The Evolving Network Model
VLAN Implementation
Spanning Tree
InterVLAN Routing
Layer 3 Redundancy
CCNP BCMSN Using Wireless LANs
Quick Reference Sheets VoIP in a Campus Network
Exam 642-812 Campus Network Security
Brent Stewart
Denise Donohue
ciscopress.com
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ICONS USED IN THIS BOOK CCNP BCMSN Quick Reference Sheets
Icons Used in This Book
Si
Router 7507 Multilayer Switch Multilayer Communication Switch
Router with Text Switch Server
I DC
Internal Firewall IDS Web Database App Server
Browser
© 2007 Cisco Systems Inc. All rights reserved. This publication is protected by copyright. Please see page 67 for more details.
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CHAPTER 1 CCNP BCMSN Quick Reference Sheets
The Evolving
Network Model FIGURE 1-1 THE HIERARCHICAL DESIGN MODEL
Core
Cisco has developed specific architecture recommendations for Campus,
Data Center, WAN, branches, and telecommuting. These recommendations Si
add specific ideas about how current technologies and capabilities match
the network roles within an enterprise. Distribution
Each of these designs builds on a traditional hierarchical design and Si Si Si Si
adds features such as security, Quality of Service (QoS), caching,
and convergence. Access
The Hierarchical
Design Model
Cisco has used the three level Hierarchical Design Model for years. The hierarchical design model divides a network into three layers:
This older model provided a high-level idea of how a reliable network n Access—End stations attach to VLANs.
might be conceived, but it was largely conceptual because it did not
provide specific guidance. Figure 1-1 is a simple drawing of how the — Clients attach to switch ports.
three-layer model might have been built out. A distribution layer-3 — VLAN assigned/broadcast domains established.
switch would be used for each building on campus, tying together the
— Built using low-cost ports.
access-switches on the floors. The core switches would links the
various buildings together. n Distribution—Intermediate devices route and apply policies.
— VLANs terminated, routing between.
— Policies applied, such as route selection.
— Access-lists.
— Quality of Service (QoS).
© 2007 Cisco Systems Inc. All rights reserved. This publication is protected by copyright. Please see page 67 for more details.
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CHAPTER 1 CCNP BCMSN Quick Reference Sheets
THE EVOLVING NET WORK MODEL
n Core—The backbone that provides a high-speed path between
distribution elements.
Enterprise Composite
— Distribution devices are interconnected.
Network Model
The newer Cisco model—the Enterprise Composite Model—is signifi-
— High speed (there is a lot of traffic). cantly more complex and attempts to address the major shortcoming of
— No policies (it is tough enough to keep up). the Hierarchical Design Model by expanding the older version and
making specific recommendations about how and where certain
Later versions of this model include redundant distribution and core network functions should be implemented. This model is based on the
devices, and connections that make the model more fault-tolerant. A set principles described in the Cisco Architecture for Voice, Video, and
of distribution devices and their accompanying access layer switches Integrated Data (AVVID).
are called a switch block.
The Enterprise Composite Model is broken up into three large sections:
n Enterprise Campus—The portion of the design that is like the old
Problems with the hiearchical model.
Hierarchical Design Model n Enterprise Edge—The connections to the public network.
This early model was a good starting point, but it failed to address key n Service Provider Edge—The different public networks that are
issues, such as: attached.
n Where do wireless devices fit in?
The first section, the Enterprise Campus, looks like the old Hierarchical
n How should Internet access and security be provisioned? model with some added details. The Enterprise Campus is shown in
n How to account for remote-access, such as dial-up or virtual Figure 1-2. It features six sections:
private network (VPN)? n Campus Backbone—The center of the network, like the old “core”.
n Where should workgroup and enterprise services be located? n Building Distribution—Intermediate devices that route from the
core to access devices.
© 2007 Cisco Systems Inc. All rights reserved. This publication is protected by copyright. Please see page 67 for more details.
[6]
CHAPTER 1 CCNP BCMSN Quick Reference Sheets
THE EVOLVING NET WORK MODEL
n Building Access—Connections for end systems. The Enterprise Edge (shown in Figure 1-3) details the connections from
the campus to the Wide Area Network and includes:
n Management—Command, control, and auditing features.
n Edge Distribution—A distribution layer out to the WAN. n E-Commerce—Externally accessible services that have ties to
internal data stores.
n Server Farm—For Enterprise services.
n Internet Connectivity—Connectivity to outside services.
n Remote Access—Dial and VPN.
n WAN—Internal links.
FIGURE 1-2 THE ENTERPRISE CAMPUS
Campus Backbone A Campus Backbone B
CORE
Building Building Building Building Building
Distribution A Distribution B Distribution A Distribution B Distribution A Building
Distribution B
1st Floor Access 3rd Floor Access 1st Floor Access 3rd Floor Access 1st Floor Access 3rd Floor Access
2nd Floor Access 2nd Floor Access 2nd Floor Access
BUILDING A 4th Floor Access BUILDING B 4th Floor Access BUILDING C 4th Floor Access
© 2007 Cisco Systems Inc. All rights reserved. This publication is protected by copyright. Please see page 67 for more details.
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CHAPTER 1 CCNP BCMSN Quick Reference Sheets
THE EVOLVING NET WORK MODEL
FIGURE 1-3 THE ENTERPRISE EDGE
Frame Relay ATM PPP
WAN
Corporate
Router
E-Commerce
Web
DMZ Firewall Internet Router
Database
I DC
App Server
Internal Router Internal Firewall
Internet
Internal Firewall DMZ Firewall Internet
Internal Router
Router
Public
Servers
Internet Caching
Internal Router Firewall VPN
Edge
Campus Backbone Distribution Remote Access IDS Dial-In
PSTN
Enterprise Edge Service Provider Edge
© 2007 Cisco Systems Inc. All rights reserved. This publication is protected by copyright. Please see page 67 for more details.
