Friday, May 30, 2008

Troubleshooting OSPF over Frame-Relay Part 1

Scenario:
Full mesh of PVCs between 3 routers: R4 R5 and R6
Frame-relay map statements DO NOT have broadcast statement
Adjacencies do not form.

This is from debug ip packet on R6:

R6#debug ip packet
IP packet debugging is on
*Mar 1 01:00:26.367: IP: s=172.12.45.6 (local), d=224.0.0.5 (Serial1/1), len 76, sending broad/multicast
*Mar 1 01:00:26.371: IP: s=172.12.45.6 (local), d=224.0.0.5 (Serial1/1), len 76, encapsulation failed

After enabling broadcast on the frame maps, adjacencies came up

Solution:
Point-to-multipoint ospf networks need broadcast keyword on frame-relay map.
Without it you will see "encapsulation failed" when the router tries to send multicast hellos.

2 comments:

  1. I would like to add that if inverse arp were enabled then broadcast would be mapped by default. In the example above, inverse arp was disabled.

    ReplyDelete
  2. I am really having a hard time with OSPF and Frame relay. Thanks for sharing this solution. It helps me a lot. Encapsulation didn't failed.
    Thank you so much!

    Jo-An from collier d'ambre pour bébé 

    ReplyDelete

Note: Only a member of this blog may post a comment.