EIGRP- Query Loop - SIA

 The basic topology is dual hub (HUB-A|B) & spoke, with all spoke
routers configured as stubs, except for two, which I will call nonStub
A|B ( this was a miss-configuration that had been overlooked for years
).

HUB-A has an arbitrary connected route, (passive interface) being
advertised into EIGRP. Shortly after that interface goes down, I would
notice the EIGRP adjacency reset between: HUB-A & HUB-B, HUB-A &
nonStubA, and HUB-B & nonStubA.

When the above interface on HUB-A goes down, the following can be observed:

*HUB-A shows the route active, and is waiting for a reply from nonStubA.

*nonStubA shows the route active, and is waiting for a reply from HUB-B

*HUB-B shows the route active, and is waiting for a reply from HUB-A

Finally after some time, the adjacency[s] reset!

I will try to reproduce all of this in a lab environment, and will
hopefully have some better data.I thought you guys would find this
interesting though. If anything, this underlines the importance of
limiting you query domain, by using summarization & stubs, when
appropriate.

-Yuri

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Received on Thu Jul 05 2012 - 16:07:36 ART