Users Guide

Security Commands 1152
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 issue a trap and drop traffic in excess of the
configured rate (level), or shut down the ingress port if the rate is exceeded.
Multicast storm control can only be enabled on Ethernet 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.
Example
The following example configures any port to shut down if the received
multicast traffic rate exceeds 20% of link bandwidth:
console(config)#interface range gi1/0/1-24
console(config-if)#storm-control multicast level 20
console(config-if)#storm-control multicast action shutdown
console(config-if)#exit
storm-control unicast
Use the storm-control unicast command in Interface Configuration mode to
enable storm control for an interface. Unicast storm control limits the
number of unicast destination lookup failures (DLFs). Use the no form of the
command to disable unicast storm control or to return the configuration to
the default.