Backup Interface with GNS3

configuring "backup interface" on frame-relay interface with GNS3, you need to modify the frame-relay command on primary "frame-relay" interface. The reason is that frame-relay sub-interface on router might not recognize end-to-end LMI using shutting down serial interface (neither main FR i/f or sub FR i/f).

In that case, you need to take "interface-dlci" command out from FR sub-interface.

Rack1R4(config)#int se0/0.1
Rack1R4(config-subif)#no frame-relay interface-dlci 405
Rack1R4(config-subif)#end
Rack1R4#
*Mar  1 00:47:30.111: BACKUP(Serial0/0.1): event = primary interface went down
*Mar  1 00:47:30.111: BACKUP(Serial0/0.1): changed state to "waiting to backup"
Rack1R4#
*Mar  1 00:47:30.539: %SYS-5-CONFIG_I: Configured from console by console
Rack1R4#
*Mar  1 00:47:33.111: BACKUP(Serial0/0.1): event = timer expired on primary
*Mar  1 00:47:33.139: BACKUP(Serial0/0.1): secondary interface (Serial0/1) made active
*Mar  1 00:47:33.143: BACKUP(Serial0/0.1): changed state to "backup mode"
Rack1R4#
*Mar  1 00:47:35.115: %LINK-3-UPDOWN: Interface Serial0/1, changed state to up
Rack1R4#
*Mar  1 00:47:35.131: BACKUP(Serial0/1): event = secondary interface came up
*Mar  1 00:47:36.123: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, changed state to up

Rack1R4#sh backup          
Primary Interface   Secondary Interface   Status
-----------------   -------------------   ------
Serial0/0.1         Serial0/1             backup mode
 
Rack1R4#





If you want to bring backup i/f back to "normal operation" status, you need to put "interface-dlci" command back to original.