Failing over to Backup on EIGRP

[thomuff]

I have a Frame Relay circuit primary and a ISDN circuit backup. What is the best way to force traffic down the ISDN circuit?

[Georg Pauwen]

Hello,

it depends: if you have a Frame Relay subinterface, you could use the 'backup' command, e.g.:

interface Serial0/0.1

backup interface dialer 1

When you have only the physical (Serial0) interface configured, the 'backup' command won't work. In taht case, you could try Dialer Watch. Can you post your router configuration ?

Regards,

GP

[thomuff]

We have the backup interface command and back up delay on the subinterface. The serial interface is not completely down but it it having intermittent problems so it is not failing over because the sub interface is not going down completely.

[thomuff]

I guess I am looking for a graceful to change it over. I know how to do it with OSPF but not in EIGRP.

Thanks for the response

[mlanglois]

We use Dialer Watch to accomplish a failover. That way it watches a specified route in your routing table. When it 'vanishes' due to any loss in intermediary devices (between your eigrp neighbors) the ISDN dials up and then learns and broadcasts it's routes through that path. When the primary link is once again seen, the ISDN shuts down and primary takes over.

[thomuff]

That is something we definitely have to review. Because We have rougly 50 connections with very similiar configurations.

[neclink]

I am just curious to know. wht would not the back command work on the single physical serial interface. is it due to Framerelay?

pls send me the reply to cisco_voip2002@yahoo.com

[mlanglois]

The backup interface command only works when the interface loses link so if a device in the middle fails you will never see the link go down. So the router doesn't realize that it's traffic isn't reaching it's destination.

http://www.cisco.com/en/US/customer/tech/tk801/tk133/technologies_tech_note09186a008009457d.shtml