hi,

We are facing problem or ISDN call detting dropped after exactly 20 seconds. The configurtaion was working ok , suddenly isdn calls in dropping.

We have configured ISDN as aback up of serial line and we have published both interfaces in ospf process. So when leased line goes down isdn triggers and forms ospf neighbor relationship with it's counterpart router. But suddenly it has stopped working. What we observe is that is is not authenticationg as when call is establised it doesnt shows remote name in the output of show isdn active command.

We have taken output of debug ppp authe command and also debug q921 and q931 command output. Attaching sample conf and debug output.

Any link on Cisco.com is appreciated.

Thanks in advance

Subodh