EIGRP flapping over layer 2 WAN multiple sites

[Richard Dellaterza]

We are are experiencing EIGRP flapping between 8 remote sites over a Layer 2 WAN. 3 remote sites do not flap and are configured the same.

We are trying to monitor to see if IP connectivity is lost when the flapps occur.

Has anyone experienced this type of issue?

[mfurnival]

My first step would be to try "debug ip eigrp packet" and see if you are losing hello packets causing the adjacency to go down. If so check the physical interface to see if you are getting errors or packet loss on the link.

If it is an unreliable or high latency link you could increase the eigrp timers to allow a bit more tolerance but a flapping adjacency usually points to an underlying link issue.

[Richard Dellaterza]

Thanks for the reply, I should have stated that we also did "debug eigrp packets hello" as we'll as "debug ip eigrp neighbors" no hello packets were dropped and nothing was found

The physical interfaces are showing no inputs errors, CRC errors, or total output drops

I will try to increase the timers and see if this helps

[paul driver]

Hello
What are the eigrp logs reporting regards the flapping route?
res
Paul

Sent from Cisco Technical Support iPad App

[Richard Burts]

It is possible that packets are being dropped at the other end of the connection and not at your end. You should check both ends. Because drops at one end can cause that device to tear down the neighbor relationship and the other end will see flaps.

It might be helpful if you would tell us precisely what message you are getting from your EIGRP. There are some different messages depending on whether it is your end that initiates the flap or the other end.

HTH

Rick