Storm-Control - Best Practices

[whistleblower]

Hi,

are there any suggestions on which %level the limit should be configured?

I´ve been gone through the official documentation which also states:

"...Suppression monitors the bandwidth of each individual switch port every 1 second. On classic MS switches, if the specified type of traffic exceeds the defined limit, only excess packets will be dropped."

are there (interface) statistics or Logging entries that will show those kind of drops?

[GIdenJoe]

As having experience with networks halting endpoints even at 1% broadcast storm there is no reason not to choose 1% for 100/1000 links and higher.

I found that on Catalyst switches where you can also limit on packets per second that alot of hosts/access points start having big issues around 80-100 pps of broadcast traffic.  Since those frames usually are a few kilobytes in size you can imagine that even a 1% of 1 Gig = 10 Mbps is still enough to hamper your network.  Of course this was at that specific situation.  Ultimately I had to configure a forced shutdown if broadcast packets exceeded 50 pps which still is way higher than the normal 0 - 3 pps broadcast on that network.

Alas you can't configure packets per second or do a shutdown of the port if this happens so testing with a dumb switch is required to determine at what point your network becomes unstable.  If your network is predominantly 100/1000 Mbps links you could use these:
Broadcast: 1%

Unknown unicast: 1%
Multicast: 1% if you don't actively use audio/video streams in multicast over your network (if you do then you need to figure out total bandwidth for these).