Seeing a lot of ROUTING-FIB-3-UPD_MSG_TOO_BIG messages today

Mon Apr 25 16:43:16 UTC 2022

Firstly 😉,

Second, I was mostly just mentioning it because of the quantity of routes which fit this criteria since about 9AM (ET).

It's not that uncommon to see this on one prefix on a monthly basis, the velocity of occurrence today made it seems "different".

That was the only reason I mentioned it.

Thanks and sorry for my noise.
-Drew

-----Original Message-----
From: Saku Ytti <saku at ytti.fi> 
Sent: Monday, April 25, 2022 12:35 PM
To: Drew Weaver <drew.weaver at thenap.com>
Cc: nanog at nanog.org
Subject: Re: Seeing a lot of ROUTING-FIB-3-UPD_MSG_TOO_BIG messages today

Hey Drew,

> I’ve seen this a bit in the past with 1-2 routes, but today it’s been happening basically all morning with several different routes.
> ROUTING-FIB-3-UPD_MSG_TOO_BIG
> I’ve chased it down from a vendor level and they implied that it is just informational, my question is why do these sort of updates seem to be sent to the Internet’s routing table in bursts?

This is really cisco-nsp issue, not nanog, nanog is about unfalsiable politics and explaining how simple things are which you've never done at any scale or availability needs.

You probably have 'bgp attribute-download' configured, which means things like communities, as-paths etc are given for FIB consumption, usually because you want netflow to export AS data, instead of enriching it at the receiver.
So likely you have some RIB entry with a very long path or many communities, and this made the IPC message too large, and those attributes were not sent to the FIB. The prefix and forwarding information is there, juste the attribute download failed.

--
  ++ytti