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CHAPTER
21-1
Catalyst 2950 and Catalyst 2955 Switch Software Configuration Guide
OL-10101-02
21
Configuring Port-Based Traffic Control
This chapter describes how to configure the port-based traffic control features on your Catalyst 2950 or
Catalyst
2955 switch.
Note For complete syntax and usage information for the commands used in this chapter, see the command
reference for this release.
This chapter consists of these sections:
• Configuring Storm Control, page 21-1
• Configuring Protected Ports, page 21-4
• Configuring Port Blocking, page 21-5
• Configuring Port Security, page 21-6
• Displaying Port-Based Traffic Control Settings, page 21-13
Configuring Storm Control
These sections include storm control configuration information and procedures:
• Understanding Storm Control, page 21-1
• Default Storm Control Configuration, page 21-2
• Configuring Storm Control and Threshold Levels, page 21-2
Understanding Storm Control
Storm control prevents traffic on a LAN from being disrupted by a broadcast, multicast, or unicast storm
on a port. 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 configuration,
or users issuing a denial-of-service attack can cause a storm.
Storm control is configured for the switch as a whole but operates on a per-port basis. By default, storm
control is disabled.
Storm control uses rising and falling thresholds to block and then restore the forwarding of broadcast,
unicast, or multicast packets. You can also set the switch to shut down the port when the rising threshold
is reached.