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Allied Telesis AT-S62 User Manual

Page 316

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Chapter 20: Quality of Service (QoS) Commands

316

QoS Command Sequence Examples

Creating a QoS policy involves a command sequence that creates one or
more classifiers, a flow group, a traffic class, and finally the policy. The
following sections contain examples of the command sequences for
different types of policies.

Example 1: Voice Application

Voice applications typically require a small bandwidth but it must be
consistent. They are sensitive to latency (interpacket delay) and jitter
(delivery delay). Voice applications can be set up to have the highest
priority.

This example creates two policies that ensure low latency for all traffic
sent by and destined to a voice application located on a node with the IP
address 149.44.44.44. The policies raise the priority level of the packets
to 7, the highest level. Policy 6 is for traffic from the application that
enter the switch on port 1. Policy 11 is for traffic arriving on port 8 going
to the application.

Policy 6 Commands:

create classifier=22 description=”VoIP flow”
ipsadddr=149.44.44.44

create qos flowgroup=14 description=”VoIP flow”
priority=7 classifierlist=22

create qos trafficclass=18 description=”VoIP flow”
flowgrouplist=14

create qos policy=6 description=”VoIP flow”
trafficclasslist=18 ingressport=1

Policy 11 Commands:

create classifier=23 description=”VoIP flow”
ipdadddr=149.44.44.44

create qos flowgroup=17 description=”VoIP flow”
priority=7 classifierlist=23

create qos trafficclass=15 description=”VoIP flow”
flowgrouplist=17

create qos policy=11 description=”VoIP flow”
trafficclasslist=15 ingressport=8

The parts of the policies are:

❑ Classifiers - Define the traffic flow by specifying the IP address of

the node with the voice application. The classifier for Policy 6
specifies the address as a source address since this classifier is part