Backup interface

Unanswered Question
Apr 5th, 2007
User Badges:

Dear all,

I have confiured Leased line as primary with ISDN as back up. When leased line goes down , we are able to ping ISDN IP from router . But from PC we are not able to ping LAN of remote side.

When we do show ip router in router , it still shows next hop as leased line .

Both ends static router have been configured with ISDN AD as 50 & for leased line AD as 1.

My concern is that why next hop is pointing towards Leased line when ISDN is UP.



  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Danilo Dy Thu, 04/05/2007 - 23:11
User Badges:
  • Blue, 1500 points or more


Are both lines (serial and ISDN) terminates in the same router in each site?

Can you post the config of the routers in each site?

Richard Burts Fri, 04/06/2007 - 05:43
User Badges:
  • Super Silver, 17500 points or more
  • Hall of Fame,

    Founding Member

  • Cisco Designated VIP,

    2017 LAN, WAN


I agree with Danilo that seeing the config would be helpful. This would show us how the interface is configured and how the routes are defined. It would also be helpful if you could post the output of show ip route (especially when the serial is down and the ISDN is active).



rajesh_colt Tue, 04/10/2007 - 03:48
User Badges:

Dear Aman,

configure backup interface command under serial interface...with backup delay...and specify static route for both serial interface and isdn interface with out giving administrative distance... so when leased line goes down it will automatically picks up isdn...




This Discussion