Administrator Guide

Security Commands 1045
Default Configuration
By default, multicast storm control is not enabled on any interfaces.
If multicast storm-control is enabled, the rate of L2 multicast traffic received
on an interface increases beyond the configured threshold, traffic will be
dropped.
The default threshold for multicast traffic is 5% of link bandwidth.
The default behavior is to rate limit (drop) traffic exceeding the configured
threshold.
The default action is no action.
Command Mode
Interface Configuration (Ethernet) mode, Interface Range mode
User Guidelines
Multicast storm control applies to unknown multicast (i.e., multicast groups
that are not control plane traffic and are not currently active on any
interface). This is multicast traffic that normally is flooded in the VLAN.
Multicast storm control can only be enabled on physical interfaces. It cannot
be configured on port channels.
Setting the level, rate or action does not enable multicast storm control. Issue
the storm-control multicast command separately to enable multicast storm
control.
Either the level or the rate threshold may be configured, but not both.
Either the trap action or the shutdown action may be specified, but not both.
The trap action issues a log message (WARNING) and a trap when the
configured threshold is exceeded. Traffic exceeding the threshold is dropped.
The shutdown action shuts down the interface, puts the interface into the D-
disable state, issues a log message and a trap. The operator may bring the port
back into service using the no shutdown command.
Use the show storm-control action and show storm-control all commands to
display the storm control settings.
2CSNXXX_SWUM204.book Page 1045 Monday, January 25, 2016 1:25 PM