Users Guide

Security Commands 1153
Syntax
storm-control unicast [level level |rate rate|action{shutdown|trap}]
no storm-control unicast [level | rate]
• level— The configured rate as a percentage of link bandwidth (Range: 0-
100)
• rate—The configured rate in packets per second. (Range: 0-14880000)
• action—The configured action: shutdown or trap.
Default Configuration
By default, unicast storm control is not enabled on any interfaces.
The default threshold for unicast traffic is 5% of link bandwidth.
Command Mode
Interface Configuration (Ethernet) mode, Interface Range mode
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.
Unicast storm control can issue a trap and drop packets in excess of the
configured rate (level) or shut down the port when the rate is exceeded.
Setting the level, rate or action enables storm control. The shutdown action
disables the interface when a packet storm is detected. The trap action issues
an SNMP trap to configured SNMP agents.
Unicast storm control can only be enabled on Ethernet 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.