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Storm protection – Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) User Manual

Page 998

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Quality of Service (QoS) Introduction

Software Reference for x310 Series Switches

38.26

AlliedWare Plus

TM

Operating System - Version 5.4.4C

C613-50046-01 REV A

Storm Protection

Storm protection uses QoS mechanisms to classify on traffic likely to cause a packet storm
(broadcast and multicast). Unless you are running an enhanced storm protection feature
such as Loop Protection, the per-port storm protection mechanism simply discards any
traffic over the configured limit. However, with QoS storm protection, several actions are
possible when a storm is detected:

You can disable the port physically.

You can disable the port logically.

You can disable the port for a particular VLAN.

To enable the policy-based storm protection, use the

storm-protection command on

page 39.46

.

Storm protection is activated as soon as a port is enabled, before the port forwards frames.

When a storm is detected on a port, a message is automatically recorded in the log, and
you can configure an SNMP trap to signal that a port has been disabled. When a storm is
detected on a trunk or port group, the entire trunk or port group is disabled.

The following table explains the basic concepts involved with storm protection.

To set the action to take when triggered by QoS Storm Protection (QSP), use the

storm-

action command on page 39.44

.

To set the time to re-enable the port once disabled by QSP, use the

storm-downtime

command on page 39.45

.

Concept

Description

Window

The frequency at which traffic is measured to determine whether storm
protection should be activated.

Rate

The amount of traffic per second that must be exceeded before the switch
takes the configured action.

Action

What the switch does when it detects a storm on a port.

Timeout

The length of time the port remains disabled after a port has been disabled
due to a packet storm.