[c-nsp] Storm-Control on server switch uplinks.

[Phil Mayers]

On 24/08/10 09:27, Saku Ytti wrote:
> On (2010-08-24 09:50 +0200), Peter Rathlev wrote:
>
>> We use broadcast og multicast storm-control on downlinks towards access
>> switches, generally at 50% just to make sure a broadcast storm doesn't
>> spread too much.
>
> I would run<1% broadcast storm control, preferably entered in pps and
> rather low number. On 10GE 7600 receiving<0.34% bps broadcast (L3 or L2
> port, doesn't matter) it can still drop IGP on unrelated interface and
> cause serious downtime.

Doubtless you know this because you specified 0.34, but for other 
readers, a cautionary tale: We recently deployed an edge 10gig port on a 
6716, and I set the broadcast storm level to 0.10 as per our standard 
config:

  storm-control broadcast level 0.10

Unfortunately on this linecard, anything <0.34 == 0, i.e. all broadcasts 
trigger it. This makes things like ARP rather unhappy! So beware the 
varying linecard limits.

It's a real shame the broadcast limiter (along with all the other limits 
on this platform) aren't more granular e.g. per-vlan broadcast and glean 
limits on a trunk port, etc.