan 30
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# ip ospf area 1
RS G8124(config-ip-if)# ip ospf enable
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 2
RS G8124(config-ip-if)# ip address 172.1.4.12 255.255.255.0
RS G8124(config-ip-if)# vlan 40
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# ip ospf area 1
RS G8124(config-ip-if)# ip ospf enable
RS G8124(config-ip-if)# exit

10. Place the VLAG port(s) in their port trunk groups.

RS G8124(config)# interface port 10

RS G8124(config-if)# lacp mode active
RS G8124(config-if)# lacp key 1000
RS G8124(config-if)# exit
RS G8124(config)# interface port 11
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# lacp key 1100
RS G8124(config-if)# exit
RS G8124(config)# interface port 12
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# lacp key 1200
RS G8124(config-if)# exit

154 RackSwitch G8124: Application Guide

 11. Assign the trunks to the VLAGs:

RS G8124(config)# vlag adminkey 1000 enable

RS G8124(config)# vlag adminkey 1100 enable
RS G8124(config)# vlag adminkey 1200 enable

12. Verify the completed configuration:

# show vlag information

Configuring VLAGs in Multiple Layers

Figure 19. VLAG in Multiple Layers

Layer 2/3 Border LACP-capable

Routers
Trunk Trunk
VLAG 5 VLAG 6
Layer 2 Region ISL
with multiple levels VLAG
Switch A Switch B Peers C

VLAG 3 Trunk
VLAG 3 VLAG 4

ISL ISL
VLAG VLAG
Peers A Switch C Switch D Switch E Switch F Peers B
VLAG 1 VLAG 2
Trunk Trunk
LACP-capable
Switch G Switch
LACP-capable
Server
Servers

Figure 19 shows an example of VLAG being used in a multi-layer environment.

Following are the configuration steps for the topology.

Task 1: Configure Layer 2/3 border switches.

Configure ports on border switch as follows:

RS G8124(config)# interface port 1,2

RS G8124(config-if)# lacp key 100
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# exit

Repeat the previous steps for the second border switch.

© Copyright IBM Corp. 2014 Chapter 10: Virtual Link Aggregation Groups 155
 Task 2: Configure switches in the Layer 2 region.

Consider the following:

• ISL ports on switches A and B - ports 1, 2
• Ports connecting to Layer 2/3 - ports 5, 6
• Ports on switches A and B connecting to switches C and D: ports 10, 11
• Ports on switch B connecting to switch E: ports 15, 16
• Ports on switch B connecting to switch F: ports 17, 18
1. Configure VLAG tier ID and enable VLAG globally.

RS G8124(config)# vlag tier-id 10

RS G8124(config)# vlag enable

2. Configure ISL ports on Switch A.

RS G8124(config)# interface port 1,2

RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# lacp key 200
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# exit

RS G8124(config)# vlag isl adminkey 200

RS G8124(config-vlan)# exit

3. Configure port on Switch A connecting to Layer 2/3 router 1.

RS G8124(config)# vlan 10
VLAN number 10 with name “VLAN 10” created
VLAN 10 was assigned to STG 10
RS G8124(config-vlan)# exit
RS G8124(config)# interface port 1,2,5
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 10
RS G8124(config-if)# exit

RS G8124(config)# interface port 5

RS G8124(config-if)# lacp key 400
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# exit

RS G8124(config)# vlag adminkey 400 enable

Repeat the previous steps on Switch B for ports connecting to Layer 2/3 router 1.

156 RackSwitch G8124: Application Guide

 4. Configure port on Switch A connecting to Layer 2/3 router 2.

RS G8124(config)# vlan 20
VLAN number 20 with name “VLAN 20” created
VLAN 20 was assigned to STG 20
RS G8124(config-vlan)# exit
RS G8124(config)# interface port 1,2,6
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 20
RS G8124(config-if)# exit

RS G8124(config)# interface port 6

RS G8124(config-if)# lacp key 500
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# exit

RS G8124(config)# vlag adminkey 500 enable

Repeat the previous steps on Switch B for ports connecting to Layer 2/3 router 2.
5. Configure ports on Switch A connecting to downstream VLAG switches C and
D.

RS G8124(config)# vlan 20
RS G8124(config-vlan)# exit
RS G8124(config)# interface port 10,11
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 20
RS G8124(config-if)# lacp key 600
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# exit

RS G8124(config)# vlag adminkey 600 enable

Repeat the above steps on Switch B for ports connecting to downstream VLAG
switch C and D.
6. Configure ports on Switch B connecting to downstream switches E and F.

RS G8124(config)# vlan 30
RS G8124(config-vlan)# exit
RS G8124(config)# interface port 15-18
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 30
RS G8124(config-if)# lacp key 700
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# exit

7. Configure ISL between switches C and D, and between E and F as shown in

Step 1.
8. Configure the Switch G as shown in Step 2.

© Copyright IBM Corp. 2014 Chapter 10: Virtual Link Aggregation Groups 157
VLAG with PIM
Note: This section is applicable only to G8124-E.

Protocol Independent Multicast (PIM) is designed for efficiently routing multicast

traffic across one or more IPv4 domains. PIM is used by multicast source stations,
client receivers, and intermediary routers and switches, to build and maintain
efficient multicast routing trees. PIM is protocol independent; It collects routing
information using the existing unicast routing functions underlying the IPv4 network,
but does not rely on any particular unicast protocol. For PIM to function, a Layer 3
routing protocol (such as BGP, OSPF, RIP, or static routes) must first be configured
on the switch.

IBM Networking OS supports PIM in Sparse Mode (PIM-SM) and Dense Mode
(PIM-DM). For more details on PIM, see Chapter 26, “Protocol Independent
Multicast"” on page 361.

PIM, when configured in a VLAG topology, provides efficient multicast routing along
with redundancy and failover. When the multicast source is located in the core L3
network, only the primary VLAG switch forwards multicast data packets to avoid
duplicate packets reaching the access layer switch. The secondary VLAG switch is
available as backup and forwards packets only when the primary VLAG switch is not
available and during failover. When the multicast source is located in the L2 domain,
behind the VLAG ports, either the primary or the secondary switch will forward the
data traffic to the receiver, based on the shortest path detected by PIM.

See Figure 17 on page 144 for a basic VLAG topology. For PIM to function in a
VLAG topology, the following are required:
• IGMP (v1 or v2) must be configured on the VLAG switches.
• A Layer 3 routing protocol (such as BGP, OSPF, RIP, or static routes) must be
globally enabled and on VLAG-associated IP interfaces for multicast routing.
• The VLAG switches must be connected to upstream multicast routers.
• The Rendezvous Point (RP) and/or the Bootstrap router (BSR) must be
configured on the upstream router.
• Flooding must be disabled on the VLAG switches or in the VLAN associated with
the VLAG ports.
• ISL ports must be members of VLANs that have VLAG ports as members.

For PIM configuration steps and commands, see “PIM Configuration Examples” on
page 370.

Traffic Forwarding
In a VLAG with PIM topology, traffic forwarded by the upstream router is managed
as follows when the multicast source is located in the core L3 network and the
receiver is located in the L2 network:
• If the primary and secondary VLAG ports are up, the primary switch forwards
traffic to the receiver. The secondary switch blocks the traffic. Multicast entries
are created on both the VLAG switches: primary VLAG switch with forward state;
secondary VLAG switch with pruned state.
• If the primary VLAG port fails, the secondary VLAG switch forwards traffic to the
receiver. Multicast entries are created on both the VLAG switches: primary VLAG
switch with forward state; secondary VLAG switch with VLAG pruned state.

158 RackSwitch G8124: Application Guide

 • If the secondary VLAG port fails, the primary VLAG switch forwards traffic to the
receiver. Multicast entries are created on both the VLAG switches: primary VLAG
switch with forward state; secondary VLAG switch with pruned state.
• If the primary VLAG switch is down, the secondary VLAG switch forwards traffic
to the receiver. When the primary VLAG switch boots up again, it becomes the
secondary VLAG switch and blocks traffic to the receiver. The VLAG switch that
was secondary initially becomes the primary and continues forwarding traffic to
the receiver.
• If the secondary VLAG switch is down, the primary VLAG switch forwards traffic
to the receiver. When the secondary VLAG switch is up, it blocks traffic. The
primary switch forwards traffic to the receiver.
• If the uplink to the primary VLAG switch is down, the secondary VLAG switch
forwards traffic to the receiver and to the primary VLAG switch over the ISL. The
primary VLAG switch blocks traffic to the receiver so the receiver does not get
double traffic. Both the VLAG switches will have multicast entries in forward
state.
• If the uplink to the secondary VLAG switch is down, the primary VLAG switch
forwards traffic to the receiver and to the secondary VLAG switch over the ISL.
The secondary VLAG switch blocks traffic to the receiver so the receiver does
not get double traffic. Both the VLAG switches will have multicast entries in the
forward state.

When the multicast source is connected to VLAG ports (layer 2 domain), traffic
forwarded by the VLAG routers is managed as follows:
• IPMC traffic from the access switch can be hashed to any of the VLAG switches.
Consequently, both the primary and secondary VLAG switches must synchronize
the (S,G) entries for faster failover.
• The Rendezvous Point sends (S,G) entries to either the primary or secondary
VLAG switch, depending on which provides the shortest path to the source.
However, Register-Stop messages are only sent to the primary VLAG switch.
Based on the shortest path, one of the VLAG switches will forward traffic for a
particular (S,G) entry to the receiver.
• For the VLAG multi-tier topology, an additional L3 backup path to ISL is
supported. On the L3 backup interface, both L3 routing protocols and PIM must
be enabled.

Health Check
In a VLAG with PIM topology, you must configure health check. See “Configuring
Health Check” on page 149.

When health check is configured, and the ISL is down, the primary VLAG switch
forwards traffic to the receiver. The secondary VLAG switch ports will be errdisable
state and will block traffic to the receiver.

© Copyright IBM Corp. 2014 Chapter 10: Virtual Link Aggregation Groups 159
160 RackSwitch G8124: Application Guide
Chapter 11. Quality of Service
Quality of Service features allow you to allocate network resources to
mission-critical applications at the expense of applications that are less sensitive to
such factors as time delays or network congestion. You can configure your network
to prioritize specific types of traffic, ensuring that each type receives the appropriate
Quality of Service (QoS) level.

The following topics are discussed in this section:

• “QoS Overview” on page 162
• “Using ACL Filters” on page 163
• “Using DSCP Values to Provide QoS” on page 166
• “Using 802.1p Priority to Provide QoS” on page 171
• “Queuing and Scheduling” on page 172

© Copyright IBM Corp. 2014 161

QoS Overview
QoS helps you allocate guaranteed bandwidth to the critical applications, and limit
bandwidth for less critical applications. Applications such as video and voice must
have a certain amount of bandwidth to work correctly; using QoS, you can provide
that bandwidth when necessary. Also, you can put a high priority on applications
that are sensitive to timing out or that cannot tolerate delay, by assigning their traffic
to a high-priority queue.

By assigning QoS levels to traffic flows on your network, you can ensure that
network resources are allocated where they are needed most. QoS features allow
you to prioritize network traffic, thereby providing better service for selected
applications.

Figure 20 shows the basic QoS model used by the switch.

Figure 20. QoS Model
Ingress Ports Classify Perform Queue and Egress
Packets Actions Schedule

ACL Permit/Deny COS

Filter Queue

The basic QoS model works as follows:

• Classify traffic:
– Read DSCP value.
– Read 802.1p priority value.
– Match ACL filter parameters.
• Perform actions:
– Define bandwidth and burst parameters
– Select actions to perform on in-profile and out-of-profile traffic
– Deny packets
– Permit packets
– Mark DSCP or 802.1p Priority
– Set COS queue (with or without re-marking)
• Queue and schedule traffic:
– Place packets in one of the COS queues.
– Schedule transmission based on the COS queue.

162 RackSwitch G8124: Application Guide

Using ACL Filters
Access Control Lists (ACLs) are filters that allow you to classify and segment traffic,
so you can provide different levels of service to different traffic types. Each filter
defines the conditions that must match for inclusion in the filter, and also the actions
that are performed when a match is made.

IBM Networking OS 7.11 supports up to 127 ACLs when the switch is operating in
the Balanced deployment mode (see “Deployment Profiles” on page 175). ACL
menus and commands are not available in the Routing deployment mode.

The G8124 allows you to classify packets based on various parameters. For
example:
• Ethernet: source MAC, destination MAC, VLAN number/mask, Ethernet type,
priority.
• IPv4: Source IP address/mask, destination address/mask, type of service, IP
protocol number.
• TCP/UPD: Source port, destination port, TCP flag.
• Packet format

For ACL details, see “Access Control Lists” on page 79.

Summary of ACL Actions

Actions determine how the traffic is treated. The G8124 QoS actions include the
following:
• Pass or Drop
• Re-mark a new DiffServ Code Point (DSCP)
• Re-mark the 802.1p field
• Set the COS queue

© Copyright IBM Corp. 2014 Chapter 11: Quality of Service 163

ACL Metering and Re-Marking
You can define a profile for the aggregate traffic flowing through the G8124 by
configuring a QoS meter (if desired) and assigning ACLs to ports. When you add
ACLs to a port, make sure they are ordered correctly in terms of precedence.

Actions taken by an ACL are called In-Profile actions. You can configure additional
In-Profile and Out-of-Profile actions on a port. Data traffic can be metered, and
re-marked to ensure that the traffic flow provides certain levels of service in terms of
bandwidth for different types of network traffic.

Metering

QoS metering provides different levels of service to data streams through

user-configurable parameters. A meter is used to measure the traffic stream against
a traffic profile, which you create. Thus, creating meters yields In-Profile and
Out-of-Profile traffic for each ACL, as follows:
• In-Profile–If there is no meter configured or if the packet conforms to the meter,
the packet is classified as In-Profile.
• Out-of-Profile–If a meter is configured and the packet does not conform to the
meter (exceeds the committed rate or maximum burst rate of the meter), the
packet is classified as Out-of-Profile.

Using meters, you set a Committed Rate in Kbps (multiples of 64 Mbps). All traffic
within this Committed Rate is In-Profile. Additionally, you set a Maximum Burst Size
that specifies an allowed data burst larger than the Committed Rate for a brief
period. These parameters define the In-Profile traffic.

Meters keep the sorted packets within certain parameters. You can configure a
meter on an ACL, and perform actions on metered traffic, such as packet
re-marking.

164 RackSwitch G8124: Application Guide

 Re-Marking

Re-marking allows for the treatment of packets to be reset based on new network
specifications or desired levels of service. You can configure the ACL to re-mark a
packet as follows:
• Change the DSCP value of a packet, used to specify the service level traffic
receives.
• Change the 802.1p priority of a packet.

The following example includes steps to configure a meter and out-of-profile DSCP
remarking:
1. Create an ACL.

RS G8124(config)# access-control list 2 tcp-udp destination-port 80

2. Configure the meter with a committed rate.

RS G8124(config)# access-control list 2 meter committed-rate 10000000

RS G8124(config)# access-control list 2 meter enable

3. Set out-of-profile action to re-mark DSCP value based on the global DSCP
mapping. The DSCP remarking value is global for all ACLs that have DSCP
re-marking enabled.

RS G8124(config)# access-control list out-profile dscp 5 mkdn-dscp 0

4. Enable DSCP re-marking for the ACL.

RS G8124(config)# access-control list 2 re-mark out-profile dscp enable

© Copyright IBM Corp. 2014 Chapter 11: Quality of Service 165

Using DSCP Values to Provide QoS
The switch uses the Differentiated Services (DiffServ) architecture to provide QoS
functions. DiffServ is described in IETF RFCs 2474 and 2475.

The six most significant bits in the TOS byte of the IP header are defined as DiffServ
Code Points (DSCP). Packets are marked with a certain value depending on the
type of treatment the packet must receive in the network device. DSCP is a measure
of the Quality of Service (QoS) level of the packet.

The switch can classify traffic by reading the DiffServ Code Point (DSCP) or IEEE
802.1p priority value, or by using filters to match specific criteria. When network traffic
attributes match those specified in a traffic pattern, the policy instructs the switch to
perform specified actions on each packet that passes through it. The packets are
assigned to different Class of Service (COS) queues and scheduled for transmission.

Differentiated Services Concepts

To differentiate between traffic flows, packets can be classified by their DSCP value.
The Differentiated Services (DS) field in the IP header is an octet, and the first six
bits, called the DS Code Point (DSCP), can provide QoS functions. Each packet
carries its own QoS state in the DSCP. There are 64 possible DSCP values (0-63).
Figure 21. Layer 3 IPv4 packet

Version Length ID Offset TTL Proto FCS SIP DIP Data

ToS
Length

Differentiated Services Code Point (DSCP) unused

7 6 5 4 3 2 1 0

The switch can perform the following actions to the DSCP:

• Read the DSCP value of ingress packets.
• Re-mark the DSCP value to a new value
• Map the DSCP value to a Class of Service queue (COSq).

The switch can use the DSCP value to direct traffic prioritization.

With DiffServ, you can establish policies to direct traffic. A policy is a traffic-controlling
mechanism that monitors the characteristics of the traffic, (for example, its source,
destination, and protocol) and performs a controlling action on the traffic when certain
characteristics are matched.

Trusted/Untrusted Ports
By default, all ports on the G8124 are trusted. To configure untrusted ports, re-mark
the DSCP value of the incoming packet to a lower DSCP value using the following
commands:

RS G8124(config)# interface port 1

RS G8124(config-if)# dscp-marking
RS G8124(config-if)# exit
RS G8124(config)# qos dscp dscp-mapping <DSCP value (0-63)> <new value>
RS G8124(config)# qos dscp re-marking

166 RackSwitch G8124: Application Guide

Per Hop Behavior
The DSCP value determines the Per Hop Behavior (PHB) of each packet. The PHB
is the forwarding treatment given to packets at each hop. QoS policies are built by
applying a set of rules to packets, based on the DSCP value, as they hop through
the network.

The default settings are based on the following standard PHBs, as defined in the
IEEE standards:
• Expedited Forwarding (EF)—This PHB has the highest egress priority and
lowest drop precedence level. EF traffic is forwarded ahead of all other traffic. EF
PHB is described in RFC 2598.
• Assured Forwarding (AF)—This PHB contains four service levels, each with a
different drop precedence, as shown in the following table. Routers use drop
precedence to determine which packets to discard last when the network
becomes congested. AF PHB is described in RFC 2597.

Drop Class 1 Class 2 Class 3 Class 4

Precedence

Low AF11 (DSCP 10) AF21 (DSCP 18) AF31 (DSCP 26) AF41 (DSCP 34)

Medium AF12 (DSCP 12) AF22 (DSCP 20) AF32 (DSCP 28) AF42 (DSCP 36)

High AF13 (DSCP 14) AF23 (DSCP 22) AF33 (DSCP 30) AF43 (DSCP 38)

• Class Selector (CS)—This PHB has eight priority classes, with CS7 representing
the highest priority, and CS0 representing the lowest priority, as shown in the
following table. CS PHB is described in RFC 2474.

Priority Class Selector DSCP

Highest CS7 56

CS6 48

CS5 40

CS4 32

CS3 24

CS2 16

CS1 8

Lowest CS0 0

© Copyright IBM Corp. 2014 Chapter 11: Quality of Service 167

QoS Levels
Table 16 shows the default service levels provided by the switch, listed from highest
to lowest importance:
Table 16. Default QoS Service Levels

Service Level Default PHB 802.1p Priority

Critical CS7 7

Network Control CS6 6

Premium EF, CS5 5

Platinum AF41, AF42, AF43, CS4 4

Gold AF31, AF32, AF33, CS3 3

Silver AF21, AF22, AF23, CS2 2

Bronze AF11, AF12, AF13, CS1 1

Standard DF, CS0 0

DSCP Re-Marking and Mapping

The switch can use the DSCP value of ingress packets to re-mark the DSCP to a
new value, and to set an 802.1p priority value. Use the following command to view
the default settings.

RS G8124# show qos dscp

Current DSCP Remarking Configuration: OFF

DSCP New DSCP New 802.1p Prio

-------- -------- ---------------
0 0 0
1 1 0
2 2 0
3 3 0
4 4 0
5 5 0
6 6 0
7 7 0
8 8 1
9 9 0
10 10 1
...
54 54 0
55 55 0
56 56 7
57 57 0
58 58 0
59 59 0
60 60 0
61 61 0
62 62 0
63 63 0

168 RackSwitch G8124: Application Guide

 Use the following command to turn on DSCP re-marking globally:

RS G8124(config)# qos dscp re-marking

Then you must enable DSCP re-marking on any port that you wish to perform this
function (Interface Port mode).
Note: If an ACL meter is configured for DSCP re-marking, the meter function takes
precedence over QoS re-marking.

DSCP Re-Marking Configuration Examples

Example 1

The following example includes the basic steps for re-marking DSCP value and
mapping DSCP value to 802.1p.
1. Turn DSCP re-marking on globally, and define the DSCP-DSCP-802.1p
mapping. You can use the default mapping.

RS G8124(config)# qos dscp re-marking

RS G8124(config)# qos dscp dscp-mapping <DSCP value (0-63)> <new value>
RS G8124(config)# qos dscp dot1p-mapping <DSCP value (0-63)> <802.1p value>

2. Enable DSCP re-marking on a port.

RS G8124(config)# interface port 1

RS G8124(config-if)# qos dscp re-marking
RS G8124(config-if)# exit

Example 2

The following example assigns strict priority to VoIP traffic and a lower priority to all
other traffic.
1. Create an ACL to re-mark DSCP value and COS queue for all VoIP packets.

RS G8124(config)# access-control list 2 tcp-udp source-port 5060 0xffff

RS G8124(config)# access-control list 2 meter committed-rate 10000000
RS G8124(config)# access-control list 2 meter enable
RS G8124(config)# access-control list 2 re-mark in-profile dscp 56
RS G8124(config)# access-control list 2 re-mark dot1p 7
RS G8124(config)# access-control list 2 action permit

2. Create an ACL to set a low priority to all other traffic.

RS G8124(config)# access-control list 3 action set-priority 1

RS G8124(config)# access-control list 3 action permit

3. Apply the ACLs to a port and enable DSCP marking.

RS G8124(config)# interface port 5

RS G8124(config-if)# access-control list 2
RS G8124(config-if)# access-control list 3 ethernet source-mac-address
00:00:00:00:00:00 00:00:00:00:00:00
RS G8124(config-if)# dscp-marking
RS G8124(config-if)# exit

© Copyright IBM Corp. 2014 Chapter 11: Quality of Service 169

 4. Enable DSCP re-marking globally.

RS G8124(config)# qos dscp re-marking

5. Assign the DSCP re-mark value.

RS G8124(config)# qos dscp dscp-mapping 40 9

RS G8124(config)# qos dscp dscp-mapping 46 9

6. Assign strict priority to VoIP COS queue.

RS G8124(config)# qos transmit-queue weight-cos 7 0

7. Map priority value to COS queue for non-VoIP traffic.

RS G8124(config)# qos transmit-queue mapping 1 1

8. Assign weight to the non-VoIP COS queue.

RS G8124(config)# qos transmit-queue weight-cos 1 2

170 RackSwitch G8124: Application Guide

Using 802.1p Priority to Provide QoS
The G8124 provides Quality of Service functions based on the priority bits in a
packet’s VLAN header. (The priority bits are defined by the 802.1p standard within
the IEEE 802.1Q VLAN header.) The 802.1p bits, if present in the packet, specify
the priority to be given to packets during forwarding. Packets with a numerically
higher (non-zero) priority are given forwarding preference over packets with lower
priority value.

The IEEE 802.1p standard uses eight levels of priority (0-7). Priority 7 is assigned to
highest priority network traffic, such as OSPF or RIP routing table updates, priorities
5-6 are assigned to delay-sensitive applications such as voice and video, and lower
priorities are assigned to standard applications. A value of 0 (zero) indicates a “best
effort” traffic prioritization, and this is the default when traffic priority has not been
configured on your network. The switch can filter packets based on the 802.1p
values.
Figure 22. Layer 2 802.1q/802.1p VLAN tagged packet

Preamble SFD DMAC SMAC Tag E Type Data FCS

Priority VLAN Identifier (VID)

7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0

Ingress packets receive a priority value, as follows:

• Tagged packets—switch reads the 802.1p priority in the VLAN tag.
• Untagged packets—switch tags the packet and assigns an 802.1p priority
value, based on the port’s default 802.1p priority.

Egress packets are placed in a COS queue based on the priority value, and
scheduled for transmission based on the COS queue number. Higher COS queue
numbers provide forwarding precedence.

To configure a port’s default 802.1p priority value, use the following commands.

RS G8124(config)# interface port 1

RS G8124(config-if)# dot1p <802.1p value (0-7)>
RS G8124(config-if)# exit

© Copyright IBM Corp. 2014 Chapter 11: Quality of Service 171

Queuing and Scheduling
The G8124 has 8 output Class of Service (COS) queues per port. If CEE is enabled,
this is changed to 3 queues per port and ETS is then used to configure the
scheduling in a manner different than what is described in this section. Each
packet’s 802.1p priority determines its COS queue, except when an ACL action sets
the COS queue of the packet.
Note: When vNIC operations are enabled, the total number of COS queues
available is 4.

You can configure the following attributes for COS queues:

• Map 802.1p priority value to a COS queue
• Define the scheduling weight of each COS queue

You can map 802.1p priority value to a COS queue, as follows:

RS G8124(config)# qos transmit-queue mapping <802.1p priority value (0-7)> <COS queue (0-7)>

To set the COS queue scheduling weight, use the following command.

RS G8124(config)# qos transmit-queue weight-cos <COSq number> <COSq weight (0-15)>

To achieve a balanced bandwidth allocation among the various priority groups,

packets are scheduled according to a weighted deficit round-robin (WDRR)
algorithm. WDRR is aware of packet sizes, which can vary significantly in a CEE
environment, making WDRR more suitable than a regular weighted round-robin
(WRR) method, which selects groups based only on packet counts. In addition,
forwarding precedence is determined by COS queue number, with higher-numberd
queues given higher precedence.
Note: For setting traffic ratios, COSq weight values are internally rounded up to 2,
4, 8, or 16.

172 RackSwitch G8124: Application Guide

Part 4: Advanced
Switching Features

© Copyright IBM Corp. 2014 173

174 RackSwitch G8124: Application Guide
Chapter 12. Deployment Profiles
The IBM Networking OS software for the RackSwitch G8124 can be configured to
operate in different modes for different deployment scenarios. Each deployment
profile sets different capacity levels for basic switch resources, such as the number
of IP routes and ARP entries, to optimize the switch for different types of networks.

This chapter covers the following topics

• “Available Profiles” on page 176
• “Selecting Profiles” on page 177
• “Automatic Configuration Changes” on page 178

© Copyright IBM Corp. 2014 175

Available Profiles
The following deployment profiles are currently available on the G8124:
• Default Profile—This profile is recommended for general network usage. Switch
resources are balanced to provide moderate capacity for IP routes, ARP entries,
ACLs, and VMAPs.
• Aggregation Profile—This special deployment profile emphasizes ARP and
routing. ACLs are unsupported in this mode.
• IPv6 Profile—For extended IPv6 applications.
• Routing Profile—This is a special deployment profile. It is recommended when
additional IP routes are required on the switch. To provide the additional IP
routes, the number of ARP entries is reduced, and the ACL, VMAP, and IGMP
snooping features are unsupported.
• High-Frequency Traders (HFT) Profile—This special deployment profile
emphasizes IPv4 multicast route entries and provides a moderate number of
unicast routes. ARP entries and dynamic routes are reduced, and IPv6,
VMready, DCBX/FCoE features are not supported in this mode.

The properties of each mode are compared in the following table.

Table 17. Deployment Mode Comparison

Capacity, by Mode
Switch
Feature Default Aggregation IPv6 Routing HFT

ACLs 127 Unsupported 127 Unsupported 127

ARP entries 2,048 8,000 2,048 1,000 512

Dynamic 2,684 2,000 2,807 9,000 1024

routes

IGMP Available Unsupported Unsupported 2900

Snooping

VM Policy Available Unsupported Unsupported Unsupported Unsupported

Bandwidth
Control

VMAPs 127 Unsupported Unsupported Unsupported Unsupported

VMready Available Available Unsupported Unsupported Unsupported

Note: Throughout this guide, where feature capacities are listed, values reflect
those of the Default profile only, unless otherwise noted.

176 RackSwitch G8124: Application Guide

Selecting Profiles
To change the deployment profile, the new profile must first be selected, and the
switch must then be rebooted to use the new profile.
Note: Before changing profiles, it is recommended that you save the active switch
configuration to a backup file so that it may be restored later if desired.

The following ISCLI commands are used to change the deployment profile:

RS G8124(config)# boot profile {default|aggregation|ipv6|routing}

(Select deployment profile)
RS G8124(config)# exit (To privileged EXEC mode)
RS G8124# reload (Reboot the switch)

To view the currently selected deployment profile, use the following ISCLI privileged
EXEC command:

RS G8124# show boot

Note: When using a specialized profile, menus and commands are unavailable for
features that are not supported under the profile. Such menus and
commands will be available again only when a supporting profile is used.
Note: Deployment profiles other than those listed in this section should be used
only under the direction of your support personnel.

© Copyright IBM Corp. 2014 Chapter 12: Deployment Profiles 177

Automatic Configuration Changes
IBM N/OS 7.11 configuration blocks and backup files generated under a specific
deployment profile are generally compatible among all other deployment profiles.
However, if commands or capacities configured under a prior profile are not
available using the current profile, the switch will ignore the unsupported
commands. Mutually supported commands will be processed normally between
profiles.

All configuration commands from the prior profile are initially retained when
changing profiles, even though some may be ignored when the switch starts with
new profile. This allows the administrator to change back to the prior deployment
profile with the prior configuration intact if desired. However, once the administrator
saves the configuration under the new profile, all unsupported commands are
immediately cleared. For example, when using the Routing profile, because ACLs
are unsupported in that mode, their settings will be excluded when the configuration
is saved. Then, if returning to the Default profile, it will be necessary to reconfigure
the desired ACLs, or to use the backup configuration.

178 RackSwitch G8124: Application Guide

Chapter 13. Virtualization
Virtualization allows resources to be allocated in a fluid manner based on the logical
needs of the data center, rather than on the strict, physical nature of components.
The following virtualization features are included in IBM Networking OS 7.11 on the
RackSwitch G8124 (G8124):
• Virtual Local Area Networks (VLANs)
VLANs are commonly used to split groups of networks into manageable
broadcast domains, create logical segmentation of workgroups, and to enforce
security policies among logical network segments.
For details on this feature, see “VLANs” on page 95.
• Port trunking
A port trunk pools multiple physical switch ports into a single, high-bandwidth
logical link to other devices. In addition to aggregating capacity, trunks provides
link redundancy.
For details on this feature, see “Ports and Trunking” on page 109.
• Virtual Link Aggregation (VLAGs)
With VLAGs, two switches can act as a single logical device for the purpose of
establishing port trunking. Active trunk links from one device can lead to both
VLAG peer switches, providing enhanced redundancy, including active-active
VRRP configuration.
For details on this feature, see “Virtual Link Aggregation Groups” on page 139
• Virtual Network Interface Card (vNIC) support
Some NICs, such as the Emulex Virtual Fabric Adapter, can virtualize NIC
resources, presenting multiple virtual NICs to the server’s OS or hypervisor.
Each vNIC appears as a regular, independent NIC with some portion of the
physical NIC’s overall bandwidth. IBM N/OS 7.11 supports up to four vNICs over
each server-side switch port.
For details on this feature, see “Virtual NICs” on page 181.
• VMready
The switch’s VMready software makes it virtualization aware. Servers that run
hypervisor software with multiple instances of one or more operating systems
can present each as an independent virtual machine (VM). With VMready, the
switch automatically discovers virtual machines (VMs) connected to switch.
For details on this feature, see “VMready” on page 193.

N/OS virtualization features provide a highly-flexible framework for allocating and

managing switch resources.

© Copyright IBM Corp. 2014 179

180 RackSwitch G8124: Application Guide
Chapter 14. Virtual NICs
A Network Interface Controller (NIC) is a component within a server that allows the
server to be connected to a network. The NIC provides the physical point of
connection, as well as internal software for encoding and decoding network packets.

Virtualizing the NIC helps to resolve issues caused by limited NIC slot availability. By
virtualizing a 10Gbps NIC, its resources can be divided into multiple logical
instances known as virtual NICs (vNICs), Each vNIC appear as a regular,
independent NIC to the server operating system or a hypervisor, with each vNIC
using some portion of the physical NIC’s overall bandwidth.
Figure 23. Virtualizing the NIC for Multiple Virtual Pipes on Each Link

Server
NIC
Physical Switch Switch 1
VNIC NIC Ports Ports
VNIC
VNIC
OS or
10 Gbps Link with
Hypervisor VNIC Multiple Virtual Pipes
Switch 2
VNIC
VNIC
VNIC
VNIC

A G8124 with IBM Networking OS 7.11 supports the Emulex Virtual Fabric Adapter
(VFA) to provide the following vNIC features:
• Up to four vNICs are supported on each server port.
• vNICs can be grouped together, along with regular server ports, uplink ports, or
trunk groups, to define vNIC groups for enforcing communication boundaries.
• In the case of a failure on the uplink ports associated with a vNIC group, the
switch can signal affected vNICs for failover while permitting other vNICs to
continue operation.
• Each vNIC can be independently allocated a symmetric percentage of the
10Gbps bandwidth on the link (from NIC to switch, and from switch to NIC).
• The G8124 can be used as the single point of vNIC configuration as long as the
Emulex NIC is working in IBM Virtual Fabric mode.

The following restrictions apply to vNICs:

• vNICs are not supported simultaneously with VM groups (see “VMready” on
page 193) on the same switch ports.
• vNICs are not supported simultaneously with DCBX (see “Data Center Bridging
Capability Exchange” on page 239) or FCoE (see “Fibre Channel over Ethernet”
on page 218) on the same switch.

By default, vNICs are disabled. As described in the following sections, the

administrator must first define server ports prior to configuring and enabling vNICs
as discussed in the rest of this section.

© Copyright IBM Corp. 2014 181

Defining Server Ports
vNICs are supported only on ports connected to servers. Before you configure
vNICs on a port, the port must first be defined as a server port using the following
command:

RS G8124(config)# system server-ports port <port alias or number>

Ports that are not defined as server ports are considered uplink ports and do not
support vNICs.

Enabling the vNIC Feature

The vNIC feature can be globally enabled using the following command:

RS G8124(config)# vnic enable

Note: When the vNIC feature is enabled, the maximum number of QOS Class of
Service queues available is four.

vNIC IDs
vNIC IDs on the Switch
IBM N/OS 7.11 supports up to four vNICs attached to each server port. Each vNIC is
provided its own independent virtual pipe on the port.

On the switch, each vNIC is identified by its port and vNIC number as follows:
<port number or alias>.<vNIC pipe number (1-4)>

For example:
1.1, 1.2, 1.3, and 1.4 represent the vNICs on port 1.
2.1, 2.2, 2.3, and 2.4 represent the vNICs on port 2, etc.

These vNIC IDs are used when adding vNICs to vNIC groups, and are shown in
some configuration and information displays.

182 RackSwitch G8124: Application Guide

vNIC Interface Names on the Server
When running in virtualization mode, the Emulex Virtual Fabric Adapter presents
eight vNICs to the OS or hypervisor (four for each of the two physical NIC ports).
Each vNIC is identified in the OS or hypervisor with a different vNIC function number
(0-7). vNIC function numbers correlate to vNIC IDs on the switch as follows:
Table 18. vNIC ID Correlation

PCIe NIC vNIC vNIC

Function ID Port Pipe ID

0 0 1 x.1

2 0 2 x.2

4 0 3 x.3

6 0 4 x.4

1 1 1 x.1

3 1 2 x.2

5 1 3 x.3

7 1 4 x.4

In this, the x in the vNIC ID represents the switch port to which the NIC port is
connected.

© Copyright IBM Corp. 2014 Chapter 14: Virtual NICs 183

vNIC Bandwidth Metering
N/OS 7.11 supports bandwidth metering for vNIC traffic. By default, each of the four
vNICs on any given port is allowed an equal share (25%) of NIC capacity when
enabled. However, you may configure the percentage of available switch port
bandwidth permitted to each vNIC.

vNIC bandwidth can be configured as a value from 1 to 100, with each unit
representing 1% (or 100Mbps) of the 10Gbps link. By default, each vNICs enabled
on a port is assigned 25 units (equal to 25% of the link, or 2.5Gbps). When traffic
from the switch to the vNIC reaches its assigned bandwidth limit, the switch will drop
packets egressing to the affected vNIC. Likewise, if traffic from the vNIC to the
switch reaches its limit, the NIC will drop egress of any further packets. When traffic
falls to less than the configured thresholds, traffic resumes at its allowed rate.
Note: Bandwidth metering drops excess packets when configured limits are
reached. Consider using the ETS feature in applications where packet loss
is not desirable (see “Enhanced Transmission Selection” on page 232).

To change the bandwidth allocation, use the following commands:

RS G8124(config)# vnic port <port alias or number> index <vNIC number (1-4)>
RS G8124(vnic-config)# bandwidth <allocated percentage>

Note: vNICs that are disabled are automatically allocated a bandwidth value of 0.

A combined maximum of 100 units can be allocated among vNIC pipes enabled for
any specific port (bandwidth values for disabled pipes are not counted). If more than
100 units are assigned to enabled pipes, an error will be reported when attempting
to apply the configuration.

The bandwidth metering configuration is synchronized between the switch and

vNICs. Once configured on the switch, there is no need to manually configure vNIC
bandwidth metering limits on the NIC as long as it is in IBM Virtual Fabric mode.

184 RackSwitch G8124: Application Guide

vNIC Groups
vNICs can be grouped together, along with uplink ports and trunks, as well as other
ports that were defined as server ports but not connected to vNICs. Each vNIC
group is essentially a separate virtual network within the switch. Elements within a
vNIC group have a common logical function and can communicate with each other,
while elements in different vNIC groups are separated.

N/OS 7.11 supports up to 32 independent vNIC groups.

To enforce group boundaries, each vNIC group is assigned its own unique VLAN.
The vNIC group VLAN ID is placed on all vNIC group packets as an “outer” tag. As
shown in Figure 24, the outer vNIC group VLAN ID is placed on the packet in
addition to any regular VLAN tag assigned by the network, server, or hypervisor.
The outer vNIC group VLAN is used only between the G8124 and the NIC.
Figure 24. Outer and Inner VLAN Tags

vNIC-Capable Server Ports with IBM Switch Ports without

OS/Hypervisor NIC vNICs vNICs
Regular
NIC attached outer Switching uses outer tag; Switch strips
VLAN ID vNIC group VLAN ID Ignores regular VLAN outer tag
Outbound
Packet

Outer tag sets vNIC; Switching uses outer tag; Switch adds outer
NIC strips outer tag Ignores regular VLAN vNIC group VLAN ID
Inbound
Packet

Within the G8124, all Layer 2 switching for packets within a vNIC group is based on
the outer vNIC group VLAN. The G8124 does not consider the regular, inner VLAN
ID (if any) for any VLAN-specific operation.

The outer vNIC group VLAN is removed by the NIC before the packet reaches the
server OS or hypervisor, or by the switch before the packet egresses any switch port
which does not need it for vNIC processing.

The VLAN configured for the vNIC group will be automatically assigned to member
vNICs, ports, and trunks must not be manually configured for those elements.
Note: Once a VLAN is assigned to a vNIC group, that VLAN is used only for vNIC
purposes and is no longer available for configuration. Likewise, any VLAN
configured for regular purposes cannot be configured as a vNIC group
VLAN.

Other vNIC group rules are as follows:

• vNIC groups may have one or more vNIC members. However, any given vNIC
can be a member of only one vNIC group.
• All vNICs on a given port must belong to different vNIC groups.
• All members of a vNIC group must have the same vNIC pipe index. For instance,
1.1 and 2.1 share the same “.1” vNIC pipe index, but 3.2 uses the “.2” vNIC pipe
index and cannot be placed in the same vNIC group.

© Copyright IBM Corp. 2014 Chapter 14: Virtual NICs 185

 • Uplink ports which are part of a trunk may not be individually added to a vNIC
group. Only one individual uplink port or one static trunk (consisting of multiple
uplink ports) may be added to any given vNIC group.
• When a port is added to a vNIC group, flow control is disabled automatically. If
the port is removed from the vNIC group, the flow-control setting remains
disabled.
• For any switch ports or port trunk group connected to regular (non-vNIC)
devices:
– These elements can be placed in only one vNIC group (they cannot be
members of multiple vNIC groups).
– Once added to a vNIC group, the PVID for the element is automatically set to
use the vNIC group VLAN number, and PVID tagging on the element is
automatically disabled.
– By default, STP is disabled on non-server ports or trunk groups added to a
vNIC group. STP cannot be re-enabled on the port.
• Because regular, inner VLAN IDs are ignored by the switch for traffic in vNIC
groups, following rules and restrictions apply:
– The inner VLAN tag may specify any VLAN ID in the full, supported range (1
to 4095) and may even duplicate outer vNIC group VLAN IDs.
– Per-VLAN IGMP snooping is not supported in vNIC groups.
– The inner VLAN tag is not processed in any way in vNIC groups: The inner
tag cannot be stripped or added on egress port, is not used to restrict
multicast traffic, is not matched against ACL filters, and does not influence
Layer 3 switching.
– For vNIC ports on the switch, because the outer vNIC group VLAN is
transparent to the OS/hypervisor and upstream devices, configure VLAN
tagging as normally required (on or off) for the those devices, ignoring any
outer tag.
• Virtual machines (VMs) and other VEs associated with vNICs are automatically
detected by the switch when VMready is enabled (see “VMready” on page 193).
However, vNIC groups are isolated from other switch elements. VEs in vNIC
groups cannot be assigned to VM groups.

186 RackSwitch G8124: Application Guide

vNIC Teaming Failover
For NIC failover in a non-virtualized environment, when a service group’s uplink
ports fail or are disconnected, the switch disables the affected group’s server ports,
causing the server to failover to the backup NIC and switch.

However, in a virtualized environment, disabling the affected server ports would

disrupt all vNIC pipes on those ports, not just those that have lost their uplinks (see
Figure 25).
Figure 25. Regular Failover in a Virtualized Environment

Primary
Switch Virtual Servers
NIC Hypervisor
Pipes VNIC vSwitch
VNIC

X VNIC
Group 1
X VNIC
VNIC
VM 1
Port 1 Port 10 VNIC
VM 2
VNIC
VNIC
VNIC

VNIC vSwitch
VNIC
VNIC
Group 2 X VNIC
VNIC VM 3
VM 4
Port 2 Port 11 VNIC
VNIC
VNIC
VNIC
NIC Hypervisor

Port 1 link failure automatically

disables associated server ports, To Backup
prompting failover on all VMs Switch

To avoid disrupting vNICs that have not lost their uplinks, N/OS 7.11 and the Emulex
Virtual Fabric Adapter provide vNIC-aware failover. When a vNIC group’s uplink
ports fail, the switch cooperates with the affected NIC to prompt failover only on the
appropriate vNICs. This allows the vNICs that are not affected by the failure to
continue without disruption (see Figure 26 on page 188).

© Copyright IBM Corp. 2014 Chapter 14: Virtual NICs 187

 Figure 26. vNIC Failover Solution

Primary Servers
Switch Virtual
NIC Hypervisor
Pipes VNIC vSwitch
VNIC

X VNIC
Group 1
X VNIC
VNIC
VM 1
VM 2
Port 1 Port 10 VNIC
VNIC
VNIC
VNIC

VNIC vSwitch
VNIC
VNIC X VNIC
VNIC VM 3
Group 2 VM 4
Port 2 Port 11 VNIC
VNIC
VNIC
VNIC
NIC Hypervisor

Upon Port 1 link failure, the switch

informs the server hypervisor To Backup
for failover on affected VNICs only Switch

By default, vNIC Teaming Failover is disabled on each vNIC group, but can be
enabled or disabled independently for each vNIC group using the following
commands:

RS G8124(config)# vnic vnicgroup <group number>

RS G8124(vnic-group-config)# failover

188 RackSwitch G8124: Application Guide

vNIC Configuration Example
Basic vNIC Configuration
Consider the following example configuration:
Figure 27. Multiple vNIC Groups

Switch 1 Servers
.1 60% VNIC
.2 40% VNIC
.3 VNIC
Port Port .4 VNIC OS or
11 1 VNIC Hypervisor
VNIC
To Switch 2 VNIC
VNIC Group 1 VNIC
.1 25% VNIC
VLAN 1000 .2 25% VNIC
.3 VNIC
Port Port .4 VNIC OS or
12 2 VNIC Hypervisor
VNIC
To Switch 2 VNIC
VNIC

Port .1 25% VNIC

.2 VNIC
13 .3 VNIC
Port .4 VNIC OS or
3 VNIC Hypervisor
VNIC
To Switch 2 VNIC
VNIC

VNIC Group 2
Port VLAN 1774 Port OS or
14 4 Hypervisor
To Switch 2

Port Port OS or
15 5 Hypervisor
To Switch 2

Figure 27 has the following vNIC network characteristics:

• vNIC group 1 has an outer tag for VLAN 1000. The group is comprised of vNIC
pipes 1.1 and 2.1, switch server port 4 (a non-vNIC port), and uplink port 11.
• vNIC group 2 has an outer tag for VLAN 1774. The group is comprised of vNIC
pipes 1.2, 2.2 and 3.2, switch server port 5, and an uplink trunk of ports 13 and
14.
• vNIC failover is enabled for both vNIC groups.
• vNIC bandwidth on port 1 is set to 60% for vNIC 1 and 40% for vNIC 2.
• Other enabled vNICs (2.1, 2.2, and 3.2) are permitted the default bandwidth of
25% (2.5Gbsp) on their respective ports.
• All remaining vNICs are disabled (by default) and are automatically allocated 0
bandwidth.

© Copyright IBM Corp. 2014 Chapter 14: Virtual NICs 189

 1. Define the server ports.

RS G8124(config)# system server-ports port 1-5

2. Configure the external trunk to be used with vNIC group 2.

RS G8124(config)# portchannel 1 port 13,14

RS G8124(config)# portchannel 1 enable

3. Enable the vNIC feature on the switch.

RS G8124(config)# vnic enable

4. Configure the virtual pipes for the vNICs attached to each server port:

RS G8124(config)# vnic port 1 index 1 (Select vNIC 1 on the port)

RS G8124(vnic-config)# enable (Enable the vNIC pipe)
RS G8124(vnic-config)# bandwidth 60 (Allow 60% egress bandwidth)
RS G8124(vnic-config)# exit
RS G8124(config)# vnic port 1 index 2 (Select vNIC 2 on the port)
RS G8124(vnic-config)# enable (Enable the vNIC pipe)
RS G8124(vnic-config)# bandwidth 40 (Allow 40% egress bandwidth)
RS G8124(vnic-config)# exit

RS G8124(config)# vnic port 2 index 1 (Select vNIC 1 on the port)

RS G8124(vnic-config)# enable (Enable the vNIC pipe)
RS G8124(vnic-config)# exit
RS G8124(config)# vnic port 2 index 2 (Select vNIC 2 on the port)
RS G8124(vnic-config)# enable (Enable the vNIC pipe)
RS G8124(vnic-config)# exit

As a configuration shortcut, vNICs do not have to be explicitly enabled in this

step. When a vNIC is added to the vNIC group (in the next step), the switch will
prompt you to confirm automatically enabling the vNIC if it is not yet enabled
(shown for 3.2).

Note: vNICs are not supported simultaneously on the same switch ports as
VMready.

190 RackSwitch G8124: Application Guide

 5. Add ports, trunks, and virtual pipes to their vNIC groups.

RS G8124(config)# vnic vnicgroup 1 (Select vNIC group)

RS G8124(vnic-group-config)# vlan 1000 (Specify the VLAN)
RS G8124(vnic-group-config)# member 1.1 (Add vNIC pipes to the group)
RS G8124(vnic-group-config)# member 2.1
RS G8124(vnic-group-config)# port 4 (Add non-vNIC port to the group)
RS G8124(vnic-group-config)# port 11 (Add uplink port to the group
RS G8124(vnic-group-config)# failover (Enable vNIC failover for the group)
RS G8124(vnic-group-config)# enable (Enable the vNIC group)
RS G8124(vnic-group-config)# exit

RS G8124(config)# vnic vnicgroup 2

RS G8124(vnic-group-config)# vlan 1774
RS G8124(vnic-group-config)# member 1.2
RS G8124(vnic-group-config)# member 2.2
RS G8124(vnic-group-config)# member 3.2
vNIC 3.2 is not enabled.
Confirm enabling vNIC3.2 [y/n]: y
RS G8124(vnic-group-config)# port 5
RS G8124(vnic-group-config)# trunk 1
RS G8124(vnic-group-config)# failover
RS G8124(vnic-group-config)# enable
RS G8124(vnic-group-config)# exit

Once VLAN 1000 and 1774 are configured for vNIC groups, they will not be
available for configuration in the regular VLAN menus
(RS G8124(config)# vlan <VLAN number>).
Note: vNICs are not supported simultaneously on the same switch ports as
VMready.
6. Save the configuration.

© Copyright IBM Corp. 2014 Chapter 14: Virtual NICs 191

vNICs for iSCSI on Emulex Endeavor 2
The N/OS vNIC feature works with standard network applications like iSCSI as
previously described. However, the Emulex Endeavor 2 NIC expects iSCSI traffic to
occur only on a single vNIC pipe. When using the Emulex Endeavor 2, only vNIC
pipe 2 may participate in ISCSI.

To configure the switch for this solution, place iSCSI traffic in its own vNIC group,
comprised of the uplink port leading to the iSCSI target, and the related <port>.2
vNIC pipes connected to the participating servers. For example:
1. Define the server ports.

RS G8124(config)# system server-ports port 1-3

2. Enable the vNIC feature on the switch.

RS G8124 # vnic enable

3. Configure the virtual pipes for the iSCSI vNICs attached to each server port:

RS G8124(config)# vnic port 1 index 2 (Select vNIC 2 on the server port)

RS G8124(vnic_config)# enable (Enable the vNIC pipe)
RS G8124(vnic_config)# exit
RS G8124(config)# vnic port 2 index 2 (Select vNIC 2 on the server port)
RS G8124(vnic_config)# enable (Enable the vNIC pipe)
RS G8124(vnic_config)# exit
RS G8124(config)# vnic port 3 index 2 (Select vNIC 2 on the server port)
RS G8124(vnic_config)# enable (Enable the vNIC pipe)
RS G8124(vnic_config)# exit

Note: vNICs are not supported simultaneously on the same switch ports as
VMready, or on the same switch as DCBX or FCoE.
4. Add ports and virtual pipes to a vNIC group.

RS G8124(config)# vnic vnicgroup 1 (Select vNIC group)

RS G8124(vnic-group-config)# vlan 1000 (Specify the VLAN)
RS G8124(vnic-group-config)# member 1.2 (Add iSCSI vNIC pipes to the group)
RS G8124(vnic-group-config)# member 2.2
RS G8124(vnic-group-config)# member 3.2
RS G8124(vnic-group-config)# port 4 (Add the uplink port to the group)
RS G8124(vnic-group-config)# enable (Enable the vNIC group)
RS G8124(vnic-group-config)# exit

5. Save the configuration.

192 RackSwitch G8124: Application Guide

Chapter 15. VMready
Virtualization is used to allocate server resources based on logical needs, rather
than on strict physical structure. With appropriate hardware and software support,
servers can be virtualized to host multiple instances of operating systems, known as
virtual machines (VMs). Each VM has its own presence on the network and runs its
own service applications.
Software known as a hypervisor manages the various virtual entities (VEs) that
reside on the host server: VMs, virtual switches, and so on. Depending on the
virtualization solution, a virtualization management server may be used to configure
and manage multiple hypervisors across the network. With some solutions, VMs
can even migrate between host hypervisors, moving to different physical hosts while
maintaining their virtual identity and services.
The IBM Networking OS 7.11 VMready feature supports up to 2048 VEs in a
virtualized data center environment. The switch automatically discovers the VEs
attached to switch ports, and distinguishes between regular VMs, Service Console
Interfaces, and Kernel/Management Interfaces in a VMware® environment.
VEs may be placed into VM groups on the switch to define communication
boundaries: VEs in the same VM group may communicate with each other, while
VEs in different groups may not. VM groups also allow for configuring group-level
settings such as virtualization policies and ACLs.
The administrator can also pre-provision VEs by adding their MAC addresses (or
their IPv4 address or VM name in a VMware environment) to a VM group. When a
VE with a pre-provisioned MAC address becomes connected to the switch, the
switch will automatically apply the appropriate group membership configuration.
The G8124 with VMready also detects the migration of VEs across different
hypervisors. As VEs move, the G8124 NMotion™ feature automatically moves the
appropriate network configuration as well. NMotion gives the switch the ability to
maintain assigned group membership and associated policies, even when a VE
moves to a different port on the switch.
VMready also works with VMware Virtual Center (vCenter) management software.
Connecting with a vCenter allows the G8124 to collect information about more
distant VEs, synchronize switch and VE configuration, and extend migration
properties.
Note: VM groups and policies, VE pre-provisioning, and VE migration features are
not supported simultaneously on the same ports as vNICs (see “Virtual
NICs” on page 181).

© Copyright IBM Corp. 2014 193

VE Capacity
When VMready is enabled, the switch will automatically discover VEs that reside in
hypervisors directly connected on the switch ports. IBM N/OS 7.11 supports up to
2048 VEs. Once this limit is reached, the switch will reject additional VEs.
Note: In rare situations, the switch may reject new VEs prior to reaching the
supported limit. This can occur when the internal hash corresponding to the
new VE is already in use. If this occurs, change the MAC address of the VE
and retry the operation. The MAC address can usually be changed from the
virtualization management server console (such as the VMware Virtual
Center).

Defining Server Ports

Before you configure VMready features, you must first define whether ports are
connected to servers or are used as uplink ports. Use the following ISCLI
configuration command to define a port as a server port:

RS G8124(config)# system server-ports port <port alias or number>

Ports that are not defined as server ports are automatically considered uplink ports.

VM Group Types
VEs, as well as switch server ports, switch uplink ports, static trunks, and LACP
trunks, can be placed into VM groups on the switch to define virtual communication
boundaries. Elements in a given VM group are permitted to communicate with each
other, while those in different groups are not. The elements within a VM group
automatically share certain group-level settings.

N/OS 7.11 supports up to 1024 VM groups. There are two different types:
• Local VM groups are maintained locally on the switch. Their configuration is not
synchronized with hypervisors. Of the 2048 VEs supported on the switch, up to
500 VEs may be used in local groups.
• Distributed VM groups are automatically synchronized with a virtualization man-
agement server (see “Assigning a vCenter” on page 204).

Each VM group type is covered in detail in the following sections.

Note: VM groups are not supported simultaneously on the same ports as vNICs
(see “Virtual NICs” on page 181).

194 RackSwitch G8124: Application Guide

Local VM Groups
The configuration for local VM groups is maintained on the switch (locally) and is not
directly synchronized with hypervisors. Local VM groups may include only local
elements: local switch ports and trunks, and only those VEs connected to one of the
switch ports or pre-provisioned on the switch. Of the 2048 VEs supported on the
switch, up to 500 VEs may be used in local groups.

Local VM groups support limited VE migration: as VMs and other VEs move to
different hypervisors connected to different ports on the switch, the configuration of
their group identity and features moves with them. However, VE migration to and
from more distant hypervisors (those not connected to the G8124, may require
manual configuration when using local VM groups.

Configuring a Local VM Group

Use the following ISCLI configuration commands to assign group properties and
membership:

RS G8124(config)# virt vmgroup <VM group number> ?

key <LACP trunk key> (Add LACP trunk to group)
port <port alias or number> (Add port member to group)
portchannel <trunk group number> (Add static trunk to group)
profile <profile name> (Not used for local groups)
stg <Spanning Tree group> (Add STG to group)
tag (Set VLAN tagging on ports)
validate <advanced|basic> (Validate mode for the group)
vlan <VLAN number> (Specify the group VLAN)
vm <MAC>|<index>|<UUID>|<IPv4 address>|<name> (Add VM member to group)
vmap <VMAP number> [intports|extports] (Specify VMAP number)
vport (Add a virtual port to the group)

© Copyright IBM Corp. 2014 Chapter 15: VMready 195

 The following rules apply to the local VM group configuration commands:
• key: Add LACP trunks to the group.
• port: Add switch server ports or switch uplink ports to the group. Note that VM
groups and vNICs (see “Virtual NICs” on page 181) are not supported
simultaneously on the same port.
• portchannel: Add static port trunks to the group.
• profile: The profile options are not applicable to local VM groups. Only
distributed VM groups may use VM profiles (see “VM Profiles” on page 197).
• stg: The group may be assigned to a Spanning-Tree group for broadcast loop
control (see “Spanning Tree Protocols” on page 119).
• tag: Enable VLAN tagging for the VM group. If the VM group contains ports
which also exist in other VM groups, enable tagging in both VM groups.
• validate: Set validation mode for the group.
• vlan: Each VM group must have a unique VLAN number. This is required for
local VM groups. If one is not explicitly configured, the switch will automatically
assign the next unconfigured VLAN when a VE or port is added to the VM group.
• vmap: Each VM group may optionally be assigned a VLAN-based ACL (see
“VLAN Maps” on page 208).
• vm: Add VMs.
VMs and other VEs are primarily specified by MAC address. They can also be
specified by UUID, IP address, or by the index number as shown in various
VMready information output (see “VMready Information Displays” on page 211).
• vport: Add a virtual port to the group.
If VMware Tools software is installed in the guest operating system (see VMware
documentation for information on installing recommended tools), VEs may also
be specified by IPv4 address or VE name. However, if there is more than one
possible VE for the input (such as an IPv4 address for a VM that uses multiple
vNICs), the switch will display a list of candidates and prompt for a specific MAC
address.
Only VEs currently connected to the switch port (local) or pending connection
(pre-provisioned) are permitted in local VM groups.
Because VM groups and vNIC groups (see “Virtual NICs” on page 181) are
isolated from each other, VMs detected on vNICs cannot be assigned to VM
groups.

Use the no variant of the commands to remove or disable VM group configuration

settings:

RS G8124(config)# no virt vmgroup <VM group number> [?]

Note: Local VM groups are not supported simultaneously on the same ports as
vNICs (see “Virtual NICs” on page 181).

196 RackSwitch G8124: Application Guide

Distributed VM Groups
Distributed VM groups allow configuration profiles to be synchronized between the
G8124 and associated hypervisors and VEs. This allows VE configuration to be
centralized, and provides for more reliable VE migration across hypervisors.
Using distributed VM groups requires a virtualization management server. The
management server acts as a central point of access to configure and maintain
multiple hypervisors and their VEs (VMs, virtual switches, and so on).
The G8124 must connect to a virtualization management server before distributed
VM groups can be used. The switch uses this connection to collect configuration
information about associated VEs, and can also automatically push configuration
profiles to the virtualization management server, which in turn configures the
hypervisors and VEs. See “Virtualization Management Servers” on page 204 for
more information.
Note: Distributed VM groups are not supported simultaneously on the same ports
as vNICs (see “Virtual NICs” on page 181).

VM Profiles
VM profiles are required for configuring distributed VM groups. They are not used
with local VM groups. A VM profile defines the VLAN and virtual switch bandwidth
shaping characteristics for the distributed VM group. The switch distributes these
settings to the virtualization management server, which in turn distributes them to
the appropriate hypervisors for VE members associated with the group.

Creating VM profiles is a two part process. First, the VM profile is created as shown
in the following command on the switch:

RS G8124(config)# virt vmprofile <profile name>

Next, the profile must be edited and configured using the following configuration
commands:

RS G8124(config)# virt vmprofile edit <profile name> ?

eshaping <average bandwidth> <burst size> <peak>
shaping <average bandwidth> <burst size> <peak>
vlan <VLAN number>

For virtual switch bandwidth shaping parameters, average and peak bandwidth are
specified in kilobits per second (a value of 1000 represents 1 Mbps). Burst size is
specified in kilobytes (a value of 1000 represents 1 MB). Eshaping (egress shaping)
is used for distributed virtual switch.
Note: The bandwidth shaping parameters in the VM profile are used by the
hypervisor virtual switch software. To set bandwidth policies for individual
VEs, see “VM Policy Bandwidth Control” on page 209.

Once configured, the VM profile may be assigned to a distributed VM group as

shown in the following section.

© Copyright IBM Corp. 2014 Chapter 15: VMready 197

Initializing a Distributed VM Group
Note: A VM profile is required before a distributed VM group may be configured.
See “VM Profiles” on page 197 for details.

Once a VM profile is available, a distributed VM group may be initialized using the

following configuration command:

RS G8124(config)# virt vmgroup <VM group number> profile <VM profile name>

Only one VM profile can be assigned to a given distributed VM group. To change the
VM profile, the old one must first be removed using the following ISCLI configuration
command:

RS G8124(config)# no virt vmgroup <VM group number> profile

Note: The VM profile can be added only to an empty VM group (one that has no
VLAN, VMs, or port members). Any VM group number currently configured
for a local VM group (see “Local VM Groups” on page 195) cannot be
converted and must be deleted before it can be used for a distributed VM
group.

Assigning Members
VMs, ports, and trunks may be added to the distributed VM group only after the VM
profile is assigned. Group members are added, pre-provisioned, or removed from
distributed VM groups in the same manner as with local VM groups (“Local VM
Groups” on page 195), with the following exceptions:
• VMs: VMs and other VEs are not required to be local. Any VE known by the
virtualization management server can be part of a distributed VM group.
• The VM group vlan option (see page 196) cannot be used with distributed VM
groups. For distributed VM groups, the VLAN is assigned in the VM profile.

198 RackSwitch G8124: Application Guide

Synchronizing the Configuration
When the configuration for a distributed VM group is modified, the switch updates
the assigned virtualization management server. The management server then
distributes changes to the appropriate hypervisors.

For VM membership changes, hypervisors modify their internal virtual switch port
groups, adding or removing server port memberships to enforce the boundaries
defined by the distributed VM groups. Virtual switch port groups created in this
fashion can be identified in the virtual management server by the name of the VM
profile, formatted as follows:
IBM_<VM profile name>
(or)
IBM_<VM profile name> <index number> (for vDS)

Adding a server host interface to a distributed VM group does not create a new port
group on the virtual switch or move the host. Instead, because the host interface
already has its own virtual switch port group on the hypervisor, the VM profile
settings are applied to its existing port group.
Note: When applying the distributed VM group configuration, the virtualization
management server and associated hypervisors must take appropriate
actions. If a hypervisor is unable to make requested changes, an error
message will be displayed on the switch. Be sure to evaluate all error
message and take the appropriate actions for the expected changes to
apply.

Removing Member VEs

Removing a VE from a distributed VM group on the switch will have the following
effects on the hypervisor:
• The VE will be moved to the IBM_Default port group in VLAN 0 (zero).
• Traffic shaping will be disabled for the VE.
• All other properties will be reset to default values inherited from the virtual switch.

© Copyright IBM Corp. 2014 Chapter 15: VMready 199

VMcheck
The G8124 primarily identifies virtual machines by their MAC addresses. An
untrusted server or a VM could identify itself by a trusted MAC address leading to
MAC spoofing attacks. Sometimes, MAC addresses get transferred to another VM,
or they get duplicated.

The VMcheck solution addresses these security concerns by validating the MAC
addresses assigned to VMs. The switch periodically sends hello messages on
server ports. These messages include the switch identifier and port number. The
hypervisor listens to these messages on physical NICs and stores the information,
which can be retrieved using the VMware Infrastructure Application Programming
Interface (VI API). This information is used to validate VM MAC addresses. Two
modes of validation are available: Basic and Advanced.

Use the following command to select the validation mode or to disable validation:

RS G8124(config)# [no] virt vmgroup <VM group number> validate {basic|advanced}

Basic Validation

This mode provides port-based validation by identifying the port used by a

hypervisor. It is suitable for environments in which MAC reassignment or duplication
cannot occur.

The switch, using the hello message information, identifies a hypervisor port. If the
hypervisor port is found in the hello message information, it is deemed to be a
trusted port. Basic validation should be enabled when:
• A VM is added to a VM group, and the MAC address of the VM interface is in the
Layer 2 table of the switch.
• A VM interface that belongs to a VM group experiences a “source miss” i.e. is not
able to learn new MAC address.
• A trusted port goes down. Port validation must be performed to ensure that the
port does not get connected to an untrusted source when it comes back up.

Use the following command to set the action to be performed if the switch is unable
to validate the VM MAC address:

RS G8124(config)# virt vmcheck action basic {log|link}

log - generates a log

link - disables the port

200 RackSwitch G8124: Application Guide

 Advanced Validation

This mode provides VM-based validation by mapping a switch port to a VM MAC

address. It is suitable for environments in which spoofing, MAC reassignment, or
MAC duplication is possible.

When the switch receives frames from a VM, it first validates the VM interface based
on the VM MAC address, VM Universally Unique Identifier (UUID), Switch port, and
Switch ID available in the hello message information. Only if all the four parameters
are matched, the VM MAC address is considered valid.

In advanced validation mode, if the VM MAC address validation fails, an ACL can be
automatically created to drop the traffic received from the VM MAC address on the
switch port. Use the following command to specify the number of ACLs to be
automatically created for dropping traffic:

RS G8124(config)# virt vmcheck acls max <1-127>

Use the following command to set the action to be performed if the switch is unable
to validate the VM MAC address:

RS G8124(config)# virt vmcheck action advanced {log|link|acl}

Following are the other VMcheck commands:

Table 19. VMcheck Commands

Command Description

RS G8124(config)# virt vmware hello {ena| Hello messages setting:

hport <port number>|haddr|htimer} enable/add port/advertise
this IP address in the hello
messages instead of the
default management IP
address/set the timer to
send the hello messages

RS G8124(config)# no virt vmware hello Disable hello

{enable|hport <port number>} messages/remove port

RS G8124(config)# [no] virt vmcheck Mark a port as trusted; Use

trust <port number or range> the no form of the command
to mark port as untrusted

RS G8124# no virt vmcheck acls ACLs cannot be used for

VMcheck

© Copyright IBM Corp. 2014 Chapter 15: VMready 201

Virtual Distributed Switch
A virtual Distributed Switch (vDS ) allows the hypervisor’s NIC to be attached to the
vDS instead of its own virtual switch. The vDS connects to the vCenter and spans
across multiple hypervisors in a datacenter. The administrator can manage virtual
machine networking for the entire data center from a single interface. The vDS
enables centralized provisioning and administration of virtual machine networking in
the data center using the VMware vCenter server.

When a member is added to a distributed VM group, a distributed port group is

created on the vDS. The member is then added to the distributed port group.

Distributed port groups on a vDS are available to all hypervisors that are connected
to the vDS. Members of a single distributed port group can communicate with each
other.
Note: vDS works with ESX 4.0 or higher versions.

To add a vDS, use the command:

RS G8124# virt vmware dvswitch add <datacenter name> <dvSwitch name> [<dvSwitch-version>]

Prerequisites
Before adding a vDS on the G8124, ensure the following:
• VMware vCenter is fully installed and configured and includes a “bladevm”
administration account and a valid SSL certificate.
• A virtual distributed switch instance has been created on the vCenter. The vDS
version must be higher or the same as the hypervisor version on the hosts.
• At least two hypervisors are configured.

Guidelines
Before migrating VMs to a vDS, consider the following:
• At any one time, a VM NIC can be associated with only one virtual switch: to the
hypervisor’s virtual switch, or to the vDS.
• Management connection to the server must be ensured during the migration.
The connection is via the Service Console or the Kernel/Management Interface.
• The vDS configuration and migration can be viewed in vCenter at the following
locations:
– vDS: Home> Inventory > Networking
– vDS Hosts: Home > Inventory > Networking > vDS > Hosts

Note: These changes will not be displayed in the running configuration on the
G8124.

202 RackSwitch G8124: Application Guide

Migrating to vDS
You can migrate VMs to the vDS using vCenter. The migration may also be
accomplished using the operational commands on the G8124 available in the
following CLI menus:

For VMware vDS operations:

RS G8124# virt vmware dvswitch ?

For VMware distributed port group operations:

RS G8124# virt vmware dpg ?

© Copyright IBM Corp. 2014 Chapter 15: VMready 203

Virtualization Management Servers
The G8124 can connect with a virtualization management server to collect
configuration information about associated VEs. The switch can also automatically
push VM group configuration profiles to the virtualization management server, which
in turn configures the hypervisors and VEs, providing enhanced VE mobility.
One virtual management server must be assigned on the switch before distributed
VM groups may be used. N/OS 7.11 currently supports only the VMware Virtual
Center (vCenter).
Note: Although VM groups and policies are not supported simultaneously on the
same ports as vNICs (“Virtual NICs” on page 181), vCenter synchronization
can provide additional information about VEs on vNIC and non-vNIC ports.

Assigning a vCenter
Assigning a vCenter to the switch requires the following:
• The vCenter must have a valid IPv4 address which is accessible to the switch
(IPv6 addressing is not supported for the vCenter).
• A user account must be configured on the vCenter to provide access for the
switch. The account must have (at a minimum) the following vCenter user privi-
leges:
– Network
– Host Network > Configuration
– Virtual Machine > Modify Device Settings
Once vCenter requirements are met, the following configuration command can be
used on the G8124 to associate the vCenter with the switch:

RS G8124(config)# virt vmware vcspec <vCenter IPv4 address> <username> [noauth]

This command specifies the IPv4 address and account username that the switch
will use for vCenter access. Once entered, the administrator will be prompted to
enter the password for the specified vCenter account.
The noauth option causes to the switch to ignores SSL certificate authentication.
This is required when no authoritative SSL certificate is installed on the vCenter.
Note: By default, the vCenter includes only a self-signed SSL certificate. If using
the default certificate, the noauth option is required.
Once the vCenter configuration has been applied on the switch, the G8124 will
connect to the vCenter to collect VE information.

204 RackSwitch G8124: Application Guide

vCenter Scans
Once the vCenter is assigned, the switch will periodically scan the vCenter to collect
basic information about all the VEs in the datacenter, and more detailed information
about the local VEs that the switch has discovered attached to its own ports.

The switch completes a vCenter scan approximately every two minutes. Any major
changes made through the vCenter may take up to two minutes to be reflected on
the switch. However, you can force an immediate scan of the vCenter by using one
of the following ISCLI privileged EXEC commands:

RS G8124# virt vmware scan (Scan the vCenter)

-or-
RS G8124# show virt vm -v -r (Scan vCenter and display result)

Deleting the vCenter

To detach the vCenter from the switch, use the following configuration command:

RS G8124(config)# no virt vmware vcspec

Note: Without a valid vCenter assigned on the switch, any VE configuration

changes must be manually synchronized.

Deleting the assigned vCenter prevents synchronizing the configuration between

the G8124 and VEs. VEs already operating in distributed VM groups will continue to
function as configured, but any changes made to any VM profile or distributed VM
group on the switch will affect only switch operation; changes on the switch will not
be reflected in the vCenter or on the VEs. Likewise, any changes made to VE
configuration on the vCenter will no longer be reflected on the switch.

© Copyright IBM Corp. 2014 Chapter 15: VMready 205

Exporting Profiles
VM profiles for discovered VEs in distributed VM groups are automatically
synchronized with the virtual management server and the appropriate hypervisors.
However, VM profiles can also be manually exported to specific hosts before
individual VEs are defined on them.

By exporting VM profiles to a specific host, virtual machine port groups will be

available to the host’s internal virtual switches so that new VMs may be configured
to use them.

VM migration requires that the target hypervisor includes all the virtual switch port
groups to which the VM connects on the source hypervisor. The VM profile export
feature can be used to distribute the associated port groups to all the potential hosts
for a given VM.

A VM profile can be exported to a host using the following ISCLI privileged EXEC
command:

RS G8124# virt vmware export <VM profile name> <host list> <virtual switch name>

The host list can include one or more target hosts, specified by host name, IPv4
address, or UUID, with each list item separated by a space.

Once executed, the requisite port group will be created on the specified virtual
switch. If the specified virtual switch does not exist on the target host, the port group
will not be created.

VMware Operational Commands

The G8124 may be used as a central point of configuration for VMware virtual
switches and port groups using the following ISCLI privileged EXEC commands:

RS G8124# virt vmware ?

dpg Distributed port group operations
dvswitch VMWare dvSwitch operations
export Create or update a vm profile on one host
pg Add a port group to a host
scan Perform a VM Agent scan operation now
updpg Update a port group on a host
vmacpg Change a vnic's port group
vsw Add a vswitch to a host

206 RackSwitch G8124: Application Guide

Pre-Provisioning VEs
VEs may be manually added to VM groups in advance of being detected on the
switch ports. By pre-provisioning the MAC address of VEs that are not yet active,
the switch will be able to later recognize the VE when it becomes active on a switch
port, and immediately assign the proper VM group properties without further
configuration.

Undiscovered VEs are added to or removed from VM groups using the following
configuration commands:

RS G8124(config)# [no] virt vmgroup <VM group number> vm <VE MAC address>

For the pre-provisioning of undiscovered VEs, a MAC address is required. Other

identifying properties, such as IPv4 address or VM name permitted for known VEs,
cannot be used for pre-provisioning.
Note: Because VM groups are isolated from vNIC groups (see “vNIC Groups” on
page 185), pre-provisioned VEs that appear on vNIC ports will not be added
to the specified VM group upon discovery.

© Copyright IBM Corp. 2014 Chapter 15: VMready 207

VLAN Maps
A VLAN map (VMAP) is a type of Access Control List (ACL) that is applied to a
VLAN or VM group rather than to a switch port as with regular ACLs (see “Access
Control Lists” on page 79). In a virtualized environment, VMAPs allow you to create
traffic filtering and metering policies that are associated with a VM group VLAN,
allowing filters to follow VMs as they migrate between hypervisors.
Note: VLAN maps for VM groups are not supported simultaneously on the same
ports as vNICs (see “Virtual NICs” on page 181).

N/OS 7.11 supports up to 127 VMAPs when the switch is operating in the Balanced
deployment mode (see “Deployment Profiles” on page 175). VMAP menus and
commands are not available in the Routing deployment mode.

Individual VMAP filters are configured in the same fashion as regular ACLs, except
that VLANs cannot be specified as a filtering criteria (unnecessary, since VMAPs
are assigned to a specific VLAN or associated with a VM group VLAN).

VMAPs are configured using the following ISCLI configuration command path:

RS G8124(config)# access-control vmap <VMAP ID> ?

action Set filter action
ethernet Ethernet header options
ipv4 IP version 4 header options
meter ACL metering configuration
mirror Mirror options
re-mark ACL re-mark configuration
statistics Enable access control list statistics
tcp-udp TCP and UDP filtering options

Once a VMAP filter is created, it can be assigned or removed using the following
commands:
• For regular VLANs, use config-vlan mode:

RS G8124(config)# vlan <VLAN ID>

RS G8124(config-vlan)# [no] vmap <VMAP ID> [serverports| non-serverports]

• For a VM group, use the global configuration mode:

RS G8124(config)# [no] virt vmgroup <ID> vmap <VMAP ID>

[serverports|non-serverports]

Note: Each VMAP can be assigned to only one VLAN or VM group. However, each
VLAN or VM group may have multiple VMAPs assigned to it.

The optional serverports or non-serverports parameter can be specified to

apply the action (to add or remove the VMAP) for either the switch server ports
(serverports) or switch uplink ports (non-serverports). If omitted, the
operation will be applied to all ports in the associated VLAN or VM group.
Note: VMAPs have a lower priority than port-based ACLs. If both an ACL and a
VMAP match a particular packet, both filter actions will be applied as long as
there is no conflict. In the event of a conflict, the port ACL will take priority,
though switch statistics will count matches for both the ACL and VMAP.

208 RackSwitch G8124: Application Guide

VM Policy Bandwidth Control
Note: VM policy bandwidth control is supported only when the switch is operating
with the Default deployment profile (see “Deployment Profiles” on page 175).
If using the Routing profile, VM policy bandwidth control commands will not
be available.
In a virtualized environment where VEs can migrate between hypervisors and thus
move among different ports on the switch, traffic bandwidth policies must be
attached to VEs, rather than to a specific switch port.
VM Policy Bandwidth Control allows the administrator to specify the amount of data
the switch will permit to flow from a particular VE, without defining a complicated
matrix of ACLs or VMAPs for all port combinations where a VE may appear.

VM Policy Bandwidth Control Commands

VM Policy Bandwidth Control can be configured using the following configuration
commands:

RS G8124(config)# virt vmpolicy vmbwidth <VM MAC>|<index>|<UUID>| <IPv4 address>|<name>?

txrate <committed rate> <burst> [<ACL number>] (Set the VM transmit bandwidth – ingress for switch)
rxrate <committed rate> <burst> (Set the VM receive bandwidth – egress for switch)
bwctrl (Enable bandwidth control)

Bandwidth allocation can be defined for transmit (TX) traffic or receive (RX) traffic.
Because bandwidth allocation is specified from the perspective of the VE, the switch
command for TX Rate Control (txrate) sets the data rate to be sent from the VM to
the switch, and the RX rate sets the data rate to be received by the VM from the
switch.
The committed rate is specified in multiples of 64 kbps, from 64 to 40,000,000. The
maximum burst rate is specified as 32, 64, 128, 256, 1024, 2048, or 4096 kb. If both
the committed rate and burst are set to 0, bandwidth control will be disabled.
When txrate is specified, the switch automatically selects an available ACL for
internal use with bandwidth control. Optionally, if automatic ACL selection is not
desired, a specific ACL may be selected. If there are no unassigned ACLs available,
txrate cannot be configured.

© Copyright IBM Corp. 2014 Chapter 15: VMready 209

Bandwidth Policies vs. Bandwidth Shaping
VM Profile Bandwidth Shaping differs from VM Policy Bandwidth Control.

VM Profile Bandwidth Shaping (see “VM Profiles” on page 197) is configured per
VM group and is enforced on the server by a virtual switch in the hypervisor.
Shaping is unidirectional and limits traffic transmitted from the virtual switch to the
G8124. Shaping is performed prior to transmit VM Policy Bandwidth Control. If the
egress traffic for a virtual switch port group exceeds shaping parameters, the traffic
is dropped by the virtual switch in the hypervisor. Shaping uses server CPU
resources, but prevents extra traffic from consuming bandwidth between the server
and the G8124. Shaping is not supported simultaneously on the same ports as
vNICs.

VM Policy Bandwidth Control is configured per VE, and can be set independently for
transmit traffic. Bandwidth policies are enforced by the G8124. VE traffic that
exceeds configured levels is dropped by the switch upon ingress. Setting txrate
uses ACL resources on the switch.

Bandwidth shaping and bandwidth policies can be used separately or in concert.

210 RackSwitch G8124: Application Guide

VMready Information Displays
The G8124 can be used to display a variety of VMready information.
Note: Some displays depict information collected from scans of a VMware vCenter
and may not be available without a valid vCenter. If a vCenter is assigned
(see “Assigning a vCenter” on page 204), scan information might not be
available for up to two minutes after the switch boots or when VMready is
first enabled. Also, any major changes made through the vCenter may take
up to two minutes to be reflected on the switch unless you force an
immediate vCenter scan (see “vCenter Scans” on page 205.

Local VE Information

A concise list of local VEs and pre-provisioned VEs is available with the following
ISCLI privileged EXEC command:

RS G8124# show virt vm

IP Address VMAC Address Index Port VM Group (Profile) Check status

---------------- ----------------- ----- -------- ------------------ ------------
0.0.0.0 00:50:56:55:47:0c 5 17.3
~0.0.0.0 00:50:56:b3:1e:7b 2 17.3 1 test
~0.0.0.0 00:50:56:b3:1f:16 1 17.3 1 test
~0.0.0.0 00:50:56:b3:2c:b9 4 18 2
~0.0.0.0 00:50:56:b3:5f:32 3 18 1 test
~0.0.0.0 00:50:56:b3:69:5a 0 19.3 1 test
VMReady ports: 17-21

Number of entries: 6
~ indicates inactive VMs
0.0.0.0 indicates IP address not yet available

Note: The Index numbers shown in the VE information displays can be used to
specify a particular VE in configuration commands.

© Copyright IBM Corp. 2014 Chapter 15: VMready 211

 If a vCenter is available, more verbose information can be obtained using the
following ISCLI privileged EXEC command option:

RS G8124# show virt vm -v

Index MAC Address, Name (VM or Host), Port, Group Vswitch,

IP Address @Host (VMs only) VLAN Port Group
----- ------------ ------------------ ----- ----- ----------
~0 00:50:56:b3:69:5a T7010 19 1 vSwitch1
0.0.0.0 @10.11.43.107 0 IBM_Default

~1 00:50:56:b3:1f:16 T5009 17 1 vSwitch1

0.0.0.0 @10.11.43.105 0 IBM_Default

~2 00:50:56:b3:1e:7b T5010 17 1 vSwitch1

0.0.0.0 @10.11.43.105 0 IBM_Default

~3 00:50:56:b3:5f:32 T6009 18 1 vSwitch1

0.0.0.0 @10.11.43.106 301 IBM_301

~4 00:50:56:b3:2c:b9 T6009 18 2 vSwitch1

0.0.0.0 @10.11.43.106 301 IBM_301

5 00:50:56:55:47:0c 17
0.0.0.0

--
6 of 6 entries printed
~ indicates inactive VMs
0.0.0.0 indicates IP Address is not available
Use the "-v -r" options to refresh data before displaying results

EVB Virtual Station Interface Information:

Total number of VM Association entries : 0

To view additional detail regarding any specific VE, see “vCenter VE Details” on
page 214).

212 RackSwitch G8124: Application Guide

 vCenter Hypervisor Hosts

If a vCenter is available, the following ISCLI privileged EXEC command displays the
name and UUID of all VMware hosts, providing an essential overview of the data
center:

RS G8124# show virt vmware hosts

UUID Name(s), IP Address
---------------------------------------------------------------
00a42681-d0e5-5910-a0bf-bd23bd3f7800 172.16.41.30
002e063c-153c-dd11-8b32-a78dd1909a00 172.16.46.10
00f1fe30-143c-dd11-84f2-a8ba2cd7ae00 172.16.44.50
0018938e-143c-dd11-9f7a-d8defa4b8300 172.16.46.20
...

Using the following command, the administrator can view more detailed vCenter
host information, including a list of virtual switches and their port groups, as well as
details for all associated VEs:

RS G8124# show virt vmware showhost {<UUID>|<IPv4 address>|<host name>}

Vswitches available on the host:
vSwitch0
Port Groups and their Vswitches on the host:
BNT_Default vSwitch0
VM Network vSwitch0
Service Console vSwitch0
VMkernel vSwitch0
----------------------------------------------------------------------
MAC Address 00:50:56:9c:21:2f
Port 4
Type Virtual Machine
VM vCenter Name halibut
VM OS hostname localhost.localdomain
VM IP Address 172.16.46.15
VM UUID 001c41f3-ccd8-94bb-1b94-6b94b03b9200
Current VM Host 172.16.46.10
Vswitch vSwitch0
Port Group BNT_Default
VLAN ID 0
...

© Copyright IBM Corp. 2014 Chapter 15: VMready 213

 vCenter VEs

If a vCenter is available, the following ISCLI privileged EXEC command displays a

list of all known VEs:

RS G8124# show virt vmware vms

UUID Name(s), IP Address
----------------------------------------------------------------------
001cdf1d-863a-fa5e-58c0-d197ed3e3300 30vm1
001c1fba-5483-863f-de04-4953b5caa700 VM90
001c0441-c9ed-184c-7030-d6a6bc9b4d00 VM91
001cc06e-393b-a36b-2da9-c71098d9a700 vm_new
001c6384-f764-983c-83e3-e94fc78f2c00 sturgeon
001c7434-6bf9-52bd-c48c-a410da0c2300 VM70
001cad78-8a3c-9cbe-35f6-59ca5f392500 VM60
001cf762-a577-f42a-c6ea-090216c11800 30VM6
001c41f3-ccd8-94bb-1b94-6b94b03b9200 halibut, localhost.localdomain,
172.16.46.15
001cf17b-5581-ea80-c22c-3236b89ee900 30vm5
001c4312-a145-bf44-7edd-49b7a2fc3800 vm3
001caf40-a40a-de6f-7b44-9c496f123b00 30VM7

vCenter VE Details

If a vCenter is available, the following ISCLI privileged EXEC command displays

detailed information about a specific VE:

RS G8124# show virt vmware showvm {<VM UUID>|<VM IPv4 address>|<VM name>}
----------------------------------------------------------------------
MAC Address 00:50:56:9c:21:2f
Port 4
Type Virtual Machine
VM vCenter Name halibut
VM OS hostname localhost.localdomain
VM IP Address 172.16.46.15
VM UUID 001c41f3-ccd8-94bb-1b94-6b94b03b9200
Current VM Host 172.16.46.10
Vswitch vSwitch0
Port Group BNT_Default
VLAN ID 0

214 RackSwitch G8124: Application Guide

VMready Configuration Example
This example has the following characteristics:
• A VMware vCenter is fully installed and configured prior to VMready configura-
tion and includes a “bladevm” administration account and a valid SSL certifi-
cate.
• The distributed VM group model is used.
• The VM profile named “Finance” is configured for VLAN 30, and specifies
NIC-to-switch bandwidth shaping for 1Mbps average bandwidth, 2MB bursts,
and 3Mbps maximum bandwidth.
• The VM group includes four discovered VMs on switch server ports 1 and 2, and
one static trunk (previously configured) that includes switch uplink ports 3 and 4.
1. Define the server ports.

RS G8124(config)# system server-ports port 1-2

2. Enable the VMready feature.

RS G8124(config)# virt enable

3. Specify the VMware vCenter IPv4 address.

RS G8124(config)# virt vmware vmware vcspec 172.16.100.1 bladevm

When prompted, enter the user password that the switch must use for access to
the vCenter.
4. Create the VM profile.

RS G8124(config)# virt vmprofile Finance

RS G8124(config)# virt vmprofile edit Finance vlan 30
RS G8124(config)# virt vmprofile edit Finance shaping 1000 2000 3000

5. Define the VM group.

RS G8124(config)# virt vmgroup 1 profile Finance

RS G8124(config)# virt vmgroup 1 vm arctic
RS G8124(config)# virt vmgroup 1 vm monster
RS G8124(config)# virt vmgroup 1 vm sierra
RS G8124(config)# virt vmgroup 1 vm 00:50:56:4f:f2:00
RS G8124(config)# virt vmgroup 1 portchannel 1

When VMs are added, the server ports on which they appear are automatically
added to the VM group. In this example, there is no need to manually add ports
1 and 2.
Note: VM groups and vNICs (see “Virtual NICs” on page 181) are not supported
simultaneously on the same switch ports.
6. If necessary, enable VLAN tagging for the VM group:

RS G8124(config)# virt vmgroup 1 tag

Note: If the VM group contains ports that also exist in other VM groups, make sure
tagging is enabled in both VM groups. In this example configuration, no ports
exist in more than one VM group.
7. Save the configuration.

© Copyright IBM Corp. 2014 Chapter 15: VMready 215

216 RackSwitch G8124: Application Guide
Chapter 16. FCoE and CEE
This chapter provides conceptual background and configuration examples for using
Converged Enhanced Ethernet (CEE) features of the RackSwitch G8124, with an
emphasis on Fibre Channel over Ethernet (FCoE) solutions. The following topics
are addressed in this chapter:
• “Fibre Channel over Ethernet” on page 218
Fibre Channel over Ethernet (FCoE) allows Fibre Channel traffic to be
transported over Ethernet links. This provides an evolutionary approach toward
network consolidation, allowing Fibre Channel equipment and tools to be
retained, while leveraging cheap, ubiquitous Ethernet networks for growth.
– “FCoE Initialization Protocol Snooping” on page 224
Using FCoE Initialization Protocol (FIP) snooping, the G8124 examines the
FIP frames exchanged between ENodes and FCFs. This information is used
to dynamically determine the ACLs required to block certain types of
undesired or unvalidated traffic on FCoE links.
• “Converged Enhanced Ethernet” on page 221
Converged Enhanced Ethernet (CEE) refers to a set of IEEE standards
developed primarily to enable FCoE, requiring enhancing the existing Ethernet
standards to make them lossless on a per-priority traffic basis, and providing a
mechanism to carry converged (LAN/SAN/IPC) traffic on a single physical link.
CEE features can also be utilized in traditional LAN (non-FCoE) networks to
provide lossless guarantees on a per-priority basis, and to provide efficient
bandwidth allocation.
– “Priority-Based Flow Control” on page 229
Priority-Based Flow Control (PFC) extends 802.3x standard flow control to
allow the switch to pause traffic based on the 802.1p priority value in each
packet’s VLAN tag. PFC is vital for FCoE environments, where SAN traffic
must remain lossless and must be paused during congestion, while LAN
traffic on the same links is delivered with “best effort” characteristics.
– “Enhanced Transmission Selection” on page 232
Enhanced Transmission Selection (ETS) provides a method for allocating
link bandwidth based on the 802.1p priority value in each packet’s VLAN tag.
Using ETS, different types of traffic (such as LAN, SAN, and management)
that are sensitive to different handling criteria can be configured either for
specific bandwidth characteristics, low-latency, or best-effort transmission,
despite sharing converged links as in an FCoE environment.
– “Data Center Bridging Capability Exchange” on page 239
Data Center Bridging Capability Exchange Protocol (DCBX) allows
neighboring network devices to exchange information about their
capabilities. This is used between CEE-capable devices for the purpose of
discovering their peers, negotiating peer configurations, and detecting
misconfigurations.

© Copyright IBM Corp. 2014 217

Fibre Channel over Ethernet
Fibre Channel over Ethernet (FCoE) is an effort to converge two of the different
physical networks in today’s data centers. It allows Fibre Channel traffic (such as
that commonly used in Storage Area Networks, or SANs) to be transported without
loss over 10Gb Ethernet links (typically used for high-speed Local Area Networks,
or LANs). This provides an evolutionary approach toward network consolidation,
allowing Fibre Channel equipment and tools to be retained, while leveraging cheap,
ubiquitous Ethernet networks for growth.

With server virtualization, servers capable of hosting both Fibre Channel and
Ethernet applications will provide advantages in server efficiency, particularly as
FCoE-enabled network adapters provide consolidated SAN and LAN traffic
capabilities.

The RackSwitch G8124 with IBM Networking OS 7.11 software is compliant with the
INCITS T11.3, FC-BB-5 FCoE specification.
Note: The G8124 supports up to 2048 FCoE login sessions.

The FCoE Topology

In an end-to-end Fibre Channel network, switches and end devices generally
establish trusted, point-to-point links. Fibre Channel switches validate end devices,
enforce zoning configurations and device addressing, and prevent certain types of
errors and attacks on the network.

In a converged multi-hop FCoE network where Fibre Channel devices are bridged
to Ethernet devices, the direct point-to-point QoS capabilities normally provided by
the Fibre Channel fabric may be lost in the transition between the different network
types. The G8124 provides a solution to overcome this.
Figure 28. A Mixed Fibre Channel and FCoE Network

Fibre
Channel LAN

Port 1

FCF Port 2 IBM

Device Switch
Port 3 Port 4

FCoE 802.1p Priority & Usage

CNA
3 FCoE Applications

802.1p Priority & Usage

0-2 LAN CNA
4 Business-Critical LAN
Servers

In Figure 28 on page 218, the Fibre Channel network is connected to the FCoE
network through an FCoE Forwarder (FCF). The FCF acts as a Fibre Channel
gateway to and from the FCoE network.

218 RackSwitch G8124: Application Guide

 For the FCoE portion of the network, the FCF is connected to the FCoE-enabled
G8124, which is connected to a server (running Fibre Channel applications) through
an FCoE-enabled Converged Network Adapter (CNA) known in Fibre Channel as
Ethernet Nodes (ENodes).
Note: The figure also shows a non-FCoE LAN server connected to the G8124
using a CNA. This allows the LAN server to take advantage of some CEE
features that are useful even outside of an FCoE environment.

To block undesired or unvalidated traffic on FCoE links that exists outside the
regular Fibre Channel topology, Ethernet ports used in FCoE are configured with
Access Control Lists (ACLs) that are narrowly tailored to permit expected FCoE
traffic to and from confirmed FCFs and ENodes, and deny all other FCoE or FIP
traffic. This ensures that all FCoE traffic to an from the ENode passes through the
FCF.

Because manual ACL configuration is an administratively complex task, the G8124

can automatically and dynamically configure the ACLs required for use with FCoE.
Using FCoE Initialization Protocol (FIP) snooping (see “FCoE Initialization Protocol
Snooping” on page 224), the G8124 examines the FIP frames normally exchanged
between the FCF and ENodes to determine information about connected FCoE
devices. This information is used to automatically determine the appropriate ACLs
required to block certain types of undesired or unvalidated FCoE traffic.

Automatic FCoE-related ACLs are independent from ACLs used for typical Ethernet
purposes.

FCoE Requirements
The following are required for implementing FCoE using the RackSwitch G8124
(G8124) with N/OS 7.11 software:
• The G8124 must be connected to the Fibre Channel network through an FCF
such as a Cisco Nexus 5000 Series Switch.
• For each G8124 port participating in FCoE, the connected server must use the
supported FCoE CNA. The QLogic CNA is currently the first CNA supported for
this purpose. Also supported is the Emulex Virtual Fabric Adapter.
• CEE must be turned on (see “Turning CEE On or Off” on page 221). When CEE
is on, the DCBX, PFC, and ETS features are enabled and configured with
default FCoE settings. These features may be reconfigured, but must remain
enabled for FCoE to function.
• FIP snooping must be turned on (see “FCoE Initialization Protocol Snooping” on
page 224). When FIP snooping is turned on, the feature is enabled on all ports
by default. The administrator can disable FIP snooping on individual ports that
do not require FCoE, but FIP snooping must remain enabled on all FCoE ports
for FCoE to function.
Note: FCoE and vNICs (see “Virtual NICs” on page 181) are not supported
simultaneously on the same G8124.

© Copyright IBM Corp. 2014 Chapter 16: FCoE and CEE 219
Port Trunking
IBM N/OS 7.11 supports port trunking for FCoE connections. The Link Aggregation
(LAG) can be used for separate FCoE traffic, or for Ethernet and FCoE traffic. Ports
directly connected to servers cannot be combined in a LAG group.

Uplink ports, connected to the FCF, can be grouped as static or dynamic trunks.

Normal trunk operations such as creating/enabling the trunk, and adding/removing

member ports can be performed. When a port is added to a trunk group, FCFs
previously detected on the port will be deleted. The deleted FCF may be relearned
later. However, this may cause flickering in the network traffic. We recommend that
you make trunk group changes, if any, prior to live FCoE traffic.

Data Center Bridging (DCBX) is configured on a per-port basis. Each port in a trunk
must have the same ETS, PFC, and DCBX configuration. When a port ceases to be
the trunk group member, its configuration does not change.

220 RackSwitch G8124: Application Guide

Converged Enhanced Ethernet
Converged Enhanced Ethernet (CEE) refers to a set of IEEE standards designed to
allow different physical networks with different data handling requirements to be
converged together, simplifying management, increasing efficiency and utilization,
and leveraging legacy investments without sacrificing evolutionary growth.

CEE standards were developed primarily to enable Fibre Channel traffic to be

carried over Ethernet networks. This required enhancing the existing Ethernet
standards to make them lossless on a per-priority traffic basis, and to provide a
mechanism to carry converged (LAN/SAN/IPC) traffic on a single physical link.
Although CEE standards were designed with FCoE in mind, they are not limited to
FCoE installations. CEE features can be utilized in traditional LAN (non-FCoE)
networks to provide lossless guarantees on a per-priority basis, and to provide
efficient bandwidth allocation based on application needs.

Turning CEE On or Off

By default on the G8124, CEE is turned off. To turn CEE on or off, use the following
CLI commands:

RS G8124(config)# [no] cee enable

CAUTION:
Turning CEE on will automatically change some 802.1p QoS and 802.3x
standard flow control settings on the G8124. Read the following material
carefully to determine whether you will need to take action to reconfigure
expected settings.

It is recommended that you backup your configuration prior to turning CEE on.
Viewing the file will allow you to manually re-create the equivalent configuration
once CEE is turned on, and will also allow you to recover your prior configuration if
you need to turn CEE off.

Effects on Link Layer Discovery Protocol

When CEE is turned on, Link Layer Discovery Protocol (LLDP) is automatically
turned on and enabled for receiving and transmitting DCBX information. LLDP
cannot be turned off while CEE is turned on.

© Copyright IBM Corp. 2014 Chapter 16: FCoE and CEE 221
Effects on 802.1p Quality of Service
While CEE is off (the default), the G8124 allows 802.1p priority values to be used for
Quality of Service (QoS) configuration (see page 161). 802.1p QoS default settings
are shown in Table 20, but can be changed by the administrator.

When CEE is turned on, 802.1p QoS is replaced by ETS (see “Enhanced
Transmission Selection” on page 232). As a result, while CEE is turned on, the
802.1p QoS configuration commands are no longer available on the switch (the
menu is restored when CEE is turned off).

In addition, when CEE is turned on, prior 802.1p QoS settings are replaced with new
defaults designed for use with ETS priority groups (PGIDs) as shown in Table 20:
Table 20. CEE Effects on 802.1p Defaults

802.1p QoS Configuration ETS Configuration

With CEE Off (default) With CEE On
Priority- COSq Weight Priority COSq PGID

0 0 1 0 2 2

1 1 2 1 2 2

2 2 3 2 2 2

3 3 4 3 3 3

4 4 5 4 4 4

5 5 7 5 4 4

6 6 15 6 4 4

7 7 0 7 7 15

When CEE is on, the default ETS configuration also allocates a portion of link
bandwidth to each PGID as shown in Table 21:
Table 21. Default ETS Bandwidth Allocation

PGID Typical Use Bandwidth

2 LAN 10%

3 SAN 50%

4 Latency-sensitive LAN 40%

If the prior, non-CEE configuration used 802.1p priority values for different
purposes, or does not expect bandwidth allocation as shown in Table 21 on
page 222, when CEE is turned on, have the administrator reconfigure ETS settings
as appropriate.

It is recommended that a configuration backup be made prior to turning CEE on or

off. Viewing the configuration file will allow the administrator to manually re-create the
equivalent configuration under the new CEE mode, and will also allow for the
recovery of the prior configuration if necessary.

222 RackSwitch G8124: Application Guide

Effects on Flow Control
When CEE is off (the default), 802.3x standard flow control is enabled on all switch
ports by default.

When CEE is turned on, standard flow control is disabled on all ports, and in its
place, PFC (see “Priority-Based Flow Control” on page 229) is enabled on all ports
for 802.1p priority value 3. This default is chosen because priority value 3 is
commonly used to identify FCoE traffic in a CEE environment and must be
guaranteed lossless behavior. PFC is disabled for all other priority values.

Each time CEE is turned off, the prior 802.3x standard flow control settings will be
restored (including any previous changes from the defaults).

It is recommend that a configuration backup be made prior to turning CEE on or off.

Viewing the configuration file will allow the administrator to manually re-create the
equivalent configuration under the new CEE mode, and will also allow for the
recovery of the prior configuration if necessary.

When CEE is on, PFC can be enabled only on priority value 3 and one other priority.
If flow control is required on additional priorities on any given port, consider using
standard flow control on that port, so that regardless of which priority traffic
becomes congested, a flow control frame is generated.

© Copyright IBM Corp. 2014 Chapter 16: FCoE and CEE 223
FCoE Initialization Protocol Snooping
FCoE Initialization Protocol (FIP) snooping is an FCoE feature. To enforce
point-to-point links for FCoE traffic outside the regular Fibre Channel topology,
Ethernet ports used in FCoE can be automatically and dynamically configured with
Access Control Lists (ACLs).

Using FIP snooping, the G8124 examines the FIP frames normally exchanged
between the FCF and ENodes to determine information about connected FCoE
devices. This information is used to create narrowly tailored ACLs that permit
expected FCoE traffic to and from confirmed Fibre Channel nodes, and deny all
other undesirable FCoE or FIP traffic.

In case of trunk groups, FIP traffic from a particular FCF can be received by any
member port on which the FCF was detected.

Global FIP Snooping Settings

By default, the FIP snooping feature is turned off for the G8124. The following
commands are used to turn the feature on or off:

RS G8124(config)# [no] fcoe fips enable

Note: FIP snooping requires CEE to be turned on (see “Turning CEE On or Off” on
page 221).

When FIP snooping is on, port participation may be configured on a port-by-port

basis (see the next sections).

When FIP snooping is off, all FCoE-related ACLs generated by the feature are
removed from all switch ports.

FIP snooping configuration must be the same on all member ports in a trunk group.
If the configuration of a member port is changed, an error message, similar to the
following, will be displayed.

“FAIL: Trunk X FIP Snooping port Yand port Z need to have the same fcf
mode config”

The configuration changes are applied to all member ports in a trunk group.

224 RackSwitch G8124: Application Guide

FIP Snooping for Specific Ports
When FIP snooping is globally turned on (see the previous section), ports may be
individually configured for participation in FIP snooping and automatic ACL
generation. By default, FIP snooping is enabled for each port. To change the setting
for any specific port, use the following CLI commands:

RS G8124(config)# [no] fcoe fips port <port alias, number, list, or range> enable

When FIP snooping is enabled on a port, FCoE-related ACLs will be automatically

configured.

When FIP snooping is disabled on a port, all FCoE-related ACLs on the port are
removed, and the switch will enforce no FCoE-related rules for traffic on the port.

Port FCF and ENode Detection

When FIP snooping is enabled on a port, the port is placed in FCF auto-detect mode
by default. In this mode, the port assumes connection to an ENode unless FIP
packets show the port is connected to an FCF.

Ports can also be specifically configured as to whether automatic FCF detection will
be used, or whether the port is connected to an FCF or ENode:

RS G8124(config)# fcoe fips port <port alias, number, list, or range> fcf-mode {auto|on|off}

When FCF mode is on, the port is assumed to be connected to a trusted FCF, and
only ACLs appropriate to FCFs will be installed on the port. When off, the port is
assumed to be connected to an ENode, and only ACLs appropriate to ENodes will
be installed. When the mode is changed (either through manual configuration or as
a result of automatic detection), the appropriate ACLs are automatically added,
removed, or changed to reflect the new FCF or ENode connection.

FCoE Connection Timeout

FCoE-related ACLs are added, changed, and removed as FCoE device connection
and disconnection are discovered. In addition, the administrator can enable or
disable automatic removal of ACLs for FCFs and other FCoE connections that
timeout (fail or are disconnected) without FIP notification.

By default, automatic removal of ACLs upon timeout is enabled. To change this

function, use the following CLI command:

RS G8124(config)# [no] fcoe fips timeout-acl

© Copyright IBM Corp. 2014 Chapter 16: FCoE and CEE 225
FCoE ACL Rules
When FIP Snooping is enabled on a port, the switch automatically installs the
appropriate ACLs to enforce the following rules for FCoE traffic:
• Ensure that FIP frames from ENodes may only be addressed to FCFs.
• Flag important FIP packets for switch processing.
• Ensure no end device uses an FCF MAC address as its source.
• Each FCoE port is assumed to be connected to an ENode and include
ENode-specific ACLs installed, until the port is either detected or configured to
be connected to an FCF.
• Ports that are configured to have FIP snooping disabled will not have any FIP or
FCoE related ACLs installed.
• Prevent transmission of all FCoE frames from an ENode prior to its successful
completion of login (FLOGI) to the FCF.
• After successful completion of FLOGI, ensure that the ENode uses only those
FCoE source addresses assigned to it by FCF.
• After successful completion of FLOGI, ensure that all ENode FCoE source
addresses originate from or are destined to the appropriate ENode port.
• After successful completion of each FLOGI, ensure that FCoE frames may only
be addressed to the FCFs that accept them.

Initially, a basic set of FCoE-related ACLs will be installed on all ports where FIP
snooping is enabled. As the switch encounters FIP frames and learns about FCFs
and ENodes that are attached or disconnect, ACLs are dynamically installed or
expanded to provide appropriate security.

When an FCoE connection logs out, or times out (if ACL timeout is enabled), the
related ACLs will be automatically removed.

FCoE-related ACLs are independent of manually configured ACLs used for regular
Ethernet purposes (see “Access Control Lists” on page 79). FCoE ACLs generally
have a higher priority over standard ACLs, and do not inhibit non-FCoE and non-FIP
traffic.

FCoE VLANs
FCoE packets to any FCF will be confined to the VLAN advertised by the FCF
(typically VLAN 1002). The appropriate VLAN must be configured on the switch with
member FCF ports and must be supported by the participating CNAs. The switch
will then automatically add ENode ports to the appropriate VLAN and enable
tagging on those ports.
Note: If using Emulex CNA, you must create the FCoE VLAN add the ENode and
FCF ports to that VLAN using the CLI.

226 RackSwitch G8124: Application Guide

Viewing FIP Snooping Information
ACLs automatically generated under FIP snooping are independent of regular,
manually configure ACLs, and are not listed with regular ACLs in switch information
and statistics output. Instead, FCoE ACLs are shown using the following CLI
commands:

RS G8124# show fcoe fips information (Show all FIP-related information)

RS G8124# show fcoe fips port <ports> information (Show FIP info for a selected port)

For example:

RS G8124# show fcoe fips port 21 information

FIP Snooping on port 21:

This port has been configured to automatically detect FCF.
It has currently detected to have 0 FCF connecting to it.

FIPS ACLs configured on this port:

SMAC 00:05:73:ce:96:67, action deny.
DMAC 00:05:73:ce:96:67, ethertype 0x8914, action permit.
SMAC 0e:fc:00:44:04:04, DMAC 00:05:73:ce:96:67, ethertype 0x8906, vlan
1002, action permit.
DMAC 01:10:18:01:00:01, Ethertype 0x8914, action permit.
DMAC 01:10:18:01:00:02, Ethertype 0x8914, action permit.
Ethertype 0x8914, action deny.
Ethertype 0x8906, action deny.
SMAC 0e:fc:00:00:00:00, SMAC mask ff:ff:ff:00:00:00, action deny.

For each ACL, the required traffic criteria are listed, along with the action taken
(permit or deny) for matching traffic. ACLs are listed in order of precedence and
evaluated in the order shown.

The administrator can also view other FCoE information:

RS G8124# show fcoe fips fcf (Show all detected FCFs)

RS G8124# show fcoe fips fcoe (Show all FCoE connections)

Operational Commands
The administrator may use the operational commands to delete FIP-related entries
from the switch.

To delete a specific FCF entry and all associated ACLs from the switch, use the
following command:

RS G8124# no fcoe fips fcf <FCF MAC address> [<VLAN number>]

© Copyright IBM Corp. 2014 Chapter 16: FCoE and CEE 227
FIP Snooping Configuration
In this example, as shown in Figure 28 on page 218, FCoE devices are connected
to port 2 for the FCF device, and port 3 for an ENode. FIP snooping can be
configured on these ports using the following ISCLI commands:
1. Enable VLAN tagging on the FCoE ports:

RS G8124(config)# interface port 2,3 (Select FCoE ports)

RS G8124(config-if)# switchport mode trunk (Enable VLAN tagging)
RS G8124(config-if)# exit (Exit port configuration mode)

Note: If you are using Emulex CNA BE 2 - FCoE mode, you must enable PVID
tagging on the Enode ports.
2. Place FCoE ports into a VLAN supported by the FCF and CNAs (typically
VLAN 1002):

RS G8124(config)# vlan 1002 (Select a VLAN)

RS G8124(config-vlan)# exit (Exit VLAN configuration mode)
RS G8124(config)# interface port 2,3 (Add FCoE ports to the VLAN)
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan add 1002
RS G8124(config-if)# exit

Note: Placing ports into the VLAN (Step 2) after tagging is enabled (Step 1) helps
to ensure that their port VLAN ID (PVID) is not accidentally changed.
3. Turn CEE on.

RS G8124(config)# cee enable

Note: Turning CEE on will automatically change some 802.1p QoS and 802.3x
standard flow control settings and menus (see “Turning CEE On or Off” on
page 221).
4. Turn global FIP snooping on:

RS G8124(config)# fcoe fips enable

5. If using Emulex CNA, disable automatic VLAN creation.

RS G8124(config)# no fcoe fips automatic-vlan

6. Enable FIP snooping on FCoE ports, and set the desired FCF mode:

RS G8124(config)# fcoe fips port 2 enable (Enable FIPS on port 2)

RS G8124(config)# fcoe fips port 2 fcf-mode on(Set as FCF connection)
RS G8124(config)# fcoe fips port 3 enable (Enable FIPS on port 3)
RS G8124(config)# fcoe fips port 3 fcf-mode off(Set as ENode connection)

Note: By default, FIP snooping is enabled on all ports and the FCF mode set for
automatic detection. The configuration in this step is unnecessary, if
default settings have not been changed, and is shown merely as a manual
configuration example.
7. Save the configuration.

228 RackSwitch G8124: Application Guide

Priority-Based Flow Control
Priority-based Flow Control (PFC) is defined in IEEE 802.1Qbb. PFC extends the
IEEE 802.3x standard flow control mechanism. Under standard flow control, when a
port becomes busy, the switch manages congestion by pausing all the traffic on the
port, regardless of the traffic type. PFC provides more granular flow control, allowing
the switch to pause specified types of traffic on the port, while other traffic on the
port continues.

PFC pauses traffic based on 802.1p priority values in the VLAN tag. The
administrator can assign different priority values to different types of traffic and then
enable PFC for up to two specific priority values: priority value 3, and one other. The
configuration can be applied globally for all ports on the switch. Then, when traffic
congestion occurs on a port (caused when ingress traffic exceeds internal buffer
thresholds), only traffic with priority values where PFC is enabled is paused. Traffic
with priority values where PFC is disabled proceeds without interruption but may be
subject to loss if port ingress buffers become full.

Although PFC is useful for a variety of applications, it is required for FCoE

implementation where storage (SAN) and networking (LAN) traffic are converged on
the same Ethernet links. Typical LAN traffic tolerates Ethernet packet loss that can
occur from congestion or other factors, but SAN traffic must be lossless and
requires flow control.

For FCoE, standard flow control would pause both SAN and LAN traffic during
congestion. While this approach would limit SAN traffic loss, it could degrade the
performance of some LAN applications that expect to handle congestion by
dropping traffic. PFC resolves these FCoE flow control issues. Different types of
SAN and LAN traffic can be assigned different IEEE 802.1p priority values. PFC can
then be enabled for priority values that represent SAN and LAN traffic that must be
paused during congestion, and disabled for priority values that represent LAN traffic
that is more loss-tolerant.

PFC requires CEE to be turned on (“Turning CEE On or Off” on page 221). When
CEE is turned on, PFC is enabled on priority value 3 by default. Optionally, the
administrator can also enable PFC on one other priority value, providing lossless
handling for another traffic type, such as for a business-critical LAN application.
Note: For any given port, only one flow control method can be implemented at any
given time: either PFC or standard IEEE 802.3x flow control.

© Copyright IBM Corp. 2014 Chapter 16: FCoE and CEE 229
Global Configuration
PFC requires CEE to be turned on (“Turning CEE On or Off” on page 221). When
CEE is turned on, standard flow control is disabled on all ports, and PFC is enabled
on all ports for 802.1p priority value 3. While CEE is turned on, PFC cannot be
disabled for priority value 3. This default is chosen because priority value 3 is
commonly used to identify FCoE traffic in a CEE environment and must be
guaranteed lossless behavior. PFC is disabled for all other priority values by default,
but can be enabled for one additional priority value.
• Global PFC configuration is preferable in networks that implement end-to-end
CEE devices. For example, if all ports are involved with FCoE and can use the
same SAN and LAN priority value configuration with the same PFC settings,
global configuration is easy and efficient.
• Global PFC configuration can also be used in some mixed environments where
traffic with PFC-enabled priority values occurs only on ports connected to CEE
devices, and not on any ports connected to non-CEE devices. In such cases,
PFC can be configured globally on specific priority values even though not all
ports make use them.
• PFC is not restricted to CEE and FCoE networks. In any LAN where traffic is
separated into different priorities, PFC can be enabled on priority values for
loss-sensitive traffic.
• If you want to enable PFC on a priority, add the priority to a priority group with the
same number. For example, if you want to enable PFC on priority 0, you must
map priority 0 to PG 0.
Note: When using global PFC configuration in conjunction with the ETS feature
(see “Enhanced Transmission Selection” on page 232), ensure that only
pause-tolerant traffic (such as lossless FCoE traffic) is assigned priority
values where PFC is enabled. Pausing other types of traffic can have
adverse effects on LAN applications that expect uninterrupted traffic flow
and tolerate dropping packets during congestion.

230 RackSwitch G8124: Application Guide

PFC Configuration Example
Note: DCBX may be configured to permit sharing or learning PFC configuration
with or from external devices. This example assumes that PFC configuration
is being performed manually. See “Data Center Bridging Capability
Exchange” on page 239 for more information on DCBX. Even if the G8124
learns the PFC configuration from a DCBX peer, the PFC configuration must
be performed manually.

This example is consistent with the network shown in Figure 28 on page 218. In this
example, the following topology is used.
Table 22. PFC Configuration

Switch 802.1p PFC

Usage
Port Priority Setting

1-4 0-2 LAN Disabled

3 FCoE Enabled

4 Business-critical LAN Enabled

others (not used) Disabled

In this example, PFC is to facilitate lossless traffic handling for FCoE (priority value
3) and a business-critical LAN application (priority value 4).

Assuming that CEE is off (the G8124 default), the example topology shown in the
table above can be configured using the following commands:
1. Turn CEE on.

RS G8124(config)# cee enable

Note: Turning CEE on will automatically change some 802.1p QoS and 802.3x
standard flow control settings and menus (see “Turning CEE On or Off” on
page 221).
2. Enable PFC for the FCoE traffic.

Note: PFC is enabled on priority 3 by default. If using the defaults, the manual
configuration commands shown in this step are not necessary.

RS G8124(config)# cee global pfc priority 3 enable (Enable on FCoE priority)

RS G8124(config)# cee global pfc priority 3 description "FCoE"
(Optional description)

3. Enable PFC for the business-critical LAN application:

RS G8124(config)# cee global ets priority-group pgid 5 priority 5,6 pgid 4

bandwidth 20 pgid 5 bandwidth 20
RS G8124(config)# cee global pfc priority 4 enable ( Enable on LAN priority)
RS G8124(config)# cee global pfc priority 4 description "Critical LAN"
(Optional description)

4. Save the configuration.

© Copyright IBM Corp. 2014 Chapter 16: FCoE and CEE 231
Enhanced Transmission Selection
Enhanced Transmission Selection (ETS) is defined in IEEE 802.1Qaz. ETS
provides a method for allocating port bandwidth based on 802.1p priority values in
the VLAN tag. Using ETS, different amounts of link bandwidth can specified for
different traffic types (such as for LAN, SAN, and management).

ETS is an essential component in a CEE environment that carries different types of

traffic, each of which is sensitive to different handling criteria, such as Storage Area
Networks (SANs) that are sensitive to packet loss, and LAN applications that may
be latency-sensitive. In a single converged link, such as when implementing FCoE,
ETS allows SAN and LAN traffic to coexist without imposing contrary handling
requirements upon each other.

The ETS feature requires CEE to be turned on (see “Turning CEE On or Off” on
page 221).

802.1p Priority Values

Under the 802.1p standard, there are eight available priority values, with values
numbered 0 through 7, which can be placed in the priority field of the 802.1Q VLAN
tag:
16 bits 3 bits 1 12 bits

Tag Protocol ID (0x8100) Priority CF VLAN ID

I

0 15 16 32

Servers and other network devices may be configured to assign different priority
values to packets belonging to different traffic types (such as SAN and LAN).

ETS uses the assigned 802.1p priority values to identify different traffic types. The
various priority values are assigned to priority groups (PGID), and each priority
group is assigned a portion of available link bandwidth.

Priorities values within in any specific ETS priority group are expected to have
similar traffic handling requirements with respect to latency and loss.

802.1p priority values may be assigned by the administrator for a variety of

purposes. However, when CEE is turned on, the G8124 sets the initial default
values for ETS configuration as follows:
Figure 29. Default ETS Priority Groups

802.1p Bandwidth
Typical Traffic Type PGID
Priority Allocation
LAN 0
LAN 1 2 10%
LAN 2
SAN 3 3 50%
Latency-Sensitive LAN 4
Latency-Sensitive LAN 5 4 40%
Latency-Sensitive LAN 6
Network Management 7 15 -

232 RackSwitch G8124: Application Guide

 In the assignment model shown in Figure 29 on page 232, priorities values 0
through 2 are assigned for regular Ethernet traffic, which has “best effort” transport
characteristics.

Because CEE and ETS features are generally associated with FCoE, Priority 3 is
typically used to identify FCoE (SAN) traffic.

Priorities 4-7 are typically used for latency sensitive traffic and other important
business applications. For example, priority 4 and 5 are often used for video and
voice applications such as IPTV, Video on Demand (VoD), and Voice over IP (VoIP).
Priority 6 and 7 are often used for traffic characterized with a “must get there”
requirement, with priority 7 used for network control which is requires guaranteed
delivery to support configuration and maintenance of the network infrastructure.
Note: The default assignment of 802.1p priority values on the G8124 changes
depending on whether CEE is on or off. See “Turning CEE On or Off” on
page 221 for details.

Priority Groups
For ETS use, each 801.2p priority value is assigned to a priority group which can
then be allocated a specific portion of available link bandwidth. To configure a
priority group, the following is required:
• CEE must be turned on (“Turning CEE On or Off” on page 221) for the ETS
feature to function.
• A priority group must be assigned a priority group ID (PGID), one or more 802.1p
priority values, and allocated link bandwidth greater than 9%.

PGID
Each priority group is identified with number (0 through 7, and 15) known as the
PGID.

PGID 0 through 7 may each be assigned a portion of the switch’s available

bandwidth.

PGID 8 through 14 are reserved as per the 802.1Qaz ETS standard.

PGID 15 is a strict priority group. It is generally used for critical traffic, such as
network management. Any traffic with priority values assigned to PGID 15 is
permitted as much bandwidth as required, up to the maximum available on the
switch. After serving PGID 15, any remaining link bandwidth is shared among the
other groups, divided according to the configured bandwidth allocation settings.

Make sure all 802.1p priority values assigned to a particular PGID have similar
traffic handling requirements. For example, PFC-enabled traffic must not be
grouped with non-PFC traffic. Also, traffic of the same general type must be
assigned to the same PGID. Splitting one type of traffic into multiple 802.1p
priorities, and then assigning those priorities to different PGIDs may result in
unexpected network behavior.

Each 802.1p priority value may be assigned to only one PGID. However, each PGID
may include multiple priority values. Up to eight PGIDs may be configured at any
given time. However, no more than three ETS Priority Groups may include priority
values for which PFC is disabled.

© Copyright IBM Corp. 2014 Chapter 16: FCoE and CEE 233
 Assigning Priority Values to a Priority Group
Each priority group may be configured from its corresponding ETS Priority Group,
available using the following command:

RS G8124(config)# cee global ets priority-group pgid <group number (0-7, or 15)> priority
<priority list>

where priority list is one or more 802.1p priority values (with each separated by a
comma). For example, to assign priority values 0 through 2:

RS G8124(config)# cee global ets priority-group pgid <group number (0-7, or 15)> priority
0,1,2

Note: Within any specific PGID, the PFC settings (see “Priority-Based Flow
Control” on page 229) must be the same (enabled or disabled) for all priority
values within the group. PFC can be enabled only on priority value 3 and one
other priority. If the PFC setting is inconsistent within a PGID, an error is
reported when attempting to apply the configuration. Also, no more than
three ETS Priority Groups may include priority values for which PFC is
disabled.

When assigning priority values to a PGID, the specified priority value will be
automatically removed from its old group and assigned to the new group when the
configuration is applied.

Each priority value must be assigned to a PGID. Priority values may not be deleted
or unassigned. To remove a priority value from a PGID, it must be moved to another
PGID.

For PGIDs 0 through 7, bandwidth allocation can also be configured through the
ETS Priority Group menu. See for “Allocating Bandwidth” on page 235 for details.

Deleting a Priority Group

A priority group is automatically deleted when it contains no associated priority
values, and its bandwidth allocation is set to 0%.
Note: The total bandwidth allocated to PGID 0 through 7 must equal exactly 100%.
Reducing the bandwidth allocation of any group will require increasing the
allocation to one or more of the other groups (see “Allocating Bandwidth” on
page 235).

234 RackSwitch G8124: Application Guide

 Allocating Bandwidth
Allocated Bandwidth for PGID 0 Through 7
The administrator may allocate a portion of the switch’s available bandwidth to
PGIDs 0 through 7. Available bandwidth is defined as the amount of link bandwidth
that remains after priorities within PGID 15 are serviced (see “Unlimited Bandwidth
for PGID 15” on page 235), and assuming that all PGIDs are fully subscribed. If any
PGID does not fully consume its allocated bandwidth, the unused portion is made
available to the other priority groups.
Priority group bandwidth allocation can be configured using the following command:

RS G8124(config)# cee global ets priority-group pgid <priority group number> bandwidth
<bandwidth allocation> pgid

where bandwidth allocation represents the percentage of link bandwidth, specified as

a number between 10 and 100, in 1% increments, or 0.
The following bandwidth allocation rules apply:
• Bandwidth allocation must be 0% for any PGID that has no assigned 802.1p pri-
ority values.
• Any PGID assigned one or more priority values must have a bandwidth allocation
greater than 9%.
• Total bandwidth allocation for groups 0 through 7 must equal exactly 100%.
Increasing or reducing the bandwidth allocation of any PGID also requires
adjusting the allocation of other PGIDs to compensate.
• The total bandwidth allocated to all PGIDs which include priority values where
PFC is disabled must not exceed 50%.
If these conditions are not met, the switch will report an error when applying the
configuration.
To achieve a balanced bandwidth allocation among the various priority groups,
packets are scheduled according to a weighted deficit round-robin (WDRR)
algorithm. WDRR is aware of packet sizes, which can vary significantly in a CEE
environment, making WDRR more suitable than a regular weighted round-robin
(WRR) method, which selects groups based only on packet counts.
Note: Actual bandwidth used by any specific PGID may vary from configured
values by up to 10% of the available bandwidth in accordance with 802.1Qaz
ETS standard. For example, a setting of 10% may be served anywhere from
0% to 20% of the available bandwidth at any given time.

Unlimited Bandwidth for PGID 15

PGID 15 is permitted unlimited bandwidth and is generally intended for critical traffic
(such as switch management). Traffic in this group is given highest priority and is
served before the traffic in any other priority group.
If PGID 15 has low traffic levels, most of the switch’s bandwidth will be available to
serve priority groups 0 through 7. However, if PGID 15 consumes a larger part of the
switch’s total bandwidth, the amount available to the other groups is reduced.
Note: Consider traffic load when assigning priority values to PGID 15. Heavy traffic
in this group may restrict the bandwidth available to other groups.

© Copyright IBM Corp. 2014 Chapter 16: FCoE and CEE 235
Configuring ETS
Consider an example consistent with that used forPFC configuration (on
page 231):1
Table 23. ETS Configuration

Priority Usage PGID Bandwidth

0 LAN (best effort delivery)

1 LAN (best effort delivery) 2 10%

2 LAN (best effort delivery)

3 SAN (Fibre Channel over Ethernet, with PFC) 3 20%

4 Business Critical LAN (lossless Ethernet, with 4

30%
PFC)

5 Latency-sensitive LAN
5 40%
6 Latency-sensitive LAN

7 Network Management (strict) 15 unlimited

The example shown in Table 23 is only slightly different than the default
configuration shown in Figure 29 on page 232. In this example, latency-sensitive
LAN traffic (802.1p priority 5 through 6) are moved from priority group 4 to priority
group 5. This leaves Business Critical LAN traffic (802.1p priority 4) in priority group
4 by itself. Also, a new group for network management traffic has been assigned.
Finally, the bandwidth allocation for priority groups 3, 4, and 5 are revised.
Note: DCBX may be configured to permit sharing or learning PFC configuration
with or from external devices. This example assumes that PFC configuration
is being performed manually. See “Data Center Bridging Capability
Exchange” on page 239 for more information on DCBX.

This example can be configured using the following commands:

1. Turn CEE on.

RS G8124(config)# cee enable

Note: Turning CEE on will automatically change some 802.1p QoS and 802.3x
standard flow control settings and menus (see “Turning CEE On or Off” on
page 221).

236 RackSwitch G8124: Application Guide

 2. Configure each allocated priority group with a description (optional), list of
802.1p priority values, and bandwidth allocation:

RS G8124(config)# cee global ets priority-group pgid 2 priority 0,1,2

(Select a group for regular LAN, and
set for 802.1p priorities 0, 1, and 2)
RS G8124(config)# cee global ets priority-group pgid 2 description "Regular LAN"
(Set a group description—optional)
RS G8124(config)# cee global ets priority-group pgid 3 priority 3
(Select a group for SAN traffic, and
set for 802.1p priority 3)
RS G8124(config)# cee global ets priority-group pgid 3 description "SAN"
(Set a group description—optional)
RS G8124(config)# cee global ets priority-group pgid 4 priority 4
(Select a group for latency traffic,
and set for 802.1p priority 4)
RS G8124(config)# cee global ets priority-group pgid 4 description "Biz-Critical
LAN" (Set a group description—optional)

RS G8124(config)# cee global ets priority-group pgid 5 priority 5,6 pgid 4

bandwidth 20 pgid 5 bandwidth 20

3. Enable PFC on priority 4.

RS G8124(config)# cee global pfc priority 4 enable

RS G8124(config)# cee global ets priority-group pgid 2 bandwidth 10 pgid 3
bandwidth 20 pgid 4 bandwidth 30 pgid 5 bandwidth 40

4. Save the configuration.

To view the configuration, use the following command:

RS G8124(config)# show cee global ets

Current ETS Configuration:

Number of COSq: 8

Current Mapping of 802.1p Priority to Priority Groups:

Priority PGID COSq

-------- ---- ----
0 2 2
1 2 2
2 2 2
3 3 3
4 4 4
5 5 4
6 5 4
7 15 7

Current Bandwidth Allocation to Priority Groups:

PGID PG% Description

---- --- -----------
2 10 Regular LAN
3 20 SAN
4 30 Biz-Critical LAN
5 40 Latency-sensitive LAN
15 - Network Management

© Copyright IBM Corp. 2014 Chapter 16: FCoE and CEE 237
 RS G8124(config)# show cee global pfc

Current Global PFC Configuration:

PFC - ON

Priority State Description

-------- ----- -----------
0 Dis
1 Dis
2 Dis
3 Ena
4 Ena
5 Dis
6 Dis
7 Dis
-------------------------------------------------------------------------
State - indicates whether PFC is Enabled/Disabled on a particular
priority

238 RackSwitch G8124: Application Guide

Data Center Bridging Capability Exchange
Data Center Bridging Capability Exchange (DCBX) protocol is a vital element of
CEE. DCBX allows peer CEE devices to exchange information about their
advanced capabilities. Using DCBX, neighboring network devices discover their
peers, negotiate peer configurations, and detect misconfigurations.

DCBX provides two main functions on the G8124:

• Peer information exchange
The switch uses DCBX to exchange information with connected CEE devices.
For normal operation of any FCoE implementation on the G8124, DCBX must
remain enabled on all ports participating in FCoE.
• Peer configuration negotiation
DCBX also allows CEE devices to negotiate with each other for the purpose of
automatically configuring advanced CEE features such as PFC, ETS, and (for
some CNAs) FIP. The administrator can determine which CEE feature settings
on the switch are communicated to and matched by CEE neighbors, and also
which CEE feature settings on the switch may be configured by neighbor
requirements.

The DCBX feature requires CEE to be turned on (see “Turning CEE On or Off” on
page 221).

© Copyright IBM Corp. 2014 Chapter 16: FCoE and CEE 239
DCBX Settings
When CEE is turned on, DCBX is enabled for peer information exchange on all
ports. For configuration negotiation, the following default settings are configured:
• Application Protocol: FCoE and FIP snooping is set for traffic with 802.1p priority
3
• PFC: Enabled on 802.1p priority 3
• ETS
– Priority group 2 includes priority values 0 through 2, with bandwidth
allocation of 10%
– Priority group 3 includes priority value 3, with bandwidth allocation of 50%
– Priority group 4 includes priority values 4 through 7, with bandwidth
allocation of 40%

Enabling and Disabling DCBX

When CEE is turned on, DCBX can be enabled and disabled on a per-port basis,
using the following commands:

RS G8124(config)# [no] cee port <port alias or number> dcbx enable

Note: DCBX and vNICs (see “Virtual NICs” on page 181) are not supported
simultaneously on the same G8124.

When DCBX is enabled on a port, Link Layer Detection Protocol (LLDP) is used to
exchange DCBX parameters between CEE peers. Also, the interval for LLDP
transmission time is set to one second for the first five initial LLDP transmissions,
after which it is returned to the administratively configured value. The minimum
delay between consecutive LLDP frames is also set to one second as a DCBX
default.

240 RackSwitch G8124: Application Guide

 Peer Configuration Negotiation

CEE peer configuration negotiation can be set on a per-port basis for a number of
CEE features. For each supported feature, the administrator can configure two
independent flags:
• The advertise flag
When this flag is set for a particular feature, the switch settings will be transmit to
the remote CEE peer. If the peer is capable of the feature, and willing to accept
the G8124 settings, it will be automatically reconfigured to match the switch.
• The willing flag
Set this flag when required by the remote CEE peer for a particular feature as
part of DCBX signaling and support. Although some devices may also expect
this flag to indicate that the switch will accept overrides on feature settings, the
G8124 retains its configured settings. As a result, the administrator must
configure the feature settings on the switch to match those expected by the
remote CEE peer.

These flags are available for the following CEE features:

• Application Protocol
DCBX exchanges information regarding FCoE and FIP snooping, including the
802.1p priority value used for FCoE traffic. The advertise flag is set or reset
using the following command:

RS G8124(config)# [no] cee port <port alias or number> dcbx app_proto advertise

The willing flag is set or reset using the following command:

RS G8124(config)# [no] cee port <port alias or number> dcbx app_proto willing

• PFC
DCBX exchanges information regarding whether PFC is enabled or disabled on
the port. The advertise flag is set or reset using the following command:

RS G8124(config)# [no] cee port <port alias or number> dcbx pfc advertise

The willing flag is set or reset using the following command:

RS G8124(config)# [no] cee port <port alias or number> dcbx pfc willing

• ETS
DCBX exchanges information regarding ETS priority groups, including their
802.1p priority members and bandwidth allocation percentages. The
advertise flag is set or reset using the following command:

RS G8124(config)# [no] cee port <port alias or number> dcbx ets advertise

The willing flag is set or reset using the following command:

RS G8124(config)# [no] cee port <port alias or number> dcbx pfc willing

© Copyright IBM Corp. 2014 Chapter 16: FCoE and CEE 241
Configuring DCBX
Consider an example consistent Figure 28 on page 218 and used with the previous
FCoE examples in this chapter:
• FCoE is used on ports 2 and 3.
• CEE features are also used with LANs on ports 1 and 4.
• All other ports are disabled or are connected to regular (non-CEE) LAN devices.

In this example, the G8124 acts as the central point for CEE configuration.
FCoE-related ports will be configured for advertising CEE capabilities, but not to
accept external configuration. Other LAN ports that use CEE features will also be
configured to advertise feature settings to remote peers, but not to accept external
configuration. DCBX will be disabled on all non-CEE ports.

This example can be configured using the following commands:

1. Turn CEE on.

RS G8124(config)# cee enable

Note: Turning CEE on will automatically change some 802.1p QoS and 802.3x
standard flow control settings and menus (see “Turning CEE On or Off” on
page 221).
2. Enable desired DCBX configuration negotiation on FCoE ports:

RS G8124(config)# cee port 2 dcbx enable

RS G8124(config)# cee port 2 dcbx app_proto advertise
RS G8124(config)# cee port 2 dcbx ets advertise
RS G8124(config)# cee port 2 dcbx pfc advertise
RS G8124(config)# cee port 3 dcbx enable
RS G8124(config)# cee port 3 dcbx app_proto advertise
RS G8124(config)# cee port 3 dcbx ets advertise
RS G8124(config)# cee port 3 dcbx pfc advertise

3. Enable desired DCBX advertisements on other CEE ports:

RS G8124(config)# cee port 1 dcbx enable

RS G8124(config)# cee port 1 dcbx app_proto advertise
RS G8124(config)# cee port 1 dcbx ets advertise
RS G8124(config)# cee port 1 dcbx pfc advertise
RS G8124(config)# cee port 4 dcbx enable
RS G8124(config)# cee port 4 dcbx app_proto advertise
RS G8124(config)# cee port 4 dcbx ets advertise
RS G8124(config)# cee port 4 dcbx pfc advertise

4. Disable DCBX for each non-CEE port as appropriate:

RS G8124(config)# no cee port 5-24 dcbx enable

5. Save the configuration.

242 RackSwitch G8124: Application Guide

Part 5: IP Routing
This section discusses Layer 3 switching functions. In addition to switching traffic at
near line rates, the application switch can perform multi-protocol routing. This
section discusses basic routing and advanced routing protocols:
• Basic Routing
• Routed Ports
• IPv6 Host Management
• Routing Information Protocol (RIP)
• Internet Group Management Protocol (IGMP)
• Border Gateway Protocol (BGP)
• Open Shortest Path First (OSPF)
• Protocol Independent Multicast (PIM)

© Copyright IBM Corp. 2014 243

244 RackSwitch G8124: Application Guide
Chapter 17. Basic IP Routing
This chapter provides configuration background and examples for using the G8124
to perform IP routing functions. The following topics are addressed in this chapter:
• “IP Routing Benefits” on page 246
• “Routing Between IP Subnets” on page 246
• “Example of Subnet Routing” on page 247
• “ECMP Static Routes” on page 251
• “Dynamic Host Configuration Protocol” on page 253

© Copyright IBM Corp. 2014 245

IP Routing Benefits
The switch uses a combination of configurable IP switch interfaces and IP routing
options. The switch IP routing capabilities provide the following benefits:
• Connects the server IP subnets to the rest of the backbone network.
• Provides the ability to route IP traffic between multiple Virtual Local Area
Networks (VLANs) configured on the switch.

Routing Between IP Subnets

The physical layout of most corporate networks has evolved over time. Classic
hub/router topologies have given way to faster switched topologies, particularly now
that switches are increasingly intelligent. The G8124 is intelligent and fast enough to
perform routing functions at wire speed.

The combination of faster routing and switching in a single device allows you to
build versatile topologies that account for legacy configurations.

For example, consider a corporate campus that has migrated from a router-centric
topology to a faster, more powerful, switch-based topology. As is often the case, the
legacy of network growth and redesign has left the system with a mix of illogically
distributed subnets.

This is a situation that switching alone cannot cure. Instead, the router is flooded
with cross-subnet communication. This compromises efficiency in two ways:
• Routers can be slower than switches. The cross-subnet side trip from the switch
to the router and back again adds two hops for the data, slowing throughput
considerably.
• Traffic to the router increases, increasing congestion.

Even if every end-station could be moved to better logical subnets (a daunting task),
competition for access to common server pools on different subnets still burdens the
routers.

This problem is solved by using switches with built-in IP routing capabilities.

Cross-subnet LAN traffic can now be routed within the switches with wire speed
switching performance. This eases the load on the router and saves the network
administrators from reconfiguring every end-station with new IP addresses.

246 RackSwitch G8124: Application Guide

Example of Subnet Routing
Consider the role of the G8124 in the following configuration example:
Figure 30. Switch-Based Routing Topology
Default router:
205.21.17.1

IF 1
VLAN 1

IF 2 IF 4
VLAN 2 VLAN 4
IF 3
VLAN 3

Server subnet 1: Server subnet 3:

100.20.10.2-254 206.30.15.2-254

Server subnet 2:
131.15.15.2-254

The switch connects the Gigabit Ethernet and Fast Ethernet trunks from various
switched subnets throughout one building. Common servers are placed on another
subnet attached to the switch. A primary and backup router are attached to the
switch on yet another subnet.

Without Layer 3 IP routing on the switch, cross-subnet communication is relayed to

the default gateway (in this case, the router) for the next level of routing intelligence.
The router fills in the necessary address information and sends the data back to the
switch, which then relays the packet to the proper destination subnet using Layer 2
switching.

With Layer 3 IP routing in place on the switch, routing between different IP subnets
can be accomplished entirely within the switch. This leaves the routers free to
handle inbound and outbound traffic for this group of subnets.

© Copyright IBM Corp. 2014 Chapter 17: Basic IP Routing 247

Using VLANs to Segregate Broadcast Domains
If you want to control the broadcasts on your network, use VLANs to create distinct
broadcast domains. Create one VLAN for each server subnet, and one for the
router.

Configuration Example
This section describes the steps used to configure the example topology shown in
Figure 30 on page 247.
1. Assign an IP address (or document the existing one) for each router and each
server.
The following IP addresses are used:

Table 24. Subnet Routing Example: IP Address Assignments

Subnet Devices IP Addresses

1 Default router 205.21.17.1

2 Web servers 100.20.10.2-254

3 Database servers 131.15.15.2-254

4 Terminal Servers 206.30.15.2-254

2. Assign an IP interface for each subnet attached to the switch.

Since there are four IP subnets connected to the switch, four IP interfaces are
needed:

Table 25. Subnet Routing Example: IP Interface Assignments

Interface Devices IP Interface Address

IF 1 Default router 205.21.17.3

IF 2 Web servers 100.20.10.1

IF 3 Database servers 131.15.15.1

IF 4 Terminal Servers 206.30.15.1

3. Determine which switch ports and IP interfaces belong to which VLANs.

The following table adds port and VLAN information:

Table 26. Subnet Routing Example: Optional VLAN Ports

Devices IP Interface Switch Ports VLAN #

Default router 1 22 1

Web servers 2 1 and 2 2

Database servers 3 3 and 4 3

Terminal Servers 4 5 and 6 4

Note: To perform this configuration, you must be connected to the switch Industry
Standard Command Line Interface (ISCLI) as the administrator.

248 RackSwitch G8124: Application Guide

 4. Add the switch ports to their respective VLANs.
The VLANs shown in Table 26 are configured as follows:

RS G8124(config)# vlan 1
RS G8124(config-vlan)# exit
RS G8124(config)# interface port 22 (Add ports to VLAN 1)
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 1
RS G8124(config-if)# exit

RS G8124(config)# vlan 2
RS G8124(config-vlan)# exit
RS G8124(config)# interface port 1,2 (Add ports to VLAN 2)
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 2
RS G8124(config-if)# exit

RS G8124(config)# vlan 3
RS G8124(config-vlan)# exit
RS G8124(config)# interface port 3,4 (Add ports to VLAN 3)
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 3
RS G8124(config-if)# exit

RS G8124(config)# vlan 4
RS G8124(config-vlan)# exit
RS G8124(config)# interface port 5,6 (Add ports to VLAN 4)
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 4
RS G8124(config-if)# exit

Each time you add a port to a VLAN, you may get the following prompt:

Port 4 is an untagged port and its PVID is changed from 1 to 3.

© Copyright IBM Corp. 2014 Chapter 17: Basic IP Routing 249

 5. Assign a VLAN to each IP interface.
Now that the ports are separated into VLANs, the VLANs are assigned to the
appropriate IP interface for each subnet. From Table 26 on page 248, the
settings are made as follows:

RS G8124(config)# interface ip 1 (Select IP interface 1)

RS G8124(config-ip-if)# ip address 205.21.17.3
RS G8124(config-ip-if)# ip netmask 255.255.255.0
RS G8124(config-ip-if)# vlan 1 (Add VLAN 1)
RS G8124(config-ip-if)# enable
RS G8124(config-vlan)# exit
RS G8124(config)# interface ip 2 (Select IP interface 2)
RS G8124(config-ip-if)# ip address 100.20.10.1
RS G8124(config-ip-if)# ip netmask 255.255.255.0
RS G8124(config-ip-if)# vlan 2 (Add VLAN 2)
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 3 (Select IP interface 3)
RS G8124(config-ip-if)# ip address 131.15.15.1
RS G8124(config-ip-if)# ip netmask 255.255.255.0
RS G8124(config-ip-if)# vlan 3 (Add VLAN 3)
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 4 (Select IP interface 4)
RS G8124(config-ip-if)# ip address 206.30.15.1
RS G8124(config-ip-if)# ip netmask 255.255.255.0
RS G8124(config-ip-if)# vlan 4 (Add VLAN 4)
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit

6. Configure the default gateway to the routers’ addresses.

The default gateway allows the switch to send outbound traffic to the router:

RS G8124(config)# ip gateway 1 address 205.21.17.1

RS G8124(config)# ip gateway 1 enable

7. Enable IP routing.

RS G8124(config)# ip routing

8. Verify the configuration.

RS G8124(config)# show vlan

RS G8124(config)# show interface information
RS G8124(config)# show interface ip

Examine the resulting information. If any settings are incorrect, make the
appropriate changes.

250 RackSwitch G8124: Application Guide

ECMP Static Routes
Equal-Cost Multi-Path (ECMP) is a forwarding mechanism that routes packets along
multiple paths of equal cost. ECMP provides equally-distributed link load sharing
across the paths. The hashing algorithm used is based on the destination IP and
source IP (DIPSIP) addresses or only on the source IP address (SIP). ECMP routes
allow the switch to choose between several next hops toward a given destination.
The switch performs periodic health checks (ping) on each ECMP gateway. If a
gateway fails, it is removed from the routing table, and an SNMP trap is sent.

ECMP Route Hashing

You can configure the parameters used to perform ECMP route hashing, as follows:
• sip: Source IP address
• dip: Destination IP address
• sport: Source port
• dport: Destination port
Note: Source port (sport) and/or destination port (dport) options for the ECMP
route hash (ip route ecmphash) are supported only when Layer 4 tcpl4
and/or udpl4 options are enabled. Conversely, when tcp14 and/or udpl4
are enabled, hashing options for sport and/or dport must also be
enabled.
• protocol: Layer 3 protocol
• tcpl4: Layer 4 TCP port
• udpl4: Layer 4 UDP port
Note: The default ECMP has mechanism is based on sip, dip, tcpl4, udpl4, and
dport.

The ECMP hash setting applies to all ECMP routes.

© Copyright IBM Corp. 2014 Chapter 17: Basic IP Routing 251

Configuring ECMP Static Routes
To configure ECMP static routes, add the same route multiple times, each with the
same destination IP address, but with a different gateway IP address. These routes
become ECMP routes.
1. Add a static route (IP address, subnet mask, gateway, and interface number).

RS G8124(config)# ip route 10.10.1.1 255.255.255.255 100.10.1.1 1

2. Add another static route with the same IP address and mask, but a different
gateway address.

RS G8124(config)# ip route 10.10.1.1 255.255.255.255 200.20.2.2 1

3. Select an ECMP hashing method (optional).

RS G8124(config)# ip route ecmphash [sip|dip|protocol|tcpl4|udpl4|

sport|dport]

You may add up to 16 gateways for each static route.

Use the following commands to check the status of ECMP static routes:

RS G8124(config)# show ip route static

Current static routes:
Destination Mask Gateway If ECMP
--------------- --------------- --------------- ---- ------
10.20.2.2 255.255.255.255 10.4.4.1 *
10.5.5.1 *
10.6.6.1 *
...
10.35.35.1 *
ECMP health-check ping interval: 1
ECMP health-check retries number: 3
ECMP Hash Mechanism: dipsip
Gateway healthcheck: enabled

RS G8124(config)# show ip ecmp

Current ecmp static routes:
Destination Mask Gateway If GW Status
--------------- --------------- --------------- ---- -----------
10.20.2.2 255.255.255.255 10.4.4.1 up
10.5.5.1 up
10.6.6.1 up
...
10.34.34.1 up
10.35.35.1 up

252 RackSwitch G8124: Application Guide

Dynamic Host Configuration Protocol
Dynamic Host Configuration Protocol (DHCP) is a transport protocol that provides a
framework for automatically assigning IP addresses and configuration information to
other IP hosts or clients in a large TCP/IP network. Without DHCP, the IP address
must be entered manually for each network device. DHCP allows a network
administrator to distribute IP addresses from a central point and automatically send
a new IP address when a device is connected to a different place in the network.

The switch accepts gateway configuration parameters if they have not been
configured manually. The switch ignores DHCP gateway parameters if the gateway
is configured.

DHCP is an extension of another network IP management protocol, Bootstrap

Protocol (BOOTP), with an additional capability of being able to allocate reusable
network addresses and configuration parameters for client operation.

Built on the client/server model, DHCP allows hosts or clients on an IP network to

obtain their configurations from a DHCP server, thereby reducing network
administration. The most significant configuration the client receives from the server
is its required IP address; (other optional parameters include the “generic” file name
to be booted, the address of the default gateway, and so forth).

To enable DHCP on a switch management interface, use the following command:

RS G8124(config)# system dhcp mgta

To configure DHCP operation on data interfaces, use the following command:

RS G8124(config)# system bootp

© Copyright IBM Corp. 2014 Chapter 17: Basic IP Routing 253

 DHCP Relay Agent

DHCP is described in RFC 2131, and the DHCP relay agent supported on the
G8124 is described in RFC 1542. DHCP uses UDP as its transport protocol. The
client sends messages to the server on port 67 and the server sends messages to
the client on port 68.

DHCP defines the methods through which clients can be assigned an IP address for
a finite lease period and allowing reassignment of the IP address to another client
later. Additionally, DHCP provides the mechanism for a client to gather other IP
configuration parameters it needs to operate in the TCP/IP network.

In the DHCP environment, the G8124 acts as a relay agent. The DHCP relay feature
enables the switch to forward a client request for an IP address to two BOOTP
servers with IP addresses that have been configured on the switch.

When a switch receives a UDP broadcast on port 67 from a DHCP client requesting
an IP address, the switch acts as a proxy for the client, replacing the client source IP
(SIP) and destination IP (DIP) addresses. The request is then forwarded as a UDP
Unicast MAC layer message to two BOOTP servers whose IP addresses are
configured on the switch. The servers respond as a UDP Unicast message back to
the switch, with the default gateway and IP address for the client. The destination IP
address in the server response represents the interface address on the switch that
received the client request. This interface address tells the switch on which VLAN to
send the server response to the client.

To enable the G8124 to be the BOOTP forwarder, you need to configure the
DHCP/BOOTP server IP addresses on the switch. Generally, it is best tomust
configure the switch IP interface on the client side to match the client’s subnet, and
configure VLANs to separate client and server subnets. The DHCP server knows
from which IP subnet the newly allocated IP address will come.

In G8124 implementation, there is no need for primary or secondary servers. The

client request is forwarded to the BOOTP servers configured on the switch. The use
of two servers provide failover redundancy. However, no health checking is
supported.

Use the following commands to configure the switch as a DHCP relay agent:

RS G8124(config)# ip bootp-relay server 1 <IP address>

RS G8124(config)# ip bootp-relay server 2 <IP address>
RS G8124(config)# ip bootp-relay enable
RS G8124(config)# show ip bootp-relay

Additionally, DHCP Relay functionality can be assigned on a per interface basis.

Use the following commands to enable the Relay functionality:

RS G8124(config)# interface ip <Interface number>

RS G8124(config-ip-if)# relay

254 RackSwitch G8124: Application Guide

Chapter 18. Routed Ports
By default, all ports on the RackSwitch G8124 behave as switch ports, which are
capable of performing Layer 2 switch functions, such as VLANs, STP, or bridging.
Switch ports also provide a physical point of access for the switch IP interfaces,
which can perform global Layer 3 functions, such as routing for BGP or OSPF.

However, G8124 ports can also be configured as routed ports. Routed ports are
configured with their own IP address belonging to a unique Layer 3 network, and
behave similar to a port on a conventional router. Routed ports are typically used for
connecting to a server or to a router.

When a switch port is configured as a routed port, it forwards Layer 3 traffic and no
longer performs Layer 2 switching functions.

Overview
A routed port has the following characteristics:
• Does not participate in bridging.
• Does not belong to any user-configurable VLAN.
• Does not implement any Layer 2 functionality, such as Spanning Tree Protocol
(STP).
• Is always in a forwarding state.
• Can participate in IPv4 routing.
• Can be configured with basic IP protocols, such as Internet Control Message
Protocol (ICMP), and with Layer 3 protocols, such as Protocol-Independent
Multicast (PIM), Routing Information Protocol (RIP), Open Shortest Path First
(OSPF), and Border Gateway Protocol (BGP).
• Can be configured with Internet Group Management Protocol (IGMP) querier
and snooping functionality.
• Layer 3 configuration is saved even when the interface is shutdown.
• MAC address learning is always enabled.
• Tagging and port VLAN ID (PVID) tagging is disabled.
• Flooding is disabled.
• Bridge Protocol Data Unit (BPDU)-guard is disabled.
• Link Aggregation Control Protocol (LACP) is disabled.
• Multicast threshold is disabled.
• Static Multicast MAC and static unicast MAC can be configured.

Note: Ports on which LACP or portchannel is enabled cannot be changed to

routed ports.

Note: Ports that have Static MAC addresses configured cannot be changed to
routed ports.

© Copyright IBM Corp. 2014 255

 When a switch port is configured as a routed port, the following configuration
changes are automatically implemented:
• The port is removed from all the VLANs it belonged to.
• The port is added to an internal VLAN on which flooding is disabled. The ID of
this internal VLAN could be 4094 or lower. The internal VLAN is assigned to
Spanning Tree Group (STG) 1, if RSTP/PVRST is configured; or to Common
Internal Spanning Tree (CIST), if MSTP is configured. You cannot change the
VLAN number assigned to the routed port.
• STP is disabled and the port is set to a forwarding state.

Note: The maximum number of VLANs you can configure on the RackSwitch
G8124 is 4095. This maximum number will be reduced by the number of
routed ports you configure.
• All the Layer 2 configuration is lost.

When a routed port is changed back to a switch port, the following changes take
place:
• All the IP configuration is lost.
• The ARP entry corresponding to the IP address is lost.
• The switch port is added to the default VLAN and STG. In case of MSTP, it is
added to the CIST.
• STP is turned on.
• The switch port can participate in STG and VLAN flooding.
• Can participate in bridging.
• LACP port attributes are set to default.
• Multicast threshold remains disabled.
• BPDU guard remains disabled.
• IGMP configuration is lost.
Note: When you configure a routed port to back to a switch port, it does not restore
the Layer 2 configuration it had before it was changed to a routed port.

256 RackSwitch G8124: Application Guide

Configuring a Routed Port
Note: Use only the ISCLI to configure routed ports. Configurations using BBI or
IBM N/OS CLI are not supported. Configurations made using SNMP cannot
be saved or applied.
Note: You cannot configure a management port to be a routed port.

Following are the basic steps for configuring a routed port:

1. Enter the interface configuration mode for the port.

RS G8124(config)# interface port <port number>

Note: You must enter only one port number. If you need to change multiple ports
to routed ports, repeat the configuration steps for each port.
2. Enable routing.

RS G8124(config-if)# no switchport

3. Assign an IP address.

RS G8124(config-if)# ip address <IP address> <Subnet Mask> enable

4. (Optional) Enable a Layer 3 routing protocol.

RS G8124(config-if)# ip {<ospf>|<pim>|<rip>}

Note: Configure the Layer 3 routing protocol-related parameters in the interface

configuration mode.

Configuring OSPF on Routed Ports

The following OSPF configuration commands are supported on routed ports:

RS G8124(config-if)# ip ospf ?

area Set area index

cost Set interface cost
dead-interval Set dead interval in seconds or milliseconds
enable Enable OSPF for this interface
hello-interval Set hello interval in seconds or milliseconds
key Set authentication key
message-digest-key Set MD5 key ID
passive-interface Enable passive interface
point-to-point Enable point-to-point interface
priority Set interface router priority
retransmit-interval Set retransmit interval in seconds
transit-delay Set transit delay in seconds

See Chapter 25, “OSPF for details on the OSPF protocol and its configuration.

OSPFv3 cannot be configured on routed ports.

© Copyright IBM Corp. 2014 Chapter 18: Routed Ports 257

 OSPF Configuration Example
The following example includes the basic steps for configuring OSPF on a routed
port:

RS G8124(config)# router ospf

RS G8124(config-router-ospf)# area 0 enable
RS G8124(config-router-ospf)# enable
RS G8124(config-router-ospf)# exit
RS G8124(config)# interface port 1
RS G8124(config-if)# no switchport
wait...
RS G8124(config-if)# ip address 11.1.12.1 255.255.255.0 enable
wait...
RS G8124(config-if)# ip ospf area 0
RS G8124(config-if)# ip ospf enable
RS G8124(config-if)# exit

Configuring RIP on Routed Ports

The following RIP configuration commands are supported on routed ports:

RS G8124(config-if)# ip rip ?

authentication Set IP authentication

default-action Set default route action
enable Enable RIP interface
listen Enable listening to route updates
metric Set metric
multicast-updates Enable multicast updates
poison Enable poisoned reverse
split-horizon Enable split horizon
supply Enable supplying route updates
triggered Enable triggered updates
version RIP version

See Chapter 21, “Routing Information Protocol for details on the RIP protocol and its
configuration.

RIP Configuration Example

The following example includes steps for a basic RIP configuration on a routed port:

RS G8124(config)# router rip

RS G8124(config-router-rip)# enable
RS G8124(config-router-rip)# exit
RS G8124(config)# interface port 1
RS G8124(config-if)# no switchport
wait...
RS G8124(config-if)# ip address 11.1.12.1 255.255.255.0 enable
wait...
RS G8124(config-if)# ip rip enable
RS G8124(config-if)# exit

258 RackSwitch G8124: Application Guide

Configuring PIM on Routed Ports
The following PIM configuration commands are supported on routed ports:

RS G8124(config-if)# ip pim ?

border-bit Set interface as border interface

cbsr-preference Set preference for local interface as a candidate
bootstrap router
component-id Add interface to the component
dr-priority Set designated router priority for the router
interface
enable Enable PIM on this interface
hello-holdtime Set hello message holdtime for the interface
hello-interval Set the frequency of PIM hello messages on the
interface
join-prune-interval Set frequency of PIM Join or Prune interval
lan-delay Set lan delay for the router interface
lan-prune-delay Enable lan delay advertisement on interface
neighbor-addr Neighbor address
neighbor-filter Enable neighbor filter
override-interval Set override interval for router interface

See Chapter 26, “Protocol Independent Multicast for details on the PIM protocol and
its configuration.

PIM Configuration Example

The following example includes the basic steps for configuring PIM on a routed port:

RS G8124(config)# ip pim enable

RS G8124(config)# interface port 26
RS G8124(config-if)# no switchport
wait...
RS G8124(config-if)# ip address 26.26.26.1 255.255.255.0 enable
wait...
RS G8124(config-if)# ip pim enable
RS G8124(config-if)# exit

RS G8124(config)# ip pim component 1

RS G8124(config-ip-pim-component)# rp-candidate rp-address 224.0.0.0 240.0.0.0
26.26.26.1
RS G8124(config-ip-pim-component)# rp-candidate holdtime 200
RS G8124(config-ip-pim-component)# exit

RS G8124(config)# interface port 26

RS G8124(config-if)# ip pim cbsr-preference 200
RS G8124(config-if)# exit

Verify the configuration using the following command:

RS G8124(config)# show ip pim interface port 26

Address IfName/IfId Ver/Mode Nbr Qry DR-Address DR-Prio

Count Interval
------- ----------- -------- ----- -------- ---------- -------
26.26.26.1 Rport 26 2/Sparse 0 30 26.26.26.1 1

© Copyright IBM Corp. 2014 Chapter 18: Routed Ports 259

Configuring BGP on Routed Ports
The routed port can be used to establish a TCP connection to form peer relationship
with another BGP router. See Chapter 24, “Border Gateway Protocol for details on
the BGP protocol and its configuration.

The following BGP configurations are not supported on routed ports:

• Update source - configuring a local IP interface

Configuring IGMP on Routed Ports

IGMP querier and snooping can be configured on routed ports. For details, see
Chapter 22, “Internet Group Management Protocol.

To configure IGMP snooping on a routed port, enter the following command in the
Global Configuration mode:

RS G8124(config)# ip igmp snoop port <routed port ID>

To configure fastleave on routed ports, enter the following command in the Global
Configuration mode:

RS G8124(config)# ip igmp snoop port <routed port ID> fast-leave

The following IGMP querier commands are supported on routed ports:

RS G8124(config)# ip igmp querier port <routed port ID> ?

election-type Set IGMP querier type

enable Turn IGMP Querier on
max-response Set Queriers max response time
query-interval Set general query interval for IGMP Querier only
robustness Set IGMP robustness
source-ip Set source IP to be used for IGMP
startup-count Set startupcount for IGMP
startup-interval Set startup query interval for IGMP
version Sets the operating version of the IGMP snooping switch

260 RackSwitch G8124: Application Guide

Limitations
Following features/configurations are not supported on routed ports:
• Subinterfaces
• BPDU Guard
• Broadcast Threshold
• Multicast Threshold
• Link Aggregation Control Protocol (LACP)
• Static Trunking
• Fibre Channel over Ethernet (FCoE)
• Converged Enhanced Ethernet (CEE)
• IPv6
• IP Security (IPsec)
• Internet Key Exchange version 2 (IKEv2)
• Virtual Router Redundancy Protocol (VRRP)
• Policy-based Routing (PBR)
• Hotlinks
• Failover
• 802.1X
• Dynamic Host Configuration Protocol (DHCP)
• BOOTP
• Simple Network Management Protocol (SNMP)
• IGMP Relay
• Static Mrouter Port
• Management Port

© Copyright IBM Corp. 2014 Chapter 18: Routed Ports 261

262 RackSwitch G8124: Application Guide
Chapter 19. Internet Protocol Version 6
Internet Protocol version 6 (IPv6) is a network layer protocol intended to expand the
network address space. IPv6 is a robust and expandable protocol that meets the
need for increased physical address space. The switch supports the following RFCs
for IPv6-related features:

• RFC 1981 • RFC 3306 • RFC 4007 • RFC 4443

• RFC 2404 • RFC 3307 • RFC 4213 • RFC 4552
• RFC 2410 • RFC 3411 • RFC 4291 • RFC 4718
• RFC 2451 • RFC 3412 • RFC 4292 • RFC 4835
• RFC 2460 • RFC 3413 • RFC 4293 • RFC 4861
• RFC 2474 • RFC 3414 • RFC 4301 • RFC 4862
• RFC 2526 • RFC 3484 • RFC 4302 • RFC 5095
• RFC 2711 • RFC 3602 • RFC 4303 • RFC 5114
• RFC 2740 • RFC 3810 • RFC 4306 • RFC 5340
• RFC 3289 • RFC 3879 • RFC 4307

This chapter describes the basic configuration of IPv6 addresses and how to
manage the switch via IPv6 host management.

IPv6 Limitations
The following IPv6 features are not supported in this release.
• Dynamic Host Control Protocol for IPv6 (DHCPv6)
• Border Gateway Protocol for IPv6 (BGP)
• Routing Information Protocol for IPv6 (RIPng)

Most other IBM Networking OS 7.11 features permit IP addresses to be configured

using either IPv4 or IPv6 address formats. However, the following switch features
support IPv4 only:
• Bootstrap Protocol (BOOTP) and DHCP
• RADIUS, TACACS+ and LDAP
• VMware Virtual Center (vCenter) for VMready
• Routing Information Protocol (RIP)
• Border Gateway Protocol (BGP)
• Protocol Independent Multicast (PIM)
• Virtual Router Redundancy Protocol (VRRP)
• sFlow

© Copyright IBM Corp. 2014 263

IPv6 Address Format
The IPv6 address is 128 bits (16 bytes) long and is represented as a sequence of
eight 16-bit hex values, separated by colons.

Each IPv6 address has two parts:

• Subnet prefix representing the network to which the interface is connected
• Local identifier, either derived from the MAC address or user-configured

The preferred hexadecimal format is as follows:

xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx

Example IPv6 address:

FEDC:BA98:7654:BA98:FEDC:1234:ABCD:5412

Some addresses can contain long sequences of zeros. A single contiguous

sequence of zeros can be compressed to :: (two colons). For example, consider the
following IPv6 address:
FE80:0:0:0:2AA:FF:FA:4CA2

The address can be compressed as follows:

FE80::2AA:FF:FA:4CA2

Unlike IPv4, a subnet mask is not used for IPv6 addresses. IPv6 uses the subnet
prefix as the network identifier. The prefix is the part of the address that indicates the
bits that have fixed values or are the bits of the subnet prefix. An IPv6 prefix is
written in address/prefix-length notation. For example, in the following address, 64
is the network prefix:
21DA:D300:0000:2F3C::/64

IPv6 addresses can be either user-configured or automatically configured.

Automatically configured addresses always have a 64-bit subnet prefix and a 64-bit
interface identifier. In most implementations, the interface identifier is derived from
the switch's MAC address, using a method called EUI-64.

Most IBM N/OS 7.11 features permit IP addresses to be configured using either
IPv4 or IPv6 address formats. Throughout this manual, IP address is used in places
where either an IPv4 or IPv6 address is allowed. In places where only one type of
address is allowed, the type (IPv4 or IPv6 is specified.

264 RackSwitch G8124: Application Guide

IPv6 Address Types
IPv6 supports three types of addresses: unicast (one-to-one), multicast
(one-to-many), and anycast (one-to-nearest). Multicast addresses replace the use
of broadcast addresses.

Unicast Address

Unicast is a communication between a single host and a single receiver. Packets

sent to a unicast address are delivered to the interface identified by that address.
IPv6 defines the following types of unicast address:
• Global Unicast address: An address that can be reached and identified globally.
Global Unicast addresses use the high-order bit range up to FF00, therefore all
non-multicast and non-link-local addresses are considered to be global unicast.
A manually configured IPv6 address must be fully specified. Autoconfigured IPv6
addresses are comprised of a prefix combined with the 64-bit EUI. RFC 4291
defines the IPv6 addressing architecture.
The interface ID must be unique within the same subnet.
• Link-local unicast address: An address used to communicate with a neighbor on
the same link. Link-local addresses use the format FE80::EUI
Link-local addresses are designed to be used for addressing on a single link for
purposes such as automatic address configuration, neighbor discovery, or when
no routers are present.
Routers must not forward any packets with link-local source or destination
addresses to other links.

Multicast

Multicast is communication between a single host and multiple receivers. Packets

are sent to all interfaces identified by that address. An interface may belong to any
number of multicast groups.

A multicast address (FF00 - FFFF) is an identifier for a group interface. The

multicast address most often encountered is a solicited-node multicast address
using prefix FF02::1:FF00:0000/104 with the low-order 24 bits of the unicast or
anycast address.

The following well-known multicast addresses are pre-defined. The group IDs
defined in this section are defined for explicit scope values, as follows:
FF00:::::::0 through FF0F:::::::0

Anycast

Packets sent to an anycast address or list of addresses are delivered to the nearest
interface identified by that address. Anycast is a communication between a single
sender and a list of addresses.

Anycast addresses are allocated from the unicast address space, using any of the
defined unicast address formats. Thus, anycast addresses are syntactically
indistinguishable from unicast addresses. When a unicast address is assigned to
more than one interface, thus turning it into an anycast address, the nodes to which
the address is assigned must be explicitly configured to know that it is an anycast
address.

© Copyright IBM Corp. 2014 Chapter 19: Internet Protocol Version 6 265
IPv6 Address Autoconfiguration
IPv6 supports the following types of address autoconfiguration:
• Stateful address configuration
Address configuration is based on the use of a stateful address configuration
protocol, such as DHCPv6, to obtain addresses and other configuration options.
• Stateless address configuration
Address configuration is based on the receipt of Router Advertisement
messages that contain one or more Prefix Information options.

N/OS 7.11 supports stateless address configuration.

Stateless address configuration allows hosts on a link to configure themselves with

link-local addresses and with addresses derived from prefixes advertised by local
routers. Even if no router is present, hosts on the same link can configure
themselves with link-local addresses and communicate without manual
configuration.

266 RackSwitch G8124: Application Guide

IPv6 Interfaces
Each IPv6 interface supports multiple IPv6 addresses. You can manually configure
up to two IPv6 addresses for each interface, or you can allow the switch to use
stateless autoconfiguration.

You can manually configure two IPv6 addresses for each interface, as follows:
• Initial IPv6 address is a global unicast or anycast address.

RS G8124(config)# interface ip <interface number>

RS G8124(config-ip-if)# ipv6 address <IPv6 address>

Note that you cannot configure both addresses as anycast. If you configure an
anycast address on the interface you must also configure a global unicast
address on that interface.
• Second IPv6 address can be a unicast or anycast address.

RS G8124(config-ip-if)# ipv6 secaddr6 <IPv6 address>

RS G8124(config-ip-if)# exit

You cannot configure an IPv4 address on an IPv6 management interface. Each

interface can be configured with only one address type: either IPv4 or IPv6, but not
both. When changing between IPv4 and IPv6 address formats, the prior address
settings for the interface are discarded.

Each IPv6 interface can belong to only one VLAN. Each VLAN can support only one
IPv6 interface. Each VLAN can support multiple IPv4 interfaces.

Use the following commands to configure the IPv6 gateway:

RS G8124(config)# ip gateway6 1 address <IPv6 address>

RS G8124(config)# ip gateway6 1 enable

IPv6 gateway 1 is reserved for IPv6 data interfaces. IPv6 gateway 4 is the default
IPv6 management gateway.

© Copyright IBM Corp. 2014 Chapter 19: Internet Protocol Version 6 267
Neighbor Discovery
Neighbor Discovery Overview

The switch uses Neighbor Discovery protocol (ND) to gather information about other
router and host nodes, including the IPv6 addresses. Host nodes use ND to
configure their interfaces and perform health detection. ND allows each node to
determine the link-layer addresses of neighboring nodes, and to keep track of each
neighbor’s information. A neighboring node is a host or a router that is linked directly
to the switch. The switch supports Neighbor Discovery as described in RFC 4861.

Neighbor Discover messages allow network nodes to exchange information, as

follows:
• Neighbor Solicitations allow a node to discover information about other nodes.
• Neighbor Advertisements are sent in response to Neighbor Solicitations. The
Neighbor Advertisement contains information required by nodes to determine the
link-layer address of the sender, and the sender’s role on the network.
• IPv6 hosts use Router Solicitations to discover IPv6 routers. When a router
receives a Router Solicitation, it responds immediately to the host.
• Routers uses Router Advertisements to announce its presence on the network,
and to provide its address prefix to neighbor devices. IPv6 hosts listen for Router
Advertisements, and uses the information to build a list of default routers. Each
host uses this information to perform autoconfiguration of IPv6 addresses.
• Redirect messages are sent by IPv6 routers to inform hosts of a better first-hop
address for a specific destination. Redirect messages are only sent by routers for
unicast traffic, are only unicast to originating hosts, and are only processed by
hosts.

ND configuration for general advertisements, flags, and interval settings, as well as

for defining prefix profiles for router advertisements, is performed on a per-interface
basis using the following command path:

RS G8124(config)# interface ip <interface number>

RS G8124(config-ip-if)# [no] ipv6 nd ?
RS G8124(config-ip-if)# exit

To add or remove entries in the static neighbor cache, use the following command
path:

RS G8124(config)# [no] ip neighbors ?

268 RackSwitch G8124: Application Guide

 Host vs. Router

Each IPv6 interface can be configured as a router node or a host node, as follows:
• A router node’s IP address is configured manually. Router nodes can send
Router Advertisements.
• A host node’s IP address can be autoconfigured. Host nodes listen for Router
Advertisements that convey information about devices on the network.
Note: When IP forwarding is turned on, all IPv6 interfaces configured on the switch
can forward packets.

You can configure each IPv6 interface as either a host node or a router node. You
can manually assign an IPv6 address to an interface in host mode, or the interface
can be assigned an IPv6 address by an upstream router, using information from
router advertisements to perform stateless auto-configuration.

To set an interface to host mode, use the following command:

RS G8124(config)# interface ip <interface number>

RS G8124(config-ip-if)# ip6host
RS G8124(config-ip-if)# exit

The G8124 supports up to 1156 IPv6 routes.

© Copyright IBM Corp. 2014 Chapter 19: Internet Protocol Version 6 269
Supported Applications
The following applications have been enhanced to provide IPv6 support.
• Ping
The ping command supports IPv6 addresses. Use the following format to ping
an IPv6 address:
ping <host name>|<IPv6 address> [-n <tries (0-4294967295)>]
[-w <msec delay (0-4294967295)>] [-l <length (0/32-65500/2080)>]
[-s <IP source>] [-v <TOS (0-255)>] [-f] [-t]
To ping a link-local address (begins with FE80), provide an interface index, as
follows:
ping <IPv6 address>%<Interface index> [-n <tries (0-4294967295)>]
[-w <msec delay (0-4294967295)>] [-l <length (0/32-65500/2080)>]
[-s <IP source>] [-v <TOS (0-255)>] [-f] [-t]
• Traceroute
The traceroute command supports IPv6 addresses (but not link-local
addresses).
Use the following format to perform a traceroute to an IPv6 address:
traceroute <host name>| <IPv6 address> [<max-hops (1-32)>
[<msec delay (1-4294967295)>]]
• Telnet server
The telnet command supports IPv6 addresses (but not link-local addresses).
Use the following format to Telnet into an IPv6 interface on the switch:
telnet <host name>| <IPv6 address> [<port>]
• Telnet client
The telnet command supports IPv6 addresses (but not link-local addresses).
Use the following format to Telnet to an IPv6 address:
telnet <host name>| <IPv6 address> [<port>]
• HTTP/HTTPS
The HTTP/HTTPS servers support both IPv4 and IPv6 connections.
• SSH
Secure Shell (SSH) connections over IPv6 are supported (but not link-local
addresses). The following syntax is required from the client:
ssh -u <IPv6 address>
Example:
ssh -u 2001:2:3:4:0:0:0:142
• TFTP
The TFTP commands support both IPv4 and IPv6 addresses. Link-local
addresses are not supported.
• FTP
The FTP commands support both IPv4 and IPv6 addresses. Link-local
addresses are not supported.

270 RackSwitch G8124: Application Guide

 • DNS client
DNS commands support both IPv4 and IPv6 addresses. Link-local addresses
are not supported. Use the following command to specify the type of DNS query
to be sent first:

RS G8124(config)# ip dns ipv6 request-version {ipv4|ipv6}

If you set the request version to ipv4, the DNS application sends an A query
first, to resolve the hostname with an IPv4 address. If no A record is found for
that hostname (no IPv4 address for that hostname) an AAAA query is sent to
resolve the hostname with a IPv6 address.
If you set the request version to ipv6, the DNS application sends an AAAA query
first, to resolve the hostname with an IPv6 address. If no AAAA record is found
for that hostname (no IPv6 address for that hostname) an A query is sent to
resolve the hostname with an IPv4 address.

Configuration Guidelines
When you configure an interface for IPv6, consider the following guidelines:
• Support for subnet router anycast addresses is not available.
• A single interface can accept either IPv4 or IPv6 addresses, but not both IPv4
and IPv6 addresses.
• A single interface can accept multiple IPv6 addresses.
• A single interface can accept only one IPv4 address.
• If you change the IPv6 address of a configured interface to an IPv4 address, all
IPv6 settings are deleted.
• A single VLAN can support only one IPv6 interface.
• Health checks are not supported for IPv6 gateways.
• IPv6 interfaces support Path MTU Discovery. The CPU’s MTU is fixed at 1500
bytes.
• Support for jumbo frames (1,500 to 9,216 byte MTUs) is limited. Any jumbo
frames intended for the CPU must be fragmented by the remote node. The
switch can re-assemble fragmented packets up to 9k. It can also fragment and
transmit jumbo packets received from higher layers.

© Copyright IBM Corp. 2014 Chapter 19: Internet Protocol Version 6 271
IPv6 Configuration Examples
This section provides steps to configure IPv6 on the switch.

IPv6 Example 1

The following example uses IPv6 host mode to autoconfigure an IPv6 address for
the interface. By default, the interface is assigned to VLAN 1.
1. Enable IPv6 host mode on an interface.

RS G8124(config)# interface ip 2
RS G8124(config-ip-if)# ip6host
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit

2. Configure the IPv6 default gateway.

RS G8124(config)# ip gateway6 1 address 2001:BA98:7654:BA98:FEDC:1234:ABCD:5412

RS G8124(config)# ip gateway6 1 enable

3. Verify the interface address.

RS G8124(config)# show interface ip 2

IPv6 Example 2

Use the following example to manually configure IPv6 on an interface.

1. Assign an IPv6 address and prefix length to the interface.

RS G8124(config)# interface ip 3
RS G8124(config-ip-if)# ipv6 address 2001:BA98:7654:BA98:FEDC:1234:ABCD:5214
RS G8124(config-ip-if)# ipv6 prefixlen 64
RS G8124(config-ip-if)# ipv6 seccaddr6 2003::1 32
RS G8124(config-ip-if)# vlan 2
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit

The secondary IPv6 address is compressed, and the prefix length is 32.
2. Configure the IPv6 default gateway.

RS G8124(config)# ip gateway6 1 address 2001:BA98:7654:BA98:FEDC:1234:ABCD:5412

RS G8124(config)# ip gateway6 1 enable

3. Configure router advertisements for the interface (optional)

RS G8124(config)# interface ip 3
RS G8124(config-ip-if)# no ipv6 nd suppress-ra

4. Verify the configuration.

RS G8124(config-ip-if)# show layer3

272 RackSwitch G8124: Application Guide

Chapter 20. IPsec with IPv6
Internet Protocol Security (IPsec) is a protocol suite for securing Internet Protocol
(IP) communications by authenticating and encrypting each IP packet of a
communication session. IPsec also includes protocols for establishing mutual
authentication between agents at the beginning of the session and negotiation of
cryptographic keys to be used during the session.

Since IPsec was implemented in conjunction with IPv6, all implementations of IPv6
must contain IPsec. To support the National Institute of Standards and Technology
(NIST) recommendations for IPv6 implementations, IBM Networking OS IPv6
feature compliance has been extended to include the following IETF RFCs, with an
emphasis on IP Security (IPsec) and Internet Key Exchange version 2, and
authentication/confidentiality for OSPFv3:
• RFC 4301 for IPv6 security
• RFC 4302 for the IPv6 Authentication Header
• RFCs 2404, 2410, 2451, 3602, and 4303 for IPv6 Encapsulating Security
Payload (ESP), including NULL encryption, CBC-mode 3DES and AES ciphers,
and HMAC-SHA-1-96.
• RFCs 4306, 4307, 4718, and 4835 for IKEv2 and cryptography
• RFC 4552 for OSPFv3 IPv6 authentication
• RFC 5114 for Diffie-Hellman groups
Note: This implementation of IPsec supports DH groups 1, 2, 5, 14, and 24.

The following topics are discussed in this chapter:

• “IPsec Protocols” on page 274
• “Using IPsec with the RackSwitch G8124” on page 275

© Copyright IBM Corp. 2014 Chapter 20: IPsec with IPv6 273
IPsec Protocols
The IBM N/OS implementation of IPsec supports the following protocols:
• Authentication Header (AH)
AHs provide connectionless integrity outand data origin authentication for IP
packets, and provide protection against replay attacks. In IPv6, the AH protects
the AH itself, the Destination Options extension header after the AH, and the IP
payload. It also protects the fixed IPv6 header and all extension headers before
the AH, except for the mutable fields DSCP, ECN, Flow Label, and Hop Limit. AH
is defined in RFC 4302.
• Encapsulating Security Payload (ESP)
ESPs provide confidentiality, data origin authentication, integrity, an anti-replay
service (a form of partial sequence integrity), and some traffic flow confidentiality.
ESPs may be applied alone or in combination with an AH. ESP is defined in RFC
4303.
• Internet Key Exchange Version 2 (IKEv2)
IKEv2 is used for mutual authentication between two network elements. An IKE
establishes a security association (SA) that includes shared secret information to
efficiently establish SAs for ESPs and AHs, and a set of cryptographic algorithms
to be used by the SAs to protect the associated traffic. IKEv2 is defined in RFC
4306.
Using IKEv2 as the foundation, IPsec supports ESP for encryption and/or
authentication, and/or AH for authentication of the remote partner.

Both ESP and AH rely on security associations. A security association (SA) is the
bundle of algorithms and parameters (such as keys) that encrypt and authenticate a
particular flow in one direction.

274 RackSwitch G8124: Application Guide

Using IPsec with the RackSwitch G8124
IPsec supports the fragmentation and reassembly of IP packets that occurs when
data goes to and comes from an external device. The RackSwitch G8124 acts as an
end node that processes any fragmentation and reassembly of packets but does not
forward the IPsec traffic. The IKEv2 key must be authenticated before you can use
IPsec.

The security protocol for the session key is either ESP or AH. Outgoing packets are
labeled with the SA SPI (Security Parameter Index), which the remote device will
use in its verification and decryption process.

Every outgoing IPv6 packet is checked against the IPsec policies in force. For each
outbound packet, after the packet is encrypted, the software compares the packet
size with the MTU size that it either obtains from the default minimum maximum
transmission unit (MTU) size (1500) or from path MTU discovery. If the packet size
is larger than the MTU size, the receiver drops the packet and sends a message
containing the MTU size to the sender. The sender then fragments the packet into
smaller pieces and retransmits them using the correct MTU size.

The maximum traffic load for each IPsec packet is limited to the following:
• IKEv2 SAs: 5
• IPsec SAs: 10 (5 SAs in each direction)
• SPDs: 20 (10 policies in each direction)

IPsec is implemented as a software cryptography engine designed for handling

control traffic, such as network management. IPsec is not designed for handling
data traffic, such as a VPN.

Setting up Authentication
Before you can use IPsec, you need to have key policy authentication in place.
There are two types of key policy authentication:
• Preshared key (default)
The parties agree on a shared, secret key that is used for authentication in an
IPsec policy. During security negotiation, information is encrypted before
transmission by using a session key created by using a Diffie-Hellman
calculation and the shared, secret key. Information is decrypted on the receiving
end using the same key. One IPsec peer authenticates the other peer's packet
by decryption and verification of the hash inside the packet (the hash inside the
packet is a hash of the preshared key). If authentication fails, the packet is
discarded.
• Digital certificate (using RSA algorithms)
The peer being validated must hold a digital certificate signed by a trusted
Certificate Authority and the private key for that digital certificate. The side
performing the authentication only needs a copy of the trusted certificate
authorities digital certificate. During IKEv2 authentication, the side being
validated sends a copy of the digital certificate and a hash value signed using the
private key. The certificate can be either generated or imported.
Note: During the IKEv2 negotiation phase, the digital certificate takes precedence
over the preshared key.

© Copyright IBM Corp. 2014 Chapter 20: IPsec with IPv6 275
 Creating an IKEv2 Proposal
With IKEv2, a single policy can have multiple encryption and authentication types,
as well as multiple integrity algorithms.

To create an IKEv2 proposal:

1. Enter IKEv2 proposal mode.

RS G8124(config)# ikev2 proposal

2. Set the DES encryption algorithm.

RS G8124(config-ikev2-prop)# encryption 3des|aes-cbc (default: 3des)

3. Set the authentication integrity algorithm type.

RS G8124(config-ikev2-prop)# integrity md5|sha1 (default: sha1)

4. Set the Diffie-Hellman group.

RS G8124(config-ikev2-prop)# group 1|2|5|14|24 (default: 24)

Importing an IKEv2 Digital Certificate

To import an IKEv2 digital certificate for authentication:
1. Import the CA certificate file.

RS G8124(config)# copy tftp ca-cert address <hostname or IPv4 address>

Source file name: <path and filename of CA certificate file>

Port type ["DATA"/"MGT"]: >
Confirm download operation [y/n]: y

2. Import the host key file.

RS G8124(config)# copy tftp host-key address <hostname or IPv4 address>

Source file name: <path and filename of host private key file>
Port type ["DATA"/"MGT"]: >
Confirm download operation [y/n]: y

3. Import the host certificate file.

RS G8124(config)# copy tftp host-cert address <hostname or IPv4 address>

Source file name: <path and filename of host certificate file>

Port type ["DATA"/"MGT"]: >
Confirm download operation [y/n]: y

Note: When prompted for the port to use for download the file, if you used a
management port to connect the switch to the server, enter mgt, otherwise
enter data.

276 RackSwitch G8124: Application Guide

 Generating an IKEv2 Digital Certificate
To create an IKEv2 digital certificate for authentication:
1. Create an HTTPS certificate defining the information you want to be used in the
various fields.

RS G8124(config)# access https generate-certificate

Country Name (2 letter code) [US]:
State or Province Name (full name) [CA]:
Locality Name (eg, city) [Santa Clara]:
Organization Name (eg, company) [IBM Networking Operating System]:
Organizational Unit Name (eg, section) [Network Engineering]:
Common Name (eg, YOUR name) [host’s IP address]:
Email (eg, email address) [info@IBM.com]:
Confirm generat‘eywing certificate? [y/n]: y
Generating certificate. Please wait (approx 30 seconds)
restarting SSL agent

2. Save the HTTPS certificate.

The certificate is valid only until the switch is rebooted. To save the certificate so
that it is retained beyond reboot or power cycles, use the following command:

RS G8124(config)# access https save-certificate

3. Enable IKEv2 RSA-signature authentication:

RS G8124(config)# access https enable

Enabling IKEv2 Preshared Key Authentication

To set up IKEv2 preshared key authentication:
1. Enter the local preshared key.

RS G8124(config)# ikev2 preshare-key local <preshared key, a string of 1-256 chars>

2. If asymmetric authentication is supported, enter the remote key:

RS G8124(config)# ikev2 preshare-key remote <preshared key> <IPv6 host>

where the following parameters are used:

– preshared keyA string of 1-256 characters
– IPv6 hostAn IPv6-format host, such as “3000::1”
3. Set up the IKEv2 identification type by entering one of the following commands:

RS G8124(config)# ikev2 identity local address (use an IPv6 address)

RS G8124(config)# ikev2 identity local email <email address>
RS G8124(config)# ikev2 identity local fqdn <domain name>

To disable IKEv2 RSA-signature authentication method and enable preshared key

authentication, enter:

RS G8124(config)# access https disable

© Copyright IBM Corp. 2014 Chapter 20: IPsec with IPv6 277
Setting Up a Key Policy
When configuring IPsec, you must define a key policy. This key policy can be either
manual or dynamic. Either way, configuring a policy involves the following steps:
• Create a transform set—This defines which encryption and authentication algo-
rithms are used.
• Create a traffic selector—This describes the packets to which the policy applies.
• Establish an IPsec policy.
• Apply the policy.
1. To define which encryption and authentication algorithms are used, create a
transform set:

RS G8124(config)# ipsec transform-set <transform ID> <encryption method> <integrity algorithm>

<AH authentication algorithm>

where the following parameters are used:

– transform IDA number from 1-10
– encryption methodOne of the following: esp-des | esp-3des | esp-aes-cbc |
esp-null
– integrity algorithmOne of the following: esp-sha1 | esp-md5 | none
– AH authentication algorithmOne of the following: ah-sha1 | ah-md5 | none
2. Decide whether to use tunnel or transport mode. The default mode is transport.

RS G8124(config)# ipsec transform-set tunnel|transport

3. To describe the packets to which this policy applies, create a traffic selector
using the following command:

RS G8124(config)# ipsec traffic-selector <traffic selector number> permit|deny any|icmp

<type|any> |tcp > <source IP address|any> <destination IP address|any> [<prefix length>]

where the following parameters are used:

– traffic selector numberan integer from 1-10
– permit|denywhether or not to permit IPsec encryption of traffic that meets
the criteria specified in this command
– anyapply the selector to any type of traffic
– icmp <type>|anyonly apply the selector only to ICMP traffic of the specified
type (an integer from 1-255) or to any ICMP traffic
– tcponly apply the selector to TCP traffic
– source IP address|anythe source IP address in IPv6 format or “any” source
– destination IP address|anythe destination IP address in IPv6 format or “any”
destination
– prefix length(Optional) the length of the destination IPv6 prefix; an integer
from 1-128
Permitted traffic that matches the policy in force is encrypted, while denied traffic
that matches the policy in force is dropped. Traffic that does not match the policy
bypasses IPsec and passes through clear (unencrypted).
4. Choose whether to use a manual or a dynamic policy.

278 RackSwitch G8124: Application Guide

Using a Manual Key Policy
A manual policy involves configuring policy and manual SA entries for local and
remote peers.
To configure a manual key policy, you need:
• The IP address of the peer in IPv6 format (for example, “3000::1”).
• Inbound/Outbound session keys for the security protocols.
You can then assign the policy to an interface. The peer represents the other end of
the security association. The security protocol for the session key can be either ESP
or AH.

To create and configure a manual policy:

1. Enter a manual policy to configure.

RS G8124(config)#ipsec manual-policy <policy number>

2. Configure the policy.

RS G8124(config-ipsec-manual)#peer <peer’s IPv6 address>

RS G8124(config-ipsec-manual)#traffic-selector <IPsec traffic selector>
RS G8124(config-ipsec-manual)#transform-set <IPsec transform set>
RS G8124(config-ipsec-manual)#in-ah auth-key <inbound AH IPsec key>
RS G8124(config-ipsec-manual)#in-ah auth-spi <inbound AH IPsec SPI>
RS G8124(config-ipsec-manual)#in-esp cipher-key <inbound ESP cipher key>
RS G8124(config-ipsec-manual)#in-esp auth-spi <inbound ESP SPI>
RS G8124(config-ipsec-manual)#in-esp auth-key <inbound ESP authenticator key>
RS G8124(config-ipsec-manual)#out-ah auth-key <outbound AH IPsec key>
RS G8124(config-ipsec-manual)#out-ah auth-spi <outbound AH IPsec SPI>
RS G8124(config-ipsec-manual)#out-esp cipher-key <outbound ESP cipher key>
RS G8124(config-ipsec-manual)#out-esp auth-spi <outbound ESP SPI>
RS G8124(config-ipsec-manual)#out-esp auth-key <outbound ESP authenticator key>

where the following parameters are used:

– peer’s IPv6 address The IPv6 address of the peer (for example,
3000::1)
– IPsec traffic-selector A number from1-10
– IPsec of transform-set A number from1-10
– inbound AH IPsec key The inbound AH key code, in hexadecimal
– inbound AH IPsec SPI A number from 256-4294967295
– inbound ESP cipher key The inbound ESP key code, in hexadecimal
– inbound ESP SPI A number from 256-4294967295
– inbound ESP authenticator keyThe inbound ESP authenticator key code, in
hexadecimal
– outbound AH IPsec key The outbound AH key code, in hexadecimal
– outbound AH IPsec SPI A number from 256-4294967295
– outbound ESP cipher key The outbound ESP key code, in hexadecimal
– outbound ESP SPI A number from 256-4294967295
– outbound ESP authenticator keyThe outbound ESP authenticator key code, in
hexadecimal

© Copyright IBM Corp. 2014 Chapter 20: IPsec with IPv6 279
 Note: When configuring a manual policy ESP, the ESP authenticator key is
optional.
Note: If using third-party switches, the IPsec manual policy session key must be of
fixed length as follows:
For AH key: SHA1 is 20 bytes; MD5 is 16 bytes
For ESP cipher key: 3DES is 24 bytes; AES-cbc is 24 bytes; DES is 8 bytes
For ESP auth key: SHA1 is 20 bytes; MD5 is 16 bytes
3. After you configure the IPSec policy, you need to apply it to the interface to
enforce the security policies on that interface and save it to keep it in place after
a reboot. To accomplish this, enter:

RS G8124(config-ip)#interface ip <IP interface number, 1-128>

RS G8124(config-ip-if)#address <IPv6 address>
RS G8124(config-ip-if)#ipsec manual-policy <policy index, 1-10>
RS G8124(config-ip-if)#enable (enable the IP interface)
RS G8124#write (save the current configuration)

280 RackSwitch G8124: Application Guide

Using a Dynamic Key Policy
When you use a dynamic key policy, the first packet triggers IKE and sets the IPsec
SA and IKEv2 SA. The initial packet negotiation also determines the lifetime of the
algorithm, or how long it stays in effect. When the key expires, a new key is
automatically created. This helps prevent break-ins.

To configure a dynamic key policy:

1. Choose a dynamic policy to configure.

RS G8124(config)#ipsec dynamic-policy <policy number>

2. Configure the policy.

RS G8124(config-ipsec-dynamic)#peer <peer’s IPv6 address>

RS G8124(config-ipsec-dynamic)#traffic-selector <index of traffic selector>
RS G8124(config-ipsec-dynamic)#transform-set <index of transform set>
RS G8124(config-ipsec-dynamic)#sa-lifetime <SA lifetime, in seconds>
RS G8124(config-ipsec-dynamic)#pfs enable|disable

where the following parameters are used:

– peer’s IPv6 address The IPv6 address of the peer (for example,
3000::1)
– index of traffic-selector A number from1-10
– index of transform-set A number from1-10
– SA lifetime, in seconds The length of time the SA is to remain in effect; an
integer from120-86400
– pfs enable|disable Whether to enable or disable the perfect forward
security feature. The default is disable.
Note: In a dynamic policy, the AH and ESP keys are created by IKEv2.
3. After you configure the IPSec policy, you need to apply it to the interface to
enforce the security policies on that interface and save it to keep it in place after
a reboot. To accomplish this, enter:

RS G8124(config-ip)#interface ip <IP interface number, 1-128>

RS G8124(config-ip-if)#address <IPv6 address>
RS G8124(config-ip-if)#ipsec dynamic-policy <policy index, 1-10>
RS G8124(config-ip-if)#enable (enable the IP interface)
RS G8124#write (save the current configuration)

© Copyright IBM Corp. 2014 Chapter 20: IPsec with IPv6 281
282 RackSwitch G8124: Application Guide
Chapter 21. Routing Information Protocol
In a routed environment, routers communicate with one another to keep track of
available routes. Routers can learn about available routes dynamically using the
Routing Information Protocol (RIP). IBM Networking OS software supports RIP
version 1 (RIPv1) and RIP version 2 (RIPv2) for exchanging TCP/IPv4 route
information with other routers.
Note: IBM N/OS 7.11 does not support IPv6 for RIP.

Distance Vector Protocol

RIP is known as a distance vector protocol. The vector is the network number
and next hop, and the distance is the metric associated with the network number.
RIP identifies network reachability based on metric, and metric is defined as hop
count. One hop is considered to be the distance from one switch to the next, which
typically is 1.

When a switch receives a routing update that contains a new or changed destination
network entry, the switch adds 1 to the metric value indicated in the update and
enters the network in the routing table. The IPv4 address of the sender is used as
the next hop.

Stability
RIP includes a number of other stability features that are common to many routing
protocols. For example, RIP implements the split horizon and hold-down
mechanisms to prevent incorrect routing information from being propagated.

RIP prevents routing loops from continuing indefinitely by implementing a limit on

the number of hops allowed in a path from the source to a destination. The
maximum number of hops in a path is 15. The network destination network is
considered unreachable if increasing the metric value by 1 causes the metric to be
16 (that is infinity). This limits the maximum diameter of a RIP network to less than
16 hops.

RIP is often used in stub networks and in small autonomous systems that do not
have many redundant paths.

© Copyright IBM Corp. 2014 283

Routing Updates
RIP sends routing-update messages at regular intervals and when the network
topology changes. Each router “advertises” routing information by sending a routing
information update every 30 seconds. If a router doesn’t receive an update from
another router for 180 seconds, those routes provided by that router are declared
invalid. The routes are removed from the routing table, but they remain in the RIP
routes table. After another 120 seconds without receiving an update for those
routes, the routes are removed from respective regular updates.

When a router receives a routing update that includes changes to an entry, it

updates its routing table to reflect the new route. The metric value for the path is
increased by 1, and the sender is indicated as the next hop. RIP routers maintain
only the best route (the route with the lowest metric value) to a destination.

For more information, see the Configuration section, Routing Information Protocol
Configuration in the IBM Networking OS Command Reference.

RIPv1
RIP version 1 use broadcast User Datagram Protocol (UDP) data packets for the
regular routing updates. The main disadvantage is that the routing updates do not
carry subnet mask information. Hence, the router cannot determine whether the
route is a subnet route or a host route. It is of limited usage after the introduction of
RIPv2. For more information about RIPv1 and RIPv2, refer to RFC 1058 and RFC
2453.

RIPv2
RIPv2 is the most popular and preferred configuration for most networks. RIPv2
expands the amount of useful information carried in RIP messages and provides a
measure of security. For a detailed explanation of RIPv2, refer to RFC 1723 and
RFC 2453.

RIPv2 improves efficiency by using multicast UDP (address 224.0.0.9) data packets
for regular routing updates. Subnet mask information is provided in the routing
updates. A security option is added for authenticating routing updates, by using a
shared password. N/OS supports using clear password for RIPv2.

RIPv2 in RIPv1 Compatibility Mode

N/OS allows you to configure RIPv2 in RIPv1compatibility mode, for using both
RIPv2 and RIPv1 routers within a network. In this mode, the regular routing updates
use broadcast UDP data packet to allow RIPv1 routers to receive those packets.
With RIPv1 routers as recipients, the routing updates have to carry natural or host
mask. Hence, it is not a recommended configuration for most network topologies.
Note: When using both RIPv1 and RIPv2 within a network, use a single subnet
mask throughout the network.

284 RackSwitch G8124: Application Guide

RIP Features
N/OS provides the following features to support RIPv1 and RIPv2:
Poison
Simple split horizon in RIP scheme omits routes learned from one neighbor in
updates sent to that neighbor. That is the most common configuration used in RIP,
that is setting this Poison to DISABLE. Split horizon with poisoned reverse includes
such routes in updates, but sets their metrics to 16. The disadvantage of using this
feature is the increase of size in the routing updates.
Triggered Updates
Triggered updates are an attempt to speed up convergence. When Triggered
Updates is enabled, whenever a router changes the metric for a route, it sends
update messages almost immediately, without waiting for the regular update
interval. It is recommended to enable Triggered Updates.
Multicast
RIPv2 messages use IPv4 multicast address (224.0.0.9) for periodic broadcasts.
Multicast RIPv2 announcements are not processed by RIPv1 routers. IGMP is not
needed since these are inter-router messages which are not forwarded.
To configure RIPv2 in RIPv1 compatibility mode, set multicast to disable, and set
version to both.
Default
The RIP router can listen and supply a default route, usually represented as IPv4
0.0.0.0 in the routing table. When a router does not have an explicit route to a
destination network in its routing table, it uses the default route to forward those
packets.
Metric
The metric field contains a configurable value between 1 and 15 (inclusive) which
specifies the current metric for the interface. The metric value typically indicates the
total number of hops to the destination. The metric value of 16 represents an
unreachable destination.
Authentication
RIPv2 authentication uses plaintext password for authentication. If configured using
Authentication password, then it is necessary to enter an authentication key value.
The following method is used to authenticate an RIP message:
• If the router is not configured to authenticate RIPv2 messages, then RIPv1 and
unauthenticated RIPv2 messages are accepted; authenticated RIPv2 messages
are discarded.
• If the router is configured to authenticate RIPv2 messages, then RIPv1
messages and RIPv2 messages which pass authentication testing are accepted;
unauthenticated and failed authentication RIPv2 messages are discarded.

For maximum security, RIPv1 messages are ignored when authentication is

enabled; otherwise, the routing information from authenticated messages is
propagated by RIPv1 routers in an unauthenticated manner.

© Copyright IBM Corp. 2014 Chapter 21: Routing Information Protocol 285
RIP Configuration Example
The following is an example of RIP configuration.
Note: An interface RIP disabled uses all the default values of the RIP, no matter
how the RIP parameters are configured for that interface. RIP sends out RIP
regular updates to include an UP interface, but not a DOWN interface.
1. Add VLANs for routing interfaces.

>> (config)# vlan 2

>> (config-vlan)# exit
>> (config)# interface port 2
>> (config-if)# switchport mode trunk
>> (config-if)# switchport trunk allowed vlan add 2
>> (config-if)# exit

Port 2 is an UNTAGGED port and its current PVID is 1.

Confirm changing PVID from 1 to 2 [y/n]: y
>> (config)# vlan 3
>> (config-vlan)# exit
>> (config)# interface port 3
>> (config-if)# switchport mode trunk
>> (config-if)# switchport trunk allowed vlan add 3
>> (config-if)# exit
Port 3 is an UNTAGGED port and its current PVID is 1.
Confirm changing PVID from 1 to 3 [y/n]: y

2. Add IP interfaces with IPv4 addresses to VLANs.

>> # interface ip 2
>> (config-ip-if)# enable
>> (config-ip-if)# ip address 102.1.1.1
>> (config-ip-if)# vlan 2
>> (config-ip-if)# exit
>> # interface ip 3
>> (config-ip-if)# enable
>> (config-ip-if)# ip address 103.1.1.1
>> (config-ip-if)# vlan 3

3. Turn on RIP globally and enable RIP for each interface.

>> # router rip

>> (config-router-rip)# enable
>> (config-router-rip)# exit
>> # interface ip 2
>> (config-ip-if)# ip rip enable
>> (config-ip-if)# exit
>> # interface ip 3
>> (config-ip-if)# ip rip enable
>> (config-ip-if)# exit

Use the following command to check the current valid routes in the routing table of
the switch:

>> # show ip route

286 RackSwitch G8124: Application Guide

 For those RIP routes learned within the garbage collection period, that are routes
phasing out of the routing table with metric 16, use the following command:

>> # show ip rip routes

Locally configured static routes do not appear in the RIP Routes table.

© Copyright IBM Corp. 2014 Chapter 21: Routing Information Protocol 287
288 RackSwitch G8124: Application Guide
Chapter 22. Internet Group Management Protocol
Internet Group Management Protocol (IGMP) is used by IPv4 Multicast routers
(Mrouters) to learn about the existence of host group members on their directly
attached subnet. The IPv4 Mrouters get this information by broadcasting IGMP
Membership Queries and listening for IPv4 hosts reporting their host group
memberships. This process is used to set up a client/server relationship between an
IPv4 multicast source that provides the data streams and the clients that want to
receive the data. The switch supports three versions of IGMP:
• IGMPv1: Defines the method for hosts to join a multicast group. However, this
version does not define the method for hosts to leave a multicast group. See
RFC 1112 for details.
• IGMPv2: Adds the ability for a host to signal its desire to leave a multicast group.
See RFC 2236 for details.
• IGMPv3: Adds support for source filtering by which a host can report interest in
receiving packets only from specific source addresses, or from all but specific
source addresses, sent to a particular multicast address. See RFC 3376 for
details.

The G8124 can perform IGMP Snooping, and connect to static Mrouters. The
G8124 can act as a Querier, and participate in the IGMP Querier election process.

The following topics are discussed in this chapter:

• “IGMP Terms” on page 290
• “How IGMP Works” on page 291
• “IGMP Capacity and Default Values” on page 292
• “IGMP Snooping” on page 293
• “Additional IGMP Features” on page 304

© Copyright IBM Corp. 2014 289

IGMP Terms
The following are commonly used IGMP terms:
• Multicast traffic: Flow of data from one source to multiple destinations.
• Group: A multicast stream to which a host can join. Multicast groups have IP
addresses in the range: 224.0.1.0 to 239.255.255.255.
• IGMP Querier: A router or switch in the subnet that generates Membership
Queries.
• IGMP Snooper: A Layer 3 device that forwards multicast traffic only to hosts that
are interested in receiving multicast data. This device can be a router or a Layer
3 switch.
• Multicast Router: A router configured to make routing decisions for multicast
traffic. The router identifies the type of packet received (unicast or multicast) and
forwards the packet to the intended destination.
• IGMP Proxy: A device that filters Join messages and Leave messages sent
upstream to the Mrouter to reduce the load on the Mrouter.
• Membership Report: A report sent by the host that indicates an interest in
receiving multicast traffic from a multicast group.
• Leave: A message sent by the host when it wants to leave a multicast group.
• FastLeave: A process by which the switch stops forwarding multicast traffic to a
port as soon as it receives a Leave message.
• Membership Query: Message sent by the Querier to verify if hosts are listening to
a group.
• General Query: A Membership Query sent to all hosts. The Group address field
for general queries is 0.0.0.0 and the destination address is 224.0.0.1.
• Group-specific Query: A Membership Query sent to all hosts in a multicast group.

290 RackSwitch G8124: Application Guide

How IGMP Works
When IGMP is not configured, switches forward multicast traffic through all ports,
increasing network load. When IGMPv2 is configured on a switch, multicast traffic
flows as follows:
• A server sends multicast traffic to a multicast group.
• The Mrouter sends Membership Queries to the switch, which forwards them to all
ports in a given VLAN.
• Hosts respond with Membership Reports if they want to join a group. The switch
forwards these reports to the Mrouter.
• The switch forwards multicast traffic only to hosts that have joined a group.
• The Mrouter periodically sends Membership Queries to ensure that a host wants
to continue receiving multicast traffic. If a host does not respond, the IGMP
Snooper stops sending traffic to the host.
• The host can initiate the Leave process by sending an IGMP Leave packet to the
IGMP Snooper.
• When a host sends an IGMPv2 Leave packet, the IGMP Snooper queries to find
out if any other host connected to the port is interested in receiving the multicast
traffic. If it does not receive a Join message in response, the IGMP Snooper
removes the group entry and passes on the information to the Mrouter.

The G8124 supports the following:

• IGMP version 1, 2, and 3
• 20 Mrouters (in default switch profile) / 128 Mrouters (in HFT switch profile)
Note: Unknown multicast traffic is sent to all ports if the flood option is enabled and
no Membership Report was learned for that specific IGMP group. If the flood
option is disabled, unknown multicast traffic is discarded if no hosts or
Mrouters are learned on a switch.
To enable or disable IGMP flood, use the following command:
RS G8124(config)# [no] ip ipmcfld

© Copyright IBM Corp. 2014 Chapter 22: Internet Group Management Protocol 291
IGMP Capacity and Default Values
The following table lists the maximum and minimum values of the G8124 variables.
Table 27. G8124 Capacity Table

Variable Maximum

IGMP Entries - Snoop 1000

VLANs - Snoop 1023

Static Mrouters 20

Dynamic Mrouters 20

Number of IGMP Filters 16

The following table lists the default settings for IGMP features and variables.
Table 28. IGMP Default Configuration Settings

Field Default Value

Global IGMP State Disabled

IGMP Querier Disabled

IGMP Snooping Disabled

IGMP Filtering Disabled

IP Multicast (IPMC) Flood Enabled

IGMP FastLeave Disabled for all VLANs

IGMP Mrouter Timeout 255 Seconds

IGMP Report Timeout Variable 10 Seconds

IGMP Query-Interval Variable 125 Seconds

IGMP Robustness Variable 2

IGMPv3 Disabled

IGMPv3 number of sources 8 (The switch processes only the first

eight sources listed in the IGMPv3 group
record.)

Valid range: 1 - 64

IGMPv3 - allow v1v2 Snooping Enabled

292 RackSwitch G8124: Application Guide

IGMP Snooping
IGMP Snooping allows a switch to listen to the IGMP conversation between hosts
and Mrouters. By default, a switch floods multicast traffic to all ports in a broadcast
domain. With IGMP Snooping enabled, the switch learns the ports interested in
receiving multicast data and forwards it only to those ports. IGMP Snooping
conserves network resources.

The switch can sense IGMP Membership Reports from attached hosts and acts as a
proxy to set up a dedicated path between the requesting host and a local IPv4
Mrouter. After the path is established, the switch blocks the IPv4 multicast stream
from flowing through any port that does not connect to a host member, thus
conserving bandwidth.

IGMP Querier
For IGMP Snooping to function, you must have an Mrouter on the network that
generates IGMP Query packets. Enabling the IGMP Querier feature on the switch
allows it to participate in the Querier election process. If the switch is elected as the
Querier, it will send IGMP Query packets for the LAN segment.

Querier Election

If multiple Mrouters exist on the network, only one can be elected as a Querier. The
Mrouters elect the one with the lowest source IPv4 address or MAC address as the
Querier. The Querier performs all periodic membership queries. All other Mrouters
(non-Queriers) do not send IGMP Query packets.
Note: When IGMP Querier is enabled on a VLAN, the switch performs the role of
an IGMP Querier only if it meets the IGMP Querier election criteria.

Each time the Querier switch sends an IGMP Query packet, it initializes a general
query timer. If a Querier receives a General Query packet from an Mrouter with a
lower IP address or MAC address, it transitions to a non-Querier state and initializes
an other querier present timer. When this timer expires, the Mrouter transitions back
to the Querier state and sends a General Query packet.

Follow this procedure to configure IGMP Querier.

1. Enable IGMP and configure the source IPv4 address for IGMP Querier on a
VLAN.

RS G8124(config)# ip igmp enable

RS G8124(config)# ip igmp querier vlan 2 source-ip 10.10.10.1

2. Enable IGMP Querier on the VLAN.

RS G8124(config)# ip igmp querier vlan 2 enable

3. Configure the querier election type and define the address.

RS G8124(config)# ip igmp querier vlan 2 election-type ipv4

© Copyright IBM Corp. 2014 Chapter 22: Internet Group Management Protocol 293
 4. Verify the configuration.

RS G8124# show ip igmp querier vlan 2

Current IGMP snooping Querier information:

IGMP Querier information for vlan 2:
Other IGMP querier - none
Switch-querier enabled, current state: Querier
Switch-querier type: Ipv4, address 10.10.10.1,
Switch-querier general query interval: 125 secs,
Switch-querier max-response interval: 100 'tenths of secs',
Switch-querier startup interval: 31 secs, count: 2
Switch-querier robustness: 2
IGMP configured version is v3
IGMP Operating version is v3

IGMP Groups
One IGMP entry is allocated for each unique join request, based on the VLAN and
IGMP group address. If multiple ports join the same IGMP group using the same
VLAN, only a single IGMP entry is used.

IGMPv3 Snooping
IGMPv3 includes new Membership Report messages that extend IGMP functionality.
The switch provides snooping capability for all types of IGMPv3 Membership Reports.

IGMPv3 supports Source-Specific Multicast (SSM). SSM identifies session traffic by

both source and group addresses.

The IGMPv3 implementation keeps records on the multicast hosts present in the
network. If a host is already registered, when it receives a new IS_INC, TO_INC,
IS_EXC, or TO_EXC report from same host, the switch makes the correct transition
to new (port-host-group) registration based on the IGMPv3 RFC. The registrations
of other hosts for the same group on the same port are not changed.

The G8124 supports the following IGMPv3 filter modes:

• INCLUDE mode: The host requests membership to a multicast group and pro-
vides a list of IPv4 addresses from which it wants to receive traffic.
• EXCLUDE mode: The host requests membership to a multicast group and provides
a list of IPv4 addresses from which it does not want to receive traffic. This indicates
that the host wants to receive traffic only from sources that are not part of the Exclude
list. To disable snooping on EXCLUDE mode reports, use the following command:

RS G8124(config)# no ip igmp snoop igmpv3 exclude

By default, the G8124 snoops the first eight sources listed in the IGMPv3 Group
Record. Use the following command to change the number of snooping sources:

RS G8124(config)# ip igmp snoop igmpv3 sources <1-64>

IGMPv3 Snooping is compatible with IGMPv1 and IGMPv2 Snooping. To disable

snooping on version 1 and version 2 reports, use the following command:

RS G8124(config)# no ip igmp snoop igmpv3 v1v2

294 RackSwitch G8124: Application Guide

IGMP Snooping Configuration Guidelines
Consider the following guidelines when you configure IGMP Snooping:
• IGMP operation is independent of the routing method. You can use RIP, OSPF, or
static routes for Layer 3 routing.
• When multicast traffic flood is disabled, the multicast traffic sent by the multicast
server is discarded if no hosts or Mrouters are learned on the switch.
• The Mrouter periodically sends IGMP Queries.
• The switch learns the Mrouter on the port connected to the router when it sees
Query messages. The switch then floods the IGMP queries on all other ports
including a Trunk Group, if any.
• Multicast hosts send IGMP Reports as a reply to the IGMP Queries sent by the
Mrouter.
• The switch can also learn an Mrouter when it receives a PIM hello packet from
another device. However, an Mrouter learned from a PIM packet has a lower
priority than an Mrouter learned from an IGMP Query. A switch overwrites an
Mrouter learned from a PIM packet when it receives an IGMP Query on the same
port.
• A host sends an IGMP Leave message to its multicast group. The expiration
timer for this group is updated to 10 seconds. The Layer 3 switch sends IGMP
Group-Specific Query to the host that had sent the Leave message. If the host
does not respond with an IGMP Report during these 10 seconds, all the groups
expire and the switch deletes the host from the IGMP groups table. The switch
then proxies the IGMP Leave messages to the Mrouter.

© Copyright IBM Corp. 2014 Chapter 22: Internet Group Management Protocol 295
IGMP Snooping Configuration Example
This section provides steps to configure IGMP Snooping on the G8124.
1. Configure port and VLAN membership on the switch.
2. Add VLANs to IGMP Snooping.

RS G8124(config)# ip igmp snoop vlan 1

3. Enable IGMPv3 Snooping (optional).

RS G8124(config)# ip igmp snoop igmpv3 enable

4. Enable the IGMP feature.

RS G8124(config)# ip igmp enable

5. View dynamic IGMP information.

RS G8124# show ip igmp groups

Command mode: All

Total entries: 5 Total IGMP groups: 2
Note: The <Total IGMP groups> number is computed as
the number of unique (Group, Vlan) entries!
Note: Local groups (224.0.0.x) are not snooped/relayed and will not appear.
Source Group VLAN Port Version Mode Expires Fwd
-------------- --------------- ------- ------ -------- ----- ------- ---
10.1.1.1 232.1.1.1 2 4 V3 INC 4:16 Yes
10.1.1.5 232.1.1.1 2 4 V3 INC 4:16 Yes
* 232.1.1.1 2 4 V3 INC - No
10.10.10.43 235.0.0.1 9 1 V3 EXC 2:26 No
* 235.0.0.1 9 1 V3 EXC - Yes

RS G8124# show ip igmp mrouter

SrcIP VLAN Port Version Expires MRT QRV QQIC

-------------------- ------- ------- --------- -------- ------- ---- ----

10.1.1.1 2 21 V3 4:09 128 2 125
10.1.1.5 2 23 V2 4:09 125 - -
10.10.10.43 9 24 V2 static unknown - -

These commands display information about IGMP Groups and Mrouters learned by
the switch.

296 RackSwitch G8124: Application Guide

Advanced Configuration Example: IGMP Snooping
Figure 31 shows an example topology. Switches B and C are configured with IGMP
Snooping.
Figure 31. Topology
Multicast Multicast Multicast Multicast
Host 1 Host 2 Host 3 Router

VLAN 2 VLANs 2,3 VLAN 3 VLANs 2,3

Switch B Trunk 3 Switch C

5 6 VLANs 2, 3
5 6
3 3
4 4
1 2 1 2
Switch A
Trunk 1 Trunk 2
VLANs 2, 3 VLANs 2, 3
2 4
1 3
5
VLANs 2,3

Multicast
Server

Devices in this topology are configured as follows:

• STG2 includes VLAN2; STG3 includes VLAN3.
• The multicast server sends IP multicast traffic for the following groups:
– VLAN 2, 225.10.0.11 – 225.10.0.12, Source: 22.10.0.11
– VLAN 2, 225.10.0.13 – 225.10.0.15, Source: 22.10.0.13
– VLAN 3, 230.0.2.1 – 230.0.2.2, Source: 22.10.0.1
– VLAN 3, 230.0.2.3 – 230.0.2.5, Source: 22.10.0.3
• The Mrouter sends IGMP Query packets in VLAN 2 and VLAN 3. The Mrouter’s
IP address is 10.10.10.10.
• The multicast hosts send the following IGMP Reports:
– IGMPv2 Report, VLAN 2, Group: 225.10.0.11, Source: *
– IGMPv2 Report, VLAN 3, Group: 230.0.2.1, Source: *
– IGMPv3 IS_INCLUDE Report, VLAN 2, Group: 225.10.0.13, Source:
22.10.0.13
– IGMPv3 IS_INCLUDE Report, VLAN 3, Group: 230.0.2.3, Source: 22.10.0.3

© Copyright IBM Corp. 2014 Chapter 22: Internet Group Management Protocol 297
 • The hosts receive multicast traffic as follows:
– Host 1 receives multicast traffic for groups (*, 225.10.0.11), (22.10.0.13,
225.10.0.13)
– Host 2 receives multicast traffic for groups (*, 225.10.0.11), (*, 230.0.2.1),
(22.10.0.13, 225.10.0.13), (22.10.0.3, 230.0.2.3)
– Host 3 receives multicast traffic for groups (*, 230.0.2.1), (22.10.0.3,
230.0.2.3)
• The Mrouter receives all the multicast traffic.

Prerequisites
Before you configure IGMP Snooping, ensure you have performed the following
actions:
• Configured VLANs.
• Enabled IGMP.
• Added VLANs to IGMP Snooping.
• Configured a switch or Mrouter as the Querier.
• Identified the IGMP version(s) you want to enable.
• Disabled IGMP flooding.

Configuration
This section provides the configuration details of the switches shown in Figure 31.

Switch A Configuration
1. Configure VLANs and tagging.

RS G8124(config)# interface port 1-5

RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 2,3
RS G8124(config-if)# exit

2. Configure an IP interface with IPv4 address, and assign a VLAN.

RS G8124(config)# interface ip 1
RS G8124(config-ip-if)# ip address 10.10.10.1 enable
RS G8124(config-ip-if)# vlan 2
RS G8124(config-ip-if)# exit

3. Assign a bridge priority lower than the default bridge priority to enable the
switch to become the STP root in STG 2 and 3.

RS G8124(config)# spanning-tree stp 2 bridge priority 4096

RS G8124(config)# spanning-tree stp 3 bridge priority 4096

298 RackSwitch G8124: Application Guide

 4. Configure LACP dynamic trunk groups (portchannels).

RS G8124(config)# interface port 1

RS G8124(config-if)# lacp key 100
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# exit

RS G8124(config)# interface port 2

RS G8124(config-if)# lacp key 100
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# exit

RS G8124(config)# interface port 3

RS G8124(config-if)# lacp key 200
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# exit

RS G8124(config)# interface port 4

RS G8124(config-if)# lacp key 200
RS G8124(config-if)# lacp mode active

Switch B Configuration
1. Configure VLANs and tagging.

RS G8124(config)# vlan 2,3

RS G8124(config-vlan)# interface port 1-4,6
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 2,3
RS G8124(config-if)# exit
RS G8124(config)# interface port 5
RS G8124(config-if)# switchport access vlan 2

2. Configure an IP interface with IPv4 address, and assign a VLAN.

RS G8124(config)# interface ip 1
RS G8124(config-ip-if)# ip address 10.10.10.2 enable
RS G8124(config-ip-if)# vlan 2
RS G8124(config-ip-if)# exit

3. Configure STP. Reset the ports to make the edge configuration operational.

RS G8124(config)# interface port 5,6

RS G8124(config-if)# spanning-tree portfast
RS G8124(config-if)# shutdown
RS G8124(config-if)# no shutdown
RS G8124(config-if)# exit

4. Configure an LACP dynamic trunk group (portchannel).

RS G8124(config)# interface port 1,2

RS G8124(config-if)# lacp key 300
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# exit

5. Configure a static trunk group (portchannel).

RS G8124(config)# portchannel 1 port 3,4 enable

© Copyright IBM Corp. 2014 Chapter 22: Internet Group Management Protocol 299
 6. Configure IGMP Snooping.

RS G8124(config)# ip igmp enable

RS G8124(config)# ip igmp snoop vlan 2,3
RS G8124(config)# ip igmp snoop source-ip 10.10.10.2
RS G8124(config)# ip igmp snoop igmpv3 enable
RS G8124(config)# ip igmp snoop igmpv3 sources 64
RS G8124(config)# ip igmp snoop enable
RS G8124(config)# no ip ipmcfld

Switch C Configuration
1. Configure VLANs and tagging.

RS G8124(config)# vlan 2,3

RS G8124(config-vlan)# interface port 1-4,6
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 2,3
RS G8124(config-if)# exit
RS G8124(config)# interface port 5
RS G8124(config-if)# switchport access vlan 3

2. Configure an IP interface with IPv4 address, and assign a VLAN.

RS G8124(config)# interface ip 1
RS G8124(config-ip-if)# ip address 10.10.10.3 enable
RS G8124(config-ip-if)# vlan 2
RS G8124(config-ip-if)# exit

3. Configure STP. Reset the ports to make the edge configuration operational.

RS G8124(config)# interface port 5,6

RS G8124(config-if)# spanning-tree portfast
RS G8124(config-if)# shutdown
RS G8124(config-if)# no shutdown
RS G8124(config-if)# exit

4. Configure an LACP dynamic trunk group (portchannel).

RS G8124(config)# interface port 1,2

RS G8124(config-if)# lacp key 400
RS G8124(config-if)# lacp mode active
RS G8124(config-if)# exit

5. Configure a static trunk group (portchannel).

RS G8124(config)# portchannel 1 port 3,4 enable

6. Configure IGMP Snooping.

RS G8124(config)# ip igmp enable

RS G8124(config)# ip igmp snoop vlan 2,3
RS G8124(config)# ip igmp snoop source-ip 10.10.10.3
RS G8124(config)# ip igmp snoop igmpv3 enable
RS G8124(config)# ip igmp snoop igmpv3 sources 64
RS G8124(config)# ip igmp snoop enable
RS G8124(config)# no ip ipmcfld

300 RackSwitch G8124: Application Guide

Troubleshooting
This section provides the steps to resolve common IGMP Snooping configuration
issues. The topology described in Figure 31 is used as an example.

Multicast traffic from non-member groups reaches the host or Mrouter

• Check if traffic is unregistered. For unregistered traffic, an IGMP entry is not
displayed in the IGMP groups table.

RS G8124# show ip igmp groups

• Ensure IPMC flooding is disabled.

RS G8124(config)# no ip ipmcfld

• Check the egress port’s VLAN membership. The ports to which the hosts and
Mrouter are connected must be used only for VLAN 2 and VLAN 3.

RS G8124# show vlan

Note: To avoid such a scenario, disable IPMC flooding for all VLANs enabled on
the switches (if this is an acceptable configuration).
• Check IGMP Reports on switches B and C for information about the IGMP
groups.

RS G8124# show ip igmp groups

If the non-member IGMP groups are displayed in the table, close the application
that may be sending the IGMP Reports for these groups.
Identify the traffic source by using a sniffer on the hosts and reading the source
IP/MAC address. If the source IP/MAC address is unknown, check the port
statistics to find the ingress port.

RS G8124# show interface port <port id> interface-counters

• Ensure no static multicast MACs, static multicast groups, or static Mrouters are
configured.
• Ensure PIM is not configured.

Not all multicast traffic reaches the appropriate receivers.

• Ensure hosts are sending IGMP Reports for all the groups. Check the VLAN on
which the groups are learned.

RS G8124# show ip igmp groups

If some of the groups are not displayed, ensure the multicast application is
running on the host device and the generated IGMP Reports are correct.
• Ensure multicast traffic reaches the switch to which the host is connected.
Close the application sending the IGMP Reports. Clear the IGMP groups by
disabling, then re-enabling the port.

© Copyright IBM Corp. 2014 Chapter 22: Internet Group Management Protocol 301
 Note: To clear all IGMP groups, use the following command:
RS G8124(config)# clear ip igmp groups
However, this will clear all the IGMP groups and will influence other hosts.
Check if the multicast traffic reaches the switch.

RS G8124# show ip igmp ipmcgrp

If the multicast traffic group is not displayed in the table, check the link state,
VLAN membership, and STP convergence.
• Ensure multicast server is sending all the multicast traffic.
• Ensure no static multicast MACs, static multicast groups, or static multicast
routes are configured.

IGMP queries sent by the Mrouter do not reach the host.

• Ensure the Mrouter is learned on switches B and C.

RS G8124# show ip igmp mrouter

If it is not learned on switch B but is learned on switch C, check the link state of
the trunk group, VLAN membership, and STP convergence.
If it is not learned on any switch, ensure the multicast application is running and
is sending correct IGMP Query packets.
If it is learned on both switches, check the link state, VLAN membership, and
STP port states for the ports connected to the hosts.

IGMP Reports/Leaves sent by the hosts do not reach the Mrouter

• Ensure IGMP Queries sent by the Mrouter reach the hosts.
• Ensure the Mrouter is learned on both switches. Note that the Mrouter may not
be learned on switch B immediately after a trunk group failover/failback.

RS G8124# show ip igmp mrouter

• Ensure the host’s multicast application is started and is sending correct IGMP
Reports/Leaves.

RS G8124# show ip igmp groups

RS G8124# show ip igmp counters

A host receives multicast traffic from the incorrect VLAN

• Check port VLAN membership.
• Check IGMP Reports sent by the host.
• Check multicast data sent by the server.

The Mrouter is learned on the incorrect trunk group

• Check link state. Trunk group 1 might be down or in STP discarding state.
• Check STP convergence.
• Check port VLAN membership.

302 RackSwitch G8124: Application Guide

 Hosts receive multicast traffic at a lower rate than normal
Note: This behavior is expected if IPMC flood is disabled. As soon as the
IGMP/IPMC entries are installed on ASIC, the IPMC traffic recovers and is
forwarded at line rate. This applies to unregistered IPMC traffic.
• Ensure a storm control is not configured on the trunks.

RS G8124(config)# interface port <port id>

RS G8124(config-if)# no storm-control multicast

• Check link speeds and network congestion.

© Copyright IBM Corp. 2014 Chapter 22: Internet Group Management Protocol 303
Additional IGMP Features
The following topics are discussed in this section:
• “FastLeave” on page 304
• “IGMP Filtering” on page 304
• “Static Multicast Router” on page 305

FastLeave
In normal IGMP operation, when the switch receives an IGMPv2 Leave message, it
sends a Group-Specific Query to determine if any other devices in the same group
(and on the same port) are still interested in the specified multicast group traffic. The
switch removes the affiliated port from that particular group, if the switch does not
receive an IGMP Membership Report within the query-response-interval.

With FastLeave enabled on the VLAN, a port can be removed immediately from the
port list of the group entry when the IGMP Leave message is received.
Note: Only IGMPv2 supports FastLeave. Enable FastLeave on ports that have
only one host connected. If more than one host is connected to a port, you
may lose some hosts unexpectedly.

Use the following command to enable FastLeave.

RS G8124(config)# ip igmp snoop vlan <VLAN number> fast-leave

IGMP Filtering
With IGMP filtering, you can allow or deny certain IGMP groups to be learned on a
port.

If access to a multicast group is denied, IGMP Membership Reports from the port
are dropped, and the port is not allowed to receive IPv4 multicast traffic from that
group. If access to the multicast group is allowed, Membership Reports from the
port are forwarded for normal processing.

To configure IGMP filtering, you must globally enable IGMP filtering, define an IGMP
filter, assign the filter to a port, and enable IGMP filtering on the port. To define an
IGMP filter, you must configure a range of IPv4 multicast groups, choose whether
the filter will allow or deny multicast traffic for groups within the range, and enable
the filter.

Configuring the Range

Each IGMP filter allows you to set a start and end point that defines the range of
IPv4 addresses upon which the filter takes action. Each IPv4 address in the range
must be between 224.0.0.0 and 239.255.255.255.

304 RackSwitch G8124: Application Guide

 Configuring the Action

Each IGMP filter can allow or deny IPv4 multicasts to the range of IPv4 addresses
configured. If you configure the filter to deny IPv4 multicasts, then IGMP
Membership Reports from multicast groups within the range are dropped. You can
configure a secondary filter to allow IPv4 multicasts to a small range of addresses
within a larger range that a primary filter is configured to deny. The two filters work
together to allow IPv4 multicasts to a small subset of addresses within the larger
range of addresses.
Note: Lower-numbered filters take precedence over higher-number filters. For
example, the action defined for IGMP filter 1 supersedes the action defined
for IGMP filter 2.

Configure IGMP Filtering

1. Enable IGMP filtering on the switch.

RS G8124(config)# ip igmp filtering

2. Define an IGMP filter with IPv4 information.

RS G8124(config)# ip igmp profile 1 range 224.0.0.0 226.0.0.0

RS G8124(config)# ip igmp profile 1 action deny
RS G8124(config)# ip igmp profile 1 enable

3. Assign the IGMP filter to a port.

RS G8124(config)# interface port 3

RS G8124(config-if)# ip igmp profile 1
RS G8124(config-if)# ip igmp filtering

Static Multicast Router

A static Mrouter can be configured for a particular port on a particular VLAN. A static
Mrouter does not have to be learned through IGMP Snooping. Any data port can
accept a static Mrouter.

When you configure a static Mrouter on a VLAN, it replaces any dynamic Mrouters
learned through IGMP Snooping.

Configure a Static Multicast Router

1. For each Mrouter, configure a port, VLAN, and IGMP version of the multicast
router.

RS G8124(config)# ip igmp mrouter 5 1 2

2. Verify the configuration.

RS G8124(config)# show ip igmp mrouter

© Copyright IBM Corp. 2014 Chapter 22: Internet Group Management Protocol 305
306 RackSwitch G8124: Application Guide
Chapter 23. Multicast Listener Discovery
Multicast Listener Discovery (MLD) is an IPv6 protocol that a host uses to request
multicast data for a multicast group. An IPv6 router uses MLD to discover the
presence of multicast listeners (nodes that want to receive multicast packets) on its
directly attached links, and to discover specifically the multicast addresses that are
of interest to those neighboring nodes.

MLD version 1 is derived from Internet Group Management Protocol version 2

(IGMPv2) and MLDv2 is derived from IGMPv3. MLD uses ICMPv6 (IP Protocol 58)
message types. See RFC 2710 and RFC 3810 for details.

MLDv2 protocol, when compared to MLDv1, adds support for source filtering—the
ability for a node to report interest in listening to packets only from specific source
addresses, or from all but specific source addresses, sent to a particular multicast
address. MLDv2 is interoperable with MLDv1. See RFC 3569 for details on
Source-Specific Multicast (SSM).

The following topics are discussed in this chapter:

• “MLD Terms” on page 308
• “How MLD Works” on page 309
• “MLD Capacity and Default Values” on page 311
• “Configuring MLD” on page 312

© Copyright IBM Corp. 2014 307

MLD Terms
Following are the commonly used MLD terms:
• Multicast traffic: Flow of data from one source to multiple destinations.
• Group: A multicast stream to which a host can join.
• Multicast Router (Mrouter): A router configured to make routing decisions for
multicast traffic. The router identifies the type of packet received (unicast or
multicast) and forwards the packet to the intended destination.
• Querier: An Mrouter that sends periodic query messages. Only one Mrouter on
the subnet can be elected as the Querier.
• Multicast Listener Query: Messages sent by the Querier. There are three types of
queries:
– General Query: Sent periodically to learn multicast address listeners from an
attached link. G8124 uses these queries to build and refresh the Multicast
Address Listener state. General Queries are sent to the link-scope all-nodes
multicast address (FF02::1), with a multicast address field of 0, and a
maximum response delay of query response interval.
– Multicast Address Specific Query: Sent to learn if a specific multicast
address has any listeners on an attached link. The multicast address field is
set to the IPv6 multicast address.
– Multicast Address and Source Specific Query: Sent to learn if, for a specified
multicast address, there are nodes still listening to a specific set of sources.
Supported only in MLDv2.
Note: Multicast Address Specific Queries and Multicast Address and Source
Specific Queries are sent only in response to State Change Reports, and
never in response to Current State Reports.
• Multicast Listener Report: Sent by a host when it joins a multicast group, or in
response to a Multicast Listener Query sent by the Querier. Hosts use these
reports to indicate their current multicast listening state, or changes in the
multicast listening state of their interfaces. These reports are of two types:
– Current State Report: Contains the current Multicast Address Listening State
of the host.
– State Change Report: If the listening state of a host changes, the host
immediately reports these changes through a State Change Report
message. These reports contain either Filter Mode Change records and/or
Source List Change records. State Change Reports are retransmitted
several times to ensure all Mrouters receive it.
• Multicast Listener Done: Sent by a host when it wants to leave a multicast group.
This message is sent to the link-scope all-routers IPv6 destination address of
FF02::2. When an Mrouter receives a Multicast Listener Done message from the
last member of the multicast address on a link, it stops forwarding traffic to this
multicast address.

308 RackSwitch G8124: Application Guide

How MLD Works
The software uses the information obtained through MLD to maintain a list of
multicast group memberships for each interface and forwards the multicast traffic
only to interested listeners.

Without MLD, the switch forwards IPv6 multicast traffic through all ports, increasing
network load. Following is an overview of operations when MLD is configured on the
G8124:
• The switch acts as an Mrouter when MLDv1/v2 is configured and enabled on
each of its directly attached links. If the switch has multiple interfaces connected
to the same link, it operates the protocol on any one of the interfaces.
• If there are multiple Mrouters on the subnet, the Mrouter with the numerically
lowest IPv6 address is elected as the Querier.
• The Querier sends general queries at short intervals to learn multicast address
listener information from an attached link.
• Hosts respond to these queries by reporting their per-interface Multicast Address
Listening state, through Current State Report messages sent to a specific
multicast address that all MLD routers on the link listen to.
• If the listening state of a host changes, the host immediately reports these
changes through a State Change Report message.
• The Querier sends a Multicast Address Specific Query to verify if hosts are
listening to a specified multicast address or not. Similarly, if MLDv2 is configured,
the Querier sends a Multicast Address and Source Specific Query to verify, for a
specified multicast address, if hosts are listening to a specific set of sources, or
not. MLDv2 listener report messages consists of Multicast Address Records:
– INCLUDE: to receive packets from source specified in the MLDv2 message
– EXCLUDE: to receive packets from all sources except the ones specified in
the MLDv2 message
• A host can send a State Change Report to indicate its desire to stop listening to
a particular multicast address (or source in MLDv2). The Querier then sends a
multicast address specific query to verify if there are other listeners of the
multicast address. If there aren’t any, the Mrouter deletes the multicast address
from its Multicast Address Listener state and stops sending multicast traffic.
Similarly in MLDv2, the Mrouter sends a Multicast Address and Source Specific
Query to verify if, for a specified multicast address, there are hosts still listening
to a specific set of sources.

G8124 supports MLD versions 1 and 2.

Note: MLDv2 operates in version 1 compatibility mode when, in a specific network,
not all hosts are configured with MLDv2.

© Copyright IBM Corp. 2014 Chapter 23: Multicast Listener Discovery 309
 How Flooding Impacts MLD

By default, the flood option is enabled to allow hardware flooding in VLAN for all
unknown IP multicast (IPMC) traffic. When the flood option is disabled, unknown
IPMC is sent only to the Mrouter ports.

Enter the following command to set the flood option:

RS G8124(config)# [no] ip ipmcfld

MLD Querier
An Mrouter acts as a Querier and periodically (at short query intervals) sends query
messages in the subnet. If there are multiple Mrouters in the subnet, only one can
be the Querier. All Mrouters on the subnet listen to the messages sent by the
multicast address listeners, and maintain the same multicast listening information
state.

All MLDv2 queries are sent with the FE80::/64 link-local source address prefix.

Querier Election

Only one Mrouter can be the Querier per subnet. All other Mrouters will be
non-Queriers. MLD versions 1 and 2 elect the Mrouter with the numerically lowest
IPv6 address as the Querier.

If the switch is configured as an Mrouter on a subnet, it also acts as a Querier by

default and sends multiple general queries. If the switch receives a general query
from another Querier with a numerically lower IPv6 address, it sets the other querier
present timer to the other querier present timeout, and changes its state to
non-Querier. When the other querier present timer expires, it regains the Querier
state and starts sending general queries.
Note: When MLD Querier is enabled on a VLAN, the switch performs the role of an
MLD Querier only if it meets the MLD Querier election criteria.

Dynamic Mrouters
The switch learns Mrouters on the ingress VLANs of the MLD-enabled interface. All
report or done messages are forwarded to these Mrouters. By default, the option of
dynamically learning Mrouters is disabled. To enable it, use the following command:

RS G8124(config)# interface ip <interface number>

RS G8124(config-ip-if)# ipv6 mld dmrtr enable

310 RackSwitch G8124: Application Guide

MLD Capacity and Default Values
Table 29 lists the maximum and minimum values of the G8124 variables.
Table 29. G8124 Capacity Table

Variable Maximum Value

IPv6 Multicast Entries 256

IPv6 Interfaces for MLD 8

Table 30 lists the default settings for MLD features and variables.
Table 30. MLD Timers and Default Values

Field Default Value

Robustness Variable (RV) 2

Query Interval (QI) 125 seconds

Query Response Interval (QRI) 10 seconds

Multicast Address Listeners Interval 260 seconds [derived: RV*QI+QRI]

(MALI)

Other Querier Present Interval [OQPT] 255 seconds [derived: RV*QI + ½ QRI]

Start up Query Interval [SQI] 31.25 seconds [derived: ¼ * QI]

Startup Query Count [SQC] 2 [derived: RV]

Last Listener Query Interval [LLQI] 1 second

Last Listener Query Count [LLQC] 2 [derived: RV]

Last Listener Query Time [LLQT] 2 seconds [derived: LLQI * LLQT]

Older Version Querier Present Timeout: 260 seconds [derived: RV*QI+ QRI]
[OVQPT]

Older Version Host Present Interval 260 seconds [derived: RV* QI+QRI]
[OVHPT]

© Copyright IBM Corp. 2014 Chapter 23: Multicast Listener Discovery 311
Configuring MLD
Following are the steps to enable MLD and configure the interface parameters:
1. Enable IPv6 boot profile.

RS G8124(config)# boot profile ipv6

RS G8124(config)# exit
RS G8124# reload

2. Turn on MLD globally.

RS G8124(config)# ipv6 mld

RS G8124(config-router-mld)# enable
RS G8124(config-router-mld)# exit

3. Create an IPv6 interface.

RS G8124(config)# interface ip 2
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# ipv6 address 2002:1:0:0:0:0:0:3
RS G8124(config-ip-if)# ipv6 prefixlen 64

4. Enable MLD on the IPv6 interface.

RS G8124(config-ip-if)# ipv6 mld enable

5. Configure the MLD parameters on the interface: version, robustness, query

response interval, MLD query interval, and last listener query interval.

RS G8124(config-ip-if)# ipv6 mld version <1-2>(MLD version)

RS G8124(config-ip-if)# ipv6 mld robust <1-10>(Robustness)
RS G8124(config-ip-if)# ipv6 mld qri <1-256> (In seconds)
RS G8124(config-ip-if)# ipv6 mld qintrval <1-608>(In seconds)
RS G8124(config-ip-if)# ipv6 mld llistnr <1-32>(In seconds)

312 RackSwitch G8124: Application Guide

Chapter 24. Border Gateway Protocol
Border Gateway Protocol (BGP) is an Internet protocol that enables routers on an
IPv4 network to share and advertise routing information with each other about the
segments of the IPv4 address space they can access within their network and with
routers on external networks. BGP allows you to decide what is the “best” route for
a packet to take from your network to a destination on another network rather than
simply setting a default route from your border router(s) to your upstream
provider(s). BGP is defined in RFC 1771.

RackSwitch G8124es can advertise their IP interfaces and IPv4 addresses using
BGP and take BGP feeds from as many as 96 BGP router peers. This allows more
resilience and flexibility in balancing traffic from the Internet.
Note: IBM Networking OS 7.11 does not support IPv6 for BGP.

The following topics are discussed in this section:

• “Internal Routing Versus External Routing” on page 313
• “Forming BGP Peer Routers” on page 317
• “Loopback Interfaces” on page 319
• “What is a Route Map?” on page 319
• “Aggregating Routes” on page 323
• “Redistributing Routes” on page 323
• “BGP Attributes” on page 325
• “Selecting Route Paths in BGP” on page 327
• “BGP Failover Configuration” on page 328
• “Default Redistribution and Route Aggregation Example” on page 330

Internal Routing Versus External Routing

To ensure effective processing of network traffic, every router on your network
needs to know how to send a packet (directly or indirectly) to any other
location/destination in your network. This is referred to as internal routing and can
be done with static routes or using active, internal dynamic routing protocols, such
as RIP, RIPv2, and OSPF.
Static routes must have a higher degree of precedence than dynamic routing
protocols. If the destination route is not in the route cache, the packets are
forwarded to the default gateway which may be incorrect if a dynamic routing
protocol is enabled.
It is also useful to tell routers outside your network (upstream providers or peers)
about the routes you can access in your network. External networks (those outside
your own) that are under the same administrative control are referred to as
autonomous systems (AS). Sharing of routing information between autonomous
systems is known as external routing.
External BGP (eBGP) is used to exchange routes between different autonomous
systems whereas internal BGP (iBGP) is used to exchange routes within the same
autonomous system. An iBGP is a type of internal routing protocol you can use to do
active routing inside your network. It also carries AS path information, which is
important when you are an ISP or doing BGP transit.

© Copyright IBM Corp. 2014 313

 The iBGP peers have to maintain reciprocal sessions to every other iBGP router in
the same AS (in a full-mesh manner) to propagate route information throughout the
AS. If the iBGP session shown between the two routers in AS 20 was not present
(as indicated in Figure 32), the top router would not learn the route to AS 50, and the
bottom router would not learn the route to AS 11, even though the two AS 20 routers
are connected via the RackSwitch G8124.
Figure 32. iBGP and eBGP

Internet

When there are many iBGP peers, having a full-mesh configuration results in large
number of sessions between the iBGP peers. In such situations, configuring a route
reflector eliminates the full-mesh configuration requirement, prevents route
propagation loops, and provides better scalability to the peers. For details, see
“Route Reflector” on page 314.
Typically, an AS has one or more border routers—peer routers that exchange routes
with other ASs—and an internal routing scheme that enables routers in that AS to
reach every other router and destination within that AS. When you advertise routes
to border routers on other autonomous systems, you are effectively committing to
carry data to the IPv4 space represented in the route being advertised. For
example, if you advertise 192.204.4.0/24, you are declaring that if another router
sends you data destined for any address in 192.204.4.0/24, you know how to carry
that data to its destination.

Route Reflector
The IBM N/OS implementation conforms to the BGP Route Reflection specification
defined in RFC 4456.

As per RFC 1771 specification, a route received from an iBGP peer cannot be
advertised to another iBGP peer. This makes it mandatory to have full-mesh iBGP
sessions between all BGP routers within an AS. A route reflector—a BGP router—
breaks this iBGP loop avoidance rule. It does not affect the eBGP behavior. A route
reflector is a BGP speaker that advertises a route learnt from an iBGP peer to
another iBGP peer. The advertised route is called the reflected route.

A route reflector has two groups of internal peers: clients and non-clients. A route
reflector reflects between these groups and among the clients. The non-client peers
must be fully meshed. The route reflector and its clients form a cluster.

314 RackSwitch G8124: Application Guide

 When a route reflector receives a route from an iBGP peer, it selects the best path
based on its path selection rule. It then does the following based on the type of peer
it received the best path from:
• A route received from a non-client iBGP peer is reflected to all clients.
• A route received from an iBGP client peer is reflected to all iBGP clients and
iBGP non-clients.
In Figure 33, the G8124 is configured as a route reflector. All clients and non-clients
are in the same AS.
Figure 33. iBGP Route Reflector

Cluster
RR Client RR Client

iBGP iBGP
Route Reflector

iBGP iBGP

iBGP

RR Non-Client RR Non-Client

The following attributes are used by the route reflector functionality:

• ORIGINATOR ID: BGP identifier (BGP router ID) of the route originator in the
local AS. If the route does not have the ORIGINATOR ID attribute (it has not
been reflected before), the router ID of the iBGP peer from which the route has
been received is copied into the Originator ID attribute.This attribute is never
modified by subsequent route reflectors. A router that identifies its own ID as the
ORIGINATOR ID, it ignores the route.
• CLUSTER LIST: Sequence of the CLUSTER ID (i.e. router ID) values
representing the reflection path that the route has passed. The value configured
with the cluster-id command (or the router ID of the route reflector if the
cluster-id is not configured) is prepended to the Cluster list attribute. If a
route reflector detects its own CLUSTER ID in the CLUSTER LIST, it ignores the
route. Up to 10 CLUSTER IDs can be added to a CLUSTER LIST.

© Copyright IBM Corp. 2014 Chapter 24: Border Gateway Protocol 315
 Route reflection functionality can be configured as follows:
1. Configure an AS.

RS G8124(config)# router bgp

RS G8124(config-router-bgp)# as 22
RS G8124(config-router-bgp)# enable

2. Configure a route reflector client.

RS G8124(config-router-bgp)# neighbor 2 remote-address 10.1.50.1

RS G8124(config-router-bgp)# neighbor 2 remote-as 22
RS G8124(config-router-bgp)# neighbor 2 route-reflector-client
RS G8124(config-router-bgp)# no neighbor 2 shutdown

Note: When a client is configured on the G8124, the switch automatically gets
configured as a route reflector.
3. Verify configuration.

RS G8124(config)# show ip bgp neighbor 2 information

BGP Peer 2 Information:

2: 10.1.50.1 , version 0, TTL 255, TTL Security hops 0
Remote AS: 0, Local AS: 22, Link type: IBGP
Remote router ID: 0.0.0.0, Local router ID: 9.9.9.9
next-hop-self disabled
RR client enabled
BGP status: connect, Old status: connect
Total received packets: 0, Total sent packets: 0
Received updates: 0, Sent updates: 0
Keepalive: 0, Holdtime: 0, MinAdvTime: 60
LastErrorCode: unknown(0), LastErrorSubcode: unspecified(0)
Established state transitions: 0

Once configured as a route reflector, the switch, by default, passes routes between
clients. If required, you can disable this by using the following command:

RS G8124(config-router-bgp)# no client-to-client reflection

You can view the route reflector BGP attributes attached to a BGP route using the
following command:

RS G8124(config-router-bgp)# show ip bgp information 5.0.0.0 255.255.255.0

BGP routing table entry for 5.0.0.0/255.255.255.0
Paths: (1 available, best #1)
Multipath: eBGP
Local
30.1.1.1 (metric 0) from 22.22.1.1(17.17.17.17)
Origin: IGP, localpref 0, valid, internal, best
Originator: 1.16.0.195
Cluster list: 17.17.17.17

316 RackSwitch G8124: Application Guide

 Restrictions
Consider the following restrictions when configuring route reflection functionality:
• When a CLUSTER ID is changed, all iBGP sessions are restarted.
• When a route reflector client is enabled/disabled, the session is restarted.

Forming BGP Peer Routers

Two BGP routers become peers or neighbors once you establish a TCP connection
between them. You can configure BGP peers statically or dynamically. While it may
be desirable to configure static peers for security reasons, dynamic peers prove to
be useful in cases where the remote address of the peer is unknown. For example
in B-RAS applications, where subscriber interfaces are dynamically created and the
address is assigned dynamically from a local pool or by using RADIUS.

For each new route, if a peer is interested in that route (for example, if a peer would
like to receive your static routes and the new route is static), an update message is
sent to that peer containing the new route. For each route removed from the route
table, if the route has already been sent to a peer, an update message containing
the route to withdraw is sent to that peer.

For each Internet host, you must be able to send a packet to that host, and that host
has to have a path back to you. This means that whoever provides Internet
connectivity to that host must have a path to you. Ultimately, this means that they must
“hear a route” which covers the section of the IPv4 space you are using; otherwise,
you will not have connectivity to the host in question.

Static Peers
You can configure BGP static peers by using the commands below:

RS G8124(config)# router bgp

RS G8124(config-router-bgp)# neighbor <1-96> remote-address <IP address>
RS G8124(config-router-bgp)# neighbor <1-96> remote-as <1-65535>
RS G8124(config-router-bgp)# no neighbor <1-96> shutdown

Static peers always take precedence over dynamic peers. Consider the following:
• If the remote address of an incoming BGP connection matches both a static peer
address and an IP address from a dynamic group, the peer is configured
statically and not dynamically.
• If a new static peer is enabled while a dynamic peer for the same remote address
exists, BGP automatically removes the dynamic peer.
• If a new static peer is enabled when the maximum number of BGP peers were
already configured, then BGP deletes the dynamic peer that was last created
and adds the newly created static peer. A syslog will be generated for the peer
that was deleted.

© Copyright IBM Corp. 2014 Chapter 24: Border Gateway Protocol 317
Dynamic Peers
To configure dynamic peers, you must define a range of IP addresses for a group.
BGP waits to receive an open message initiated from BGP speakers within that
range. Dynamic peers are automatically created when a peer group member
accepts the incoming BGP connection. Dynamic peers are passive. When they are
not in the established state, they accept inbound connections but do not initiate
outbound connections.

You can configure up to 6 AS numbers per group. When the BGP speaker receives
an open message from a dynamic peer, the AS number from the packet must match
one of the remote AS numbers configured on the corresponding group.

When you delete a remote AS number, all dynamic peers established from that
remote AS will be deleted.

You can define attributes for the dynamic peers only at the group level. You cannot
configure attributes for any one dynamic peer. All static peer attributes, except the
BGP passive mode, can also be configured for groups.

To set the maximum number of dynamic peers for a group that can simultaneously
be in an established state, enter the following command:

RS G8124(config-router-bgp)# neighbor group <1-8> listen limit <1-96>

If you reset this limit to a lower number, and if the dynamic peers already
established for the group are higher than this new limit, then BGP deletes the last
created dynamic peer(s) until the new limit is reached.
Note: The maximum number of static and dynamic peers established
simultaneously cannot exceed the maximum peers, i.e. 96, that the switch
can support. If the maximum peers are established, no more dynamic peers
will be enabled even if the maximum dynamic peers limit you had configured
for the groups was not reached.

Given below are the basic commands for configuring dynamic peers:

RS G8124(config)# router bgp

RS G8124(config-router-bgp)# neighbor group <1-8> listen range
<IP address> <subnet mask> (Define IP address range)
RS G8124(config-router-bgp)# neighbor group <1-8> remote-as <1-65535>
alternate-as <1-65535> (Enter up to 5 alternate AS numbers)
RS G8124(config-router-bgp)# no neighbor group <1-96> shutdown

Removing Dynamic Peers

You cannot remove dynamic peers manually. However, you can stop a dynamic
peer using the following command:

RS G8124(config)# router bgp stop <neighbor number>

The stop command interrupts the BGP connection until the peer tries to re-establish
the connection.

Also, when a dynamic peer state changes from established to idle, BGP removes
the dynamic peer.

318 RackSwitch G8124: Application Guide

Loopback Interfaces
In many networks, multiple connections may exist between network devices. In
such environments, it may be useful to employ a loopback interface for a common
BGP router address, rather than peering the switch to each individual interface.
Note: To ensure that the loopback interface is reachable from peer devices, it must
be advertised using an interior routing protocol (such as OSPF), or a static
route must be configured on the peer.

To configure an existing loopback interface for BGP neighbor, use the following
commands:

RS G8124(config)# router bgp

RS G8124(config-router-bgp)# neighbor <#> update-source loopback <1-5>
RS G8124(config-router-bgp)# exit

What is a Route Map?

A route map is used to control and modify routing information. Route maps define
conditions for redistributing routes from one routing protocol to another or controlling
routing information when injecting it in and out of BGP. For example, a route map is
used to set a preference value for a specific route from a peer router and another
preference value for all other routes learned via the same peer router. For example,
the following command is used to enter the Route Map mode for defining a route
map:

RS G8124(config)# route-map <map number> (Select a route map)

A route map allows you to match attributes, such as metric, network address, and
AS number. It also allows users to overwrite the local preference metric and to
append the AS number in the AS route. See “BGP Failover Configuration” on
page 328.

IBM N/OS allows you to configure 64 route maps. Each route map can have up to
eight access lists. Each access list consists of a network filter. A network filter
defines an IPv4 address and subnet mask of the network that you want to include in
the filter. Figure 34 illustrates the relationship between route maps, access lists, and
network filters.

© Copyright IBM Corp. 2014 Chapter 24: Border Gateway Protocol 319
 Figure 34. Distributing Network Filters in Access Lists and Route Maps

Route Maps Network Filter

(rmap) (nwf)
Access Lists
(alist)
1 1
---
Route Map 1 ---
---
8 8

1 9
---
Route Map 2 ---
---
8 16
-----
-----
-----
-----
-----
-----
----- 1 249
---
Route Map 64 ---
---
8 256

Next Hop Peer IP Address

Next hop peer IP address can be configured only for route maps used in BGP.
When a route map is applied on ingress, the next hop of learnt routes is replaced
with peer IP address. When applied on egress, the next hop of the redistributed
routes is replaced with the local IP address.

RS G8124(config)# route-map <map number>

RS G8124(config-router-map)# set ip next-hop <peer IP address>

Incoming and Outgoing Route Maps

You can have two types of route maps: incoming and outgoing. A BGP peer router
can be configured to support up to eight route maps in the incoming route map list
and outgoing route map list.

If a route map is not configured in the incoming route map list, the router imports all
BGP updates. If a route map is configured in the incoming route map list, the router
ignores all unmatched incoming updates. If you set the action to deny, you must add
another route map to permit all unmatched updates.

Route maps in an outgoing route map list behave similar to route maps in an
incoming route map list. If a route map is not configured in the outgoing route map
list, all routes are advertised or permitted. If a route map in the outgoing route map
list is set to permit, matched routes are advertised and unmatched routes are
ignored.

320 RackSwitch G8124: Application Guide

Precedence
You can set a priority to a route map by specifying a precedence value with the
following command (Route Map mode):

RS G8124(config)# route-map <map number> (Select a route map)

RS G8124(config-route-map)# precedence <1-255> (Specify a precedence)
RS G8124(config-route-map)# exit

The smaller the value the higher the precedence. If two route maps have the same
precedence value, the smaller number has higher precedence.

Configuration Overview
To configure route maps, you need to do the following:
1. Define a network filter.

RS G8124(config)# ip match-address 1 <IPv4 address> <IPv4 subnet mask>

RS G8124(config)# ip match-address 1 enable

Enter a filter number from 1 to 256. Specify the IPv4 address and subnet mask of
the network that you want to match. Enable the network filter. You can distribute
up to 256 network filters among 64 route maps each containing eight access
lists.

Steps 2 and 3 are optional, depending on the criteria that you want to match. In Step
2, the network filter number is used to match the subnets defined in the network
filter. In Step 3, the autonomous system number is used to match the subnets. Or,
you can use both (Step 2 and Step 3) criteria: access list (network filter) and access
path (AS filter) to configure the route maps.
2. (Optional) Define the criteria for the access list and enable it.
Specify the access list and associate the network filter number configured in
Step 1.

RS G8124(config)# route-map 1
RS G8124(config-route-map)# access-list 1 match-address 1
RS G8124(config-route-map)# access-list 1 metric <metric value>
RS G8124(config-route-map)# access-list 1 action deny
RS G8124(config-route-map)# access-list 1 enable

3. (Optional) Configure the AS filter attributes.

RS G8124(config-route-map)# as-path-list 1 as 1
RS G8124(config-route-map)# as-path-list 1 action deny
RS G8124(config-route-map)# as-path-list 1 enable

© Copyright IBM Corp. 2014 Chapter 24: Border Gateway Protocol 321
 4. Set up the BGP attributes.
If you want to overwrite the attributes that the peer router is sending, define the
following BGP attributes:
– Specify up to 32 AS numbers that you want to prepend to a matched route.
Use one space between each of the entries in the list.
– Specify the local preference for the matched route.
– Specify the Multi Exit Discriminator (MED) metric for the matched route.

RS G8124(config-route-map)# as-path-preference <AS number list (up to 32 entries)>

RS G8124(config-route-map)# local-preference <local preference value>
RS G8124(config-route-map)# metric <metric value>

5. Enable the route map.

RS G8124(config-route-map)# enable
RS G8124(config-route-map)# exit

6. Turn BGP on.

RS G8124(config)# router bgp

RS G8124(config-router-bgp)# enable

7. Assign the route map to a peer router.

Select the peer router and then add the route map to the incoming route map list,

RS G8124(config-router-bgp)# neighbor 1 route-map in <1-64>

or to the outgoing route map list.

RS G8124(config-router-bgp)# neighbor 1 route-map out <1-64>

8. Exit Router BGP mode.

RS G8124(config-router-bgp)# exit

322 RackSwitch G8124: Application Guide

Aggregating Routes
Aggregation is the process of combining several different routes in such a way that
a single route can be advertised, which minimizes the size of the routing table. You
can configure aggregate routes in BGP either by redistributing an aggregate route
into BGP or by creating an aggregate entry in the BGP routing table.

To define an aggregate route in the BGP routing table, use the following commands:

RS G8124(config)# router bgp

RS G8124(config-router-bgp)# aggregate-address <1-16> <IPv4 address> <mask>
RS G8124(config-router-bgp)# aggregate-address <1-16> enable

An example of creating a BGP aggregate route is shown in “Default Redistribution

and Route Aggregation Example” on page 330.

Redistributing Routes
In addition to running multiple routing protocols simultaneously, N/OS software can
redistribute information from one routing protocol to another. For example, you can
instruct the switch to use BGP to re-advertise static routes. This applies to all of the
IP-based routing protocols.

You can also conditionally control the redistribution of routes between routing
domains by defining a method known as route maps between the two domains. For
more information on route maps, see “What is a Route Map?” on page 319.
Redistributing routes is another way of providing policy control over whether to
export OSPF routes, fixed routes, and static routes. For an example configuration,
see “Default Redistribution and Route Aggregation Example” on page 330.

Default routes can be configured using the following methods:

• Import
• Originate—The router sends a default route to peers if it does not have any
default routes in its routing table.
• Redistribute—Default routes are either configured through the default gateway
or learned via other protocols and redistributed to peer routers. If the default
routes are from the default gateway, enable the static routes because default
routes from the default gateway are static routes. Similarly, if the routes are
learned from another routing protocol, make sure you enable that protocol for
redistribution.
• None

© Copyright IBM Corp. 2014 Chapter 24: Border Gateway Protocol 323
BGP Communities
BGP communities are attribute tags that allow controlled distribution of routing
information based on an agreement between BGP peers. Communities are
commonly used by transit service providers to enable peering customers to choose
specific routing destinations for their outgoing routes. The transit service provider
would typically publish a list of well-known or proprietary communities along with
their descriptions, and take it upon itself to advertise incoming routes accordingly.
For instance, an ISP may advertise that incoming routes tagged with community
XY:01 will be advertised only to European peers while incoming routes tagged with
community XY:02 will be advertised only to Asian peers.

The RackSwitch G8124 can be configured to manage the community tags applied
to the outgoing route updates. It does not, however, modify any routing decisions
based on the community tags.

Up to 32 community tags can be applied to prefixes that pass a route-map. Valid

values are between 0:0 and 65535:65535. Newly added communities will be
appended to any existing configured communities. To append communities to
prefixes that pass the route-map, use the following commands:

RS G8124(config)# route-map <map number>

RS G8124(config-route-map)# set community {aa:nn [aa:nn]}

To remove all community tags from prefixes that pass the route-map, use the
following command:

RS G8124(config-route-map)# set community none

To remove configured communities on a routemap, use the following command:

RS G8124(config-route-map)# no set community

Prefixes with communities are propagated unchanged if there is no routemap that

alters the community attribute and if the neighbor has community tags forwarding
enabled.

To enable or disable community tags forwarding for specific neighbors or neighbor

groups, use the following commands:

RS G8124(config)# router bgp

RS G8124(config-router-bgp)# neighbor 5 send-community
RS G8124(config-router-bgp)# no neighbor 6 send-community
RS G8124(config-router-bgp)# neighbor group 1 send-community
RS G8124(config-router-bgp)# no neighbor group 2 send-community

324 RackSwitch G8124: Application Guide

BGP Attributes
The following BGP attributes are discussed in this section: Local preference, metric
(Multi-Exit Discriminator), and Next hop.

Local Preference Attribute

When there are multiple paths to the same destination, the local preference attribute
indicates the preferred path. The path with the higher preference is preferred (the
default value of the local preference attribute is 100). Unlike the weight attribute,
which is only relevant to the local router, the local preference attribute is part of the
routing update and is exchanged among routers in the same AS.

The local preference attribute can be set in one of two ways:

• The following commands use the BGP default local preference method, affecting
the outbound direction only.

RS G8124(config)# router bgp

RS G8124(config_router_bgp)# local-preference
RS G8124(config_router_bgp)# exit

• The following commands use the route map local preference method, which
affects both inbound and outbound directions.

RS G8124(config)# route-map 1
RS G8124(config_route_map)# local-preference
RS G8124(config_router_map)# exit

Metric (Multi-Exit Discriminator) Attribute

This attribute is a hint to external neighbors about the preferred path into an AS
when there are multiple entry points. A lower metric value is preferred over a higher
metric value. The default value of the metric attribute is 0.

Unlike local preference, the metric attribute is exchanged between ASs; however, a
metric attribute that comes into an AS does not leave the AS.

When an update enters the AS with a certain metric value, that value is used for
decision making within the AS. When BGP sends that update to another AS, the
metric is reset to 0.

Unless otherwise specified, the router compares metric attributes for paths from
external neighbors that are in the same AS.

© Copyright IBM Corp. 2014 Chapter 24: Border Gateway Protocol 325
 Next Hop Attribute

BGP routing updates sent to a neighbor contain the next hop IP address used to
reach a destination. In eBGP, the edge router, by default, sends its own IP address
as the next hop address. However, this can sometimes cause routing path failures in
Non-Broadcast Multiaccess Networks (NBMA) and when the edge router sends
iBGP updates.

To avoid routing failures, you can manually configure the next hop IP address. In
case of NBMA networks, you can configure the external BGP speaker to advertise
its own IP address as the next hop. In case of iBGP updates, you can configure the
edge iBGP router to send its IP address as the next hop.

Next hop can be configured on a BGP peer or a peer group. Use the following
commands:
• Next Hop for a BGP Peer

RS G8124(config)# router bgp

RS G8124(config-router-bgp)# neighbor <number> next-hop-self

• Next Hop for a BGP Peer Group:

RS G8124(config)# router bgp

RS G8124(config-router-bgp)# neighbor group <number> next-hop-self

326 RackSwitch G8124: Application Guide

Selecting Route Paths in BGP
BGP selects only one path as the best path. It does not rely on metric attributes to
determine the best path. When the same network is learned via more than one BGP
peer, BGP uses its policy for selecting the best route to that network. The BGP
implementation on the G8124 uses the following criteria to select a path when the
same route is received from multiple peers.
1. Local fixed and static routes are preferred over learned routes.
2. With iBGP peers, routes with higher local preference values are selected.
3. In the case of multiple routes of equal preference, the route with lower AS path
weight is selected.
AS path weight = 128 x AS path length (number of autonomous systems
traversed).
4. In the case of equal weight and routes learned from peers that reside in the
same AS, the lower metric is selected.
Note: A route with a metric is preferred over a route without a metric.
5. The lower cost to the next hop of routes is selected.
6. In the case of equal cost, the eBGP route is preferred over iBGP.
7. If all routes have same route type (eBGP or iBGP), the route with the lower
router ID is selected.

When the path is selected, BGP puts the selected path in its routing table and
propagates the path to its neighbors.

Multipath Relax
BGP multipath relax functionality allows load balancing across routes with different
autonomous system paths, but equal in length (same as-path length). With this
option disabled, both autonomous system paths and as-path length must be
identical for load sharing. This functionality can be enabled using the command:

RS G8124(config-router-bgp)# bestpath as-path multipath-relax

© Copyright IBM Corp. 2014 Chapter 24: Border Gateway Protocol 327
BGP Failover Configuration
Use the following example to create redundant default gateways for a G8124 at a
Web Host/ISP site, eliminating the possibility, if one gateway goes down, that
requests will be forwarded to an upstream router unknown to the switch.

As shown in Figure 35, the switch is connected to ISP 1 and ISP 2. The customer
negotiates with both ISPs to allow the switch to use their peer routers as default
gateways. The ISP peer routers will then need to announce themselves as default
gateways to the G8124.
Figure 35. BGP Failover Configuration Example

Switch

IP: 200.200.200.1
IP: 210.210.210.1

BladeCenter

Server 1 Server 2
IP: 200.200.200.10 IP: 200.200.200.11

On the G8124, one peer router (the secondary one) is configured with a longer AS
path than the other, so that the peer with the shorter AS path will be seen by the
switch as the primary default gateway. ISP 2, the secondary peer, is configured with
a metric of “3,” thereby appearing to the switch to be three router hops away.
1. Define the VLANs.
For simplicity, both default gateways are configured in the same VLAN in this
example. The gateways could be in the same VLAN or different VLANs.

RS G8124(config)# vlan 1

328 RackSwitch G8124: Application Guide

 2. Define the IP interfaces with IPv4 addresses.
The switch will need an IP interface for each default gateway to which it will be
connected. Each interface must be placed in the appropriate VLAN. These
interfaces will be used as the primary and secondary default gateways for the
switch.

RS G8124(config)# interface ip 1
RS G8124(config-ip-if)# ip address 200.200.200.1
RS G8124(config-ip-if)# ip netmask 255.255.255.0
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 2
RS G8124(config-ip-if)# ip address 210.210.210.1
RS G8124(config-ip-if)# ip netmask 255.255.255.0
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit

3. Enable IP forwarding.
IP forwarding is turned on by default and is used for VLAN-to-VLAN (non-BGP)
routing. Make sure IP forwarding is on if the default gateways are on different
subnets or if the switch is connected to different subnets and those subnets need
to communicate through the switch (which they almost always do).

RS G8124(config)# ip routing

Note: To help eliminate the possibility for a Denial of Service (DoS) attack, the
forwarding of directed broadcasts is disabled by default.
4. Configure BGP peer router 1 and 2 with IPv4 addresses.

RS G8124(config)# router bgp

RS G8124RS G8124(config-router-bgp)# neighbor 1 remote-address 200.200.200.2
RS G8124(config-router-bgp)# neighbor 1 remote-as 100
RS G8124(config-router-bgp)# no neighbor 1 shutdown
RS G8124RS G8124(config-router-bgp)# neighbor 2 remote-address 210.210.210.2
RS G8124(config-router-bgp)# neighbor 2 remote-as 200
RS G8124(config-router-bgp)# no neighbor 2 shutdown

© Copyright IBM Corp. 2014 Chapter 24: Border Gateway Protocol 329
Default Redistribution and Route Aggregation Example
This example shows you how to configure the switch to redistribute information from
one routing protocol to another and create an aggregate route entry in the BGP
routing table to minimize the size of the routing table.

As illustrated in Figure 36, you have two peer routers: an internal and an external
peer router. Configure the G8124 to redistribute the default routes from AS 200 to
AS 135. At the same time, configure for route aggregation to allow you to condense
the number of routes traversing from AS 135 to AS 200.
Figure 36. Route Aggregation and Default Route Redistribution

Switch
10.1.1.135

1. Configure the IP interface.

2. Configure the AS number (AS 135) and router ID (10.1.1.135).

RS G8124(config)# router bgp

RS G8124(config-router-bgp)# as 135
RS G8124(config-router-bgp)# exit
RS G8124(config)# ip router-id 10.1.1.135

3. Configure internal peer router 1 and external peer router 2 with IPv4
addresses.

RS G8124(config)# router bgp

RS G8124RS G8124(config-router-bgp)# neighbor 1 remote-address 10.1.1.4
RS G8124(config-router-bgp)# neighbor 1 remote-as 135
RS G8124(config-router-bgp)# no neighbor 1 shutdown
RS G8124RS G8124(config-router-bgp)# neighbor 2 remote-address 20.20.20.2
RS G8124(config-router-bgp)# neighbor 2 remote-as 200
RS G8124(config-router-bgp)# no neighbor 2 shutdown

4. Configure redistribution for Peer 1.

RS G8124(config-router-bgp)# neighbor 1 redistribute default-action redistribute

RS G8124(config-router-bgp)# neighbor 1 redistribute fixed

330 RackSwitch G8124: Application Guide

 5. Configure aggregation policy control.
Configure the IPv4 routes that you want aggregated.

RS G8124(config-router-bgp)# aggregate-address 1 135.0.0.0 255.0.0.0

RS G8124(config-router-bgp)# aggregate-address 1 enable

© Copyright IBM Corp. 2014 Chapter 24: Border Gateway Protocol 331
332 RackSwitch G8124: Application Guide
Chapter 25. OSPF
IBM Networking OS supports the Open Shortest Path First (OSPF) routing protocol.
The IBM N/OS implementation conforms to the OSPF version 2 specifications
detailed in Internet RFC 1583, and OSPF version 3 specifications in RFC 5340. The
following sections discuss OSPF support for the RackSwitch G8124:
• “OSPFv2 Overview” on page 334. This section provides information on OSPFv2
concepts, such as types of OSPF areas, types of routing devices, neighbors,
adjacencies, link state database, authentication, and internal versus external
routing.
• “OSPFv2 Implementation in IBM N/OS” on page 338. This section describes how
OSPFv2 is implemented in N/OS, such as configuration parameters, electing the
designated router, summarizing routes, defining route maps and so forth.
• “OSPFv2 Configuration Examples” on page 347. This section provides
step-by-step instructions on configuring different OSPFv2 examples:
– Creating a simple OSPF domain
– Creating virtual links
– Summarizing routes
• “OSPFv3 Implementation in IBM N/OS” on page 356. This section describes
differences and additional features found in OSPFv3.

© Copyright IBM Corp. 2014 333

OSPFv2 Overview
OSPF is designed for routing traffic within a single IP domain called an Autonomous
System (AS). The AS can be divided into smaller logical units known as areas.

All routing devices maintain link information in their own Link State Database
(LSDB). OSPF allows networks to be grouped together into an area. The topology of
an area is hidden from the rest of the AS, thereby reducing routing traffic. Routing
within an area is determined only by the area’s own topology, thus protecting it from
bad routing data. An area can be generalized as an IP subnetwork.

The following sections describe key OSPF concepts.

Types of OSPF Areas

An AS can be broken into logical units known as areas. In any AS with multiple
areas, one area must be designated as area 0, known as the backbone. The
backbone acts as the central OSPF area. All other areas in the AS must be
connected to the backbone. Areas inject summary routing information into the
backbone, which then distributes it to other areas as needed.

As shown in Figure 37, OSPF defines the following types of areas:

• Stub Area—an area that is connected to only one other area. External route
information is not distributed into stub areas.
• Not-So-Stubby-Area (NSSA)—similar to a stub area with additional capabilities.
Routes originating from within the NSSA can be propagated to adjacent transit
and backbone areas. External routes from outside the AS can be advertised
within the NSSA but can be configured to not be distributed into other areas.
• Transit Area—an area that carries data traffic which neither originates nor
terminates in the area itself.

334 RackSwitch G8124: Application Guide

 Figure 37. OSPF Area Types

Backbone
Area 0
(Also a Transit Area)

ABR ABR
ABR

Internal LSA
Routes Virtual
Stub Area Transit Area Link

Not-So-Stubby Area No External Routes

from Backbone
(NSSA) ABR

External LSA
Routes
ASBR
Stub Area, NSSA,
ABR = Area Border Router or Transit Area
ASBR = Autonomous System Connected to Backbone
Non-OSPF Area Boundary Router via Virtual Link
RIP/BGP AS

Types of OSPF Routing Devices

As shown in Figure 38, OSPF uses the following types of routing devices:
• Internal Router (IR)—a router that has all of its interfaces within the same area.
IRs maintain LSDBs identical to those of other routing devices within the local
area.
• Area Border Router (ABR)—a router that has interfaces in multiple areas. ABRs
maintain one LSDB for each connected area and disseminate routing information
between areas.
• Autonomous System Boundary Router (ASBR)—a router that acts as a gateway
between the OSPF domain and non-OSPF domains, such as RIP, BGP, and
static routes.
Figure 38. OSPF Domain and an Autonomous System

OSPF Autonomous System

BGP Backbone
Area 3
Area 0

Inter-Area Routes
External ABR
ASBR (Summary Routes)
Routes

RIP
ABR ABR

Internal
ASBR Router
Area 1 Area 2

© Copyright IBM Corp. 2014 Chapter 25: OSPF 335

Neighbors and Adjacencies
In areas with two or more routing devices, neighbors and adjacencies are formed.

Neighbors are routing devices that maintain information about each others’ state. To
establish neighbor relationships, routing devices periodically send hello packets on
each of their interfaces. All routing devices that share a common network segment,
appear in the same area, and have the same health parameters (hello and dead
intervals) and authentication parameters respond to each other’s hello packets and
become neighbors. Neighbors continue to send periodic hello packets to advertise
their health to neighbors. In turn, they listen to hello packets to determine the health
of their neighbors and to establish contact with new neighbors.

The hello process is used for electing one of the neighbors as the network
segment’s Designated Router (DR) and one as the network segment’s Backup
Designated Router (BDR). The DR is adjacent to all other neighbors on that specific
network segment and acts as the central contact for database exchanges. Each
neighbor sends its database information to the DR, which relays the information to
the other neighbors.

The BDR is adjacent to all other neighbors (including the DR). Each neighbor sends
its database information to the BDR just as with the DR, but the BDR merely stores
this data and does not distribute it. If the DR fails, the BDR will take over the task of
distributing database information to the other neighbors.

The Link-State Database

OSPF is a link-state routing protocol. A link represents an interface (or routable
path) from the routing device. By establishing an adjacency with the DR, each
routing device in an OSPF area maintains an identical Link-State Database (LSDB)
describing the network topology for its area.

Each routing device transmits a Link-State Advertisement (LSA) on each of its active
interfaces. LSAs are entered into the LSDB of each routing device. OSPF uses
flooding to distribute LSAs between routing devices. Interfaces may also be
passive. Passive interfaces send LSAs to active interfaces, but do not receive LSAs,
hello packets, or any other OSPF protocol information from active interfaces.
Passive interfaces behave as stub networks, allowing OSPF routing devices to be
aware of devices that do otherwise participate in OSPF (either because they do not
support it, or because the administrator chooses to restrict OSPF traffic exchange or
transit).

When LSAs result in changes to the routing device’s LSDB, the routing device
forwards the changes to the adjacent neighbors (the DR and BDR) for distribution to
the other neighbors.

OSPF routing updates occur only when changes occur, instead of periodically. For
each new route, if a neighbor is interested in that route (for example, if configured to
receive static routes and the new route is indeed static), an update message
containing the new route is sent to the adjacency. For each route removed from the
route table, if the route has already been sent to a neighbor, an update message
containing the route to withdraw is sent.

336 RackSwitch G8124: Application Guide

The Shortest Path First Tree
The routing devices use a link-state algorithm (Dijkstra’s algorithm) to calculate the
shortest path to all known destinations, based on the cumulative cost required to
reach the destination.

The cost of an individual interface in OSPF is an indication of the overhead required

to send packets across it.

Internal Versus External Routing

To ensure effective processing of network traffic, every routing device on your
network needs to know how to send a packet (directly or indirectly) to any other
location/destination in your network. This is referred to as internal routing and can
be done with static routes or using active internal routing protocols, such as OSPF,
RIP, or RIPv2.

It is also useful to tell routers outside your network (upstream providers or peers)
about the routes you have access to in your network. Sharing of routing information
between autonomous systems is known as external routing.

Typically, an AS will have one or more border routers (peer routers that exchange
routes with other OSPF networks) as well as an internal routing system enabling
every router in that AS to reach every other router and destination within that AS.

When a routing device advertises routes to boundary routers on other autonomous

systems, it is effectively committing to carry data to the IP space represented in the
route being advertised. For example, if the routing device advertises
192.204.4.0/24, it is declaring that if another router sends data destined for any
address in the 192.204.4.0/24 range, it will carry that data to its destination.

© Copyright IBM Corp. 2014 Chapter 25: OSPF 337

OSPFv2 Implementation in IBM N/OS
N/OS supports a single instance of OSPF and up to 4K routes on the network. The
following sections describe OSPF implementation in N/OS:
• “Configurable Parameters” on page 338
• “Defining Areas” on page 339
• “Interface Cost” on page 341
• “Electing the Designated Router and Backup” on page 341
• “Summarizing Routes” on page 341
• “Default Routes” on page 342
• “Virtual Links” on page 342
• “Router ID” on page 343
• “Authentication” on page 344

Configurable Parameters
In N/OS, OSPF parameters can be configured through the Industry Standard
Command Line Interfaces (ISCLI), Browser-Based Interface (BBI), or through
SNMP. For more information, see “Switch Administration” on page 23.

The ISCLI supports the following parameters: interface output cost, interface
priority, dead and hello intervals, retransmission interval, and interface transmit
delay.

In addition to the preceding parameters, you can specify the following:

• Shortest Path First (SPF) interval—Time interval between successive
calculations of the shortest path tree using the Dijkstra’s algorithm.
• Stub area metric—A stub area can be configured to send a numeric metric value
such that all routes received via that stub area carry the configured metric to
potentially influence routing decisions.
• Default routes—Default routes with weight metrics can be manually injected into
transit areas. This helps establish a preferred route when multiple routing
devices exist between two areas. It also helps route traffic to external networks.
• Passive—When enabled, the interface sends LSAs to upstream devices, but
does not otherwise participate in OSPF protocol exchanges.
• Point-to-Point—For LANs that have only two OSPF routing agents (the G8124
and one other device), this option allows the switch to significantly reduce the
amount of routing information it must carry and manage.

338 RackSwitch G8124: Application Guide

Defining Areas
If you are configuring multiple areas in your OSPF domain, one of the areas must be
designated as area 0, known as the backbone. The backbone is the central OSPF
area and is usually physically connected to all other areas. The areas inject routing
information into the backbone which, in turn, disseminates the information into other
areas.

Since the backbone connects the areas in your network, it must be a contiguous
area. If the backbone is partitioned (possibly as a result of joining separate OSPF
networks), parts of the AS will be unreachable, and you will need to configure virtual
links to reconnect the partitioned areas (see “Virtual Links” on page 342).

Up to 20 OSPF areas can be connected to the G8124 with N/OS software. To

configure an area, the OSPF number must be defined and then attached to a
network interface on the switch. The full process is explained in the following
sections.

An OSPF area is defined by assigning two pieces of information: an area index and
an area ID. The commands to define and enable an OSPF area are as follows:

RS G8124(config)# router ospf

RS G8124(config-router-ospf)# area <area index> area-id <n.n.n.n>
RS G8124(config-router-ospf)# area <area index> enable
RS G8124(config-router-ospf)# exit

Note: The area option is an arbitrary index used only on the switch and does not
represent the actual OSPF area number. The actual OSPF area number is
defined in the area portion of the command as explained in the following
sections.

Assigning the Area Index

The area <area index> option is actually just an arbitrary index (0-19) used only by
the G8124. This index number does not necessarily represent the OSPF area
number, though for configuration simplicity, it ought to where possible.

For example, both of the following sets of commands define OSPF area 0 (the
backbone) and area 1 because that information is held in the area ID portion of the
command. However, the first set of commands is easier to maintain because the
arbitrary area indexes agree with the area IDs:
• Area index and area ID agree
area 0 area-id 0.0.0.0 (Use index 0 to set area 0 in ID octet
format)
area 1 area-id 0.0.0.1 (Use index 1 to set area 1 in ID octet
format)
• Area index set to an arbitrary value
area 1 area-id 0.0.0.0 (Use index 1 to set area 0 in ID octet
format)
area 2 area-id 0.0.0.1 (Use index 2 to set area 1 in ID octet
format)

© Copyright IBM Corp. 2014 Chapter 25: OSPF 339

 Using the Area ID to Assign the OSPF Area Number
The OSPF area number is defined in the areaid <IP address> option. The octet
format is used to be compatible with two different systems of notation used by other
OSPF network vendors. There are two valid ways to designate an area ID:
• Single Number
Most common OSPF vendors express the area ID number as a single number.
For example, the Cisco IOS-based router command “network 1.1.1.0
0.0.0.255 area 1” defines the area number simply as “area 1.”
• Multi-octet (IP address): Placing the area number in the last octet (0.0.0.n)
Some OSPF vendors express the area ID number in multi-octet format. For
example, “area 0.0.0.2” represents OSPF area 2 and can be specified
directly on the G8124 as “area-id 0.0.0.2”.

On the G8124, using the last octet in the area ID, “area 1” is equivalent to
“area-id 0.0.0.1”.
Note: Although both types of area ID formats are supported, be sure that the area
IDs are in the same format throughout an area.

Attaching an Area to a Network

Once an OSPF area has been defined, it must be associated with a network. To
attach the area to a network, you must assign the OSPF area index to an IP
interface that participates in the area. The format for the command is as follows:

RS G8124(config)# interface ip <interface number>

RS G8124(config-ip-if)# ip ospf area <area index>
RS G8124(config-ip-if)# exit

For example, the following commands could be used to configure IP interface 14 to

use 10.10.10.1 on the 10.10.10.0/24 network, to define OSPF area 1, and to attach
the area to the network:

RS G8124(config)# router ospf

RS G8124(config-router-ospf)# area 1 area-id 0.0.0.1
RS G8124(config-router-ospf)# area 1 enable
RS G8124(config-router-ospf)# enable
RS G8124(config-router-ospf)# exit
RS G8124(config)# interface ip 14
RS G8124(config-ip-if)# ip address 10.10.10.1
RS G8124(config-ip-if)# ip netmask 255.255.255.0
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# ip ospf area 1
RS G8124(config-ip-if)# ip ospf enable

Note: OSPFv2 supports IPv4 only. IPv6 is supported in OSPFv3 (see “OSPFv3
Implementation in IBM N/OS” on page 356).

340 RackSwitch G8124: Application Guide

Interface Cost
The OSPF link-state algorithm (Dijkstra’s algorithm) places each routing device at
the root of a tree and determines the cumulative cost required to reach each
destination. You can manually enter the cost for the output route with the following
command (Interface IP mode):

RS G8124(config-ip-if)# ip ospf cost <cost value (1-65535)>

Electing the Designated Router and Backup

In any broadcast type subnet, a Designated Router (DR) is elected as the central
contact for database exchanges among neighbors. On subnets with more the one
device, a Backup Designated Router (BDR) is elected in case the DR fails.

DR and BDR elections are made through the hello process. The election can be
influenced by assigning a priority value to the OSPF interfaces on the G8124. The
command is as follows:

RS G8124(config-ip-if)# ip ospf priority <priority value (0-255)>

A priority value of 255 is the highest, and 1 is the lowest. A priority value of 0
specifies that the interface cannot be used as a DR or BDR. In case of a tie, the
routing device with the highest router ID wins. Interfaces configured as passive do
not participate in the DR or BDR election process:

RS G8124(config-ip-if)# ip ospf passive-interface

RS G8124(config-ip-if)# exit

Summarizing Routes
Route summarization condenses routing information. Without summarization, each
routing device in an OSPF network would retain a route to every subnet in the
network. With summarization, routing devices can reduce some sets of routes to a
single advertisement, reducing both the load on the routing device and the
perceived complexity of the network. The importance of route summarization
increases with network size.

Summary routes can be defined for up to 16 IP address ranges using the following
command:

RS G8124(config)# router ospf

RS G8124(config-router-ospf)# area-range <range number> address <IP address> <mask>

where <range number> is a number 1 to 16, <IP address> is the base IP address for
the range, and <mask> is the IP address mask for the range. For a detailed
configuration example, see “Example 3: Summarizing Routes” on page 354.

© Copyright IBM Corp. 2014 Chapter 25: OSPF 341

Default Routes
When an OSPF routing device encounters traffic for a destination address it does
not recognize, it forwards that traffic along the default route. Typically, the default
route leads upstream toward the backbone until it reaches the intended area or an
external router.

Each G8124 acting as an ABR automatically inserts a default route into stub and
NSSA attached areas. In simple OSPF stub areas or NSSAs with only one ABR
leading upstream (see Area 1 in Figure 39), any traffic for IP address destinations
outside the area is forwarded to the switch’s IP interface, and then into the
connected transit area (usually the backbone). Since this is automatic, no further
configuration is required for such areas.
Figure 39. Injecting Default Routes

If the switch is in a transit area and has a configured default gateway, it can inject a
default route into rest of the OSPF domain. Use the following command to configure
the switch to inject OSPF default routes (Router OSPF mode):

RS G8124(config-router-ospf)# default-information <metric value> <metric type (1 or 2)>

In this command, <metric value> sets the priority for choosing this switch for default
route. The value none sets no default and 1 sets the highest priority for default
route. Metric type determines the method for influencing routing decisions for
external routes.

When the switch is configured to inject a default route, an AS-external LSA with link
state ID 0.0.0.0 is propagated throughout the OSPF routing domain. This LSA is
sent with the configured metric value and metric type.

The OSPF default route configuration can be removed with the command:

RS G8124(config-router-ospf)# no default-information

342 RackSwitch G8124: Application Guide

Virtual Links
Usually, all areas in an OSPF AS are physically connected to the backbone. In some
cases where this is not possible, you can use a virtual link. Virtual links are created
to connect one area to the backbone through another non-backbone area (see
Figure 37 on page 335).

The area which contains a virtual link must be a transit area and have full routing
information. Virtual links cannot be configured inside a stub area or NSSA. The area
type must be defined as transit using the following command:

RS G8124(config-router-ospf)# area <area index> type transit

The virtual link must be configured on the routing devices at each endpoint of the
virtual link, though they may traverse multiple routing devices. To configure a G8124
as one endpoint of a virtual link, use the following command:

RS G8124(config-router-ospf)# area-virtual-link <link number> neighbor-router <router ID>

where <link number> is a value between 1 and 3, <area index> is the OSPF area
index of the transit area, and <router ID> is the router ID of the virtual neighbor, the
routing device at the target endpoint. Another router ID is needed when configuring
a virtual link in the other direction. To provide the G8124 with a router ID, see the
following section Router ID.

For a detailed configuration example on Virtual Links, see “Example 2: Virtual Links”
on page 350.

Router ID
Routing devices in OSPF areas are identified by a router ID. The router ID is
expressed in IP address format. The IP address of the router ID is not required to be
included in any IP interface range or in any OSPF area, and may even use the
G8124 loopback interface.

The router ID can be configured in one of the following two ways:

• Dynamically—OSPF protocol configures the lowest IP interface IP address as
the router ID (loopback interface has priority over the IP interface). This is the
default.
• Statically—Use the following command to manually configure the router ID:

RS G8124(config-router-ospf)# ip router-id <IPv4 address>

If there is a loopback interface, its IP address is always preferred as the router

ID, instead of an IP interface address. The ip router-id command is the
preferred method to set the router ID and it is always used in preference to the
other methods.
• To modify the router ID from static to dynamic, set the router ID to 0.0.0.0 and
re-initialize the OSPF process.
• To view the router ID, use the following command:

RS G8124(config-router-ospf)# show ip ospf

© Copyright IBM Corp. 2014 Chapter 25: OSPF 343

Authentication
OSPF protocol exchanges can be authenticated so that only trusted routing devices
can participate. This ensures less processing on routing devices that are not
listening to OSPF packets.

OSPF allows packet authentication and uses IP multicast when sending and
receiving packets. Routers participate in routing domains based on pre-defined
passwords. N/OS supports simple password (type 1 plain text passwords) and MD5
cryptographic authentication. This type of authentication allows a password to be
configured per interface.

We strongly recommend that you implement MD5 cryptographic authentication as a

best practice.

Figure 40 shows authentication configured for area 0 with the password test. Simple
authentication is also configured for the virtual link between area 2 and area 0. Area
1 is not configured for OSPF authentication.
Figure 40. OSPF Authentication

Switch 2

Switch 1 Switch 3
Switch 5

key=blade

Switch 4

Configuring Plain Text OSPF Passwords

To configure simple plain text OSPF passwords on the switches shown in Figure 40
use the following commands:
1. Enable OSPF authentication for Area 0 on switches 1, 2, and 3.

RS G8124(config-router-ospf)# area 0 authentication-type password

RS G8124(config-router-ospf)# exit

2. Configure a simple text password up to eight characters for each OSPF IP

interface in Area 0 on switches 1, 2, and 3.

RS G8124(config)# interface ip 1
RS G8124(config-ip-if)# ip ospf key test
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 2
RS G8124(config-ip-if)# ip ospf key test
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 3
RS G8124(config-ip-if)# ip ospf key test
RS G8124(config-ip-if)# exit

344 RackSwitch G8124: Application Guide

 3. Enable OSPF authentication for Area 2 on switch 4.

RS G8124(config)# router ospf

RS G8124(config-router-ospf)# area 2 authentication-type password

4. Configure a simple text password up to eight characters for the virtual link
between Area 2 and Area 0 on switches 2 and 4.

RS G8124(config-router-ospf)# area-virtual-link 1 key blade

Configuring MD5 Authentication

Use the following commands to configure MD5 authentication on the switches
shown in Figure 40:
1. Enable OSPF MD5 authentication for Area 0 on switches 1, 2, and 3.

RS G8124(config-router-ospf)# area 0 authentication-type md5

2. Configure MD5 key ID for Area 0 on switches 1, 2, and 3.

RS G8124(config-router-ospf)# message-digest-key 1 md5-key test

RS G8124(config-router-ospf)# exit

3. Assign MD5 key ID to OSPF interfaces on switches 1, 2, and 3.

RS G8124(config)# interface ip 1
RS G8124(config-ip-if)# ip ospf message-digest-key 1
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 2
RS G8124(config-ip-if)# ip ospf message-digest-key 1
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 3
RS G8124(config-ip-if)# ip ospf message-digest-key 1
RS G8124(config-ip-if)# exit

4. Enable OSPF MD5 authentication for Area 2 on switch 4.

RS G8124(config)# router ospf

RS G8124(config-router-ospf)# area 1 authentication-type md5

5. Configure MD5 key for the virtual link between Area 2 and Area 0 on switches
2 and 4.

RS G8124(config-router-ospf)# message-digest-key 2 md5-key test

6. Assign MD5 key ID to OSPF virtual link on switches 2 and 4.

RS G8124(config-router-ospf)# area-virtual-link 1 message-digest-key 2

RS G8124(config-router-ospf)# exit

© Copyright IBM Corp. 2014 Chapter 25: OSPF 345

Host Routes for Load Balancing
N/OS implementation of OSPF includes host routes. Host routes are used for
advertising network device IP addresses to external networks, accomplishing the
following goals:
• ABR Load Sharing
As a form of load balancing, host routes can be used for dividing OSPF traffic
among multiple ABRs. To accomplish this, each switch provides identical services
but advertises a host route for a different IP address to the external network. If
each IP address serves a different and equal portion of the external world,
incoming traffic from the upstream router must be split evenly among ABRs.
• ABR Failover
Complementing ABR load sharing, identical host routes can be configured on
each ABR. These host routes can be given different costs so that a different ABR
is selected as the preferred route for each server and the others are available as
backups for failover purposes.
• Equal Cost Multipath (ECMP)
With equal cost multipath, a router potentially has several available next hops
towards any given destination. ECMP allows separate routes to be calculated for
each IP Type of Service. All paths of equal cost to a given destination are calcu-
lated, and the next hops for all equal-cost paths are inserted into the routing table.

Loopback Interfaces in OSPF

A loopback interface is an IP interface which has an IP address, but is not
associated with any particular physical port. The loopback interface is thus always
available to the general network, regardless of which specific ports are in operation.
Because loopback interfaces are always available on the switch, loopback
interfaces may present an advantage when used as the router ID.

If dynamic router ID selection is used (see “Router ID” on page 343) loopback
interfaces can be used to force router ID selection. If a loopback interface is
configured, its IP address is automatically selected as the router ID, even if other IP
interfaces have lower IP addresses. If more than one loopback interface is
configured, the lowest loopback interface IP address is selected.

Loopback interfaces can be advertised into the OSPF domain by specifying an

OSPF host route with the loopback interface IP address.

To enable OSPF on an existing loopback interface:

RS G8124(config)# interface loopback <1-5>

RS G8124(config-ip-loopback)# ip ospf area <area ID> enable
RS G8124(config-ip-loopback)# exit

OSPF Features Not Supported in This Release

The following OSPF features are not supported in this release:
• Summarizing external routes
• Filtering OSPF routes
• Using OSPF to forward multicast routes
• Configuring OSPF on non-broadcast multi-access networks (such as frame relay,
X.25, or ATM)

346 RackSwitch G8124: Application Guide

OSPFv2 Configuration Examples
A summary of the basic steps for configuring OSPF on the G8124 is listed here.
Detailed instructions for each of the steps is covered in the following sections:
1. Configure IP interfaces.
One IP interface is required for each desired network (range of IP addresses)
being assigned to an OSPF area on the switch.
2. (Optional) Configure the router ID.
3. Enable OSPF on the switch.
4. Define the OSPF areas.
5. Configure OSPF interface parameters.
IP interfaces are used for attaching networks to the various areas.
6. (Optional) Configure route summarization between OSPF areas.
7. (Optional) Configure virtual links.
8. (Optional) Configure host routes.

© Copyright IBM Corp. 2014 Chapter 25: OSPF 347

Example 1: Simple OSPF Domain
In this example, two OSPF areas are defined—one area is the backbone and the
other is a stub area. A stub area does not allow advertisements of external routes,
thus reducing the size of the database. Instead, a default summary route of IP
address 0.0.0.0 is automatically inserted into the stub area. Any traffic for IP
address destinations outside the stub area will be forwarded to the stub area’s IP
interface, and then into the backbone.
Figure 41. A Simple OSPF Domain

Network Network
10.10.7.0/24 10.10.12.0/24

Follow this procedure to configure OSPF support as shown in Figure 41:

1. Configure IP interfaces on each network that will be attached to OSPF areas.
In this example, two IP interfaces are needed:
– Interface 1 for the backbone network on 10.10.7.0/24
– Interface 2 for the stub area network on 10.10.12.0/24

RS G8124(config)# interface ip 1
RS G8124(config-ip-if)# ip address 10.10.7.1
RS G8124(config-ip-if)# ip netmask 255.255.255.0
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 2
RS G8124(config-ip-if)# ip address 10.10.12.1
RS G8124(config-ip-if)# ip netmask 255.255.255.0
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit

Note: OSPFv2 supports IPv4 only. IPv6 is supported in OSPFv3 (see “OSPFv3
Implementation in IBM N/OS” on page 356).
2. Enable OSPF.

RS G8124(config)# router ospf

RS G8124(config-router-ospf)# enable

3. Define the backbone.

The backbone is always configured as a transit area using areaid 0.0.0.0.

RS G8124(config-router-ospf)# area 0 area-id 0.0.0.0

RS G8124(config-router-ospf)# area 0 type transit
RS G8124(config-router-ospf)# area 0 enable

348 RackSwitch G8124: Application Guide

 4. Define the stub area.

RS G8124(config-router-ospf)# area 1 area-id 0.0.0.1

RS G8124(config-router-ospf)# area 1 type stub
RS G8124(config-router-ospf)# area 1 enable
RS G8124(config-router-ospf)# exit

5. Attach the network interface to the backbone.

RS G8124(config)# interface ip 1
RS G8124(config-ip-if)# ip ospf area 0
RS G8124(config-ip-if)# ip ospf enable
RS G8124(config-ip-if)# exit

6. Attach the network interface to the stub area.

RS G8124(config)# interface ip 2
RS G8124(config-ip-if)# ip ospf area 1
RS G8124(config-ip-if)# ip ospf enable
RS G8124(config-ip-if)# exit

© Copyright IBM Corp. 2014 Chapter 25: OSPF 349

Example 2: Virtual Links
In the example shown in Figure 42, area 2 is not physically connected to the
backbone as is usually required. Instead, area 2 will be connected to the backbone
via a virtual link through area 1. The virtual link must be configured at each endpoint.
Figure 42. Configuring a Virtual Link

Switch 1 Switch 2

Note: OSPFv2 supports IPv4 only. IPv6 is supported in OSPFv3 (see “OSPFv3
Implementation in IBM N/OS” on page 356).

Configuring OSPF for a Virtual Link on Switch #1

1. Configure IP interfaces on each network that will be attached to the switch.
In this example, two IP interfaces are needed:
– Interface 1 for the backbone network on 10.10.7.0/24
– Interface 2 for the transit area network on 10.10.12.0/24

RS G8124(config)# interface ip 1
RS G8124(config-ip-if)# ip address 10.10.7.1
RS G8124(config-ip-if)# ip netmask 255.255.255.0
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 2
RS G8124(config-ip-if)# ip address 10.10.12.1
RS G8124(config-ip-if)# ip netmask 255.255.255.0
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit

2. Configure the router ID.

A router ID is required when configuring virtual links. Later, when configuring the
other end of the virtual link on Switch 2, the router ID specified here will be used
as the target virtual neighbor (nbr) address.

RS G8124(config)# ip router-id 10.10.10.1

3. Enable OSPF.

RS G8124(config)# router ospf

RS G8124(config-router-ospf)# enable

4. Define the backbone.

RS G8124(config-router-ospf)# area 0 area-id 0.0.0.0

RS G8124(config-router-ospf)# area 0 type transit
RS G8124(config-router-ospf)# area 0 enable

350 RackSwitch G8124: Application Guide

 5. Define the transit area.
The area that contains the virtual link must be configured as a transit area.

RS G8124(config-router-ospf)# area 1 area-id 0.0.0.1

RS G8124(config-router-ospf)# area 1 type transit
RS G8124(config-router-ospf)# area 1 enable
RS G8124(config-router-ospf)# exit

6. Attach the network interface to the backbone.

RS G8124(config)# interface ip 1
RS G8124(config-ip-if)# ip ospf area 0
RS G8124(config-ip-if)# ip ospf enable
RS G8124(config-ip-if)# exit

7. Attach the network interface to the transit area.

RS G8124(config)# interface ip 2
RS G8124(config-ip-if)# ip ospf area 1
RS G8124(config-ip-if)# ip ospf enable
RS G8124(config-ip-if)# exit

8. Configure the virtual link.

The nbr router ID configured in this step must be the same as the router ID that
will be configured for Switch #2 in Step 2 on page 352.

RS G8124(config)# router ospf

RS G8124(config-router-ospf)# area-virtual-link 1 area 1
RS G8124(config-router-ospf)# area-virtual-link 1 neighbor-router 10.10.14.1
RS G8124(config-router-ospf)# area-virtual-link 1 enable

Configuring OSPF for a Virtual Link on Switch #2

1. Configure IP interfaces on each network that will be attached to OSPF areas.
In this example, two IP interfaces are needed:
– Interface 1 for the transit area network on 10.10.12.0/24
– Interface 2 for the stub area network on 10.10.24.0/24

RS G8124(config)# interface ip 1
RS G8124(config-ip-if)# ip address 10.10.12.2
RS G8124(config-ip-if)# ip netmask 255.255.255.0
RS G8124(config-ip-if)# vlan 10
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 2
RS G8124(config-ip-if)# ip address 10.10.24.1
RS G8124(config-ip-if)# ip netmask 255.255.255.0
RS G8124(config-ip-if)# vlan 20
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit

© Copyright IBM Corp. 2014 Chapter 25: OSPF 351

 2. Configure the router ID.
A router ID is required when configuring virtual links. This router ID must be the
same one specified as the target virtual neighbor (nbr) on switch 1 in Step 8 on
page 351.

RS G8124(config)# ip router-id 10.10.14.1

3. Enable OSPF.

RS G8124(config)# router ospf

RS G8124(config-router-ospf)# enable

4. Define the backbone.

This version of N/OS requires that a backbone index be configured on the
non-backbone end of the virtual link as follows:

RS G8124(config-router-ospf)# area 0 area-id 0.0.0.0

RS G8124(config-router-ospf)# area 0 enable

5. Define the transit area.

RS G8124(config-router-ospf)# area 1 area-id 0.0.0.1

RS G8124(config-router-ospf)# area 1 type transit
RS G8124(config-router-ospf)# area 1 enable

6. Define the stub area.

RS G8124(config-router-ospf)# area 2 area-id 0.0.0.2

RS G8124(config-router-ospf)# area 2 type stub
RS G8124(config-router-ospf)# area 2 enable
RS G8124(config-router-ospf)# exit

7. Attach the network interface to the transmit area.

RS G8124(config)# interface ip 1
RS G8124(config-ip-if)# ip ospf area 1
RS G8124(config-ip-if)# ip ospf enable
RS G8124(config-ip-if)# exit

8. Attach the network interface to the stub area.

RS G8124(config)# interface ip 2
RS G8124(config-ip-if)# ip ospf area 2
RS G8124(config-ip-if)# ip ospf enable
RS G8124(config-ip-if)# exit

352 RackSwitch G8124: Application Guide

 9. Configure the virtual link.
The nbr router ID configured in this step must be the same as the router ID that
was configured for switch #1 in Step 2 on page 350.

RS G8124(config)# router ospf

RS G8124(config-router-ospf)# area-virtual-link 1 area 1
RS G8124(config-router-ospf)# area-virtual-link 1 neighbor-router 10.10.10.1
RS G8124(config-router-ospf)# area-virtual-link 1 enable

Other Virtual Link Options

• You can use redundant paths by configuring multiple virtual links.
• Only the endpoints of the virtual link are configured. The virtual link path may
traverse multiple routers in an area as long as there is a routable path between
the endpoints.

© Copyright IBM Corp. 2014 Chapter 25: OSPF 353

Example 3: Summarizing Routes
By default, ABRs advertise all the network addresses from one area into another
area. Route summarization can be used for consolidating advertised addresses and
reducing the perceived complexity of the network.

If network IP addresses in an area are assigned to a contiguous subnet range, you

can configure the ABR to advertise a single summary route that includes all
individual IP addresses within the area.

The following example shows one summary route from area 1 (stub area) injected
into area 0 (the backbone). The summary route consists of all IP addresses from
36.128.192.0 through 36.128.254.255 except for the routes in the range
36.128.200.0 through 36.128.200.255.
Note: OSPFv2 supports IPv4 only. IPv6 is supported in OSPFv3 (see “OSPFv3
Implementation in IBM N/OS” on page 356).
Figure 43. Summarizing Routes

Note: You can specify a range of addresses to prevent advertising by using the
hide option. In this example, routes in the range 36.128.200.0 through
36.128.200.255 are kept private.

Use the following procedure to configure OSPF support as shown in Figure 43:
1. Configure IP interfaces for each network which will be attached to OSPF areas.

RS G8124(config)# interface ip 1
RS G8124(config-ip-if)# ip address 10.10.7.1
RS G8124(config-ip-if)# ip netmask 255.255.255.0
RS G8124(config-ip-if)# vlan 10
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 2
RS G8124(config-ip-if)# ip address 36.128.192.1
RS G8124(config-ip-if)# ip netmask 255.255.255.0
RS G8124(config-ip-if)# vlan 20
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit

2. Enable OSPF.

RS G8124(config)# router ospf

RS G8124(config-router-ospf)# enable

354 RackSwitch G8124: Application Guide

 3. Define the backbone.
RS G8124(config-router-ospf)# area 0 area-id 0.0.0.0
RS G8124(config-router-ospf)# area 0 type transit
RS G8124(config-router-ospf)# area 0 enable

4. Define the stub area.

RS G8124(config-router-ospf)# area 1 area-id 0.0.0.1
RS G8124(config-router-ospf)# area 1 type stub
RS G8124(config-router-ospf)# area 1 enable
RS G8124(config-router-ospf)# exit

5. Attach the network interface to the backbone.

RS G8124(config)# interface ip 1
RS G8124(config-ip-if)# ip ospf area 0
RS G8124(config-ip-if)# ip ospf enable
RS G8124(config-ip-if)# exit

6. Attach the network interface to the stub area.

RS G8124(config)# interface ip 2
RS G8124(config-ip-if)# ip ospf area 1
RS G8124(config-ip-if)# ip ospf enable
RS G8124(config-ip-if)# exit

7. Configure route summarization by specifying the starting address and mask of

the range of addresses to be summarized.
RS G8124(config)# router ospf
RS G8124(config-router-ospf)# area-range 1 address 36.128.192.0 255.255.192.0
RS G8124(config-router-ospf)# area-range 1 area 1
RS G8124(config-router-ospf)# area-range 1 enable
RS G8124(config-router-ospf)# exit

8. Use the hide command to prevent a range of addresses from advertising to the
backbone.
RS G8124(config)# router ospf
RS G8124(config-router-ospf)# area-range 2 address 36.128.200.0 255.255.255.0
RS G8124(config-router-ospf)# area-range 2 area 1
RS G8124(config-router-ospf)# area-range 2 hide
RS G8124(config-router-ospf)# exit

Verifying OSPF Configuration

Use the following commands to verify the OSPF configuration on your switch:
• show ip ospf
• show ip ospf neighbor
• show ip ospf database database-summary
• show ip ospf routes

Refer to the IBM Networking OS Command Reference for information on the

preceding commands.

© Copyright IBM Corp. 2014 Chapter 25: OSPF 355

OSPFv3 Implementation in IBM N/OS
OSPF version 3 is based on OSPF version 2, but has been modified to support IPv6
addressing. In most other ways, OSPFv3 is similar to OSPFv2: They both have the
same packet types and interfaces, and both use the same mechanisms for neighbor
discovery, adjacency formation, LSA flooding, aging, and so on. The administrator
must be familiar with the OSPFv2 concepts covered in the preceding sections of this
chapter before implementing the OSPFv3 differences as described in the following
sections.

Although OSPFv2 and OSPFv3 are very similar, they represent independent
features on the G8124. They are configured separately, and both can run in parallel
on the switch with no relation to one another, serving different IPv6 and IPv4 traffic,
respectively.

The IBM N/OS implementation conforms to the OSPF version 3

authentication/confidentiality specifications in RFC 4552.

OSPFv3 Differences from OSPFv2

Note: When OSPFv3 is enabled, the OSPF backbone area (0.0.0.0) is created by
default and is always active.

OSPFv3 Requires IPv6 Interfaces

OSPFv3 is designed to support IPv6 addresses. This requires IPv6 interfaces to be
configured on the switch and assigned to OSPF areas, in much the same way IPv4
interfaces are assigned to areas in OSPFv2. This is the primary configuration
difference between OSPFv3 and OSPFv2.

See “Internet Protocol Version 6” on page 263 for configuring IPv6 interfaces.

OSPFv3 Uses Independent Command Paths

Though OSPFv3 and OSPFv2 are very similar, they are configured independently.
OSPFv3 command paths are located as follows:
• In the ISCLI

RS G8124(config)# ipv6 router ospf (OSPFv3 router config mode)

RS G8124(config-router-ospf3)# ?

RS G8124(config)# interface ip <Interface number>(Configure OSPFv3)

RS G8124(config-ip-if)# ipv6 ospf ? (OSPFv3 interface config)

RS G8124# show ipv6 ospf ? (Show OSPFv3 information)

356 RackSwitch G8124: Application Guide

 OSPFv3 Identifies Neighbors by Router ID
Where OSPFv2 uses a mix of IPv4 interface addresses and Router IDs to identify
neighbors, depending on their type, OSPFv3 configuration consistently uses a
Router ID to identify all neighbors.

Although Router IDs are written in dotted decimal notation, and may even be based
on IPv4 addresses from an original OSPFv2 network configuration, it is important to
realize that Router IDs are not IP addresses in OSPFv3, and can be assigned
independently of IP address space. However, maintaining Router IDs consistent
with any legacy OSPFv2 IPv4 addressing allows for easier implementation of both
protocols.

Other Internal Improvements

OSPFv3 has numerous improvements that increase the protocol efficiency in
addition to supporting IPv6 addressing. These improvements change some of the
behaviors in the OSPFv3 network and may affect topology consideration, but have
little direct impact on configuration. For example:
• Addressing fields have been removed from Router and Network LSAs.
• Flexible treatment of unknown LSA types to make integration of OSPFv3 easier.
• Interface network type can be specified using the command:
RS G8124(config-ip-if)# ipv6 ospf network
{broadcast|non-broadcast|point-to-multipoint|point-to-point}
• For an interface network type that is not broadcast or NBMA, link LSA
suppression can be enabled so link LSA is not originated for the interface. Use
the command: RS G8124(config-ip-if)# ipv6 ospf linklsasuppress

OSPFv3 Limitations
N/OS 7.11 does not currently support the following OSPFv3 features:
• Multiple interfaces of OSPFv3 on the same link.

OSPFv3 Configuration Example

The following example depicts the OSPFv3 equivalent configuration of “Example 3:
Summarizing Routes” on page 354 for OSPFv2.

In this example, one summary route from area 1 (stub area) is injected into area 0
(the backbone). The summary route consists of all IP addresses from the 36::0/32
portion of the 36::0/56 network, except for the routes in the 36::0/8 range.
Figure 44. Summarizing Routes
Backbone Stub Area
Area 0 Area 1
(0.0.0.0) (0.0.0.1)

IF 3 IF 4
10::1 36::1

ABR 36::0/32
Summary Route (- 36::0/8)
10::0/56 36::0/56
Network Network

Note: You can specify a range of addresses to prevent advertising by using the
hide option. In this example, routes in the 36::0/8 range are kept private.

© Copyright IBM Corp. 2014 Chapter 25: OSPF 357

 Use the following procedure to configure OSPFv3 support as shown in Figure 43:
1. Configure IPv6 interfaces for each link which will be attached to OSPFv3 areas.

RS G8124(config)# interface ip 3
RS G8124(config-ip-if)# ipv6 address 10:0:0:0:0:0:0:1
RS G8124(config-ip-if)# ipv6 prefixlen 56
RS G8124(config-ip-if)# vlan 10
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 4
RS G8124(config-ip-if)# ip address 36:0:0:0:0:0:1
RS G8124(config-ip-if)# ipv6 prefixlen 56
RS G8124(config-ip-if)# vlan 20
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit

This is equivalent to configuring the IP address and netmask for IPv4 interfaces.
2. Enable OSPFv3.

RS G8124(config)# ipv6 router ospf

RS G8124(config-router-ospf3)# enable

This is equivalent to the OSPFv2 enable option in the router ospf command
path.
3. Define the backbone.
RS G8124(config-router-ospf3)# area 0 area-id 0.0.0.0
RS G8124(config-router-ospf3)# area 0 type transit
RS G8124(config-router-ospf3)# area 0 enable

This is identical to OSPFv2 configuration.

4. Define the stub area.
RS G8124(config-router-ospf3)# area 1 area-id 0.0.0.1
RS G8124(config-router-ospf3)# area 1 type stub
RS G8124(config-router-ospf3)# area 1 enable
RS G8124(config-router-ospf3)# exit

This is identical to OSPFv2 configuration.

5. Attach the network interface to the backbone.
RS G8124(config)# interface ip 3
RS G8124(config-ip-if)# ipv6 ospf area 0
RS G8124(config-ip-if)# ipv6 ospf enable
RS G8124(config-ip-if)# exit

The ipv6 command path is used instead of the OSPFv2 ip command path
6. Attach the network interface to the stub area.
RS G8124(config)# interface ip 4
RS G8124(config-ip-if)# ipv6 ospf area 1
RS G8124(config-ip-if)# ipv6 ospf enable
RS G8124(config-ip-if)# exit

The ipv6 command path is used instead of the OSPFv2 ip command path

358 RackSwitch G8124: Application Guide

 7. Configure route summarization by specifying the starting address and prefix
length of the range of addresses to be summarized.
RS G8124(config)# ipv6 router ospf
RS G8124(config-router-ospf3)# area-range 1 address 36:0:0:0:0:0:0:0 32
RS G8124(config-router-ospf3)# area-range 1 area 0
RS G8124(config-router-ospf3)# area-range 1 enable

This differs from OSPFv2 only in that the OSPFv3 command path is used, and
the address and prefix are specified in IPv6 format.
8. Use the hide command to prevent a range of addresses from advertising to the
backbone.
RS G8124(config-router-ospf)# area-range 2 address 36:0:0:0:0:0:0:0 8
RS G8124(config-router-ospf)# area-range 2 area 0
RS G8124(config-router-ospf)# area-range 2 hide
RS G8124(config-router-ospf)# exit

This differs from OSPFv2 only in that the OSPFv3 command path is used, and
the address and prefix are specified in IPv6 format.

© Copyright IBM Corp. 2014 Chapter 25: OSPF 359

 Neighbor Configuration Example
When using NBMA or point to multipoint interfaces, you must manually configure
neighbors. Following example includes the steps for neighbor configuration.
1. Configure IPv6 interface parameters:
RS G8124(config# interface ip 10
RS G8124(config-ip-if)# ipv6 address 10:0:0:0:0:0:0:12 64
RS G8124(config-ip-if)# vlan 10
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# ipv6 ospf area 0
RS G8124(config-ip-if)# ipv6 ospf retransmit-interval 5
RS G8124(config-ip-if)# ipv6 ospf transmit-delay 1
RS G8124(config-ip-if)# ipv6 ospf priority 1
RS G8124(config-ip-if)# ipv6 ospf hello-interval 10
RS G8124(config-ip-if)# ipv6 ospf dead-interval 40
RS G8124(config-ip-if)# ipv6 ospf network point-to-multipoint
RS G8124(config-ip-if)# ipv6 ospf poll-interval 120
RS G8124(config-ip-if)# ipv6 ospf enable
RS G8124(config-ip-if)# exit

2. Enable OSPFv3:
RS G8124(config# ipv6 router ospf
RS G8124(config-router-ospf3)# router-id 12.12.12.12
RS G8124(config-router-ospf3)# enable

3. Define the backbone.

RS G8124(config-router-ospf3)# area 0 area-id 0.0.0.0
RS G8124(config-router-ospf3)# area 0 stability-interval 40
RS G8124(config-router-ospf3)# area 0 default-metric 1
RS G8124(config-router-ospf3)# area 0 default-metric type 1
RS G8124(config-router-ospf3)# area 0 translation-role candidate
RS G8124(config-router-ospf3)# area 0 type transit
RS G8124(config-router-ospf3)# area 0 enable

4. Configure neighbor entry:

RS G8124(config-router-ospf3)# neighbor 1 address fe80:0:0:0:dceb:ff:fe00:9
RS G8124(config-router-ospf3)# neighbor 1 interface 10
RS G8124(config-router-ospf3)# neighbor 1 priority 1
RS G8124(config-router-ospf3)# neighbor 1 enable

360 RackSwitch G8124: Application Guide

Chapter 26. Protocol Independent Multicast
IBM Networking OS supports Protocol Independent Multicast (PIM) in Sparse Mode
(PIM-SM) and Dense Mode (PIM-DM).
Note: IBM N/OS 7.11 does not support IPv6 for PIM.

The following sections discuss PIM support for the RackSwitch G8124:
• “PIM Overview” on page 362
• “Supported PIM Modes and Features” on page 363
• “Basic PIM Settings” on page 364
• “Additional Sparse Mode Settings” on page 366
• “Using PIM with Other Features” on page 369
• “PIM Configuration Examples” on page 370

© Copyright IBM Corp. 2014 361

PIM Overview
PIM is designed for efficiently routing multicast traffic across one or more IPv4
domains. This has benefits for application such as IP television, collaboration,
education, and software delivery, where a single source must deliver content (a
multicast) to a group of receivers that span both wide-area and inter-domain
networks.

Instead of sending a separate copy of content to each receiver, a multicast derives

efficiency by sending only a single copy of content toward its intended receivers.
This single copy only becomes duplicated when it reaches the target domain that
includes multiple receivers, or when it reaches a necessary bifurcation point leading
to different receiver domains.

PIM is used by multicast source stations, client receivers, and intermediary routers
and switches, to build and maintain efficient multicast routing trees. PIM is protocol
independent; It collects routing information using the existing unicast routing
functions underlying the IPv4 network, but does not rely on any particular unicast
protocol. For PIM to function, a Layer 3 routing protocol (such as BGP, OSPF, RIP,
or static routes) must first be configured on the switch.

PIM-SM is a reverse-path routing mechanism. Client receiver stations advertise

their willingness to join a multicast group. The local routing and switching devices
collect multicast routing information and forward the request toward the station that
will provide the multicast content. When the join requests reach the sending station,
the multicast data is sent toward the receivers, flowing in the opposite direction of
the original join requests.

Some routing and switching devices perform special PIM-SM functions. Within each
receiver domain, one router is elected as the Designated Router (DR) for handling
multicasts for the domain. DRs forward information to a similar device, the
Rendezvous Point (RP), which holds the root tree for the particular multicast group.

Receiver join requests as well as sender multicast content initially converge at the
RP, which generates and distributes multicast routing data for the DRs along the
delivery path. As the multicast content flows, DRs use the routing tree information
obtained from the RP to optimize the paths both to and from send and receive
stations, bypassing the RP for the remainder of content transactions if a more
efficient route is available.

DRs continue to share routing information with the RP, modifying the multicast
routing tree when new receivers join, or pruning the tree when all the receivers in
any particular domain are no longer part of the multicast group.

362 RackSwitch G8124: Application Guide

Supported PIM Modes and Features
For each interface attached to a PIM network component, PIM can be configured to
operate either in PIM Sparse Mode (PIM-SM) or PIM Dense Mode (PIM-DM).
• PIM-SM is used in networks where multicast senders and receivers comprise a
relatively small (sparse) portion of the overall network. PIM-SM uses a more
complex process than PIM-DM for collecting and optimizing multicast routes, but
minimizes impact on other IP services and is more commonly used.
• PIM-DM is used where multicast devices are a relatively large (dense) portion of
the network, with very frequent (or constant) multicast traffic. PIM-DM requires
less configuration on the switch than PIM-SM, but uses broadcasts that can
consume more bandwidth in establishing and optimizing routes.

The following PIM modes and features are not currently supported in N/OS 7.11:
• Hybrid Sparse-Dense Mode (PIM-SM/DM). Sparse Mode and Dense Mode may
be configured on separate IP interfaces on the switch, but are not currently sup-
ported simultaneously on the same IP interface.
• PIM Source-Specific Multicast (PIM-SSM)
• Anycast RP
• PIM RP filters
• Only configuration via the switch ISCLI is supported. PIM configuration is cur-
rently not available using the menu-based CLI, the BBI, or via SNMP.

© Copyright IBM Corp. 2014 Chapter 26: Protocol Independent Multicast 363
Basic PIM Settings
To use PIM the following is required:
• The PIM feature must be enabled globally on the switch.
• PIM network components and PIM modes must be defined.
• IP interfaces must be configured for each PIM component.
• PIM neighbor filters may be defined (optional).
• If PIM-SM is used, define additional parameters:
– Rendezvous Point
– Designated Router preferences (optional)
– Bootstrap Router preferences (optional)

Each of these tasks is covered in the following sections.

Note: In N/OS 7.11, PIM can be configured through the ISCLI only. PIM
configuration and information are not available using the menu-based CLI,
the BBI, or via SNMP.

Globally Enabling or Disabling the PIM Feature

By default, PIM is disabled on the switch. PIM can be globally enabled or disabled
using the following commands:

RS G8124(config)# [no] ip pim enable

Defining a PIM Network Component

The G8124 can be attached to a maximum of two independent PIM network
components. Each component represents a different PIM network, and can be
defined for either PIM-SM or PIM-DM operation. Basic PIM component
configuration is performed using the following commands:

RS G8124(config)# ip pim component <1-2>

RS G8124(config-ip-pim-comp)# mode {sparse|dense}
RS G8124(config-ip-pim-comp)# exit

The sparse option will place the component in Sparse Mode (PIM-SM). The dense
option will place the component in Dense Mode (PIM-DM). By default, PIM
component 1 is configured for Sparse Mode. PIM component 2 is unconfigured by
default.
Note: A component using PIM-SM must also be configured with a dynamic or static
Rendezvous Point (see “Specifying the Rendezvous Point” on page 366).

Defining an IP Interface for PIM Use

Each network attached to an IP interface on the switch may be assigned one of the
available PIM components. The same PIM component can be assigned to multiple
IP interfaces. The interfaces may belong to the same VLAN, and they may also
belong to different VLANs as long as their member IP addresses do not overlap.

364 RackSwitch G8124: Application Guide

 To define an IP interface for use with PIM, first configured the interface with an IPv4
address and VLAN as follows:

RS G8124(config)# interface ip <Interface number>

RS G8124(config-ip-if)# ip address <IPv4 address> <IPv4 mask>
RS G8124(config-ip-if)# vlan <VLAN number>
RS G8124(config-ip-if)# enable

Note: The PIM feature currently supports only one VLAN for each IP interface.
Configurations where different interfaces on different VLANs share IP
addresses are not supported.

Next, PIM must be enabled on the interface, and the PIM network component ID
must be specified:

RS G8124(config-ip-if)# ip pim enable

RS G8124(config-ip-if)# ip pim component-id <1-2>
RS G8124(config-ip-if)# exit

By default, PIM component 1 is automatically assigned when PIM is enabled on the

IP interface.
Note: While PIM is enabled on the interface, the interface VLAN cannot be
changed. To change the VLAN, first disable PIM on the interface.

PIM Neighbor Filters

The G8124 accepts connection to up to 72 PIM interfaces. By default, the switch
accepts all PIM neighbors attached to the PIM-enabled interfaces, up to the
maximum number. Once the maximum is reached, the switch will deny further PIM
neighbors.

To ensure that only the appropriate PIM neighbors are accepted by the switch, the
administrator can use PIM neighbor filters to specify which PIM neighbors may be
accepted or denied on a per-interface basis.

To turn PIM neighbor filtering on or off for a particular IP interface, use the following
commands:

RS G8124(config)# interface ip <Interface number>

RS G8124(config-ip-if)# [no] ip pim neighbor-filter

When filtering is enabled, all PIM neighbor requests on the specified IP interface will
be denied by default. To allow a specific PIM neighbor, use the following command:

RS G8124(config-ip-if)# ip pim neighbor-addr <neighbor IPv4 address> allow

To remove a PIM neighbor from the accepted list, use the following command.

RS G8124(config-ip-if)# ip pim neighbor-addr <neighbor IPv4 address> deny

RS G8124(config-ip-if)# exit

You can view configured PIM neighbor filters globally or for a specific IP interface
using the following commands:

RS G8124(config)# show ip pim neighbor-filters

RS G8124(config)# show ip pim interface <Interface number> neighbor-filters

© Copyright IBM Corp. 2014 Chapter 26: Protocol Independent Multicast 365
Additional Sparse Mode Settings
Specifying the Rendezvous Point
Using PIM-SM, at least one PIM-capable router must be a candidate for use as a
Rendezvous Point (RP) for any given multicast group. If desired, the G8124 can act
as an RP candidate. To assign a configured switch IP interface as a candidate, use
the following procedure.
1. Select the PIM component that will represent the RP candidate:

RS G8124(config)# ip pim component <1-2>

2. Configure the IPv4 address of the switch interface which will be advertised as a
candidate RP for the specified multicast group:

RS G8124(config-ip-pim-comp)# rp-candidate rp-address <group address> <group address

mask> <candidate IPv4 address>

The switch interface will participate in the election of the RP that occurs on the
Bootstrap Router, or BSR (see “Specifying a Bootstrap Router” on page 367).
3. If using dynamic RP candidates, configure the amount of time that the elected
interface will remain the RP for the group before a re-election is performed:

RS G8124(config-ip-pim-comp)# rp-candidate holdtime <0-255>

RS G8124(config-ip-pim-comp)# exit

Static RP

If RP no election is desired, the switch can provide a static RP. Use the following
commands:
1. Enable static RP configuration.

RS G8124(config)# ip pim static-rp enable

2. Select the PIM component that will represent the RP candidate:

RS G8124(config)# ip pim component <1-2>

3. Configure the static IPv4 address.

RS G8124(config-ip-pim-comp)# rp-static rp-address <group address> <group address mask>

<static IPv4 address>

366 RackSwitch G8124: Application Guide

Influencing the Designated Router Selection
Using PIM-SM, All PIM-enabled IP interfaces are considered as potential Designate
Routers (DR) for their domain. By default, the interface with the highest IP address
on the domain is selected. However, if an interface is configured with a DR priority
value, it overrides the IP address selection process. If more than one interface on a
domain is configured with a DR priority, the one with the highest number is selected.

Use the following commands to configure the DR priority value (Interface IP mode):

RS G8124(config)# interface ip <Interface number>

RS G8124(config-ip-if)# ip pim dr-priority <value (0-4294967294)>
RS G8124(config-ip-if)# exit

Note: A value of 0 (zero) specifies that the G8124 will not act as the DR. This
setting requires the G8124 to be connected to a peer that has a DR priority
setting of 1 or higher to ensure that a DR will be present in the network.

Specifying a Bootstrap Router

Using PIM-SM, a Bootstrap Router (BSR) is a PIM-capable router that hosts the
election of the RP from available candidate routers. For each PIM-enabled IP
interface, the administrator can set the preference level for which the local interface
becomes the BSR:

RS G8124(config)# interface ip <Interface number>

RS G8124(config-ip-if)# ip pim cbsr-preference <0 to 255>
RS G8124(config-ip-if)# exit

A value of 255 highly prefers the local interface as a BSR. A value of -1 indicates
that the PIM CBSR preference is not configured on the switch.

Configuring a Loopback Interface

Loopback interfaces can be used in PIM Sparse Mode for Rendezvous Points (RPs)
and Bootstrap Routers (BSRs). For example:
• As a static RP

interface loopback 1
ip address 55.55.1.1 255.255.255.0
enable
exit

ip pim static-rp enable

ip pim component 1
rp-static rp-address 224.0.0.0 240.0.0.0 55.55.1.1

interface loopback 1
ip pim enable
exit

© Copyright IBM Corp. 2014 Chapter 26: Protocol Independent Multicast 367
 • As a candidate RP

interface loopback 1
ip address 55.55.1.1 255.255.255.0
enable
exit

ip pim component 1
rp-candidate holdtime 60
rp-candidate rp-address 224.0.0.0 240.0.0.0 55.55.1.1

interface loopback 1
ip pim enable
exit

• As a BSR

interface loopback 1
ip address 55.55.1.1 255.255.255.0
enable
exit

interface loopback 1
ip pim enable
ip pim cbsr-preference 2
exit

368 RackSwitch G8124: Application Guide

Using PIM with Other Features
PIM with ACLs or VMAPs

If using ACLs or VMAPs, be sure to permit traffic for local hosts and routers.

PIM with IGMP

If using IGMP (see “Internet Group Management Protocol” on page 289):

• IGMP static joins can be configured with a PIM-SM or PIM-DM multicast group
IPv4 address. Using the ISCLI:

RS G8124(config)# ip mroute <multicast group IPv4 address> <VLAN> <port>

• IGMP Querier is disabled by default. If IGMP Querier is needed with PIM, be sure
to enable the IGMP Query feature globally, as well as on each VLAN where it is
needed.
• If the switch is connected to multicast receivers and/or hosts, be sure to enable
IGMP snooping globally, as well as on each VLAN where PIM receivers are
attached.

PIM with VLAG

If using VLAG, see “VLAG with PIM” on page 158.

© Copyright IBM Corp. 2014 Chapter 26: Protocol Independent Multicast 369
PIM Configuration Examples
Example 1: PIM-SM with Dynamic RP
This example configures PIM Sparse Mode for one IP interface, with the switch
acting as a candidate for dynamic Rendezvous Point (RP) selection.
1. Globally enable the PIM feature:

RS G8124(config)# ip pim enable

2. Configure a PIM network component with dynamic RP settings, and set it for
PIM Sparse Mode:

RS G8124(config)# ip pim component 1

RS G8124(config-ip-pim-comp)# mode sparse
RS G8124(config-ip-pim-comp)# rp-candidate rp-address 225.1.0.0 255.255.0.0
10.10.1.1
RS G8124(config-ip-pim-comp)# rp-candidate holdtime <0-255>
RS G8124(config-ip-pim-comp)# exit

Where 225.1.0.0 is the multicast group base IP address, 255.255.0.0 is the

multicast group address mask, and 10.10.1.1 is the switch RP candidate
address.
Note: Because, Sparse Mode is set by default for PIM component 1, the mode
command is needed only if the mode has been previously changed.
3. Define an IP interface for use with PIM:

RS G8124(config)# interface ip 111

RS G8124(config-ip-if)# ip address 10.10.1.1 255.255.255.255
RS G8124(config-ip-if)# vlan 11
RS G8124(config-ip-if)# enable

The IP interface represents the PIM network being connected to the switch. The
IPv4 addresses in the defined range must not be included in another IP interface
on the switch under a different VLAN.
4. Enable PIM on the IP interface and assign the PIM component:

RS G8124(config-ip-if)# ip pim enable

RS G8124(config-ip-if)# ip pim component-id 1

Note: Because, PIM component 1 is assigned to the interface by default, the

component-id command is needed only if the setting has been
previously changed.
5. Set the Bootstrap Router (BSR) preference:

RS G8124(config-ip-if)# ip pim cbsr-preference 135

RS G8124(config-ip-if)# exit

370 RackSwitch G8124: Application Guide

 Example 2: PIM-SM with Static RP

The following commands can be used to modify the prior example configuration to
use a static RP:

RS G8124(config)# ip pim static-rp enable

RS G8124(config)# ip pim component 1
RS G8124(config-ip-pim-comp)# rp-static rp-address 225.1.0.0 255.255.0.0 10.10.1.1
RS G8124(config-ip-pim-comp)# exit

Where 225.1.0.0 255.255.0.0 is the multicast group base address and mask, and
10.10.1.1 is the static RP address.
Note: The same static RP address must be configured for all switches in the group.

Example 3: PIM-DM

This example configures PIM Dense Mode (PIM-DM) on one IP interface. PIM-DM
can be configured independently, or it can be combined with the prior PIM-SM
examples (which are configured on a different PIM component) as shown in
Figure 45.
Figure 45. Network with both PIM-DM and PIM-SM Components

PIM-SM PIM-DM
Multicast Multicast
225.1.0.0/16 239.1.0.0/16

PIM Enabled
Switch
IP Interface 11 IP Interface 22
IP 10.10.1.1 IP 10.10.2.1
VLAN 101 VLAN 102
Component 1 Component 2

Media
Servers

1. Configure the PIM-SM component as shown in the prior examples, or if using

PIM-DM independently, enable the PIM feature.

RS G8124(config)# ip pim enable

2. Configure a PIM component and set the PIM mode:

RS G8124(config)# ip pim component 2

RS G8124(config-ip-pim-comp)# mode dense
RS G8124(config-ip-pim-comp)# exit

© Copyright IBM Corp. 2014 Chapter 26: Protocol Independent Multicast 371
 3. Define an IP interface for use with PIM:

RS G8124(config)# interface ip 22
RS G8124(config-ip-if)# ip address 10.10.2.1 255.255.255.255
RS G8124(config-ip-if)# vlan 102
RS G8124(config-ip-if)# enable

4. Enable PIM on the IP interface and assign the PIM component:

RS G8124(config-ip-if)# ip pim enable

RS G8124(config-ip-if)# ip pim component-id 2
RS G8124(config-ip-if)# exit

5. (Optional) Configure PIM border router if the IPMC traffic is flowing between
PIM domains:

RS G8124(config)# ip pim pmbr enable

RS G8124(config)# interface ip 22
RS G8124(config-ip-if)# ip pim border-bit
RS G8124(config-ip-if)# exit

Note: For PIM Dense Mode, the DR, RP, and BSR settings do not apply.

372 RackSwitch G8124: Application Guide

Part 6: High Availability
Fundamentals
Internet traffic consists of myriad services and applications which use the Internet
Protocol (IP) for data delivery. However, IP is not optimized for all the various
applications. High Availability goes beyond IP and makes intelligent switching
decisions to provide redundant network configurations.

© Copyright IBM Corp. 2014 373

374 RackSwitch G8124: Application Guide
Chapter 27. Basic Redundancy
IBM Networking OS 7.11 includes various features for providing basic link or device
redundancy:
• “Trunking for Link Redundancy” on page 376
• “Virtual Link Aggregation” on page 376
• “Hot Links” on page 377

© Copyright IBM Corp. 2014 375

Trunking for Link Redundancy
Multiple switch ports can be combined together to form robust, high-bandwidth
trunks to other devices. Since trunks are comprised of multiple physical links, the
trunk group is inherently fault tolerant. As long as one connection between the
switches is available, the trunk remains active.

In Figure 46, four ports are trunked together between the switch and the enterprise
routing device. Connectivity is maintained as long as one of the links remain active.
The links to the server are also trunked, allowing the secondary NIC to take over in
the event that the primary NIC link fails.
Figure 46. Trunking Ports for Link Redundancy

Enterprise
Server
Routing Switch

NIC 1
Internet NIC 2
Trunk Trunk

For more information on trunking, see “Ports and Trunking” on page 109.

Virtual Link Aggregation

Using the VLAG feature, switches can be paired as VLAG peers. The peer switches
appear to the connecting device as a single virtual entity for the purpose of
establishing a multi-port trunk. The VLAG-capable switches synchronize their
logical view of the access layer port structure and internally prevent implicit loops.
The VLAG topology also responds more quickly to link failure and does not result in
unnecessary MAC flooding.

VLAGs are useful in multi-layer environments for both uplink and downlink
redundancy to any regular LAG-capable device. They can also be used in for
active-active VRRP connections.

For more information on VLAGs, see “Virtual Link Aggregation Groups” on

page 139.

376 RackSwitch G8124: Application Guide

Hot Links
Hot Links provides basic link redundancy with fast recovery.

Hot Links consists of up to 25 triggers. A trigger consists of a pair of layer 2

interfaces, each containing an individual port, trunk, or LACP adminkey. One
interface is the Master, and the other is a Backup. While the Master interface is set
to the active state and forwards traffic, the Backup interface is set to the standby
state and blocks traffic until the Master interface fails. If the Master interface fails,
the Backup interface is set to active and forwards traffic. Once the Master interface
is restored, it regains its active state and forwards traffic. The Backup transitions to
the standby state.

You may select a physical port, static trunk, or an LACP adminkey as a Hot Link
interface.

Forward Delay
The Forward Delay timer allows Hot Links to monitor the Master and Backup
interfaces for link stability before selecting one interface to transition to the active
state. Before the transition occurs, the interface must maintain a stable link for the
duration of the Forward Delay interval.

For example, if you set the Forward delay timer to 10 seconds, the switch will select
an interface to become active only if a link remained stable for the duration of the
Forward Delay period. If the link is unstable, the Forward Delay period starts again.

Preemption
You can configure the Master interface to resume the active state whenever it
becomes available. With Hot Links preemption enabled, the Master interface
transitions to the active state immediately upon recovery. The Backup interface
immediately transitions to the standby state. If Forward Delay is enabled, the
transition occurs when an interface has maintained link stability for the duration of
the Forward Delay period.

FDB Update
Use the FDB update option to notify other devices on the network about updates to
the Forwarding Database (FDB). When you enable FDB update, the switch sends
multicasts of addresses in the forwarding database (FDB) over the active interface,
so that other devices on the network can learn the new path. The Hot Links FBD
update option uses the station update rate to determine the rate at which to send
FDB packets.

Configuration Guidelines
The following configuration guidelines apply to Hot links:
• When Hot Links is turned on, STP must be disabled on the hotlink ports.
• A port that is a member of the Master interface cannot be a member of the
Backup interface. A port that is a member of one Hot Links trigger cannot be a
member of another Hot Links trigger.
• An individual port that is configured as a Hot Link interface cannot be a member
of a trunk.

© Copyright IBM Corp. 2014 Chapter 27: Basic Redundancy 377

Configuring Hot Links
Spanning Tree Protocol must be disabled on Hot Links ports. For instance, if Hot
Links ports 1 and 2 belong to STGs 1 and 23, use the following commands to
disable the STGs:

RS G8124(config)# no span stp 1 enable

RS G8124(config)# no span stp 23 enable

Use the following commands to configure Hot Links.

RS G8124(config)# [no] hotlinks bpdu (Enable or disable Hot Links BPDU flood)
RS G8124(config)# [no] hotlinks enable (Enable or disable Hot Links globally)
RS G8124(config)# [no] hotlinks fdb-update (Enable or disable Hot Links FDB update)
RS G8124(config)# hotlinks fdb-update-rate (Configure FDB update rate in packets per second)
RS G8124(config)# hotlinks trigger 1 enable (Enable Hot Links Trigger 1)
RS G8124(config)# hotlinks trigger 1 master port 1 (Add port to Master interface)
RS G8124(config)# hotlinks trigger 1 backup port 2 (Add port to Backup interface)
RS G8124(config)# hotlinks enable (Turn on Hot Links)

378 RackSwitch G8124: Application Guide

Chapter 28. Layer 2 Failover
The primary application for Layer 2 Failover is to support Network Adapter Teaming.
With Network Adapter Teaming, all the NICs on each server share the same IP
address, and are configured into a team. One NIC is the primary link, and the other
is a standby link. For more details, refer to the documentation for your Ethernet
adapter.
Note: Only two links per server can be used for Layer 2 Trunk Failover (one
primary and one backup). Network Adapter Teaming allows only one backup
NIC for each server blade.

Monitoring Trunk Links

Layer 2 Failover can be enabled on any trunk group in the G8124, including LACP
trunks. Trunks can be added to failover trigger groups. Then, if some specified
number of monitor links fail, the switch disables all the control ports in the switch.
When the control ports are disabled, it causes the NIC team on the affected servers
to failover from the primary to the backup NIC. This process is called a failover
event.

When the appropriate number of links in a monitor group return to service, the
switch enables the control ports. This causes the NIC team on the affected servers
to fail back to the primary switch (unless Auto-Fallback is disabled on the NIC team).
The backup switch processes traffic until the primary switch’s control links come up,
which can take up to five seconds.

Figure 47 is a simple example of Layer 2 Failover. One G8124 is the primary, and
the other is used as a backup. In this example, all ports on the primary switch belong
to a single trunk group, with Layer 2 Failover enabled, and Failover Limit set to 2. If
two or fewer links in trigger 1 remain active, the switch temporarily disables all
control ports. This action causes a failover event on Server 1 and Server 2.
Figure 47. Basic Layer 2 Failover

Enterprise Primary
Routing Switches Switch Server 1
Trigger 1
NIC 1
NIC 2

Backup
Internet Switch Server 2
Trigger 1
NIC 1
NIC 2

Setting the Failover Limit

The failover limit lets you specify the minimum number of operational links required
within each trigger before the trigger initiates a failover event. For example, if the
limit is two, a failover event occurs when the number of operational links in the
trigger is two or fewer. When you set the limit to zero, the switch triggers a failover
event only when no links in the trigger are operational.

© Copyright IBM Corp. 2014 379

Manually Monitoring Port Links
The Manual Monitor allows you to configure a set of ports and trunks to monitor for
link failures (a monitor list), and another set of ports and trunks to disable when the
trigger limit is reached (a control list). When the switch detects a link failure on the
monitor list, it automatically disables the items in control list. When server ports are
disabled, the corresponding server’s network adapter can detect the disabled link,
and trigger a network-adapter failover to another port or trunk on the switch, or
another switch.

The switch automatically enables the control list items when the monitor list items
return to service.

Monitor Port State

A monitor port is considered operational as long as the following conditions are true:
• The port must be in the Link Up state.
• If STP is enabled, the port must be in the Forwarding state.
• If the port is part of an LACP trunk, the port must be in the Aggregated state.

If any of these conditions is false, the monitor port is considered to have failed.

Control Port State

A control port is considered Operational if the monitor trigger is up. As long as the
trigger is up, the port is considered operational from a teaming perspective, even if
the port itself is actually in the Down state, Blocking state (if STP is enabled on the
port), or Not Aggregated state (if part of an LACP trunk).

A control port is considered to have failed only if the monitor trigger is in the Down
state.

To view the state of any port, use one of the following commands:

>> # show interface link (View port link status)

>> # show interface port <x> spanning-tree stp <x>(View port STP status)
>> # show lacp information (View port LACP status)

380 RackSwitch G8124: Application Guide

L2 Failover with Other Features
L2 Failover works together with Link Aggregation Control Protocol (LACP) and with
Spanning Tree Protocol (STP), as described in the next sections.

LACP
Link Aggregation Control Protocol allows the switch to form dynamic trunks. You can
use the admin key to add up to 64 LACP trunks to a failover trigger using automatic
monitoring. When you add an admin key to a trigger, any LACP trunk with that
admin key becomes a member of the trigger.

Spanning Tree Protocol

If Spanning Tree Protocol (STP) is enabled on the ports in a failover trigger, the
switch monitors the port STP state rather than the link state. A port failure results
when STP is not in a Forwarding state (such as Learning, Discarding, or No Link) in
all the Spanning Tree Groups (STGs) to which the port belongs. The switch
automatically disables the appropriate control ports.

When the switch determines that ports in the trigger are in STP Forwarding state in
any one of the STGs it belongs to, then it automatically enables the appropriate
control ports. The switch fails back to normal operation.

For example, if a monitor port is a member of STG1, STG2, and STG3, a failover will
be triggered only if the port is not in a forwarding state in all the three STGs. When
the port state in any of the three STGs changes to forwarding, then the control port
is enabled and normal switch operation is resumed.

© Copyright IBM Corp. 2014 Chapter 28: Layer 2 Failover 381

Configuration Guidelines
This section provides important information about configuring Layer 2 Failover.
• Any specific failover trigger can monitor ports only, static trunks only, or LACP
trunks only. The different types cannot be combined in the same trigger.
• A maximum of 24 LACP keys can be added per trigger.
• Management ports cannot be monitored.
• Control ports for different triggers must not overlap. Monitor ports may overlap.

Configuring Layer 2 Failover

Use the following procedure to configure a Layer 2 Failover Manual Monitor.
1. Specify the links to monitor.

>> # failover trigger 1 mmon monitor member 1-5

2. Specify the links to disable when the failover limit is reached.

>> # failover trigger 1 mmon control member 6-10

3. Configure general Failover parameters.

>> # failover enable

>> # failover trigger 1 enable
>> # failover trigger 1 limit 2

382 RackSwitch G8124: Application Guide

Chapter 29. Virtual Router Redundancy Protocol
The IBM RackSwitch G8124 (G8124) supports IPv4 high-availability network
topologies through an enhanced implementation of the Virtual Router Redundancy
Protocol (VRRP).
Note: IBM Networking OS 7.11 does not support IPv6 for VRRP.

The following topics are discussed in this chapter:

• “VRRP Overview” on page 384. This section discusses VRRP operation and
IBM N/OS redundancy configurations.
• “Failover Methods” on page 387. This section describes the three modes of high
availability.
• “IBM N/OS Extensions to VRRP” on page 388. This section describes VRRP
enhancements implemented in N/OS.
• “Virtual Router Deployment Considerations” on page 389. This section describes
issues to consider when deploying virtual routers.
• “High Availability Configurations” on page 390. This section discusses the more
useful and easily deployed redundant configurations.

© Copyright IBM Corp. 2014 383

VRRP Overview
In a high-availability network topology, no device can create a single point-of-failure
for the network or force a single point-of-failure to any other part of the network. This
means that your network will remain in service despite the failure of any single
device. To achieve this usually requires redundancy for all vital network
components.

VRRP enables redundant router configurations within a LAN, providing alternate

router paths for a host to eliminate single points-of-failure within a network. Each
participating VRRP-capable routing device is configured with the same virtual router
IPv4 address and ID number. One of the virtual routers is elected as the master,
based on a number of priority criteria, and assumes control of the shared virtual
router IPv4 address. If the master fails, one of the backup virtual routers will take
control of the virtual router IPv4 address and actively process traffic addressed to it.

With VRRP, Virtual Interface Routers (VIR) allow two VRRP routers to share an IP
interface across the routers. VIRs provide a single Destination IPv4 (DIP) address
for upstream routers to reach various servers, and provide a virtual default Gateway
for the servers.

VRRP Components
Each physical router running VRRP is known as a VRRP router.

Virtual Router

Two or more VRRP routers can be configured to form a virtual router (RFC 2338).
Each VRRP router may participate in one or more virtual routers. Each virtual router
consists of a user-configured virtual router identifier (VRID) and an IPv4 address.

Virtual Router MAC Address

The VRID is used to build the virtual router MAC Address. The five highest-order
octets of the virtual router MAC Address are the standard MAC prefix
(00-00-5E-00-01) defined in RFC 2338. The VRID is used to form the lowest-order
octet.

Owners and Renters

Only one of the VRRP routers in a virtual router may be configured as the IPv4
address owner. This router has the virtual router’s IPv4 address as its real interface
address. This router responds to packets addressed to the virtual router’s IPv4
address for ICMP pings, TCP connections, and so on.

There is no requirement for any VRRP router to be the IPv4 address owner. Most
VRRP installations choose not to implement an IPv4 address owner. For the
purposes of this chapter, VRRP routers that are not the IPv4 address owner are
called renters.

384 RackSwitch G8124: Application Guide

 Master and Backup Virtual Router

Within each virtual router, one VRRP router is selected to be the virtual router
master. See “Selecting the Master VRRP Router” on page 386 for an explanation of
the selection process.
Note: If the IPv4 address owner is available, it will always become the virtual router
master.

The virtual router master forwards packets sent to the virtual router. It also responds
to Address Resolution Protocol (ARP) requests sent to the virtual router's IPv4
address. Finally, the virtual router master sends out periodic advertisements to let
other VRRP routers know it is alive and its priority.

Within a virtual router, the VRRP routers not selected to be the master are known as
virtual router backups. If the virtual router master fails, one of the virtual router
backups becomes the master and assumes its responsibilities.

Virtual Interface Router

At Layer 3, a Virtual Interface Router (VIR) allows two VRRP routers to share an IP
interface across the routers. VIRs provide a single Destination IPv4 (DIP) address
for upstream routers to reach various destination networks, and provide a virtual
default Gateway.
Note: Every VIR must be assigned to an IP interface, and every IP interface must
be assigned to a VLAN. If no port in a VLAN has link up, the IP interface of
that VLAN is down, and if the IP interface of a VIR is down, that VIR goes
into INIT state.

VRRP Operation
Only the virtual router master responds to ARP requests. Therefore, the upstream
routers only forward packets destined to the master. The master also responds to
ICMP ping requests. The backup does not forward any traffic, nor does it respond to
ARP requests.

If the master is not available, the backup becomes the master and takes over
responsibility for packet forwarding and responding to ARP requests.

© Copyright IBM Corp. 2014 Chapter 29: Virtual Router Redundancy Protocol 385
Selecting the Master VRRP Router
Each VRRP router is configured with a priority between 1–254. A bidding process
determines which VRRP router is or becomes the master—the VRRP router with
the highest priority.

The master periodically sends advertisements to an IPv4 multicast address. As long

as the backups receive these advertisements, they remain in the backup state. If a
backup does not receive an advertisement for three advertisement intervals, it
initiates a bidding process to determine which VRRP router has the highest priority
and takes over as master. In addition to the three advertisement intervals, a
manually set holdoff time can further delay the backups from assuming the master
status.

If, at any time, a backup determines that it has higher priority than the current
master does, it can preempt the master and become the master itself, unless
configured not to do so. In preemption, the backup assumes the role of master and
begins to send its own advertisements. The current master sees that the backup
has higher priority and will stop functioning as the master.

A backup router can stop receiving advertisements for one of two reasons—the
master can be down, or all communications links between the master and the
backup can be down. If the master has failed, it is clearly desirable for the backup
(or one of the backups, if there is more than one) to become the master.
Note: If the master is healthy but communication between the master and the
backup has failed, there will then be two masters within the virtual router. To
prevent this from happening, configure redundant links to be used between
the switches that form a virtual router.

386 RackSwitch G8124: Application Guide

Failover Methods
With service availability becoming a major concern on the Internet, service
providers are increasingly deploying Internet traffic control devices, such as
application switches, in redundant configurations. N/OS high availability
configurations are based on VRRP. The N/OS implementation of VRRP includes
proprietary extensions.

Active-Active Redundancy
In an active-active configuration, shown in Figure 48, two switches provide
redundancy for each other, with both active at the same time. Each switch
processes traffic on a different subnet. When a failure occurs, the remaining switch
can process traffic on all subnets.

For a configuration example, see “High Availability Configurations” on page 390.

Figure 48. Active-Active Redundancy

Active (subnet A and C)

Switch 1

Servers
Internet

Enterprise
Routing Switch
Switch 2
Active (subnet B and D)

Virtual Router Group

The virtual router group ties all virtual routers on the switch together as a single
entity. As members of a group, all virtual routers on the switch (and therefore the
switch itself), are in either a master or standby state.

A VRRP group has the following characteristics:

• When enabled, all virtual routers behave as one entity, and all group settings
override any individual virtual router settings.
• All individual virtual routers, once the VRRP group is enabled, assume the
group’s tracking and priority.
• When one member of a VRRP group fails, the priority of the group decreases,
and the state of the entire switch changes from Master to Standby.

Each VRRP advertisement can include up to 16 addresses. All virtual routers are
advertised within the same packet, conserving processing and buffering resources.

© Copyright IBM Corp. 2014 Chapter 29: Virtual Router Redundancy Protocol 387
IBM N/OS Extensions to VRRP
This section describes VRRP enhancements that are implemented in N/OS.
N/OS supports a tracking function that dynamically modifies the priority of a VRRP
router, based on its current state. The objective of tracking is to have, whenever
possible, the master bidding processes for various virtual routers in a LAN converge
on the same switch. Tracking ensures that the selected switch is the one that offers
optimal network performance. For tracking to have any effect on virtual router
operation, preemption must be enabled.

N/OS can track the attributes listed in Table 31 (Router VRRP mode):
Table 31. VRRP Tracking Parameters

Parameter Description

Number of IP interfaces on the switch Helps elect the virtual routers with the
that are active (“up”) most available routes as the master. (An IP
interface is considered active when there
tracking-priority-increment is at least one active port on the same
interfaces VLAN.) This parameter influences the
VRRP router's priority in virtual interface
routers.

Number of active ports on the same Helps elect the virtual routers with the
VLAN most available ports as the master. This
parameter influences the VRRP router's
tracking-priority-increment priority in virtual interface routers.
ports

Number of virtual routers in master Useful for ensuring that traffic for any
mode on the switch particular client/server pair is handled by
the same switch, increasing routing
tracking-priority-increment efficiency. This parameter influences the
virtual-routers VRRP router's priority in virtual interface
routers.

Each tracked parameter has a user-configurable weight associated with it. As the
count associated with each tracked item increases (or decreases), so does the
VRRP router's priority, subject to the weighting associated with each tracked item. If
the priority level of a standby is greater than that of the current master, then the
standby can assume the role of the master.

See “Configuring the Switch for Tracking” on page 389 for an example on how to
configure the switch for tracking VRRP priority.

388 RackSwitch G8124: Application Guide

Virtual Router Deployment Considerations
Assigning VRRP Virtual Router ID

During the software upgrade process, VRRP virtual router IDs will be automatically
assigned if failover is enabled on the switch. When configuring virtual routers at any
point after upgrade, virtual router ID numbers must be assigned. The virtual router
ID may be configured as any number between 1 and 255. Use the following
command to configure the virtual router ID:

RS G8124(config)# router vrrp

RS G8124(config-vrrp)# virtual-router 1 virtual-router-id <1-255>

Configuring the Switch for Tracking

Tracking configuration largely depends on user preferences and network

environment. Consider the configuration shown in Figure 48 on page 387. Assume
the following behavior on the network:
• Switch 1 is the master router upon initialization.
• If switch 1 is the master and it has one fewer active servers than switch 2, then
switch 1 remains the master.
This behavior is preferred because running one server down is less disruptive
than bringing a new master online and severing all active connections in the
process.
• If switch 1 is the master and it has two or more active servers fewer than switch
2, then switch 2 becomes the master.
• If switch 2 is the master, it remains the master even if servers are restored on
switch 1 such that it has one fewer or an equal number of servers.
• If switch 2 is the master and it has one active server fewer than switch 1, then
switch 1 becomes the master.

You can implement this behavior by configuring the switch for tracking as follows:
1. Set the priority for switch 1 to 101.
2. Leave the priority for switch 2 at the default value of 100.
3. On both switches, enable tracking based on ports, interfaces, or virtual routers.
You can choose any combination of tracking parameters, based on your
network configuration.
Note: There is no shortcut to setting tracking parameters. The goals must first be
set and the outcomes of various configurations and scenarios analyzed to
find settings that meet the goals.

© Copyright IBM Corp. 2014 Chapter 29: Virtual Router Redundancy Protocol 389
High Availability Configurations
VRRP High-Availability Using Multiple VIRs
Figure 49 shows an example configuration where two G8124s are used as VRRP
routers in an active-active configuration. In this configuration, both switches respond
to packets.
Figure 49. Active-Active Configuration using VRRP
VIR 1: 192.168.1.200 (Master) Server 1
L2 Switch VIR 2: 192.168.2.200 (Backup)
NIC 1: 10.0.1.1/24
1 NIC 2: 10.0.2.1/24
Server 2
2 Switch 1
Internet 4 NIC 1: 10.0.1.2/24
NIC 2: 10.0.2.2/24

Server 3
4 NIC 1: 10.0.1.3/24
Enterprise 1 Server 4 NIC 2: 10.0.2.3/24
Routing Switch
2
Switch 2
NIC 1: 10.0.1.4/24
L2 Switch VIR 1: 192.168.1.200 (Backup) NIC 2: 10.0.2.4/24
VIR 2: 192.168.2.200 (Master)

Although this example shows only two switches, there is no limit on the number of
switches used in a redundant configuration. It is possible to implement an
active-active configuration across all the VRRP-capable switches in a LAN.

Each VRRP-capable switch in an active-active configuration is autonomous.

Switches in a virtual router need not be identically configured.

In the scenario illustrated in Figure 49, traffic destined for IPv4 address 10.0.1.1 is
forwarded through the Layer 2 switch at the top of the drawing, and ingresses
G8124 1 on port 1. Return traffic uses default gateway 1 (192.168.1.1).

If the link between G8124 1 and the Layer 2 switch fails, G8124 2 becomes the
Master because it has a higher priority. Traffic is forwarded to G8124 2, which
forwards it to G8124 1 through port 4. Return traffic uses default gateway 2
(192.168.2.1), and is forwarded through the Layer 2 switch at the bottom of the
drawing.

390 RackSwitch G8124: Application Guide

 To implement the active-active example, perform the following switch configuration.

Task 1: Configure G8124 1

1. Configure client and server interfaces.

RS G8124(config)# interface ip 1
RS G8124(config-ip-if)# ip address 192.168.1.100 255.255.255.0
RS G8124(config-ip-if)# vlan 10
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 2
RS G8124(config-ip-if)# ip address 192.168.2.101 255.255.255.0
RS G8124(config-ip-if)# vlan 20
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 3
RS G8124(config-ip-if)# ip address 10.0.1.100 255.255.255.0
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 4
RS G8124(config-ip-if)# ip address 10.0.2.101 255.255.255.0
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit

2. Configure the default gateways. Each default gateway points to a Layer 3

router.

RS G8124(config)# ip gateway 1 address 192.168.1.1

RS G8124(config)# ip gateway 1 enable
RS G8124(config)# ip gateway 2 address 192.168.2.1
RS G8124(config)# ip gateway 2 enable

3. Turn on VRRP and configure two Virtual Interface Routers.

RS G8124(config)# router vrrp

RS G8124(config-vrrp)# enable
RS G8124(config-vrrp)# virtual-router 1 virtual-router-id 1
RS G8124(config-vrrp)# virtual-router 1 interface 1
RS G8124(config-vrrp)# virtual-router 1 address 192.168.1.200
RS G8124(config-vrrp)# virtual-router 1 enable
RS G8124(config-vrrp)# virtual-router 2 virtual-router-id 2
RS G8124(config-vrrp)# virtual-router 2 interface 2
RS G8124(config-vrrp)# virtual-router 2 address 192.168.2.200
RS G8124(config-vrrp)# virtual-router 2 enable

4. Enable tracking on ports. Set the priority of Virtual Router 1 to 101, so that it
becomes the Master.

RS G8124(config-vrrp)# virtual-router 1 track ports

RS G8124(config-vrrp)# virtual-router 1 priority 101
RS G8124(config-vrrp)# virtual-router 2 track ports
RS G8124(config-vrrp)# exit

© Copyright IBM Corp. 2014 Chapter 29: Virtual Router Redundancy Protocol 391
 5. Configure ports.

RS G8124(config)# vlan 10
RS G8124(config-vlan)# exit
RS G8124(config)# interface port 1
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 10
RS G8124(config-if)# exit

RS G8124(config)# vlan 20
RS G8124(config-vlan)# exit
RS G8124(config)# interface port 2
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 20
RS G8124(config-if)# exit

6. Turn off Spanning Tree Protocol globally.

RS G8124(config)# no spanning-tree stp 1

Task 2: Configure G8124 2

1. Configure client and server interfaces.

RS G8124(config)# interface ip 1
RS G8124(config-ip-if)# ip address 192.168.1.101 255.255.255.0
RS G8124(config-ip-if)# vlan 10
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 2
RS G8124(config-ip-if)# ip address 192.168.2.100 255.255.255.0
RS G8124(config-ip-if)# vlan 20
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 3
RS G8124(config-ip-if)# ip address 10.0.1.101 255.255.255.0
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit
RS G8124(config)# interface ip 4
RS G8124(config-ip-if)# ip address 10.0.2.100 255.255.255.0
RS G8124(config-ip-if)# enable
RS G8124(config-ip-if)# exit

2. Configure the default gateways. Each default gateway points to a Layer 3

router.

RS G8124(config)# ip gateway 1 address 192.168.2.1

RS G8124(config)# ip gateway 1 enable
RS G8124(config)# ip gateway 2 address 192.168.1.1
RS G8124(config)# ip gateway 2 enable

392 RackSwitch G8124: Application Guide

 3. Turn on VRRP and configure two Virtual Interface Routers.

RS G8124(config)# router vrrp

RS G8124(config-vrrp)# enable
RS G8124(config-vrrp)# virtual-router 1 virtual-router-id 1
RS G8124(config-vrrp)# virtual-router 1 interface 1
RS G8124(config-vrrp)# virtual-router 1 address 192.168.1.200
RS G8124(config-vrrp)# virtual-router 1 enable
RS G8124(config-vrrp)# virtual-router 2 virtual-router-id 2
RS G8124(config-vrrp)# virtual-router 2 interface 2
RS G8124(config-vrrp)# virtual-router 2 address 192.168.2.200
RS G8124(config-vrrp)# virtual-router 2 enable

4. Enable tracking on ports. Set the priority of Virtual Router 2 to 101, so that it
becomes the Master.

RS G8124(config-vrrp)# virtual-router 1 track ports

RS G8124(config-vrrp)# virtual-router 2 track ports
RS G8124(config-vrrp)# virtual-router 2 priority 101
RS G8124(config-vrrp)# exit

5. Configure ports.

RS G8124(config)# vlan 10
RS G8124(config-vlan)# exit
RS G8124(config)# interface port 1
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 10
RS G8124(config-if)# exit

RS G8124(config)# vlan 20
RS G8124(config-vlan)# exit
RS G8124(config)# interface port 2
RS G8124(config-if)# switchport mode trunk
RS G8124(config-if)# switchport trunk allowed vlan 20
RS G8124(config-if)# exit

6. Turn off Spanning Tree Protocol globally.

RS G8124(config)# no spanning-tree stp 1

© Copyright IBM Corp. 2014 Chapter 29: Virtual Router Redundancy Protocol 393
VRRP High-Availability Using VLAGs
VRRP can be used in conjunction with VLAGs and LACP-capable servers and
switches to provide seamless redundancy.
Figure 50. Active-Active Configuration using VRRP and VLAGs
VRRP Master
VLAG Peer 1 Server 1
Layer 3
Router VIR: 10.0.1.100 VLAG 1
10.0.1.1
1 10

11
2 Server 2
4 5 12 VLAG 2
Internet ISL 10.0.1.2
4 5 10
1 11 VLAG 3
Server 3
12
2
Layer 3 VRRP Backup 10.0.1.3
Router
VLAG Peer 2
VIR: 10.0.1.100 Network 10.0.1.0/24

See “VLAGs with VRRP” on page 150 for a detailed configuration example.

394 RackSwitch G8124: Application Guide

Part 7: Network
Management

© Copyright IBM Corp. 2014 395

396 RackSwitch G8124: Application Guide
Chapter 30. Link Layer Discovery Protocol
The IBM Networking OS software support Link Layer Discovery Protocol (LLDP).
This chapter discusses the use and configuration of LLDP on the switch:
• “LLDP Overview” on page 398
• “Enabling or Disabling LLDP” on page 399
• “LLDP Transmit Features” on page 400
• “LLDP Receive Features” on page 404
• “LLDP Example Configuration” on page 407

© Copyright IBM Corp. 2014 397

LLDP Overview
Link Layer Discovery Protocol (LLDP) is an IEEE 802.1AB-2005 standard for
discovering and managing network devices. LLDP uses Layer 2 (the data link layer),
and allows network management applications to extend their awareness of the
network by discovering devices that are direct neighbors of already known devices.

With LLDP, the G8124 can advertise the presence of its ports, their major
capabilities, and their current status to other LLDP stations in the same LAN. LLDP
transmissions occur on ports at regular intervals or whenever there is a relevant
change to their status. The switch can also receive LLDP information advertised
from adjacent LLDP-capable network devices.

In addition to discovery of network resources, and notification of network changes,

LLDP can help administrators quickly recognize a variety of common network
configuration problems, such as unintended VLAN exclusions or mis-matched port
aggregation membership.

The LLDP transmit function and receive function can be independently configured
on a per-port basis. The administrator can allow any given port to transmit only,
receive only, or both transmit and receive LLDP information.

The LLDP information to be distributed by the G8124 ports, and that which has been
collected from other LLDP stations, is stored in the switch’s Management
Information Base (MIB). Network Management Systems (NMS) can use Simple
Network Management Protocol (SNMP) to access this MIB information.
LLDP-related MIB information is read-only.

Changes, either to the local switch LLDP information or to the remotely received
LLDP information, are flagged within the MIB for convenient tracking by
SNMP-based management systems.

For LLDP to provide expected benefits, all network devices that support LLDP must
be consistent in their LLDP configuration.

398 RackSwitch G8124: Application Guide

Enabling or Disabling LLDP
Global LLDP Setting
By default, LLDP is enabled on the G8124. To turn LLDP on or off, use the following
command:

RS G8124(config)# [no] lldp enable (Turn LLDP on or off globally)

Transmit and Receive Control

The G8124 can also be configured to transmit or receive LLDP information on a
port-by-port basis. By default, when LLDP is globally enabled on the switch, G8124
ports transmit and receive LLDP information (see the tx_rx option in the following
example). To change the LLDP transmit and receive state, the following commands
are available:

RS G8124(config)# interface port 1 (Select a switch port)

RS G8124(config-if)# lldp admin-status tx_rx (Transmit and receive LLDP)
RS G8124(config-if)# lldp admin-status tx_only(Only transmit LLDP)
RS G8124(config-if)# lldp admin-status rx_only(Only receive LLDP)
RS G8124(config-if)# no lldp admin-status (Do not participate in LLDP)
RS G8124(config-if)# exit (Exit port mode)

To view the LLDP transmit and receive status, use the following commands:

RS G8124(config)# show lldp port (status of all ports)

RS G8124(config)# show interface port <n> lldp (status of selected port)

© Copyright IBM Corp. 2014 Chapter 30: Link Layer Discovery Protocol 399
LLDP Transmit Features
Numerous LLDP transmit options are available, including scheduled and minimum
transmit interval, expiration on remote systems, SNMP trap notification, and the
types of information permitted to be shared.

Scheduled Interval
The G8124 can be configured to transmit LLDP information to neighboring devices
once each 5 to 32768 seconds. The scheduled interval is global; the same interval
value applies to all LLDP transmit-enabled ports. However, to help balance LLDP
transmissions and keep them from being sent simultaneously on all ports, each port
maintains its own interval clock, based on its own initialization or reset time. This
allows switch-wide LLDP transmissions to be spread out over time, though
individual ports comply with the configured interval.
The global transmit interval can be configured using the following command:

RS G8124(config)# lldp refresh-interval <interval>

where interval is the number of seconds between LLDP transmissions. The range is
5 to 32768. The default is 30 seconds.

Minimum Interval
In addition to sending LLDP information at scheduled intervals, LLDP information is
also sent when the G8124 detects relevant changes to its configuration or status
(such as when ports are enabled or disabled). To prevent the G8124 from sending
multiple LLDP packets in rapid succession when port status is in flux, a transmit
delay timer can be configured.
The transmit delay timer represents the minimum time permitted between
successive LLDP transmissions on a port. Any interval-driven or change-driven
updates will be consolidated until the configured transmit delay expires.
The minimum transmit interval can be configured using the following command:

RS G8124(config)# lldp transmission-delay <interval>

where interval is the minimum number of seconds permitted between successive

LLDP transmissions on any port. The range is 1 to one-quarter of the scheduled
transmit interval (lldp refresh-interval <value>), up to 8192. The default is 2
seconds.

400 RackSwitch G8124: Application Guide

Time-to-Live for Transmitted Information
The transmitted LLDP information is held by remote systems for a limited time. A
time-to-live parameter allows the switch to determine how long the transmitted data
is held before it expires. The hold time is configured as a multiple of the configured
transmission interval.

RS G8124(config)# lldp holdtime-multiplier <multiplier>

where multiplier is a value between 2 and 10. The default value is 4, meaning that
remote systems will hold the port’s LLDP information for 4 x the 30-second
msgtxint value, or 120 seconds, before removing it from their MIB.

Trap Notifications
If SNMP is enabled on the G8124 (see “Using Simple Network Management
Protocol” on page 31), each port can be configured to send SNMP trap notifications
whenever LLDP transmissions are sent. By default, trap notification is disabled for
each port. The trap notification state can be changed using the following commands
(Interface Port mode):

RS G8124(config)# interface port 1

RS G8124(config-if)# [no] lldp trap-notification
RS G8124(config-if)# exit

In addition to sending LLDP information at scheduled intervals, LLDP information is

also sent when the G8124 detects relevant changes to its configuration or status
(such as when ports are enabled or disabled). To prevent the G8124 from sending
multiple trap notifications in rapid succession when port status is in flux, a global trap
delay timer can be configured.

The trap delay timer represents the minimum time permitted between successive
trap notifications on any port. Any interval-driven or change-driven trap notices from
the port will be consolidated until the configured trap delay expires.

The minimum trap notification interval can be configured using the following
command:

RS G8124(config)# lldp trap-notification-interval <interval>

where interval is the minimum number of seconds permitted between successive

LLDP transmissions on any port. The range is 1 to 3600. The default is 5 seconds.

If SNMP trap notification is enabled, the notification messages can also appear in
the system log. This is enabled by default. To change whether the SNMP trap
notifications for LLDP events appear in the system log, use the following command:

RS G8124(config)# [no] logging log lldp

© Copyright IBM Corp. 2014 Chapter 30: Link Layer Discovery Protocol 401
Changing the LLDP Transmit State
When the port is disabled, or when LLDP transmit is turned off for the port using the
LLDP admin-status command options (see “Transmit and Receive Control” on
page 399), a final LLDP packet is transmitted with a time-to-live value of 0.
Neighbors that receive this packet will remove the LLDP information associated with
the G8124 port from their MIB.

In addition, if LLDP is fully disabled on a port and then later re-enabled, the G8124
will temporarily delay resuming LLDP transmissions on the port to allow the port
LLDP information to stabilize. The reinitialization delay interval can be globally
configured for all ports using the following command:

RS G8124(config)# lldp reinit-delay <interval>

where interval is the number of seconds to wait before resuming LLDP

transmissions. The range is between 1 and 10. The default is 2 seconds.

Types of Information Transmitted

When LLDP transmission is permitted on the port (see “Enabling or Disabling LLDP”
on page 399), the port advertises the following required information in
type/length/value (TLV) format:
• Chassis ID
• Port ID
• LLDP Time-to-Live

LLDP transmissions can also be configured to enable or disable inclusion of

optional information, using the following command (Interface Port mode):

RS G8124(config)# interface port 1

RS G8124(config-if)# [no] lldp tlv <type>
RS G8124(config-if)# exit

where type is an LLDP information option from Table 32:

Table 32. LLDP Optional Information Types

Type Description Default

portdesc Port Description Enabled

sysname System Name Enabled

sysdescr System Description Enabled

syscap System Capabilities Enabled

mgmtaddr Management Address Enabled

portvid IEEE 802.1 Port VLAN ID Disabled

portprot IEEE 802.1 Port and Protocol VLAN ID Disabled

vlanname IEEE 802.1 VLAN Name Disabled

protid IEEE 802.1 Protocol Identity Disabled

402 RackSwitch G8124: Application Guide

 Table 32. LLDP Optional Information Types (continued)

Type Description Default

macphy IEEE 802.3 MAC/PHY Disabled

Configuration/Status, including the
auto-negotiation, duplex, and speed
status of the port.

powermdi IEEE 802.3 Power via MDI, indicating the Disabled

capabilities and status of devices that
require or provide power over twisted-pair
copper links.

linkaggr IEEE 802.3 Link Aggregation status for Disabled

the port.

framesz IEEE 802.3 Maximum Frame Size for the Disabled

port.

dcbx Data Center Bridging Capability Exchange Enabled

Protocol (DCBX) for the port.

all Select all optional LLDP information for Disabled

inclusion or exclusion.

© Copyright IBM Corp. 2014 Chapter 30: Link Layer Discovery Protocol 403
LLDP Receive Features
Types of Information Received
When the LLDP receive option is enabled on a port (see “Enabling or Disabling
LLDP” on page 399), the port may receive the following information from
LLDP-capable remote systems:
• Chassis Information
• Port Information
• LLDP Time-to-Live
• Port Description
• System Name
• System Description
• System Capabilities Supported/Enabled
• Remote Management Address

The G8124 stores the collected LLDP information in the MIB. Each remote
LLDP-capable device is responsible for transmitting regular LLDP updates. If the
received updates contain LLDP information changes (to port state, configuration,
LLDP MIB structures, deletion), the switch will set a change flag within the MIB for
convenient notification to SNMP-based management systems.

Viewing Remote Device Information

LLDP information collected from neighboring systems can be viewed in numerous
ways:
• Using a centrally-connected LLDP analysis server
• Using an SNMP agent to examine the G8124 MIB
• Using the G8124 Browser-Based Interface (BBI)
• Using CLI or isCLI commands on the G8124

Using the isCLI the following command displays remote LLDP information:

RS G8124(config)# show lldp remote-device [<index number>]

To view a summary of remote information, omit the Index number parameter. For
example:

RS G8124(config)# show lldp remote-device

LLDP Remote Devices Information
Legend(possible values in DMAC column) :
NB - Nearest Bridge - 01-80-C2-00-00-0E
NnTB - Nearest non-TPMR Bridge - 01-80-C2-00-00-03
NCB - Nearest Customer Bridge - 01-80-C2-00-00-00
Total number of current entries: 1

LocalPort|Index|Remote Chassis ID |Remote Port|Remote System Name|DMAC

---------|-----|----------------- |-----------|------------------|-----
MGT | 1 | 00 00 00 00 11 00| 5 | C12 | NB
20 | 2 | 74 99 75 1c 75 00| 44 | C3+ | NB

404 RackSwitch G8124: Application Guide

 To view detailed information for a remote device, specify the Index number as found
in the summary. For example, in keeping with the sample summary, to list details for
the first remote device (with an Index value of 1), use the following command:

RS G8124(config)# show lldp remote-device 1

Local Port Alias: 3
Remote Device Index : 1
Remote Device TTL : 99
Remote Device RxChanges : false
Chassis Type : Mac Address
Chassis Id : 00-18-b1-33-1d-00
Port Type : Locally Assigned
Port Id : 23
Port Description : 7

System Name :
System Description: IBM Networking Operating System RackSwitch G8124, IBM
Networking OS: version 7.11, Boot Image: version 7.11

System Capabilities Supported : bridge, router

System Capabilities Enabled : bridge, router

Remote Management Address:

Subtype : IPv4
Address : 10.100.120.181
Interface Subtype : ifIndex
Interface Number : 128
Object Identifier :

Note: Received LLDP information can change very quickly. When using show
commands, it is possible that flags for some expected events may be too
short-lived to be observed in the output.

© Copyright IBM Corp. 2014 Chapter 30: Link Layer Discovery Protocol 405
 To view detailed information of all remote devices, use the following command:

RS G8124# show lldp remote-device detail

Local Port Alias: MGTA

Remote Device Index : 1
Remote Device TTL : 4678
Remote Device RxChanges : false
Chassis Type : Mac Address
Chassis Id : 08-17-f4-a1-db-00
Port Type : Locally Assigned
Port Id : 25
Port Description : MGTA

System Name :
System Description : IBM Networking Operating System
RackSwitch G8124, IBM Networking OS: version 7.11, Boot Image: version 6.9.1.14
System Capabilities Supported : bridge, router
System Capabilities Enabled : bridge, router

Remote Management Address:

Subtype : IPv4
Address : 10.38.22.23
Interface Subtype : ifIndex
Interface Number : 127
Object Identifier :

Local Port Alias: 2

Remote Device Index : 2
Remote Device TTL : 4651
Remote Device RxChanges : false
Chassis Type : Mac Address
Chassis Id : 08-17-f4-a1-db-00
Port Type : Locally Assigned
Port Id : 2
Port Description : 2

System Name :
System Description : IBM Networking Operating System
RackSwitch G8124, IBM Networking OS: version 7.11, Boot Image: version 6.9.1.14
System Capabilities Supported : bridge, router
System Capabilities Enabled : bridge, router

Remote Management Address:

Subtype : IPv4
Address : 10.38.22.23
Interface Subtype : ifIndex
Interface Number : 127
Object Identifier :

Total entries displayed: 2

Time-to-Live for Received Information

Each remote device LLDP packet includes an expiration time. If the switch port does
not receive an LLDP update from the remote device before the time-to-live clock
expires, the switch will consider the remote information to be invalid, and will
remove all associated information from the MIB.

Remote devices can also intentionally set their LLDP time-to-live to 0, indicating to
the switch that the LLDP information is invalid and must be immediately removed.

406 RackSwitch G8124: Application Guide

LLDP Example Configuration
1. Turn LLDP on globally.

RS G8124(config)# lldp enable

2. Set the global LLDP timer features.

RS G8124(config)# lldp refresh-interval 30 (Transmit each 30 seconds)

RS G8124(config)# lldp transmission-delay 2 (No more often than 2 sec.)
RS G8124(config)# lldp holdtime-multiplier 4 (Remote hold 4 intervals)
RS G8124(config)# lldp reinit-delay 2 (Wait 2 sec. after reinit.)
RS G8124(config)# lldp trap-notification-interval 5 (Minimum 5 sec. between)

3. Set LLDP options for each port.

RS G8124(config)# interface port <n> (Select a switch port)

RS G8124(config-if)# lldp admin-status tx_rx (Transmit and receive LLDP)
RS G8124(config-if)# lldp trap-notification (Enable SNMP trap notifications)
RS G8124(config-if)# lldp tlv all (Transmit all optional information)
RS G8124(config-if)# exit

4. Enable syslog reporting.

RS G8124(config)# logging log lldp

5. Verify the configuration settings:

RS G8124(config)# show lldp

6. View remote device information as needed.

RS G8124(config)# show lldp remote-device

or
RS G8124(config)# show lldp remote-device <index number>
or
RS G8124(config)# show lldp remote-devices detail

© Copyright IBM Corp. 2014 Chapter 30: Link Layer Discovery Protocol 407
408 RackSwitch G8124: Application Guide
Chapter 31. Simple Network Management Protocol
IBM Networking OS provides Simple Network Management Protocol (SNMP)
version 1, version 2, and version 3 support for access through any network
management software, such as IBM Director or HP-OpenView.
Note: SNMP read and write functions are enabled by default. For best security
practices, if SNMP is not needed for your network, it is recommended that
you disable these functions prior to connecting the switch to the network.

SNMP Version 1 & Version 2

To access the SNMP agent on the G8124, the read and write community strings on
the SNMP manager must be configured to match those on the switch. The default
read community string on the switch is public and the default write community
string is private.

The read and write community strings on the switch can be changed using the
following commands on the CLI:

RS G8124(config)# snmp-server read-community <1-32 characters>

-and-
RS G8124(config)# snmp-server write-community <1-32 characters>

The SNMP manager must be able to reach the management interface or any one of
the IP interfaces on the switch.

For the SNMP manager to receive the SNMPv1 traps sent out by the SNMP agent
on the switch, configure the trap host on the switch with the following command:

RS G8124(config)# snmp-server trap-source <trap source IP interface>

RS G8124(config)# snmp-server host <IPv4 address> <trap host community string>

Note: You can use a loopback interface to set the source IP address for SNMP
traps. Use the following command to apply a configured loopback interface:
RS G8124(config)# snmp-server trap-source loopback <1-5>

© Copyright IBM Corp. 2014 409

SNMP Version 3
SNMP version 3 (SNMPv3) is an enhanced version of the Simple Network
Management Protocol, approved by the Internet Engineering Steering Group in
March, 2002. SNMPv3 contains additional security and authentication features that
provide data origin authentication, data integrity checks, timeliness indicators and
encryption to protect against threats such as masquerade, modification of
information, message stream modification and disclosure.

SNMPv3 allows clients to query the MIBs securely.

SNMPv3 configuration is managed using the following command path menu:

RS G8124(config)# snmp-server ?

For more information on SNMP MIBs and the commands used to configure SNMP
on the switch, see the IBM Networking OS 7.11 Command Reference.

Default Configuration
IBM N/OS has three SNMPv3 users by default. All the three users have access to
all the MIBs supported by the switch:
• User 1 name is adminmd5 (password adminmd5). Authentication used is MD5.
Privacy protocol used is DES.
• User 2 name is adminsha (password adminsha). Authentication used is SHA.
Privacy protocol used is DES.
• User 3 name is adminshaaes (password Edpq132x!#9Zpx432w). Authenti-
cation used is SHA. Privacy protocol used is AES-128.

In boot strict mode (See “Boot Strict Mode” on page 36), IBM N/OS has one
SNMPv3 user:
• User 1 name is adminshaaes (password Edpq132x!#9Zpx432w). Authenti-
cation used is SHA. Privacy protocol used is AES-128.

Up to 17 SNMP users can be configured on the switch. To modify an SNMP user,

enter the following commands:

RS G8124(config)# snmp-server user <1-17> name <1-32 characters>

Users can be configured to use the authentication/privacy options. The G8124

support two authentication algorithms: MD5 and SHA, as specified in the following
command:

RS G8124(config)# snmp-server user <1-17> authentication-protocol {md5|sha}

authentication-password
-or-
RS G8124(config)# snmp-server user <1-17> authentication-protocol none

410 RackSwitch G8124: Application Guide

 User Configuration Example
1. To configure a user with name “admin,” authentication type MD5, and
authentication password of “admin,” privacy option DES with privacy password
of “admin,” use the following CLI commands.

RS G8124(config)# snmp-server user 5 name admin

RS G8124(config)# snmp-server user 5 authentication-protocol md5
authentication-password
Changing authentication password; validation required:
Enter current admin password: <admin. password>
Enter new authentication password:
<auth. password; Should be more than 18 characters >
Re-enter new authentication password: <auth. password>
New authentication password accepted.

RS G8124(config)# snmp-server user 5 privacy-protocol des privacy-password

Changing privacy password; validation required:
Enter current admin password: <admin. password>
Enter new privacy password:
<privacy password; Should be more than 18 characters>
Re-enter new privacy password: <privacy password>
New privacy password accepted.

2. Configure a user access group, along with the views the group may access.
Use the access table to configure the group’s access level.

RS G8124(config)# snmp-server access 5 name admingrp

RS G8124(config)# snmp-server access 5 level authpriv
RS G8124(config)# snmp-server access 5 read-view iso
RS G8124(config)# snmp-server access 5 write-view iso
RS G8124(config)# snmp-server access 5 notify-view iso

Because the read view, write view, and notify view are all set to “iso,” the user
type has access to all private and public MIBs.
3. Assign the user to the user group. Use the group table to link the user to a
particular access group.

RS G8124(config)# snmp-server group 5 user-name admin

RS G8124(config)# snmp-server group 5 group-name admingrp

© Copyright IBM Corp. 2014 Chapter 31: Simple Network Management Protocol 411
Configuring SNMP Trap Hosts
SNMPv1 Trap Host
1. Configure a user with no authentication and password.

RS G8124(config)# snmp-server user 10 name v1trap

2. Configure an access group and group table entries for the user. Use the
following menu to specify which traps can be received by the user:

RS G8124(config)# snmp-server access <user number>

In the following example the user will receive the traps sent by the switch.

RS G8124(config)# snmp-server access 10 (Access group to view SNMPv1 traps)

name v1trap
security snmpv1
notify-view iso
RS G8124(config)# snmp-server group 10 ( Assign user to the access group)
security snmpv1
user-name v1trap
group-name v1trap

3. Configure an entry in the notify table.

RS G8124(config)# snmp-server notify 10 name v1trap

RS G8124(config)# snmp-server notify 10 tag v1trap

4. Specify the IPv4 address and other trap parameters in the targetAddr and
targetParam tables. Use the following commands to specify the user name
associated with the targetParam table:

RS G8124(config)# snmp-server target-address 10 name v1trap address 10.70.70.190

RS G8124(config)# snmp-server target-address 10 parameters-name v1param
RS G8124(config)# snmp-server target-address 10 taglist v1param
RS G8124(config)# snmp-server target-parameters 10 name v1param
RS G8124(config)# snmp-server target-parameters 10 user-name v1only
RS G8124(config)# snmp-server target-parameters 10 message snmpv1

Note: N/OS 7.11 supports only IPv4 addresses for SNMPv1 and SNMPv2 trap
hosts.
5. Use the community table to specify which community string is used in the trap.

RS G8124(config)# snmp-server community 10 ( Define the community string)

index v1trap
name public
user-name v1trap

412 RackSwitch G8124: Application Guide

 SNMPv2 Trap Host Configuration

The SNMPv2 trap host configuration is similar to the SNMPv1 trap host
configuration. Wherever you specify the model, use snmpv2 instead of snmpv1.

RS G8124(config)# snmp-server user 10 name v2trap

RS G8124(config)# snmp-server group 10 security snmpv2

RS G8124(config)# snmp-server group 10 user-name v2trap
RS G8124(config)# snmp-server group 10 group-name v2trap
RS G8124(config)# snmp-server access 10 name v2trap
RS G8124(config)# snmp-server access 10 security snmpv2
RS G8124(config)# snmp-server access 10 notify-view iso

RS G8124(config)# snmp-server notify 10 name v2trap

RS G8124(config)# snmp-server notify 10 tag v2trap

RS G8124(config)# snmp-server target-address 10 name v2trap

address 100.10.2.1
RS G8124(config)# snmp-server target-address 10 taglist v2trap
RS G8124(config)# snmp-server target-address 10 parameters-name
v2param
RS G8124(config)# snmp-server target-parameters 10 name v2param
RS G8124(config)# snmp-server target-parameters 10 message snmpv2c
RS G8124(config)# snmp-server target-parameters 10 user-name v2trap
RS G8124(config)# snmp-server target-parameters 10 security snmpv2

RS G8124(config)# snmp-server community 10 index v2trap

RS G8124(config)# snmp-server community 10 user-name v2trap

Note: N/OS 7.11 supports only IPv4 addresses for SNMPv1 and SNMPv2 trap
hosts.

© Copyright IBM Corp. 2014 Chapter 31: Simple Network Management Protocol 413
 SNMPv3 Trap Host Configuration

To configure a user for SNMPv3 traps, you can choose to send the traps with both
privacy and authentication, with authentication only, or without privacy or
authentication.

This is configured in the access table using the following commands:

RS G8124(config)# snmp-server access <1-32> level

RS G8124(config)# snmp-server target-parameters <1-16> level

Configure the user in the user table accordingly.

It is not necessary to configure the community table for SNMPv3 traps because the
community string is not used by SNMPv3.

The following example shows how to configure a SNMPv3 user v3trap with
authentication only:

RS G8124(config)# snmp-server user 11 name v3trap

RS G8124(config)# snmp-server user 11 authentication-protocol md5
authentication-password
Changing authentication password; validation required:
Enter current admin password: <admin. password>
Enter new authentication password: <auth. password>
Re-enter new authentication password: <auth. password>
New authentication password accepted.
RS G8124(config)# snmp-server access 11 notify-view iso
RS G8124(config)# snmp-server access 11 level authNopriv
RS G8124(config)# snmp-server group 11 user-name v3trap
RS G8124(config)# snmp-server group 11 group-name v3trap
RS G8124(config)# snmp-server notify 11 name v3trap
RS G8124(config)# snmp-server notify 11 tag v3trap
RS G8124(config)# snmp-server target-address 11 name v3trap address 47.81.25.66
RS G8124(config)# snmp-server target-address 11 taglist v3trap
RS G8124(config)# snmp-server target-address 11 parameters-name v3param
RS G8124(config)# snmp-server target-parameters 11 name v3param
RS G8124(config)# snmp-server target-parameters 11 user-name v3trap
RS G8124(config)# snmp-server target-parameters 11 level authNoPriv

414 RackSwitch G8124: Application Guide

SNMP MIBs
The N/OS SNMP agent supports SNMP version 3. Security is provided through
SNMP community strings. The default community strings are “public” for SNMP
GET operation and “private” for SNMP SET operation. The community string can
be modified only through the Industry Standard Command Line Interface (ISCLI).
Detailed SNMP MIBs and trap definitions of the N/OS SNMP agent are contained in
the N/OS enterprise MIB document.

The N/OS SNMP agent supports the following standard MIBs:

• dot1x.mib
• ieee8021ab.mib
• ieee8023ad.mib
• lldpxdcbx.mib
• rfc1213.mib
• rfc1215.mib
• rfc1493.mib
• rfc1573.mib
• rfc1643.mib
• rfc1657.mib
• rfc1757.mib
• rfc1850.mib
• rfc1907.mib
• rfc2037.mib
• rfc2233.mib
• rfc2465.mib
• rfc2571.mib
• rfc2572.mib
• rfc2573.mib
• rfc2574.mib
• rfc2575.mib
• rfc2576.mib
• rfc2790.mib
• rfc3176.mib
• rfc4133.mib
• rfc4363.mib

The N/OS SNMP agent supports the following generic traps as defined in RFC
1215:
• ColdStart
• WarmStart
• LinkDown
• LinkUp
• AuthenticationFailure

The SNMP agent also supports two Spanning Tree traps as defined in RFC 1493:
• NewRoot
• TopologyChange

© Copyright IBM Corp. 2014 Chapter 31: Simple Network Management Protocol 415
 The following are the enterprise SNMP traps supported in N/OS:
Table 33. IBM N/OS-Supported Enterprise SNMP Traps

Trap Name Description

swLoginFailure Signifies that someone failed to

enter a valid username/password
combination.
swTrapDisplayString specifies
whether the login attempt was from
CONSOLE or TELNET. In case of
TELNET login it also specifies the IP
address of the host from which the
attempt was made.

swValidLogin Signifies that a user login has

occurred.

swApplyComplete Signifies that new configuration has

been applied.

swSaveComplete Signifies that new configuration has

been saved.

swFwDownloadSucess Signifies that firmware has been

downloaded to
[image1|image2|boot image].

swFwDownloadFailure Signifies that firmware downloaded

failed to [image1|image2|boot
image].

swValidLogout Signifies that a user logout has

occurred.

swPrimaryPowerSupplyFailure Signifies that the primary power

supply has failed.

swPrimaryPowerSupplyFixed Signifies that the primary power

supply has been restored.

swDefAdminDisable Signifies that the default admin

account has been disabled.

swAcntStrngPswdNotMet Signifies that the configured

password does not match strong
password complexity.

swAcntLocked Signifies that account has been

locked.

swAcntUnlocked Signifies that account has been

unlocked.

swStgNewRoot Signifies that the bridge has

become the new root of the STG.

swCistNewRoot Signifies that the bridge has

become the new root of the CIST.

416 RackSwitch G8124: Application Guide

 Table 33. IBM N/OS-Supported Enterprise SNMP Traps (continued)

Trap Name Description

swStgTopologyChanged Signifies that there was a STG

topology change.

swCistTopologyChanged Signifies that there was a CIST

topology change.

swHotlinksMasterUp Signifies that the Master interface is

active.

swHotlinksMasterDn Signifies that the Master interface is

not active.

swHotlinksBackupUp Signifies that the Backup interface is

active.

swHotlinksBackupDn Signifies that the Backup interface is

not active.

swHotlinksNone Signifies that there are no active

interfaces.

swTeamingCtrlUp Signifies that the teaming is up.

swTeamingCtrlDown Signifies that the teaming control is

down.

swTeamingCtrlDownTearDownBlked Signifies that the teaming control is

down but teardown is blocked.

swTeamingCtrlError Signifies error, action is undefined.

swLACPPortBlocked Signifies that LACP is operationally

down on a port, and traffic is
blocked on the port.

swLACPPortUnblocked Signifies that LACP is operationally

up on a port, and traffic is no longer
blocked on the port.

swLFDPortErrdisabled Signifies that a port is error-disabled

due to excessive link flaps.

swVlagInstanceUp Signifies that VLAG instance is up

identified in the trap message.

swVlagInstanceRemoteUp Signifies that VLAG is down but

instance on the remote instance is
up.

swVlagInstanceLocalUp Signifies that VLAG is down but

local instance is up.

swVlagInstanceDown Signifies that VLAG instance is

down identified in the trap message.

swVlagIslUp Signifies that connection between

VLAG switches is up.

© Copyright IBM Corp. 2014 Chapter 31: Simple Network Management Protocol 417
 Table 33. IBM N/OS-Supported Enterprise SNMP Traps (continued)

Trap Name Description

swVlagIslDown Signifies that connection between

VLAG switches is down.

sw8021x Signifies 802.1x feature is enabled.

swDefGwUp Signifies that the default gateway is

alive. ipCurCfgGwIndex is the index
of the Gateway in
ipCurCfgGwTable. The range for
ipCurCfgGwIndex is from 1 to
ipGatewayTableMax.
ipCurCfgGwAddr is the IP address
of the default gateway.

swDefGwDown Signifies that the default gateway is

down. ipCurCfgGwIndex is the
index of the Gateway in
ipCurCfgGwTable. The range for
ipCurCfgGwIndex is from 1 to
ipGatewayTableMax.
ipCurCfgGwAddr is the IP address
of the default gateway.

swDefGwInService Signifies that the default gateway is

up and in service. ipCurCfgGwIndex
is the index of the Gateway in
ipCurCfgGwTable. The range for
ipCurCfgGwIndex is from 1 to
ipGatewayTableMax.
ipCurCfgGwAddr is the IP address
of the default gateway.

swDefGwNotInService Signifies that the default gateway is

alive but not in service.
ipCurCfgGwIndex is the index of the
Gateway in ipCurCfgGwTable. The
range for ipCurCfgGwIndex is from
1 to ipGatewayTableMax.
ipCurCfgGwAddr is the IP address
of the default gateway.

swVrrpNewMaster Indicates that the sending agent has

transitioned to “Master” state.
vrrpCurCfgVirtRtrIndx is the VRRP
virtual router table index referenced
in vrrpCurCfgVirtRtrTable. The
range is from 1 to
vrrpVirtRtrTableMaxSize.
vrrpCurCfgVirtRtrAddr is the VRRP
virtual router IP address.

418 RackSwitch G8124: Application Guide

 Table 33. IBM N/OS-Supported Enterprise SNMP Traps (continued)

Trap Name Description

swVrrpNewBackup Indicates that the sending agent has

transitioned to “Backup” state.
vrrpCurCfgVirtRtrIndx is the VRRP
virtual router table index referenced
in vrrpCurCfgVirtRtrTable. The
range is from 1 to
vrrpVirtRtrTableMaxSize.
vrrpCurCfgVirtRtrAddr is the VRRP
virtual router IP address.

swVrrpAuthFailure Signifies that a packet has been

received from a router whose
authentication key or authentication
type conflicts with this router's
authentication key or authentication
type. Implementation of this trap is
optional. vrrpCurCfgIfIndx is the
VRRP interface index. This is
equivalent to ifIndex in RFC 1213
mib. The range is from 1 to
vrrpIfTableMaxSize.
vrrpCurCfgIfPasswd is the
password for authentication. It is a
DisplayString of 0 to 7 characters.

swTcpHoldDown Signifies that new TCP connection

requests from a particular client will
be blocked for a pre-determined
amount of time since the rate of new
TCP connections from that client
has reached a pre-determined
threshold. The fltCurCfgSrcIp is the
client source IP address for which
new TCP connection requests will
be blocked. The swTrapRate
specifies the amount of time in
minutes that the particular client will
be blocked.

swNTPSyncFailed Signifies that synchronization with

the NTP server has failed.

swNTPUpdateClock Signifies that the system clock is

updated with NTP server.

swECMPGatewayUp Signifies that the ECMP gateway is

up.

swECMPGatewayDown Signifies that the ECMP gateway is

down.

swTempExceedThreshold Signifies that the switch

temperature has exceeded
maximum safety limits.

© Copyright IBM Corp. 2014 Chapter 31: Simple Network Management Protocol 419
 Table 33. IBM N/OS-Supported Enterprise SNMP Traps (continued)

Trap Name Description

swFanFailure Signifies that the fan failure has

been detected.

swFanFailureFixed Signifies that the fan failure has

been fixed.

swTempReturnThreshold Signifies that the switch

temperature has returned to under
maximum safety limits.

swVMGroupVMotion Signifies that a virtual machine has

moved from a port to another.

swVMGroupVMOnline Signifies that an advance

provisioned virtual machine has
came online.

swVMGroupVMVlanChange Signifies that a virtual machine has

entered a VLAN, or changed the
VLAN.

swVmCheckSpoofedvm Signifies that a spoofed VM MAC

was found.

420 RackSwitch G8124: Application Guide

Switch Images and Configuration Files
This section describes how to use MIB calls to work with switch images and
configuration files. You can use a standard SNMP tool to perform the actions, using
the MIBs listed in the table below.

The table lists the MIBS used to perform operations associated with the Switch
Image and Configuration files.
Table 34. MIBs for Switch Image and Configuration Files

MIB Name MIB OID

agTransferServer 1.3.6.1.4.26543.2.5.1.1.7.1.0

agTransferImage 1.3.6.1.4.26543.2.5.1.1.7.2.0

agTransferImageFileName 1.3.6.1.4.26543.2.5.1.1.7.3.0

agTransferCfgFileName 1.3.6.1.4.26543.2.5.1.1.7.4.0

agTransferDumpFileName 1.3.6.1.4.26543.2.5.1.1.7.5.0

agTransferAction 1.3.6.1.4.26543.2.5.1.1.7.6.0

agTransferLastActionStatus 1.3.6.1.4.26543.2.5.1.1.7.7.0

agTransferUserName 1.3.6.1.4.26543.2.5.1.1.7.9.0

agTransferPassword 1.3.6.1.4.1.26543.2.5.1.1.7.10.0

agTransferTSDumpFileName 1.3.6.1.4.1.26543.2.5.1.1.7.11.0

The following SNMP actions can be performed using the MIBs listed in the table:
• Load a new Switch image (boot or running) from an FTP, SFTP, or TFTP server
• Load a previously saved switch configuration from an FTP, SFTP, or TFTP server
• Save the switch configuration to an FTP, SFTP, or TFTP server
• Save a switch dump to an FTP, SFTP, or TFTP server

© Copyright IBM Corp. 2014 Chapter 31: Simple Network Management Protocol 421
Loading a New Switch Image
To load a new switch image with the name “MyNewImage-1.img” into image2,
follow these steps. This example shows an FTP, SFTP, or TFTP server at IPv4
address 192.168.10.10, though IPv6 is also supported.
1. Set the FTP, SFTP, or TFTP server address where the switch image resides:
Set agTransferServer.0 "192.168.10.10"
2. Set the area where the new image will be loaded:
Set agTransferImage.0 "image2"
3. Set the name of the image:
Set agTransferImageFileName.0 "MyNewImage-1.img"
4. If you are using an FTP or SFTP server, enter a username:
Set agTransferUserName.0 "MyName"
5. If you are using an FTP or SFTP server, enter a password:
Set agTransferPassword.0 "MyPassword"
6. Initiate the transfer. To transfer a switch image, enter 2 (gtimg):
Set agTransferAction.0 "2"

Loading a Saved Switch Configuration

To load a saved switch configuration with the name “MyRunningConfig.cfg” into the
switch, follow these steps. This example shows an FTP, SFTP, or TFTP server at
IPv4 address 192.168.10.10, though IPv6 is also supported.
1. Set the FTP, SFTP, or TFTP server address where the switch Configuration File
resides:
Set agTransferServer.0 "192.168.10.10"
2. Set the name of the configuration file:
Set agTransferCfgFileName.0 "MyRunningConfig.cfg"
3. If you are using an FTP or SFTP server, enter a username:
Set agTransferUserName.0 "MyName"
4. If you are using an FTP or SFTP server, enter a password:
Set agTransferPassword.0 "MyPassword"
5. Initiate the transfer. To restore a running configuration, enter 3:
Set agTransferAction.0 "3"

422 RackSwitch G8124: Application Guide

Saving the Switch Configuration
To save the switch configuration to a file server, follow these steps. This example
shows an FTP, SFTP, or TFTP server at IPv4 address 192.168.10.10, though IPv6
is also supported.
1. Set the FTP, SFTP, or TFTP server address where the configuration file is
saved:
Set agTransferServer.0 "192.168.10.10"
2. Set the name of the configuration file:
Set agTransferCfgFileName.0 "MyRunningConfig.cfg"
3. If you are using an FTP or SFTP server, enter a username:
Set agTransferUserName.0 "MyName"
4. If you are using an FTP or SFTP server, enter a password:
Set agTransferPassword.0 "MyPassword"
5. Initiate the transfer. To save a running configuration file, enter 4:
Set agTransferAction.0 "4"

Saving a Switch Dump

To save a switch dump to a file server, follow these steps. This example shows an
FTP, SFTP, or TFTP server at 192.168.10.10, though IPv6 is also supported.
1. Set the FTP, SFTP, or TFTP server address where the configuration will be
saved:
Set agTransferServer.0 "192.168.10.10"
2. Set the name of dump file:
Set agTransferDumpFileName.0 "MyDumpFile.dmp"
3. If you are using an FTP or SFTP server, enter a username:
Set agTransferUserName.0 "MyName"
4. If you are using an FTP or SFTP server, enter a password:
Set agTransferPassword.0 "MyPassword"
5. Initiate the transfer. To save a dump file, enter 5:
Set agTransferAction.0 "5"

© Copyright IBM Corp. 2014 Chapter 31: Simple Network Management Protocol 423
424 RackSwitch G8124: Application Guide
Chapter 32. NETCONF
The Network Configuration Protocol (NETCONF) provides a mechanism to manage
the G8124, retrieve or modify existing configuration data, and upload new
configuration data. See RFC 4741 for details on NETCONF.

NETCONF operates in a client/server model. The NETCONF client establishes a

session with the switch (acting as a NETCONF server) using a Remote Procedure
Call (RPC). NETCONF is based on the Extensible Markup Language (XML) for
encoding data and for exchanging configuration and protocol messages.

The following topics are discussed in this section:

• “NETCONF Overview” on page 426
• “XML Requirements” on page 427
• “Installing the NETCONF Client” on page 428
• “Using Juniper Perl Client” on page 430
• “Establishing a NETCONF Session” on page 431
• “NETCONF Operations” on page 433
• “Protocol Operations Examples” on page 434

© Copyright IBM Corp. 2014 425

NETCONF Overview
NETCONF provides a method to quickly configure the switch. It also allows you to
implement a configuration across multiple switches, thereby saving time and
reducing the chances of configuration errors.

The NETCONF protocol defines basic operations that are equivalent to the switch
ISCLI commands.
Note: The current implementation of NETCONF supports only ISCLI commands.

NETCONF is a connection-oriented protocol. See Figure 51 for an overview of

NETCONF operation.
Figure 51. NETCONF Operations Procedure

<hello>
<capabilities/>
</hello>
<hello>
<capabilities/>
</hello>
<rpc>
<operation/>
</rpc>
<rpc-reply>
<operation-response/>
NETCONF </rpc-reply> NETCONF
Client <rpc> Server
<close-session/>
</rpc>
<rpc-reply>
<ok/>
</rpc-reply>

Session
• Session-ID

Transport Layer Connection Transport Layer

Protocol • Authentication Protocol
• Data integrity
• Confidentiality

1. The client establishes a transport layer connection to the switch (acting as a

NETCONF server).
2. The client and switch exchange hello messages to declare their capabilities.
3. The client sends a request via rpc message to the switch.
4. The switch sends a response via rpc-reply message to the client.
Note: Steps 3 and 4 must be repeated for each request that the client sends to the
switch.
5. The client sends a close-session message to the switch to end the
NETCONF session and the transport layer connection.
6. The switch sends an ok response.

426 RackSwitch G8124: Application Guide

XML Requirements
XML is the encoding format used within NETCONF. When using XML for
NETCONF:
• All NETCONF protocol elements are defined in the following namespace:
urn:ietf:params:xml:ns:netconf:base:1.0
• NETCONF capability names must be Uniform Resource Identifiers (URIs):
urn:ietf:params:netconf:capability:{name}:1.0
where {name} is the name of the capability.
• Document type declarations must not appear in the NETCONF content.
• For Secure Shell (SSH), you must use a special message termination sequence
of six characters to provide message framing:
]]>]]>

© Copyright IBM Corp. 2014 Chapter 32: NETCONF 427

Installing the NETCONF Client
You can download the required NETCONF Client installation files from
www.ibm.com. Select Support & downloads > Fixes, updates and drivers.
Follow instructions on the IBM Support Portal page to find the files.

Before installing the NETCONF client, ensure you have completed the following
tasks:
• Install a supported version of Python (Python 2.6 or higher, up to but not
including Python 3.0) in the folder C:\.
• Install the PyCrypto application appropriate to the Python version you are using.
Note: The following steps are for the Windows operating systems.

Follow these steps to install the Blade NETCONF Python Client (BNClient):
1. Extract the file blade-netconf-python-client-v0.1.zip to the
following folder: C:\
You will see two folders under the root folder
C:\blade-netconf-python-client-v0.1:
– blade-netconf-python-client
– python-ssh-library
Note: Ensure you see Paramiko version 1.7.4 or higher in the folder
C:\blade-netconf-python-client-v0.1\python-ssh-library\
2. Open the command prompt (Select Start > Run > cmd).
3. Enter the following command to install the SSH library:

python C:\blade-netconf-python-client-v0.1\python-ssh-library\
paramiko-1.7.6\setup.py install

Note: If the python command does not work from the command prompt, you may
need to add a system variable to set the path to the directory where you
have installed Python. You can add the system variable at the following
location: My Computer > Properties > Advanced > Environment
Variables

428 RackSwitch G8124: Application Guide

 4. Follow these steps to install BNClient:
As a python script:
a. Enter the following command for help:

python C:\blade-netconf-python-client-v0.1\blade-netconf-python-
client\bnclient\bnclient.py –h

b. Enter the following command to establish a NETCONF session:

• Using SSH to connect to default port 830:

python C:\blade-netconf-python-client-v0.1\blade-netconf-python-
client\bnclient\bnclient.py {switch IP address} –u admin –p admin –o get

• Using SSH to connect to port 22:

python C:\blade-netconf-python-client-v0.1\blade-netconf-python-
client\bnclient\bnclient.py {switch IP address}:22 –u admin –p admin –o get

As a python library:
a. Open the file
C:\blade-netconf-python-client-v0.1\blade-netconf-
python-client\example\get.py in a Python editor (For example, IDLE).
b. Change the IP address in the hostname field to the switch IP address, and
save the file.
c. Enter the following command to establish a session:

python C:\blade-netconf-python-client-v0.1\blade-netconf-python-
client\setup.py install

d. Enter the following command to get the running configuration:

python C:\blade-netconf-python-client-v0.1\blade-netconf-python-
client\example\get.py

Note: get.py is an example of a NETCONF operation python script. You can edit
the script or write a new script as per your requirements.

© Copyright IBM Corp. 2014 Chapter 32: NETCONF 429

Using Juniper Perl Client
You can use Juniper Perl client instead of BNClient to communicate with the
NETCONF feature on the switch. Follow these steps to use the Juniper Perl client.
Note: You must use the Linux operating system for the Juniper Perl client.
1. Extract the file juniper-netconf-perl-client.zip to the folder
/home/user/.
You will see two folders:
– juniper-netconf-perl-client
– blade-netconf-perl-scripts
2. Follow these steps to install the Juniper Perl client:
As a Perl library:
a. Change to the following directory:
/home/user/juniper-netconf-perl-client
b. Extract the following file:
netconf-perl-10.0R2.10.tar.gz
c. Change to the following directory:
/home/user/juniper-netconf-perl-client/netconf-perl-10.0
R2.10
d. Install the client as per the instructions in the README file.
Note: If the prerequisites package installation fails, manually install each file in
/home/user/juniper-netconf-perl-client\netconf-perl-pre
reqs-patch.
As a Perl script:
a. Change to the following directory:
/home/user/blade-netconf-perl-scripts/
b. Enter the following command:

perl get/get.pl -l admin -p admin {swich IP address}

Note: get.pl is an example of a NETCONF operation Perl script. You can edit the
script or write a new script as per your requirement.

430 RackSwitch G8124: Application Guide

Establishing a NETCONF Session
SSH is the widely used protocol for NETCONF sessions. The default SSH port for
NETCONF is 830. The client may also connect to the switch through SSH port 22.

Follow these steps to establish a NETCONF session. Enter commands in the client
Linux Shell.
Note: You can open a maximum of four simultaneous sessions.
1. Enter the following command to open an SSH connection:

ssh admin@{switch IP address} -p 830 -s netconf

2. Type or paste the following hello message:

<hello>
<capabilities>
<capability>urn:ietf:params:netconf:base:1.0</capability>
</capabilities>
</hello>
]]>]]>

The switch returns a hello message:

<hello xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>
<capabilities>
<capability>urn:ietf:params:netconf:base:1.0</capability>
<capability>urn:ietf:params:netconf:capability:writable-running:1.0</c
apability>
<capability>urn:ietf:params:netconf:capability:rollback-on-error:1.0</
capability>
<capability>urn:ietf:params:netconf:capability:startup:1.0</capability
>
</capabilities>
<session-id>102</session-id>
</hello>
]]>]]>

© Copyright IBM Corp. 2014 Chapter 32: NETCONF 431

 3. Type or paste the following rpc message. The get operation is used as an
example.

<rpc message-id=“100”>
<get>
<filter type=“subtree”>
<configuration-text/>
</filter>
</get>
</rpc>
]]>]]>

The switch sends an rpc-reply message:

<rpc-reply message-id=“100”>
<data>
<configuration-text
xmlns=“http://www.ibm.com/netconf/1.0/config-text”> version
“6.9.1”
switch-type “IBM Networking Operating System RackSwitch
G8124”
!
!
no system dhcp mgta
!
!
interface ip 127
ip address 172.31.36.51
enable
exit
!
ip gateway 3 address 172.31.1.1
ip gateway 3 enable
!
!
end
</configuration-text>
</data>
</rpc-reply>
]]>]]>

Note: Repeat Step 3 for each request you need to send to the switch.
4. Type or paste the following close-session message to close the NETCONF
session and terminate the SSH connection.

<rpc message-id=“101”>
<close-session/>
</rpc>
]]>]]>

The switch sends the following response:

<rpc-reply message-id=“101”>
<ok/>
</rpc-reply>
]]>]]>

432 RackSwitch G8124: Application Guide

NETCONF Operations
The NETCONF protocol provides a set of operations to manage and retrieve switch
configuration. Table 35 provides a list of protocol operations supported by the
switch.
Table 35. Protocol Operations

Operation Description

get-config Retrieve all or part of the running or startup

configuration.

edit-config Load all or part of a specified configuration

to the running or startup configuration.

copy-config Replace the target running or startup

configuration with a source running or
startup configuration.

delete-config Delete startup configuration.

lock Lock the running configuration to prevent

other users (via another NETCONF session)
from changing it.

unlock Release a locked running configuration.

get Retrieve running configuration and device

state information.

close-session Request graceful termination of a

NETCONF session.

kill-session Force the termination of a NETCONF

session.

get-configuration Retrieve configuration data from the switch.

get-interface-information Retrieve interface status information.

© Copyright IBM Corp. 2014 Chapter 32: NETCONF 433

Protocol Operations Examples
Following are examples of the NETCONF protocol operations supported by the
G8124.

<get-config>
Usage:

<rpc message-id=“101” xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>

<get-config>
<source>
<running/>
</source>
<filter type=“subtree”>
<configuration-text
xmlns=“http://www.ibm.com/netconf/1.0/config-text”/>
</filter>
</get-config>
</rpc>

Response from the switch:

<rpc-reply message-id=“101”
xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>
<data>
<configuration-text
xmlns=“http://www.ibm.com/netconf/1.0/config-text”>
<!-- configuration text... -->
</configuration-text>
</data>
</rpc-reply>

See Table 36 for the tag elements and their values.

Table 36. get-config Tag Element Values

Tag Element Description Value

source The configuration text you running/

want to retrieve. or
startup/

filter type=“subtree” The filter type. subtree

!--configuration text...-- Contains the running

configuration in ISCLI format.

434 RackSwitch G8124: Application Guide

<edit-config>
Usage:

<rpc message-id=“101” xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>

<edit-config>
<target>
<running/>
</target>
<default-operation>
<merge/>
</default-operation>
<error-option>
<stop-on-error/>
</error-option>
<config-text xmlns=“http://www.ibm.com/netconf/1.0/config-text”>
<configuration-text>hostname Router</configuration-text>
</config-text>
</edit-config>
</rpc>

Response from the switch:

<rpc-reply message-id=“101”
xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>
<ok/>
</rpc-reply>

See Table 37 for the tag elements and their values.

Table 37. edit-config Tag Element Values

Tag Element Description Value

target The configuration you running/ or startup/

want to edit.

© Copyright IBM Corp. 2014 Chapter 32: NETCONF 435

 Table 37. edit-config Tag Element Values

Tag Element Description Value

default-operation Set the default • merge: The new

operation for the configuration is merged
edit-config request. with the target
configuration at the
corresponding level.
• replace: The new
configuration replaces the
target configuration.
• none: The target
configuration does not
change unless the
configuration data in the
configuration-text
parameter uses the
operation attribute to
request a different
operation.

error-option Set the option to handle • stop-on-error: Abort

configuration error. the edit-config
operation on first error.
This is the default
error-option.
• continue-on-error:
Continue to process
configuration data on
error.
• rollback-on-error:
Abort the edit-config
operation on first error and
discard the requested
configuration changes.

436 RackSwitch G8124: Application Guide

<copy-config>
Usage:

<rpc message-id=“101” xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>

<copy-config>
<target>
<startup/>
</target>
<source>
<running/>
</source>
</copy-config>
</rpc>

Response from the switch:

<rpc-reply message-id=“101”
xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>
<ok/>
</rpc-reply>

See Table 38 for the tag elements and their values.

Table 38. copy-config Tag Element Values

Tag Element Description Value

target Configuration that needs to be changed. running/ or

startup/

source Source configuration. running/ or

startup/

© Copyright IBM Corp. 2014 Chapter 32: NETCONF 437

<delete-config>
Usage:

<rpc message-id=“101” xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>

<delete-config>
<target>
<startup/>
</target>
</delete-config>
</rpc>

Response from the switch:

<rpc-reply message-id=“101”
xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>
<ok/>
</rpc-reply>

See Table 39 for the tag elements and their values.

Table 39. delete-config Tag Element Values

Tag Element Description Value

target Configuration that needs to be deleted. startup/

<lock>
Usage:

<rpc message-id=“101” xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>

<lock>
<target>
<running/>
</target>
</lock>
</rpc>

Response from the switch:

<rpc-reply message-id=“101”
xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>
<ok/>
</rpc-reply>

See Table 40 for the tag elements and their values.

Table 40. lock Tag Element Values

Tag Element Description Value

target Configuration that needs to be edited. running/

438 RackSwitch G8124: Application Guide

<unlock>
Usage:

<rpc message-id=“101” xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>

<unlock>
<target>
<running/>
</target>
</unlock>
</rpc>

Response from the switch:

<rpc-reply message-id=“101”
xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>
<ok/>
</rpc-reply>

See Table 41 for the tag elements and their values.

Table 41. unlock Tag Element Values

Tag Element Description Value

target Configuration being edited. running/

© Copyright IBM Corp. 2014 Chapter 32: NETCONF 439

<get>
Usage:

<rpc message-id=“101” xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>

<get>
<filter type=“subtree”>
<!-- request a text version of the configuration -->
<configuration-text
xmlns=“http://www.ibm.com/netconf/1.0/config-text”/>
</filter>
</get>
</rpc>

Response from the switch:

<rpc-reply message-id=“101”
xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>
<data>
<configuration-text
xmlns=“http://www.ibm.com/netconf/1.0/config-text”>
<!-- configuration text... -->
</configuration -text>
</data>
</rpc-reply>

See Table 42 for the tag elements and their values.

Table 42. get Tag Element Values

Tag Element Description Value

filter Filter type. subtree

configuration-text Configuration in ISCLI format.

440 RackSwitch G8124: Application Guide

<close-session>
Usage:

<rpc message-id=“101” xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>

<close-session/>
</rpc>

Response from the switch:

<rpc-reply message-id=“101”
xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>
<ok/>
</rpc-reply>

<kill-session>
Usage:

<rpc message-id=“101” xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>

<kill-session>
<session-id>4</session-id>
</kill-session>
</rpc>

Response from the switch:

<rpc-reply message-id=“101”
xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>
<ok/>
</rpc-reply>

See Table 43 for the tag elements and their values.

Table 43. kill-session Tag Element Values

Tag Element Description

session-id ID number of the session to be killed

© Copyright IBM Corp. 2014 Chapter 32: NETCONF 441

<get-configuration>
Usage:

<rpc message-id=“101” xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>

<get-configuration database=“commited” format=“text”/>
</rpc>

Response from the switch:

<rpc-reply message-id=“101”
xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>
<data>
<configuration-text
xmlns=“http://www.ibm.com/netconf/1.0/config-text”>
<!-- configuration text... -->
</configuration -text>
</data>
</rpc-reply>

See Table 44 for the tag elements and their values.

Table 44. get-configuration Tag Element Values

Tag Element Description Attributes

get-configuration Retrieve the configuration. database - supports only

committed

format - supports only text

442 RackSwitch G8124: Application Guide

<get-interface-information>
Usage:

<rpc message-id=“101”>
<get-interface-information>
<interface-name> port xx </interface-name>
<brief/>
</get-interface-information>
</rpc>

Response from switch:

• Port detail information

<rpc-reply message-id=“101”
xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>
<interface-information>
<physical-interface>
<name></name>
<admin-status></admin-status>
<oper-status></oper-status>
<local-index></local-index>
<if-type></if-type>
<link-level-type></link-level-type>
<mtu></mtu>
<speed></speed>
<link-type></link-type>
<traffic-statistics>
<input-bytes></input-bytes>
<output-bytes></output-bytes>
<input-packets></input-packets>
<output-packets></output-packets>
</traffic-statistics>
<input-error-list>
<input-errors></input-errors>
<framing-errors></framing-errors>
<input-giants></input-giants>
<input-discards></input-discards>
</input-error-list>
<output-error-list>
<output-collisions></output-collisions>
<output-errors></output-errors>
<output-drops></output-drops>
</output-error-list>
</physical-interface>
</interface-information>
</rpc-reply>

© Copyright IBM Corp. 2014 Chapter 32: NETCONF 443

 • IP detail information

<rpc-reply message-id=“101”
xmlns=“urn:ietf:params:xml:ns:netconf:base:1.0”>
<interface-information>
<physical-interface>
<logical-interface>
<name></name>
<local-index></local-index>
<address-family>
<address-family-name></address-family-name>
<mtu></mtu>
<interface-address>
<ifa-destination></ifa-destination>
<ifa-local></ifa-local>
<ifa-broadcast></ifa-broadcast>
</interface-address>
</address-family>
</logical-interface>
</physical-interface>
</interface-information>
</rpc-reply>

See Table 45 for the tag elements and their values.

Table 45. get-interface-information Tag Element Values

Tag Element Description

interface-name Interface name or number. You can use the tags

brief/ or detail/ to specify the amount of
information you need.

name Name of the port or IP interface.

admin-status Administration status of port interface; shutdown or

no shutdown.

oper-status Operational status of port interface; link-up or

link-down.

local-index Local index of port.

if-type Type of port; GE, XGE.

link-level-type Ethernet

mtu 9216 for port; 1500 for IP interface.

speed Speed of port; 1000M, 10000M.

link-type Type of duplex port; full, half.

input-bytes Number of bytes received at the port.

output-bytes Number of bytes sent from the port.

input-packets Number of frames received at port.

output-packets Number of frames sent out from the port.

input-errors Sum of discarded frames and FCS Errors.

444 RackSwitch G8124: Application Guide

 Table 45. get-interface-information Tag Element Values

Tag Element Description

framing-errors Number of failed frames received.

input-giants Number of frames that are too long.

input-discards Number of frames in discarding state.

output-collisions Number of Ethernet collisions.

output-errors Sum of the outgoing frame aborts and FCS errors.

output-drops Number of frames dropped.

address-family-name inet

ifa-destination Protocol network address of the interface.

ifa-local Protocol host address on the interface.

ifa-broadcast Network broadcast address.

© Copyright IBM Corp. 2014 Chapter 32: NETCONF 445

446 RackSwitch G8124: Application Guide
Part 8: Monitoring
The ability to monitor traffic passing through the G8124 can be invaluable for
troubleshooting some types of networking problems. This sections cover the
following monitoring features:
• Remote Monitoring (RMON)
• sFlow
• Port Mirroring

© Copyright IBM Corp. 2014 447

448 RackSwitch G8124: Application Guide
Chapter 33. Remote Monitoring
Remote Monitoring (RMON) allows network devices to exchange network
monitoring data.

RMON allows the switch to perform the following functions:

• Track events and trigger alarms when a threshold is reached.
• Notify administrators by issuing a syslog message or SNMP trap.

RMON Overview
The RMON MIB provides an interface between the RMON agent on the switch and
an RMON management application. The RMON MIB is described in RFC 1757.

The RMON standard defines objects that are suitable for the management of
Ethernet networks. The RMON agent continuously collects statistics and proactively
monitors switch performance. RMON allows you to monitor traffic flowing through
the switch.

The switch supports the following RMON Groups, as described in RFC 1757:
• Group 1: Statistics
• Group 2: History
• Group 3: Alarms
• Group 9: Events

© Copyright IBM Corp. 2014 449

RMON Group 1—Statistics
The switch supports collection of Ethernet statistics as outlined in the RMON
statistics MIB, in reference to etherStatsTable. You can configure RMON statistics
on a per-port basis.

RMON statistics are sampled every second, and new data overwrites any old data
on a given port.
Note: RMON port statistics must be enabled for the port before you can view
RMON statistics.

Example Configuration
1. Enable RMON on a port.
RS G8124(config)# interface port 1
RS G8124(config-if)# rmon

2. View RMON statistics for the port.

RS G8124(config-if)# show interface port 1 rmon-counters
------------------------------------------------------------------
RMON statistics for port 1:
etherStatsDropEvents: NA
etherStatsOctets: 7305626
etherStatsPkts: 48686
etherStatsBroadcastPkts: 4380
etherStatsMulticastPkts: 6612
etherStatsCRCAlignErrors: 22
etherStatsUndersizePkts: 0
etherStatsOversizePkts: 0
etherStatsFragments: 2
etherStatsJabbers: 0
etherStatsCollisions: 0
etherStatsPkts64Octets: 27445
etherStatsPkts65to127Octets: 12253
etherStatsPkts128to255Octets: 1046
etherStatsPkts256to511Octets: 619
etherStatsPkts512to1023Octets: 7283
etherStatsPkts1024to1518Octets: 38

450 RackSwitch G8124: Application Guide

RMON Group 2—History
The RMON History Group allows you to sample and archive Ethernet statistics for a
specific interface during a specific time interval. History sampling is done per port.
Note: RMON port statistics must be enabled for the port before an RMON History
Group can monitor the port.

Data is stored in buckets, which store data gathered during discreet sampling
intervals. At each configured interval, the History index takes a sample of the current
Ethernet statistics, and places them into a bucket. History data buckets reside in
dynamic memory. When the switch is re-booted, the buckets are emptied.

Requested buckets are the number of buckets, or data slots, requested by the user
for each History Group. Granted buckets are the number of buckets granted by the
system, based on the amount of system memory available. The system grants a
maximum of 50 buckets.

You can use an SNMP browser to view History samples.

History MIB Object ID

The type of data that can be sampled must be of an ifIndex object type, as
described in RFC 1213 and RFC 1573. The most common data type for the History
sample is as follows:
1.3.6.1.2.1.2.2.1.1.<x>

The last digit (x) represents the number of the port to monitor.

Configuring RMON History

Perform the following steps to configure RMON History on a port.
1. Enable RMON on a port.
RS G8124(config)# interface port 1
RS G8124(config-if)# rmon
RS G8124(config-if)# exit

2. Configure the RMON History parameters for a port.

RS G8124(config)# rmon history 1 interface-oid 1.3.6.1.2.1.2.2.1.1.<x>
RS G8124(config)# rmon history 1 requested-buckets 30
RS G8124(config)# rmon history 1 polling-interval 120
RS G8124(config)# rmon history 1 owner "rmon port 1 history"

where <x> is the number of the port to monitor. For example, the full OID for port
1 would be:
1.3.6.1.2.1.2.2.1.1.1

© Copyright IBM Corp. 2014 Chapter 33: Remote Monitoring 451

 3. View RMON history for the port.
RS G8124(config)# show rmon history
RMON History group configuration:

Index IFOID Interval Rbnum Gbnum

----- ----------------------- -------- ----- -----
1 1.3.6.1.2.1.2.2.1.1.1 120 30 30

Index Owner
----- ----------------------------------------------
1 rmon port 1 history

RMON Group 3—Alarms

The RMON Alarm Group allows you to define a set of thresholds used to determine
network performance. When a configured threshold is crossed, an alarm is
generated. For example, you can configure the switch to issue an alarm if more than
1,000 CRC errors occur during a 10-minute time interval.

Each Alarm index consists of a variable to monitor, a sampling time interval, and
parameters for rising and falling thresholds. The Alarm Group can be used to track
rising or falling values for a MIB object. The object must be a counter, gauge,
integer, or time interval.

Use one of the following commands to correlate an Alarm index to an Event index:
RS G8124(config)# rmon alarm <alarm number> rising-crossing-index <event number>
RS G8124(config)# rmon alarm <alarm number> falling-crossing-index <event number>

When the alarm threshold is reached, the corresponding event is triggered.

Alarm MIB objects

The most common data types used for alarm monitoring are ifStats: errors,
drops, bad CRCs, and so on. These MIB Object Identifiers (OIDs) correlate to the
ones tracked by the History Group. An example statistic follows:
1.3.6.1.2.1.5.1.0 – mgmt.icmp.icmpInMsgs

This value represents the alarm’s MIB OID, as a string. Note that for non-tables, you
must supply a .0 to specify end node.

Configuring RMON Alarms

Configure the RMON Alarm parameters to track ICMP messages.
RS G8124(config)# rmon alarm 1 oid 1.3.6.1.2.1.5.8.0
RS G8124(config)# rmon alarm 1 alarm-type rising
RS G8124(config)# rmon alarm 1 rising-crossing-index 110
RS G8124(config)# rmon alarm 1 interval-time 60
RS G8124(config)# rmon alarm 1 rising-limit 200
RS G8124(config)# rmon alarm 1 sample delta
RS G8124(config)# rmon alarm 1 owner "Alarm for icmpInEchos"

This configuration creates an RMON alarm that checks icmpInEchos on the

switch once every minute. If the statistic exceeds 200 within a 60 second interval, an
alarm is generated that triggers event index 110.

452 RackSwitch G8124: Application Guide

RMON Group 9—Events
The RMON Event Group allows you to define events that are triggered by alarms.
An event can be a log message, an SNMP trap, or both.

When an alarm is generated, it triggers a corresponding event notification. Use the

following commands to correlate an Event index to an alarm:

RS G8124(config)# rmon alarm <alarm number> rising-crossing-index <event number>

RS G8124(config)# rmon alarm <alarm number> falling-crossing-index <event number>

RMON events use SNMP and syslogs to send notifications. Therefore, an SNMP
trap host must be configured for trap event notification to work properly.

RMON uses a syslog host to send syslog messages. Therefore, an existing syslog
host must be configured for event log notification to work properly. Each log event
generates a syslog of type RMON that corresponds to the event.

For example, to configure the RMON event parameters.

RS G8124(config)# rmon event 110 type log
RS G8124(config)# rmon event 110 description "SYSLOG_this_alarm"
RS G8124(config)# rmon event 110 owner "log icmpInEchos alarm"

This configuration creates an RMON event that sends a syslog message each time
it is triggered by an alarm.

© Copyright IBM Corp. 2014 Chapter 33: Remote Monitoring 453

454 RackSwitch G8124: Application Guide
Chapter 34. sFlow
The G8124 supports sFlow technology for monitoring traffic in data networks. The
switch includes an embedded sFlow agent which can be configured to provide
continuous monitoring information of IPv4 traffic to a central sFlow analyzer.
The switch is responsible only for forwarding sFlow information. A separate sFlow
analyzer is required elsewhere on the network to interpret sFlow data.
Note: IBM Networking OS 7.11 does not support IPv6 for sFlow.

sFlow Statistical Counters

The G8124 can be configured to send network statistics to an sFlow analyzer at
regular intervals. For each port, a polling interval of 5 to 60 seconds can be
configured, or 0 (the default) to disable this feature.
When polling is enabled, at the end of each configured polling interval, the G8124
reports general port statistics and port Ethernet statistics.

sFlow Network Sampling

In addition to statistical counters, the G8124 can be configured to collect periodic
samples of the traffic data received on each port. For each sample, 128 bytes are
copied, UDP-encapsulated, and sent to the configured sFlow analyzer.
For each port, the sFlow sampling rate can be configured to occur once each 256 to
65536 packets, or 0 to disable (the default). A sampling rate of 256 means that one
sample will be taken for approximately every 256 packets received on the port. The
sampling rate is statistical, however. It is possible to have slightly more or fewer
samples sent to the analyzer for any specific group of packets (especially under low
traffic conditions). The actual sample rate becomes most accurate over time, and
under higher traffic flow.

sFlow sampling has the following restrictions:

• Sample Rate—The fastest sFlow sample rate is 1 out of every 256 packets.
• ACLs—sFlow sampling is performed before ACLs are processed. For ports
configured both with sFlow sampling and one or more ACLs, sampling will occur
regardless of the action of the ACL.
• Port Mirroring—sFlow sampling will not occur on mirrored traffic. If sFlow
sampling is enabled on a port that is configured as a port monitor, the mirrored
traffic will not be sampled.
• Egress traffic—sFlow sampling will not occur on egress traffic.
Note: Although sFlow sampling is not generally a CPU-intensive operation,
configuring fast sampling rates (such as once every 256 packets) on ports
under heavy traffic loads can cause switch CPU utilization to reach
maximum. Use larger rate values for ports that experience heavy traffic.

© Copyright IBM Corp. 2014 455

sFlow Example Configuration
1. Specify the location of the sFlow analyzer (the server and optional port to which
the sFlow information will be sent):

RS G8124(config)# sflow server <IPv4 address> (sFlow server address)

RS G8124(config)# sflow port <service port> (Set the optional service port)
RS G8124(config)# sflow enable (Enable sFlow features)

By default, the switch uses established sFlow service port 6343.

To disable sFlow features across all ports, use the no sflow enable
command.
2. On a per-port basis, define the statistics polling rate:

RS G8124(config)# interface port <port>

RS G8124(config-if)# sflow polling <polling rate>(Statistics polling rate)

Specify a polling rate between 5 and 60 seconds, or 0 to disable. By default,

polling is 0 (disabled) for each port.
3. On a per-port basis, define the data sampling rate:

RS G8124(config-if)# sflow sampling <sampling rate>(Data sampling rate)

Specify a sampling rate between 256 and 65536 packets, or 0 to disable. By

default, the sampling rate is 0 (disabled) for each port.
4. Save the configuration.

456 RackSwitch G8124: Application Guide

Chapter 35. Port Mirroring
The IBM Networking OS port mirroring feature allows you to mirror (copy) the
packets of a target port, and forward them to a monitoring port. Port mirroring
functions for all layer 2 and layer 3 traffic on a port. This feature can be used as a
troubleshooting tool or to enhance the security of your network. For example, an
IDS server or other traffic sniffer device or analyzer can be connected to the
monitoring port to detect intruders attacking the network.

The G8124 supports a “many to one” mirroring model. As shown in Figure 52,
selected traffic for ports 1 and 2 is being monitored by port 3. In the example, both
ingress traffic and egress traffic on port 2 are copied and forwarded to the monitor.
However, port 1 mirroring is configured so that only ingress traffic is copied and
forwarded to the monitor. A device attached to port 3 can analyze the resulting
mirrored traffic.
Figure 52. Mirroring Ports

Mirrored Ports Monitor Port

Ingress Connected to
Both
Traffic sniffer device

1 2 3 4

Specified traffic is copied

and forwarded to Monitor Port

The G8124 supports four monitor ports. Each monitor port can receive mirrored
traffic from any number of target ports.

IBM N/OS does not support “one to many” or “many to many” mirroring models
where traffic from a specific port traffic is copied to multiple monitor ports. For
example, port 1 traffic cannot be monitored by both port 3 and 4 at the same time,
nor can port 2 ingress traffic be monitored by a different port than its egress traffic.

Ingress and egress traffic is duplicated and sent to the monitor port after processing.

Configuring Port Mirroring

The following procedure may be used to configure port mirroring for the example
shown in Figure 52 on page 457:
1. Specify the monitoring port, the mirroring port(s), and the port-mirror direction.

RS G8124(config)# port-mirroring monitor-port 3 mirroring-port 1 in

RS G8124(config)# port-mirroring monitor-port 3 mirroring-port 2 both

2. Enable port mirroring.

RS G8124(config)# port-mirroring enable

© Copyright IBM Corp. 2014 457

 3. View the current configuration.

RS G8124# show port-mirroring

Port Monitoring : Enabled

Monitoring Ports Mirrored Ports

3 1, in
2, both

458 RackSwitch G8124: Application Guide

Part 9: Appendices
• Getting help and technical assistance
• Notices

© Copyright IBM Corp. 2014 459

460 RackSwitch G8124: Application Guide
Appendix A. Getting help and technical assistance
If you need help, service, or technical assistance or just want more information
about IBM products, you will find a wide variety of sources available from IBM to
assist you. This section contains information about where to go for additional
information about IBM and IBM products, what to do if you experience a problem
with your system, and whom to call for service, if it is necessary.

Before you call

Before you call, make sure that you have taken these steps to try to solve the
problem yourself:
• Check all cables to make sure that they are connected.
• Check the power switches to make sure that the system and any optional
devices are turned on.
• Use the troubleshooting information in your system documentation, and use the
diagnostic tools that come with your system. Information about diagnostic tools is
in the Problem Determination and Service Guide on the IBM Documentation CD
that comes with your system.
• Go to the IBM support website at http://www.ibm.com/support/ to check for tech-
nical information, hints, tips, and new device drivers or to submit a request for
information.

You can solve many problems without outside assistance by following the
troubleshooting procedures that IBM provides in the online help or in the
documentation that is provided with your IBM product. The documentation that
comes with IBM systems also describes the diagnostic tests that you can perform.
Most systems, operating systems, and programs come with documentation that
contains troubleshooting procedures and explanations of error messages and error
codes. If you suspect a software problem, see the documentation for the operating
system or program.

Using the documentation

Information about your IBM system and pre-installed software, if any, or optional
device is available in the documentation that comes with the product. That
documentation can include printed documents, online documents, ReadMe files,
and Help files. See the troubleshooting information in your system documentation
for instructions for using the diagnostic programs. The troubleshooting information
or the diagnostic programs might tell you that you need additional or updated device
drivers or other software. IBM maintains pages on the World Wide Web where you
can get the latest technical information and download device drivers and updates.
To access these pages, go to http://www.ibm.com/support/ and follow the
instructions. Also, some documents are available through the IBM Publications
Center at http://www.ibm.com/shop/publications/order/.

© Copyright IBM Corp. 2014 461

Getting help and information on the World Wide Web
On the World Wide Web, the IBM website has up-to-date information about IBM
systems, optional devices, services, and support. The address for IBM System x®
and xSeries® information is http://www.ibm.com/systems/x/. The address for IBM
BladeCenter information is http://www.ibm.com/systems/bladecenter/. The address
for IBM IntelliStation® information is http://www.ibm.com/intellistation/.

You can find service information for IBM systems and optional devices at
http://www.ibm.com/support/.

Software service and support

Through IBM Support Line, you can get telephone assistance, for a fee, with usage,
configuration, and software problems with System x and x Series servers,
BladeCenter products, IntelliStation workstations, and appliances. For information
about which products are supported by Support Line in your country or region, see
http://www.ibm.com/services/sl/products/.

For more information about Support Line and other IBM services, see
http://www.ibm.com/services/, or see http://www.ibm.com/planetwide/ for support
telephone numbers. In the U.S. and Canada, call 1-800-IBM-SERV
(1-800-426-7378).

Hardware service and support

You can receive hardware service through your IBM reseller or IBM Services. To
locate a reseller authorized by IBM to provide warranty service, go to
http://www.ibm.com/partnerworld/ and click Find Business Partners on the right
side of the page. For IBM support telephone numbers, see
http://www.ibm.com/planetwide/. In the U.S. and Canada, call
1-800-IBM-SERV (1-800-426-7378).

In the U.S. and Canada, hardware service and support is available 24 hours a day,
7 days a week. In the U.K., these services are available Monday through Friday,
from 9 a.m. to 6 p.m.

IBM Taiwan product service

IBM Taiwan product service contact information:

IBM Taiwan Corporation
3F, No 7, Song Ren Rd.
Taipei, Taiwan
Telephone: 0800-016-888

462 RackSwitch G8124: Application Guide

Appendix B. Notices
This information was developed for products and services offered in the U.S.A.

IBM may not offer the products, services, or features discussed in this document in
other countries. Consult your local IBM representative for information on the
products and services currently available in your area. Any reference to an IBM
product, program, or service is not intended to state or imply that only that IBM
product, program, or service may be used. Any functionally equivalent product,
program, or service that does not infringe any IBM intellectual property right may be
used instead. However, it is the user's responsibility to evaluate and verify the
operation of any non-IBM product, program, or service.

IBM may have patents or pending patent applications covering subject matter
described in this document. The furnishing of this document does not give you any
license to these patents. You can send license inquiries, in writing, to:

IBM Director of Licensing

IBM Corporation
North Castle Drive
Armonk, NY 10504-1785
U.S.A.

INTERNATIONAL BUSINESS MACHINES CORPORATION PROVIDES THIS

PUBLICATION “AS IS” WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF NON-INFRINGEMENT, MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE. Some states do not allow disclaimer of express or
implied warranties in certain transactions, therefore, this statement may not apply to
you.

This information could include technical inaccuracies or typographical errors.

Changes are periodically made to the information herein; these changes will be
incorporated in new editions of the publication. IBM may make improvements and/or
changes in the product(s) and/or the program(s) described in this publication at any
time without notice.

Any references in this information to non-IBM websites are provided for

convenience only and do not in any manner serve as an endorsement of those
websites. The materials at those websites are not part of the materials for this IBM
product, and use of those websites is at your own risk.

IBM may use or distribute any of the information you supply in any way it believes
appropriate without incurring any obligation to you.

© Copyright IBM Corp. 2014 463

Trademarks
IBM, the IBM logo, and ibm.com are trademarks or registered trademarks of
International Business Machines Corporation in the United States, other countries,
or both. If these and other IBM trademarked terms are marked on their first
occurrence in this information with a trademark symbol (® or ™), these symbols
indicate U.S. registered or common law trademarks owned by IBM at the time this
information was published. Such trademarks may also be registered or common law
trademarks in other countries. A current list of IBM trademarks is available on the
web at “Copyright and trademark information” at
http://www.ibm.com/legal/copytrade.shtml.

Adobe and PostScript are either registered trademarks or trademarks of Adobe

Systems Incorporated in the United States and/or other countries.

Cell Broadband Engine is a trademark of Sony Computer Entertainment, Inc., in the

United States, other countries, or both and is used under license therefrom.

Intel, Intel Xeon, Itanium, and Pentium are trademarks or registered trademarks of
Intel Corporation or its subsidiaries in the United States and other countries.

Java and all Java-based trademarks are trademarks of Sun Microsystems, Inc., in
the United States, other countries, or both.

Linux is a registered trademark of Linus Torvalds in the United States, other

countries, or both.

Microsoft, Windows, and Windows NT are trademarks of Microsoft Corporation in

the United States, other countries, or both.

UNIX is a registered trademark of The Open Group in the United States and other
countries.

Other company, product, or service names may be trademarks or service marks of

others.

464 RackSwitch G8124: Application Guide

Important Notes
Processor speed indicates the internal clock speed of the microprocessor; other
factors also affect application performance.

CD or DVD drive speed is the variable read rate. Actual speeds vary and are often
less than the possible maximum.

When referring to processor storage, real and virtual storage, or channel volume,
KB stands for 1024 bytes, MB stands for 1 048 576 bytes, and GB stands for
1 073 741 824 bytes.

When referring to hard disk drive capacity or communications volume, MB stands

for 1 000 000 bytes, and GB stands for 1 000 000 000 bytes. Total user-accessible
capacity can vary depending on operating environments.

Maximum internal hard disk drive capacities assume the replacement of any
standard hard disk drives and population of all hard disk drive bays with the largest
currently supported drives that are available from IBM.

Maximum memory might require replacement of the standard memory with an

optional memory module.

IBM makes no representation or warranties regarding non-IBM products and

services that are ServerProven, including but not limited to the implied warranties of
merchantability and fitness for a particular purpose. These products are offered and
warranted solely by third parties.

IBM makes no representations or warranties with respect to non-IBM products.

Support (if any) for the non-IBM products is provided by the third party, not IBM.

Some software might differ from its retail version (if available) and might not include
user manuals or all program functionality.

© Copyright IBM Corp. 2014 Appendix B: Notices 465

Particulate contamination
Attention: Airborne particulates (including metal flakes or particles) and reactive
gases acting alone or in combination with other environmental factors such as
humidity or temperature might pose a risk to the device that is described in this
document. Risks that are posed by the presence of excessive particulate levels or
concentrations of harmful gases include damage that might cause the device to
malfunction or cease functioning altogether. This specification sets forth limits for
particulates and gases that are intended to avoid such damage. The limits must not
be viewed or used as definitive limits, because numerous other factors, such as
temperature or moisture content of the air, can influence the impact of particulates
or environmental corrosives and gaseous contaminant transfer. In the absence of
specific limits that are set forth in this document, you must implement practices that
maintain particulate and gas levels that are consistent with the protection of human
health and safety. If IBM determines that the levels of particulates or gases in your
environment have caused damage to the device, IBM may condition provision of
repair or replacement of devices or parts on implementation of appropriate remedial
measures to mitigate such environmental contamination. Implementation of such
remedial measures is a customer responsibility.
Contaminant Limits

Particulate • The room air must be continuously filtered with 40% atmospheric dust
spot efficiency (MERV 9) according to ASHRAE Standard 52.21.
• Air that enters a data center must be filtered to 99.97% efficiency or
greater, using high-efficiency particulate air (HEPA) filters that meet
MIL-STD-282.
• The deliquescent relative humidity of the particulate contamination
must be more than 60%2.
• The room must be free of conductive contamination such as zinc whis-
kers.

Gaseous • Copper: Class G1 as per ANSI/ISA 71.04-19853

• Silver: Corrosion rate of less than 300 Å in 30 days
1 ASHRAE
52.2-2008 - Method of Testing General Ventilation Air-Cleaning Devices for Removal
Efficiency by Particle Size. Atlanta: American Society of Heating, Refrigerating and Air-Condi-
tioning Engineers, Inc.
2 The deliquescent relative humidity of particulate contamination is the relative humidity at which

the dust absorbs enough water to become wet and promote ionic conduction.
3
ANSI/ISA-71.04-1985. Environmental conditions for process measurement and control systems:
Airborne contaminants. Instrument Society of America, Research Triangle Park, North Carolina,
U.S.A.

466 RackSwitch G8124: Application Guide

Documentation format
The publications for this product are in Adobe Portable Document Format (PDF)
and should be compliant with accessibility standards. If you experience difficulties
when you use the PDF files and want to request a web-based format or accessible
PDF document for a publication, direct your mail to the following address:
Information Development
IBM Corporation
205/A0153039 E. Cornwallis Road
P.O. Box 12195
Research Triangle Park, North Carolina 27709-2195
U.S.A.

In the request, be sure to include the publication part number and title.

When you send information to IBM, you grant IBM a non-exclusive right to use or
distribute the information in any way it believes appropriate without incurring any
obligation to you.

© Copyright IBM Corp. 2014 Appendix B: Notices 467

Electronic emission notices
Federal Communications Commission (FCC) statement
Note: This equipment has been tested and found to comply with the limits for a
Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are
designed to provide reasonable protection against harmful interference when the
equipment is operated in a commercial environment. This equipment generates,
uses, and can radiate radio frequency energy and, if not installed and used in
accordance with the instruction manual, may cause harmful interference to radio
communications. Operation of this equipment in a residential area is likely to cause
harmful interference, in which case the user will be required to correct the
interference at his own expense.

Properly shielded and grounded cables and connectors must be used in order to
meet FCC emission limits. IBM is not responsible for any radio or television
interference caused by using other than recommended cables and connectors or by
unauthorized changes or modifications to this equipment. Unauthorized changes or
modifications could void the user's authority to operate the equipment.

This device complies with Part 15 of the FCC Rules. Operation is subject to the
following two conditions: (1) this device may not cause harmful interference, and (2)
this device must accept any interference received, including interference that may
cause undesired operation.

Industry Canada Class A emission compliance statement

This Class A digital apparatus complies with Canadian ICES-003.

Avis de conformité à la réglementation d'Industrie Canada

Cet appareil numérique de la classe A est conforme à la norme NMB-003 du
Canada.

Australia and New Zealand Class A statement

Attention: This is a Class A product. In a domestic environment this product may
cause radio interference in which case the user may be required to take adequate
measures.

468 RackSwitch G8124: Application Guide

European Union EMC Directive conformance statement
This product is in conformity with the protection requirements of EU Council
Directive 2004/108/EC on the approximation of the laws of the Member States
relating to electromagnetic compatibility. IBM cannot accept responsibility for any
failure to satisfy the protection requirements resulting from a nonrecommended
modification of the product, including the fitting of non-IBM option cards.

Attention: This is an EN 55022 Class A product. In a domestic environment this

product may cause radio interference in which case the user may be required to
take adequate measures.

Responsible manufacturer:

International Business Machines Corp.

New Orchard Road
Armonk, New York 10504
914-499-1900

European Community contact:

IBM Technical Regulations, Department M456

IBM-Allee 1, 71137 Ehningen, Germany
Telephone: +49 7032 15-2937
E-mail: tjahn@de.ibm.com

© Copyright IBM Corp. 2014 Appendix B: Notices 469

Germany Class A statement
Deutschsprachiger EU Hinweis:

Hinweis für Geräte der Klasse A EU-Richtlinie zur Elektromagnetischen

Verträglichkeit

Dieses Produkt entspricht den Schutzanforderungen der EU-Richtlinie

2004/108/EG zur Angleichung der Rechtsvorschriften über die elektromagnetische
Verträglichkeit in den EU-Mitgliedsstaaten und hält die Grenzwerte der EN 55022
Klasse A ein.

Um dieses sicherzustellen, sind die Geräte wie in den Handbüchern beschrieben zu

installieren und zu betreiben. Des Weiteren dürfen auch nur von der IBM
empfohlene Kabel angeschlossen werden. IBM übernimmt keine Verantwortung für
die Einhaltung der Schutzanforderungen, wenn das Produkt ohne Zustimmung der
IBM verändert bzw. wenn Erweiterungskomponenten von Fremdherstellern ohne
Empfehlung der IBM gesteckt/eingebaut werden.

EN 55022 Klasse A Geräte müssen mit folgendem Warnhinweis versehen werden:

“Warnung: Dieses ist eine Einrichtung der Klasse A. Diese Einrichtung kann im
Wohnbereich Funk-Störungen verursachen; in diesem Fall kann vom Betreiber
verlangt werden, angemessene Maßnahmen zu ergreifen und dafür aufzukommen.”

Deutschland: Einhaltung des Gesetzes über die elektromagnetische

Verträglichkeit von Geräten

Dieses Produkt entspricht dem “Gesetz über die elektromagnetische Verträglichkeit

von Geräten (EMVG)”. Dies ist die Umsetzung der EU-Richtlinie 2004/108/EG in
der Bundesrepublik Deutschland.

Zulassungsbescheinigung laut dem Deutschen Gesetz über die

elektromagnetische Verträglichkeit von Geräten (EMVG) (bzw. der EMC EG
Richtlinie 2004/108/EG) für Geräte der Klasse A

Dieses Gerät ist berechtigt, in Übereinstimmung mit dem Deutschen EMVG das
EG-Konformitätszeichen - CE - zu führen.

Verantwortlich für die Einhaltung der EMV Vorschriften ist der Hersteller:

International Business Machines Corp.

New Orchard Road
Armonk, New York 10504
914-499-1900

Der verantwortliche Ansprechpartner des Herstellers in der EU ist:

IBM Deutschland
Technical Regulations, Department M456
IBM-Allee 1, 71137 Ehningen, Germany
Telephone: +49 7032 15-2937
E-mail: tjahn@de.ibm.com

Generelle Informationen:

Das Gerät erfüllt die Schutzanforderungen nach EN 55024 und EN 55022

Klasse A.

470 RackSwitch G8124: Application Guide

Japan VCCI Class A statement

This is a Class A product based on the standard of the Voluntary Control Council for
Interference (VCCI). If this equipment is used in a domestic environment, radio
interference may occur, in which case the user may be required to take corrective
actions.

Korea Communications Commission (KCC) statement

Please note that this equipment has obtained EMC registration for commercial use.
In the event that it has been mistakenly sold or purchased, please exchange it for
equipment certified for home use.

Russia Electromagnetic Interference (EMI) Class A statement

People’s Republic of China Class A electronic emission statement

Taiwan Class A compliance statement

© Copyright IBM Corp. 2014 Appendix B: Notices 471

472 RackSwitch G8124: Application Guide