Configuring Implicit And Explicit Constituent Selection For Shaping; Constituent Selection For Shared Shaping Overview - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - QUALITY OF SERVICE CONFIGURATION GUIDE 2010-09-22 Configuration Manual

CHAPTER 13
Configuring Implicit and Explicit
Constituent Selection for Shaping

Constituent Selection for Shared Shaping Overview

Copyright © 2010, Juniper Networks, Inc.
This chapter provides information for configuring implicit and explicit constituents on
the E Series router.
QoS topics are discussed in the following sections:
Constituent Selection for Shared Shaping Overview on page 103
Implicit Constituent Selection Overview on page 105
Configuring Implicit Constituents for Simple or Compound Shared Shaping on page 110
Explicit Constituent Selection Overview on page 111
Configuring Explicit Constituents for Simple or Compound Shared Shaping on page 115
Shared shaping supports both implicit and explicit constituent selection. Implicit
constituent selection is the easier of the two methods and works well for most cases.
With implicit selection, you configure a shared-shaping rate on the best-effort node or
queue and QoS locates the other constituents automatically.
Use explicit constituent selection when you want to shape a subset of the interface traffic
to the shared rate. An example of this is when you want the sum of best-effort and voice
traffic to be shaped to the shared rate, but want video traffic to be exempt from the
shared-shaping rate.
Active constituents are selected either implicitly by QoS or explicitly by the user. Active
constituents of the simple shared shaper can be any node and queues in named
traffic-class groups. Active constituents of the compound shared shaper can be nodes
or queues. If you choose a node as an active constituent, queues above it are not active
constituents.
Inactive constituents are queues that are stacked above an active node or nodes stacked
below active queues. For both of these situations, the shared shaper controls the active
constituents, and the legacy scheduler indirectly controls the inactive constituents to
achieve the shared rate. The other case for inactive constituents is when you use explicit
constituent selection and some of the nodes and queues are explicitly not included in
the shared shaper.
103