Juniper JUNOSE 11.1.X - QUALITY OF SERVICE CONFIGURATION GUIDE 3-21-2010, Configuration Manual

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rate. The port will not become congested, and the latency caused by the round-robin
behavior of both the HRR and cell schedulers is nominal. In these undersubscribed
conditions, the latency of a strict-priority queue within each VC is calculated as if the
VC were draining onto a wire with bandwidth equal to the shaped rate.
Relative strict priority is carried out in the HRR scheduler on E Series ASIC line
modules.
Related Topics
Comparison of True Strict Priority with Relative Strict Priority Scheduling on
page 61
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■
Configuring Strict-Priority Scheduling on page 66
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Configuring Relative Strict-Priority Scheduling for Aggregate Shaping Rates on
page 68
Comparison of True Strict Priority with Relative Strict Priority Scheduling
This section explains how the HRR and SAR schedulers handle true strict-priority
and relative strict-priority configurations.
Schedulers and True Strict Priority
In the strict-priority configuration in Figure 12 on page 62, the queues stacked above
the single strict priority scheduler node make up a round-robin separate from the
nonstrict queues. All strict queues are drained to completion first, and any residual
bandwidth is allocated to the nonstrict round-robin.
Comparison of True Strict Priority with Relative Strict Priority Scheduling
■ 61
Chapter 8: Configuring Strict-Priority Scheduling