Defining Service Levels With Traffic Classes And Traffic-Class Groups; Chapter 2 Defining Service Levels With Traffic Classes And Traffic-Class Groups; Traffic Class And Traffic-Class Groups Overview; Best-Effort Forwarding - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - QUALITY OF SERVICE CONFIGURATION GUIDE 2010-09-22 Configuration Manual

CHAPTER 2
Defining Service Levels with Traffic
Classes and Traffic-Class Groups

Traffic Class and Traffic-Class Groups Overview

Best-Effort Forwarding

Copyright © 2010, Juniper Networks, Inc.
This chapter provides information for configuring traffic classes and traffic-class groups
on the E Series router.
QoS topics are discussed in the following sections:
Traffic Class and Traffic-Class Groups Overview on page 13
Configuring Traffic Classes That Define Service Levels on page 14
Configuring Traffic-Class Groups That Define Service Levels on page 15
Monitoring Traffic Classes and Traffic-Class Groups for Defined Levels of
Service on page 16
A traffic class is a systemwide collection of buffers, queues, and bandwidth that you can
allocate to provide a defined level of service to packets in the traffic class.
A traffic class corresponds to what the IETF DiffServ working group calls a traffic class
in RFC 2597—Assured Forwarding PHB Group (June 1999).
Traffic classes are global to the router. Packets are:
Classified into a traffic class on ingress or egress by input policies
Queued on fabric queues that are specific to the traffic class
Queued on the egress line module on queues that are specific to the traffic class
Scheduled for transmission by the scheduler
The router has a default traffic class called best-effort. You cannot delete this class. You
can add the best-effort class to a traffic-class group. The router assigns packets to the
best-effort class in each of the following cases:
You do not create any other traffic classes.
Packets are not classified into a traffic class.
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