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

[Jon Lewis]

Back on the topic of storm-control, I recently deployed some new 3560G 
switches and configured them with storm-control.  There are some 
interesting differences in storm-control on the 3560G and 6500.

The 3560G allowd me to configure storm-control using either bps or pps 
rates.  I chose to use pps.  My only complaint so far is that on the 6500 
I could "show int count storm" to see both the per-port config, and more 
importantly, the per-port TotalSuppDiscards, which lets me see which ports 
have been having traffic storm issues.

On the 3560G "show int count storm" isn't valid.  I can "show storm" to 
see the per-port config, interface filter state, and current 
broadcast/multicast traffic level, but there's no history, so I won't know 
if an interface dropped some packets due to storm-control.

Searching the documentation, I found

show interfaces [interface-id] counters multicast: Displays the 
storm-control multicast suppression discard counter with the number of 
packets discarded for all interfaces or the specified interface.

CLI online help / command completion doesn't seem to know about this, but 
it does work (I think):

#sh int count ?
   errors        Show interface error counters
   etherchannel  Show interface etherchannel counters
   module        Limit display to interfaces on module
   protocol      interface protocol counters
   trunk         Show interface trunk counters
   |             Output modifiers
   <cr>

#sh int count multi

Port      McastSuppDiscards
Gi0/1                     0
Gi0/2                     0
Gi0/3                     0
...

cloud-uplink-sw-1#sh int count broad

Port      BcastSuppDiscards
Gi0/1                     0
Gi0/2                     0
Gi0/3                     0
...

The switch is running the latest code (12.2(55)SE).  All the counters are 
0...which makes me wonder if they "work" because the servers on this 
switch were generating occasional broadcast/multicast storms before the 
3560G's were put in place.

----------------------------------------------------------------------
  Jon Lewis, MCP :)           |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
_________ http://www.lewis.org/~jlewis/pgp for PGP public key_________