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Cisco IE 2000 Switch Software Configuration Guide
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Configuring Port-Based Traffic Control
Finding Feature Information
Your software release may not support all the features documented in this chapter. For the latest feature
information and caveats, see the release notes for your platform and software release.
Use Cisco Feature Navigator to find information about platform support an d Cisco software image
support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on
Cisco.com is not required.

Restrictions for Port-Based Traffic Control

To use this feature, the switch must be running the LAN Base image.

Information About Port-Based Traffic Control

Storm Control

Storm control prevents traffic on a LAN from being disrupted by a broadcast, multicast, or unicast storm
on one of the physical interfaces. A LAN storm occurs when packets flood the LAN, creating excessive
traffic and degrading network performance. Errors in the protocol -stack implementation, mistakes in
network configurations, or users issuing a denial-of-service att ack can cause a storm.
Storm control (or traffic suppression) monitors packets passing from an interface to the switching bus
and determines if the packet is unicast, multicast, or broadcast. The switch counts the number of packets
of a specified type received within the 1-second time interval and compa res the measurement with a
predefined suppression-level threshold.
Storm control uses one of these methods to measure traffic activity:
Bandwidth as a percentage of the total available bandwidth of the port that can be used by the
broadcast, multicast, or unicast traffic
Traffic rate in packets per second at which broadcast, multicast, or unicast packets are received.
Traffic rate in bits per second at which broadcast, multicast, or unicast packets are received.
Traffic rate in packets per second and for small frames. This feature is enabled globally. The
threshold for small frames is configured for each interface.