Cisco IOS Wide-Area Networking Configuration Guide - Free Books

Configuring Frame RelayCustomizing Frame Relay for Your NetworkCommandPurposeStep 1 Router(config)# interface type number Specifies an interface.Step 2 Router(config-if)# encapsulation frame-relay Configures Frame Relay encapsulation on theinterface.Step 3Router(config)# interface typenumber:subinterface-number point-to-pointSpecifies a subinterface.Step 4 Router(config-subif)# frame-relay interface-dlci Associates a DLCI with the subinterface.dlciStep 5 Router(config-subif)# bridge-group bridge-group Associates the subinterface with a bridge group.Point-to-Multipoint InterfacesTo configure transparent bridging for point-to-multipoint subinterfaces, use the following commandsbeginning in global configuration mode:CommandPurposeStep 1 Router(config)# interface type number Specifies an interface.Step 2 Router(config-if)# encapsulation frame-relay Configures Frame Relay encapsulation.Step 3Step 4Router(config)# interface typenumber:subinterface-number multipointRouter(config-subif)# frame-relay map bridge dlci[broadcast] [ietf]Specifies a subinterface.Defines a DLCI destination bridge.Step 5 Router(config-subif)# bridge-group bridge-group Associates the subinterface with a bridge group.Configuring a Backup Interface for a SubinterfaceBoth point-to-point and multipoint Frame Relay subinterfaces can be configured with a backup interface.This approach allows individual PVCs to be backed up in case of failure rather than depending on theentire Frame Relay connection to fail before the backup takes over. You can configure a subinterface forbackup on failure only, not for backup based on loading of the line.If the main interface has a backup interface, it will have precedence over the subinterface’s backupinterface in the case of complete loss of connectivity with the Frame Relay network. As a result, asubinterface backup is activated only if the main interface is up, or if the interface is down and does nothave a backup interface defined. If a subinterface fails while its backup interface is in use, and the maininterface goes down, the backup subinterface remains connected.To configure a backup interface for a Frame Relay subinterface, use the following commands beginningin global configuration mode:37