Cisco Router as Frame Relay Switch

Hi all, In this article we will configure a Cisco Router to act as a Frame Relay Switch. We have used Cisco routers 3700 series in GNS3. To demonstrate comunication through Frame Relay Switch we connected to it two end devices (routers in our case), we configured them with their IP addresses and prepared to support Frame Relay Encapsulation on interfaces connected to FR Switch. (Watch the video)

But first a little bit about the logic of this configuration:

To work as Frame Relay switch must enable Frame Relay Switching on Router by using frame-relay switching, next go under interface configuration mode and set interface as DCE with frame-relay intf-type dce command, after that set clock rate with clock rate command, and use frame-relay route to route traffic from one DLCI of a interface to another DLCI of a interface. In next picture is presented topology for this lab.

Router As Frame Relay Switch

From the picture is seen that DLCI 100 is assigned to interface attached to R1 and DLCI 200 is assigned to attached to R2. In box bellow is shown how to do this:

FR1

frame-relay switching 

interface Serial0/0
no ip address
encapsulation frame-relay
clock rate 64000
frame-relay intf-type dce
frame-relay route 100 interface Serial0/1 200 

interface Serial0/1
no ip address
encapsulation frame-relay
clock rate 64000
frame-relay intf-type dce
frame-relay route 200 interface Serial0/0 100

These are simple steps that you should do on router to act as FR Switch, next will configure two end devices that are connected to FR1 and use DLCI 100 and 200 respectively.

R1

interface Serial0/0
ip address 10.0.0.1 255.255.255.0
encapsulation frame-relay

R2

interface Serial0/0
ip address 10.0.0.2 255.255.255.0
encapsulation frame-relay

Now let’s verify configuration and connectivity between end routers for this lab, in screenshots bellow are shown output of command show frame-relay route on FR switch, show frame-relay pvc and show frame-relay map on end routers and of course ping command.

Verification on FR Switch

Verification on end devices (R1) and ping output