[c-nsp] c6k msfc - hsrp flapping

[lee.e.rian at census.gov]

Hi Mike

"Michael K. Smith" <mksmith at adhost.com> wrote on 05/17/2006 10:12:27 AM:

> Hello Lee
>
> On 5/17/06 4:01 AM, "lee.e.rian at census.gov" <lee.e.rian at census.gov>
wrote:
>
> > We're having a problem on only one cat6000 MSFC where all the standby
HSRP
> > interfaces go active and routing adjacencies drop.  It's like the
packets
> > are being dropped somewhere inside the switch before they get to the
MSFC.
> >
> > The supervisor isn't complaining about any problems like links flapping
or
> > spanning tree changes and none of the regular error counters on the
> > supervisor or MSFC look all that bad - but I did see some of the show
ibc
> > counters incrementing.
> >
> <snip>
>
> Here is an excellent thread on the ins and outs of HSRP timers.  I would
> take a look at your timers, particularly in relationship to your Spanning
> Tree timers.

I appreciate the reply, but if it was a problem with the HSRP timers or
spanning tree it seems like we'd be seeing problems on both of the core
6500s.

Neither of the core switches are having link flaps, topology changes, etc.
It's just the one MSFC that has all of it's standby hsrp interfaces go
active and then less than a minute later they're all back in standby mode.
The only problems logged by msfc1 are about losing the adjacency w/ msfc2
  %DUAL-5-NBRCHANGE: IP-EIGRP 1: Neighbor xxx is down: peer restarted
  %DUAL-5-NBRCHANGE: IP-EIGRP 1: Neighbor xxx is up: new adjacency

I've been in msfc2 when it started logging all of the hsrp state changes &
done a 'sh proc cpu'.  The highest cpu utilization I've seen was 49% so it
doesn't look like it's a cpu issue.  Input queue drops aren't that bad...
the worst case is a bit over 2000 drops in 23 hours.

The fiber links to the access layer switches come into two different cards
so I don't think it's an issue with a line card.

TAC hasn't been able to figure out the problem.  They haven't explained the
ibc counters either so I was hoping someone on the list knew what they
meant.

Thanks,
Lee