Frame Relay Subinterface Command List

Frame Relay Subinterface Command List

Frame Relay Subinterface Command List

Using subinterfaces also lets you send routing updates out the same physical interface on which they were received. Using subinterfaces in this manner overcomes the split horizon problem that can occur when sending updates out the same interface. To configure Frame Relay on a subinterface, complete the following tasks:

• Enable Frame Relay on the interface and set the encapsulation method.
• Create the subinterface, specifying either point-to-point or multipoint.
• For a point-to-point connection or a multipoint connection using inverse ARP, assign the DLCI number to the subinterface.
• For a multipoint connection using static assignments, map DLCIs to protocol addresses.

In addition, you will need to assign a Network layer address to the subinterface. Do not assign an IP address to the main interface.

Use . . .	To . . .
Router(config-if)#int sX.X	Create the subinterface
Router(config-subif)#frame-relay interface-dlci	Assign the DLCI to the interface
Router(config-subif)#frame-relay map	Map protocol addresses to DLCIs

Examples
The following commands create a point-to-point subinterface on the first serial interface and assign it to DLCI 44. The subinterface is configured to use inverse ARP.

Router(config)#int s0

Router(config-if)#encap frame

Router(config-if)#int s0.55 point

Router(config-subif)#frame interface-dlci 44

The following commands create a multipoint subinterface on the second serial interface, and configure it with a static IP mapping of device 199.12.16.155 to DLCI 111.

Router(config)#int s1

Router(config-if)#encap frame

Router(config-if)#int s1.103 mult

Router(config-subif)#frame map ip 199.12.16.155 111