Quality Of Service Overview; Qos On The E Series Router Overview; Qos On The E Series Router - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - QUALITY OF SERVICE CONFIGURATION GUIDE 2010-09-22 Configuration Manual

CHAPTER 1

Quality of Service Overview

QoS on the E Series Router Overview

Copyright © 2010, Juniper Networks, Inc.
The quality of service (QoS) feature enables your E Series router to distinguish traffic
with strict timing requirements from traffic that can tolerate delay, jitter, and loss.
QoS topics are discussed in the following sections:
QoS on the E Series Router Overview on page 3
QoS Audience on page 4
QoS Platform Considerations on page 4
QoS Terms on page 5
QoS Features on page 7
Configuring QoS on the E Series Router on page 9
QoS References on page 9
QoS is a suite of features that configure queuing and scheduling on the forwarding path
of the Juniper Networks E Series Broadband Services Routers. QoS provides a level of
predictability and control beyond the best-effort delivery that the router provides by
default. Best-effort service provides packet transmission with no assurance of reliability,
delay, jitter, or throughput.
QoS as developed for E Series routers conforms to the IETF Differentiated Services
(DiffServ) model (RFCs 2597 and 2598). DiffServ networks classify packets into one of
a small number of aggregated flows or traffic classes for which you can configure different
QoS characteristics. The Juniper Networks QoS architecture extends DiffServ to support
edge features such as high-density queuing.
The E Series router supports:
IETF architecture for differentiated services
Assured forwarding per-hop-behavior (PHB) groups
Expedited forwarding PHB groups
The router supports configurable queuing and scheduling. It has an application-specific
integrated circuit (ASIC) scheduler that supports thousands of queues in a hierarchical
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