Cisco Storm Control

One of the things can happen if STP is mulfunctioning is there can be broadcast storm or Multicast storm which there are large frame- that flood the network that can cause problems.

Storm – Excessive broadcast, multicast or unicast traffic receive to a particular interface.

Note: Storm control is configured on per interface and not configure globally.


#storm-control broadcast level 30 5 <— (30 – Rising threshold 5- Falling threshold)
#storm-control muticastcast level 30 5
#storm-control unicast level 30 5

We can set specific candidate if we want to. Level is set as percentage of the bandwidth, So if we receive a traffic greater than 30% action will be shutdown/trap.

#storm-control action ( shutdown  / trap )

Shutdown if we want to shutdown the interface and the 2nd option is trap will not shut the interface down but rather send an alert.

We can prevent problems at layer 2 using storm-control.

Verification Command:

#show storm-control ?

FastEthernet – FastEthernet IEEE 802.3
broadcast – Broadcast storm control
history – Show interface storm history
multicast – Multicast storm control
unicast – Unicast storm control

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