Frame-relay switching is simple to configure. In this example we have 2 serial ports and we want to be able to switch dlci’s between them. Serial port 1/0 connects to customerA using DLCI 100 and Serial 1/1 connects to customerB using DLCI 200. Both customers need reachability to eachother.

Simply enable frame-relay switching on your router.

# frame-relay switching

Then enable the ports for frame-relay

# int ser1/0

# encapsulation frame-relay

# int ser1/1

# encapsulation frame-relay

We need to specify these ports to be DCE even though they may be DTE interfaces.

# int ser1/0

# frame-relay intf-type dce

# int ser1/1

# frame-relay intf-type dce

Now we have two options. We can use the old school route method or the modern connect method.

Old School: under interface

# int ser1/0

# frame-relay route 100 interface serial1/1 200

# int ser1/1

# frame-relay route 200 interface serial1/0 100

Modern: Global config

# connect custA_custB serial1/0 100 serial1/1 200

As you can see the modern “connect” method is much simpler and uses less config. And don’t forget to put in the clock-rate if they are indeed DCE interfaces.

Cheers.