Hierarchical Class Of Service Overview - Juniper ACX1000 Configuration Manual

Hierarchical Class of Service Overview

Copyright © 2017, Juniper Networks, Inc.
Processing of Hierarchical Policers on page 928
Actions Performed for Hierarchical Policers on page 929
Hierarchical class of service (HCoS) is the ability to apply traffic schedulers and shapers
to a hierarchy of scheduler nodes. Each level of the scheduler hierarchy can be used to
shape traffic based on different criteria such as application, user, VLAN, and physical
port.
This allows you to support the requirements of different services, applications, and users
on the same physical device and physical infrastructure.
HCoS is implemented primarily using traffic classifiers at the ingress and hierarchical
schedulers and shapers at the egress.
A classifier is a filter that labels traffic at the device ingress based on configurable
parameters such as application or destination. Traffic is classified into what is called a
forwarding equivalence class (FEC). The FEC defines a class of traffic that receives
common treatment.
Schedulers, and their associated shapers, is the function that controls the traffic
bandwidth, jitter (delay variation), and packet loss priority at the egress of the device.
Hierarchical schedulers are used to apply multiple levels of scheduling and shaping with
each level applied to different classifications such as forwarding equivalence class, VLAN,
and physical interface (port) as shown in
Chapter 27: Configuring Class of Service
Figure 58 on page 934.
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