Re: [nsp] troubleshooting stuck in active routes

From: Gert Doering (gert@greenie.muc.de)
Date: Thu Oct 04 2001 - 17:34:36 EDT


Hi,

On Thu, Oct 04, 2001 at 11:25:10AM +0200, CLAEREBOUDT Elke wrote:
> When those routes dissapear, we sometimes have the SIA's and the clearing of
> neighbourships. It isn't always the same router which isn't responding to
> the queries, there's really no line that is congested, no trouble with cpu
> or memory.
> There seems to be a loop in the queries.

This is something that I have seen as well. We have a topology with a
number of loops purposely built into it. Sometimes when routes
disappear completely ("line goes down, no route anymore"), they get SIA
and EIGRP flaps to recover.

I have not fully understood why this is happening, as it is also neither
a CPU nor memory problem on the boxes affected (7200s, 7500), and it
doesn't happen "all the time" but only "very rarely" (maybe once per a
few hundred withdrawals). Last time I actually managed to get a "show
ip ei top active" from the routers involved, and they pointed to each
other in a circle... from the docs, this should never happen (if a
router queries one that is already active, it should send a negative
response immediately).

12.0S, various subreleases, no obvious "open bugs" found.

gert

-- 
Gert Doering
Mobile communications ... right now writing from *Prague*
... mobile phone: +49 177 2160221 ... or mail me:  gert@greenie.muc.de



This archive was generated by hypermail 2b29 : Sun Aug 04 2002 - 04:13:19 EDT