OSPF flaps on interface

[Beacon Bits]

Hi Guys,

How do I check or command would tell me that OSPF neighborship drops.

Scenario:

I have few routers in network and running OSPF including Juniper and Cisco.

I can see DR (Cisco-3560) adjacency dropped from looking at other Juniper routers running OSPF in the same Broadcast Domain.

Now I'm on cisco and need to find out why OSPF adjacency dropped by Cisco SW.

Regards,

[rcmcdermott11]

run 'debug ip ospf adj' so that you can view adjacencies build or tear down.

You can refer to this doc for troubleshooting steps. http://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/12151-trouble-main.html

While this one explains neighbor states

http://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13685-13.html

[Vinit Jain]

Hello Shariq

Could you paste the show log output which shows the OSPF flap. Is it due to hold timer expiry or too many re-transmissions? Is the flapping happening continuously? Are there any drops on the interface (show interface <>)

The OSPF flap could be due to several reasons and if its a production network then running a debug might not be a good idea. Once you share the above information, we can further investigate.

Regards

Vinit

[Ganesh Hariharan]

Hi Guys,


How do I check or command would tell me that OSPF neighborship drops.

Scenario:

I have few routers in network and running OSPF including Juniper and Cisco.

I can see DR (Cisco-3560) adjacency dropped from looking at other Juniper routers running OSPF in the same Broadcast Domain.

Now I'm on cisco and need to find out why OSPF adjacency dropped by Cisco SW.


Regards,

Hi ,

Show ip ospf neighbour can give brief detail of neighbour OSPF issue.

check out the below links for more information details..

http://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13688-16.html

http://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13699-29.html

Hope it Helps..

-GI

Rate if it Helps..