Traffic-Class Groups Overview; Configuring Traffic Classes That Define Service Levels - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - QUALITY OF SERVICE CONFIGURATION GUIDE 2010-09-22 Configuration Manual

JunosE 11.3.x Quality of Service Configuration Guide

Traffic-Class Groups Overview

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Configuring Traffic Classes That Define Service Levels

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Packets arrive at an egress line module that has no queues allocated for their traffic
class.
You can put traffic classes into a group to create a hierarchy of scheduler nodes and
queues. Organizing traffic into multiple traffic-class groups enables you to manage and
shape traffic—by service class, for example—when the traffic classes are distributed
across different VCs. A traffic-class group contains one or more traffic classes, but a
particular traffic class can belong only to a single group—either the default group or one
named group.
You can configure an auto-strict group and up to three extended traffic-class groups.
You must put traffic classes that require strict-priority scheduling in the auto-strict group.
You can optionally put traffic classes that need a separate round robin (for example,
video) in an extended group.
A traffic class that is not contained in any named group is considered to belong to the
default group. Traffic classes are placed in the default traffic-class group when the
classes are configured—you can then move a class to another traffic-class group. When
you delete a traffic-class from a named group, the class is automatically moved to the
default traffic-class group. ATM VC nodes that are configured in the default group (which
is the factory default configuration) receive backpressure from the segmentation and
reassembly (SAR) feature in the default qos-mode-port node.
Traffic-class groups are global in scope by default. However, you might want to manage
certain traffic classes through particular line modules. If you have already created a
traffic-class group, you can subsequently specify a slot number to create a local instance
of the group that is restricted to the module occupying that slot. Characteristics configured
for the local group on the line module override those of the global group, for only that
line module. Traffic classes in a globally scoped traffic-class group cannot belong to any
other group. Traffic classes in a local traffic-class group cannot belong to any other group.
Configuring Traffic Classes That Define Service Levels on page 14
Configuring Traffic-Class Groups That Define Service Levels on page 15
The router supports up to eight global traffic classes. Each traffic class can appear in
only one traffic-class group. If not explicitly added to a traffic-class group, the traffic
class is considered to be ungrouped.
To configure a traffic class:
Create a traffic class by assigning a name that represents the type of service and enter
1.
Traffic Class Configuration mode.
host1(config)#traffic-class low-loss1
host1(config-traffic-class)#
The traffic class name can be up to 31 characters. It cannot include spaces.
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