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Catalyst 3550 Multilayer Switch Software Configuration Guide
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Chapter 12 Configuring Port-Based Traffic Control
Configuring Storm Control
Note
Before IOS Release 12.1(8)EA1, you set up storm control threshold values by using the switchport
broadcast, switchport multicast, and switchport unicast interface configuration commands. These
commands are now obsolete, replaced by the storm-control interface configuration commands.
Default Storm Control Configuration
By default, unicast, broadcast, and multicast storm control is disabled on the switch: that is, the
suppression level is 100 percent.
Enabling Storm Control
You enable storm control on an interface and enter the percentage of total available bandwidth that you
want to be used by a particular type of traffic; entering 100 percent allows all traffic. However, because
of hardware limitations and the way in which packets of different sizes are counted, threshold
percentages are approximations. Depending on the sizes of the packets making up the incoming traffic,
the actual enforced threshold might differ from the configured level by several percentage points.
Note
Storm control is supported only on physical interfaces; it is not supported on EtherChannel port
channels even though the command is available in the CLI.
Beginning in privileged EXEC mode, follow these steps to enable a particular type of storm control:
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Enter interface configuration mode, and enter the type and number
of the physical interface to configure, for example,
gigabitethernet0/1.
Step 3
storm-control broadcast level level [.level]
Specify the broadcast traffic suppression level for an interface as a
percentage of total bandwidth. The level can be from 1 to 100; the
optional fraction of a level can be from 0 to 99. A threshold value
of 100 percent means that no limit is placed on broadcast traffic. A
value of 0.0 means that all broadcast traffic on that port is blocked.
Step 4
storm-control multicast level level [.level]
Specify the multicast traffic suppression level for an interface as a
percentage of total bandwidth. The level can be from 1 to 100; the
optional fraction of a level can be from 0 to 99. A threshold value
of 100 percent means that no limit is placed on broadcast traffic. A
value of 0.0 means that all multicast traffic on that port is blocked.
Step 5
storm-control unicast level level [.level]
Specify the unicast traffic suppression level for an interface as a
percentage of total bandwidth. The level can be from 1 to 100; the
optional fraction of a level can be from 0 to 99. A threshold value
of 100 percent means that no limit is placed on broadcast traffic. A
value of 0.0 means that all unicast traffic on that port is blocked.
Step 6
end
Return to privileged EXEC mode.
