Wednesday, October 22, 2008

storm control - level and pps

The storm-control function can be used on the 3550 and 3560 to limit the amount of unicast, broadcast and multicast traffic on a port.

For example

config-if#storm-control unicast level 50 40
config-if#storm-control action shutdwon

The above config will limit the unicast port utilisation to 50%. At this level the port will be shutdown. When unicast utilisation drops below 40% the port will be re-enabled.

Another feature available within the storm control configuration is to set the utilisation based on the pps (packets per second). Hence if the requirement states a max throughput of 500 pps this can be achieved as follows

config-if#storm-control unicast level pps 500 400
config-if#storm-control action shutdown

With the above config the port will begin forwarding once the pps threshold drops below 400 pps.

An alternative storm control action is simply trap, this will cause the port to only generate an snmp trap when thresholds have been reached.

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