Leaflet

OL-11615-01

Note Storm control is supported in hardware on all ports on the WS-X4516 supervisor engine. In contrast, the

supervisor engines WS-X4515, WS-X4014, and WS-X4013+ support storm control in hardware on

non-blocking gigabit ports and in software on all other ports, implying that the counters for these

interfaces are approximate and computed. Multicast storm control is only supported on the WS-X4516

supervisor engine.

Because hardware broadcast suppression uses a bandwidth-based method to measure broadcast activity,

the most significant implementation factor is setting the percentage of total available bandwidth that can

be used by broadcast traffic. Because packets do not arrive at uniform intervals, the one-second interval

during which broadcast activity is measured can affect the behavior of broadcast suppression.

To configure traffic storm control on the Catalyst 4500 running Cisco IOS, perform the following steps:

Step 1 At the interface level, configure the upper threshold levels for broadcast traffic. The storm control action

occurs when traffic utilization reaches this level. Optionally specify the falling threshold level. Use the

storm-control broadcast level interface command:

Switch(config)# interface type slot/port

Switch(config-if)# storm-control broadcast level [high level] [lower level]

Step 2 Specify the action to be taken when a storm is detected using the storm-control action interface

command. The default is to filter out the broadcast traffic and to not send out traps. The shutdown

keyword sets the port to error-disable state during a storm. If the recover interval is not set, the port

remains in a shutdown state. The trap keyword generates an SNMP trap when a storm is detected.

Switch(config-if)# storm-control action {shutdown | trap}

Step 3 Optionally, enable multicast suppression using the storm-control broadcast include multicast global

configuration command:

Switch(config)# storm-control broadcast include multicast

The following example shows how to enable storm control on interface:

Switch(config)# interface fastethernet 3/1

Switch(config-if)# storm-control broadcast level 50

Switch(config-if)# end

The following example shows how to enable multicast suppression on ports that already have broadcast

suppression enabled:

Switch# configuration terminal

Enter configuration commands, one per line. End with CNTL/Z.

Switch(config)# storm-control broadcast include multicast

Switch(config)# end

For more information on port-based traffic control, refer to the following URL:

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat4000/12_2_31s/conf/bcastsup.htm