Administrator Guide

Security Commands 1047
User Guidelines
A destination lookup failure (DLF) is when a L2 unicast packet is unable to
resolve the destination MAC address to an egress interface (no MAC
forwarding address entry exists). The standard behavior for L2 DLFs is to
flood the packet on all ports in the VLAN other than the port on which the
packet was received. This flooding behavior can cause significant amounts of
bandwidth to be consumed, potentially disrupting the forwarding of other
traffic.
Setting the level, rate or action enables storm control.
Unicast storm control can only be enabled on physical interfaces. It cannot be
configured on port channels.
Either the level or the rate threshold may be configured, but not both.
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 rate limit DLF traffic rate to 5%
of link bandwidth:
console(config)#interface range gi1/0/1-24
console(config-if)#storm-control unicast level 5
console(config-if)#exit
2CSNXXX_SWUM204.book Page 1047 Monday, January 25, 2016 1:25 PM