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
Comments (1)
Shawn
| #
Excellent information which really helped me construct a much bigger frame relay lab. Well presented and really well written..thanks so much!!
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