CHAPTER
21-1
Catalyst 2960 Switch SoftwareConfiguration Guide
78-16881-01
21
Configuring Port-Based Traffic Control
This chapter describes how to configure the port-based traffic control features on the Catalyst2960
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 21-5
Configuring Port Blocking, page 21-6
Configuring Port Security, page 21-7
Displaying Port-Based Traffic Control Settings, page 21-16

Configuring Storm Control

These sections contain this conceptual and configuration in formation:
Understanding Storm Control, page 21-1
Default Storm Control Configuration, page 21-3
Configuring Storm Control and Threshold Levels, page 21-3

Understanding 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.