[c-nsp] 2950 and multicast, a cpu issue?

[Peter Rathlev]

On Tue, 2011-04-12 at 16:36 +0200, LM wrote:
> sw2950 running c2950-i6q4l2-mz.121-22.EA13
> Is normal the cpu behaviour? I attached an image, I hope it wont be removed
> switch is just managing multicast traffic

> http://postimage.org/image/2hp8nccw4/

I wouldn't think it normal for a 2950. The ones we have use somewhere
between 5% and 20% CPU depending on their role. The busiest are those
with:

 1) Lots of activity -> blinking lights (takes CPU)

 2) Lots of VLANs -> more spanning-tree to look at

 3) IGMP snooping, though never for more than 4-5 VLANs per switch

At least 1 and 2 should be rather steady, and not fluctuate with a
period of 1 hour or 6-7 hours like seen on the picture.

You should try "show proc cpu" during peak periods to see what processes
are active. Off the top of my head I can't think of any
"misconfiguration" on a 2950 that would cause this kind of load.

-- 
Peter