Question : ISDN backup to ethernet interface using Cisco Router

We are connecting Cisco Router with 2 FE interfaces and ISDN card.

What I want to know is can ISDN be a backup interface to an ethernet interace?
If so how? what is better backup interfaces, static routes or dailer watches?


Any links or configs would be great.

Answer : ISDN backup to ethernet interface using Cisco Router

Ok. If you want to make it simple, then you can go with static routes (Floating static routes).

By default you would have 'ip route 0.0.0.0 0.0.0.0 FastEthernet'

Now add another one as 'ip route 0.0.0.0 0.0.0.0 ISDN link 200'

Since the admin distance for the second link is high, it will not be used under normal conditions, but if the Ethernet connection goes down, this route will be chosen.

http://www.cisco.com/warp/public/125/fr_isdn_backup.html

Cheers,
Rajesh