How-to: Configure Frame-relay Switching
Routers can be configured as Frame Relay switches to be used mostly in service provider or LAB environments. Lets see how you can configure frame-relay switch to use your in studies.
On a Frame Relay switch, frames from a Frame Relay PVC arriving on an incoming interface are switched to a Frame Relay PVC on an outgoing interface. The switching paths taken by the frames are based on the static Frame Relay route table.
In the following example two routers (Router1 & Router2) are connected via a router acting as a dedicated frame-relay switch (FRSW) .
- Enable frame relay switching on FRSW using the global command frame-relay switching.
- Configure the frame-relay switch interfaces to act as a DCE interface using the command frame-relay intf-type.
- Configure a frame relay PVC on FRSW to switch packets coming from DLCI 100 on Serial1/0 to DLCI 200 on Serial1/1.
- Configure typical frame relay on both routers (Router1 & Router2).
- Verify and check the operation.
Frame-relay switch configuration:
FRSW(config-if)#description Connection to Router1
FRSW(config-if)#frame-relay intf-type dce !--act as a switch connected to router
!--specify a static route PVC switching.
Router1 & Router2 configuration:
This is a basic frame relay configuration using main serial interfaces and all defaults.
Router1(config-if)#ip address 18.104.22.168 255.255.255.0
Verification and troubleshooting:
The following show commands were taken from the frame relay switch "FRSW" and Router1
|FRSW#sh frame-relay route
Input Intf Input Dlci Output Intf Output Dlci Status
Serial1/0 100 Serial1/1 200 active
Serial1/1 200 Serial1/0 100 active
FRSW#sh frame-relay pvc | in DLCI
Verification from Router1 point of view "same is done on Router2"
Type escape sequence to abort.
Router1#show frame-relay map
Note: L2 to L3 resolution is accomplished dynamically using inverse arp.