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eigrp flapping after upgrades

I upgraded a 2921 router from 15.1-4.m5 to 15.2-4, both the T train and the M train. On both 15-2 releases the eigrp neighbor relationship between th 2921 and the two nexus7010s started flapping. The only thing that stopped the flapping was going to 15.--4.m7. The link was completely stable before the 15.2 upgrades. Did Cisco change something in eigrp in 15.2? Or is it not liking the Nexus?

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eigrp flapping after upgrades


It certanly looks like a buggy behavior.

I would look for that on the cisco bug toolkit cause something that would cause a failure of a Routing protocol should be removed from one version to another.

If possible check on the release notes as well.

Note: Make sure u run debugs to gather much information

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Julio Carvajal
Senior Network Security and Core Specialist

eigrp flapping after upgrades


Can you post from both routers what the eigrp log messages are reporting and also the output from

sh ip protocols | s eigrp



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New Member

eigrp flapping after upgrades

I checked Arcsight for logs from the 2 Nexus 7010 , there were no logs in the hour I had the 2921 upgraded to 10.2 before putting it back to 15.1 for todays production.     The logs on the 2921 are gone, that is also an internal zone-based firewall and the logs scrolled off.    However I was on the console, and the only logs coming across were :

neighbor established, peer terminiation received, neighbor est, peer termination received, ......

Looking at ip eigrp nei on the 2921 the neighbors were on the list, up arrrow, enter repeatedly showed the neighbor for a max of 53 seconds before going back to 0.    After the return to 15.1 the neighbors have been stable.

eigrp flapping after upgrades

I am guesssing that after upgrade to 15.2-4; drops on the interface must have started to increment causing the eigrp flaps.

Did you checked the interface at the time of issue?


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