Configuring Strict-Priority Scheduling; Strict-Priority And Relative Strict-Priority Scheduling Overview - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - QUALITY OF SERVICE CONFIGURATION GUIDE 2010-09-22 Configuration Manual

CHAPTER 8

Configuring Strict-Priority Scheduling

Strict-Priority and Relative Strict-Priority Scheduling Overview

Copyright © 2010, Juniper Networks, Inc.
This chapter provides information for configuring strict-priority scheduling.
QoS topics are discussed in the following sections:
Strict-Priority and Relative Strict-Priority Scheduling Overview on page 57
Comparison of True Strict Priority with Relative Strict Priority Scheduling on page 59
Configuring Strict-Priority Scheduling on page 63
Configuring Relative Strict-Priority Scheduling for Aggregate Shaping Rates on page 65
You can configure one or more strict-priority queues per interface. Strict-priority scheduling
is implemented with a special strict-priority scheduler node that is stacked directly above
the port. Queues stacked on top of the strict-priority scheduler node always get bandwidth
before other queues.
You can configure only one node at the first scheduler level as strict priority. If any node
or queue above the strict-priority node has packets, it is scheduled next. If multiple queues
above the strict-priority node have packets, the HRR algorithm selects which strict-priority
queue is scheduled next.
Figure 11 on page 58 illustrates an example of a QoS scheduler's hierarchy.
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