Chapter
When the storm control threshold for multicast traffic is reached, all multicast traffic except control
Note
traffic, such as bridge protocol data unit (BDPU) and Cisco Discovery Protocol (CDP) frames, are
blocked. However, the switch does not differentiate between routing updates, such as Open Shortest Path
First (OSPF) and regular multicast data traffic, so both types of traffic are blocked.
The trap and shutdown options are independent of each other.
If you configure the action to be taken as shutdown (the port is error-disabled during a storm) when a
packet storm is detected, you must use the no shutdown interface configuration command to bring the
interface out of this state. If you do not specify the shutdown action, specify the action as trap (the
switch generates a trap when a storm is detected).
When a storm occurs and the action is to filter traffic, if the falling suppression level is not specified, the
switch blocks all traffic until the traffic rate drops below the rising suppression level. If the falling
suppression level is specified, the switch blocks traffic until the traffic rate drops below this level.
When a broadcast storm occurs and the action is to filter traffic, the switch blocks only broadcast traffic.
You can verify the configuration by entering the show storm-control privileged EXEC command.
For more information, see the software configuration guide for this release.
Examples
This example shows how to enable broadcast storm control with a 75.5-percent rising suppression level:
This example shows how to enable unicast storm control on a port with an 87-percent rising suppression
level and a 65-percent falling suppression level:
Switch# configure terminal
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# storm-control unicast level 87 65
This example shows how to enable broadcast address storm control on a port to a level of 20 percent.
When the broadcast traffic exceeds the configured level of 20 percent of the total available bandwidth of
the port within the traffic-storm-control interval, the switch drops all broadcast traffic until the end of
the traffic-storm-control interval:
Switch# configure terminal
Switch(config)# interface gigabitethernet0/1
Switch(config-if)# storm-control broadcast level 20
Related Commands
Command
show storm-control
OL-28238-01
Description
Displays broadcast, multicast, or unicast storm control settings on all
interfaces or on a specified interface.
Cisco ME 3800X and ME 3600X Switch Command Reference
storm-control
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