CHAPTER
18-1
Catalyst 2950 Desktop Switch Software Configuration Guide
78-14982-01
18

Configuring Port-Base d Traffic Control

This chapter describes how to configure the port-based traffic control features on your switch.
Note For comple te syntax and us age inform ation for the co mmands used in this chapter, refer to th e command
reference for this rel ease.
This chapter consists of these sections:
Configuring Storm Cont rol, page 18-1
Configuring Pr otec ted Port s, page 18-3
Configuring Por t Secu rit y, page 18 -4
Display ing Port-B ased Traffic Control Settings, pa ge 18-12

Configuring St orm Con trol

These sec tions incl ude stor m control configurati on inform ation and procedu res:
Understa ndin g Stor m Contr ol, page 1 8-1
Default Storm C ontro l Co nfigurati on, p ag e 18- 2
Enab ling St or m Con t rol, page 1 8-2
Disabling Storm Control, pa ge 18-3

Understanding Storm Control

A packet storm occurs when a large number of broadcast, unicast, or multicast packets are received on
a port. Forward ing these packets can ca use the ne twork to slow down or to time out. Storm control is
configured for the swi tch as a whol e but operate s on a per-port basis. By de fault, stor m control is
disabled.
Storm con trol uses risi ng and falli ng thresho lds to block an d then restor e the forwa rding of bro adcast ,
unicast, or mu lticast pac ke ts. You can also set t he swit ch to shut do wn t he port when th e ri sing thresho ld
is reached.
Storm co ntro l us es a b an dwi dth-b ased m eth od to m easu re traffic activity. The thre shol ds are expresse d
as a percentage of the total available bandwidth that can be used by the broadcast, multicast, or unicast
traffic.