Frame Relay
BSCI v3.0—2-1
The Need for Frame Relay
The Need for Frame Relay
The Need for Frame Relay
The Need for Frame Relay
Virtual circuit
Virtual circuit
Virtual circuit
Selecting a Frame Relay Topology
Frame Relay default: NBMA
Frame Relay Address Mapping
LMI receives locally significant DLCI from the Frame Relay switch.
Inverse ARP maps the local DLCI to the remote router network
layer address.
LMI (Local Management Interface)
-Signaling protocol between the router and the FR
switch.
-Used for management purpose.
-It is used so as a router can get its local DLCI & their
status from the FR switch.
VC status from LMI:
1- Active=2 sides are active.
2- Inactive = remote end failed but my side is active
3- Deleted = DLCI doesn’t exist
Frame Relay Signaling
Cisco supports three LMI standards:
Cisco
ANSI T1.617 Annex D
ITU-T Q.933 Annex A
Address Resolution (MAP)
1- Manual Resolution (static).
- Mapping between the DCLI no. and the next hop ip address
using configuration.
2- Dynamic Resolution. (Inverse ARP)
- Used to know the unknown ip for a known DLCI (from LMI ).
- Works by default .
Stages of Inverse ARP and LMI Operation
(Cont.)
Configuring Basic Frame Relay
Configuring a Static Frame Relay Map
Configure a static Frame Relay map when:
A Frame Relay peer does not support Inverse ARP
You want to control broadcast traffic across a PVC
You want to have different Frame Relay encapsulations across PVCs
Frame Relay encapsulation types
CISCO cisco propriatory
IETF open standard
LMI is operating between the router & FR switch
Encapsulation is operating between source &
destination router
Frame relay configuration example
Frame relay issues
Frame relay issues
Frame relay sub-interfaces
Configuring Frame Relay Subinterfaces
• Point-to-point
– Subinterfaces act like leased lines.
– Each point-to-point subinterface requires its own subnet.
– Point-to-point is applicable to hub-and-spoke topologies.
• Multipoint
– Subinterfaces act like NBMA networks, so they do not
resolve the split-horizon issues.
– Multipoint can save address space because it uses a
single subnet.
– Multipoint is applicable to partial-mesh and full-mesh
topologies.
Configuring Frame Relay Point-to-Point
Subinterfaces
Configuring Frame Relay Multipoint
Subinterfaces
Verifying Frame Relay Operation (Cont.)
RouterX# show frame-relay pvc [type number [dlci]]
Displays PVC statistics
RouterX# show frame-relay pvc 100
PVC Statistics for interface Serial0 (Frame Relay DTE)
DLCI = 100, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0
input pkts 28 output pkts 10 in bytes 8398
out bytes 1198 dropped pkts 0 in FECN pkts 0
in BECN pkts 0 out FECN pkts 0 out BECN pkts 0
in DE pkts 0 out DE pkts 0
out bcast pkts 10 out bcast bytes 1198
pvc create time 00:03:46, last time pvc status changed 00:03:47
Verifying Frame Relay Operation (Cont.)
RouterX# show frame-relay map
Displays the current Frame Relay map entries
RouterX# clear frame-relay-inarp
Clears dynamically created Frame Relay maps, created by using Inverse ARP
RouterX# show frame-relay map
Serial0 (up): ip 10.140.1.1 dlci 100(0x64,0x1840), dynamic,
broadcast,, status defined, active
RouterX# clear frame-relay-inarp
RouterX# show frame map
RouterX#
