Configuring Storm Control

Summary: Networking › Switching › Edge › Synapse

Overview of Storm Control

Storm control prevents traffic on a LAN from being disrupted by a broadcast, multicast, or unicast storm on one of the physical interfaces. A LAN storm occurs when packets flood the LAN, creating excessive traffic and degrading network performance. Errors in the protocol-stack implementation, mistakes in network configurations, or users issuing a denial-of-service attack can cause a storm.。 Storm control uses bandwidth as a percentage of the total available bandwidth of the port that can be used by the broadcast, multicast, or unicast traffic, to measure traffic activity. because of hardware limitations and the way in which packets of different sizes are counted, threshold percentages are approximations.

Configuring

• Configuring Storm Control

SWITCH(config-if)#storm-control {broadcast | multicast | unicast | all | unicast-broadcast | multicast-broadcast} level LINE

SWITCH(config-if)#no storm-control

Configure broadcast, multicast, or unicast storm control. By default, storm control is disabled. If you set the threshold to the maximum value (100 percent), no limit is placed on the traffic. If you set the threshold to 0.0, traffic on that port is blocked. The range is 0.00 to 100.00. Support adaptive port rate change. Unicast only containing unknown unicast packets.

Examples

Example 1：Configure the unknown multicast storm control on port gigabitEthernet0/1 to 10% of the total bandwidth. Step 1: Specify the interface gigabitEthernet0/1 to be configured, and enter interface configuration mode.

SWITCH#

SWITCH#configure terminal

Enter configuration commands, one per line. End with CNTL/Z.

SWITCH(config)#interface gigabitEthernet0/1

SWITCH(config-if)#

Step 2: Configure the unknown multicast storm control on port gigabitEthernet0/1 to 10%.

SWITCH(config-if)#storm-control multicast level 10

Display information

• Display All Port Storm Control Configurations

SWITCH#show storm-control

Port BcastLevel McastLevel Unicastlevel

GiE0/1 100.00% 10.00% 100.00% GiE0/2 100.00% 100.00% 100.00% GiE0/3 100.00% 100.00% 100.00% GiE0/4 100.00% 100.00% 100.00% GiE0/5 100.00% 100.00% 100.00% GiE0/6 100.00% 100.00% 100.00% GiE0/7 100.00% 100.00% 100.00% GiE0/8 100.00% 100.00% 100.00% GiE0/9 100.00% 100.00% 100.00% GiE0/10 100.00% 100.00% 100.00% GiE0/11 100.00% 100.00% 100.00% GiE0/12 100.00% 100.00% 100.00%