Currently I have a primary 1M primary DSL link going to internet. I'm using DSL modem and a Cisco 1721 router as my gateway. I have BRI S/T interface and need to use my ISDN line as a backup link.
How do i make my ethernet interface go down when my sdsl link goes down? At the moment at my router i have put 'backup interface dialer 1' on my ethernet interface, however the ethernet wont go down when the sdsl line goes down.
Another method i tried was setting the default route going to internet with the ISDN link having an AD of 2 as shown below;-
ip route 0.0.0.0 0.0.0.0 BVI1
ip route 0.0.0.0 0.0.0.0 Dialer1 2
When i disconnected the line, the router wont go through the ISDN even after sometimes. If I remove the line 'ip route 0.0.0.0 0.0.0.0 BVI1' then the router goes through the ISDN link. Any way for me to make this automated.