Configuring An Assured Rate For A Scheduler Node Or Queue; Figure 10: Hierarchical Assured Rate; Configuring The Hrr Weight For A Scheduler Node Or Queue - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - QUALITY OF SERVICE CONFIGURATION GUIDE 2010-09-22 Configuration Manual

JunosE 11.3.x Quality of Service Configuration Guide
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Configuring an Assured Rate for a Scheduler Node or Queue

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bandwidth-on-demand. Eventually, this complicated manual recalculation process
becomes unreasonable and virtually impossible.
HAR replaces the manual recalculation process by directing the router to dynamically
calculate the assured rate for a scheduler node based on the sum of the assured rates
of all its child nodes and queues. For example, you might use HAR to increase the effective
weight of an ATM-VC scheduler node when a video queue is created, and to later restore
the effective rate of the node when the video queue is deleted.
HAR is applicable only to level 1 and level 2 scheduler nodes, and is not applicable to
queues or ports. When you configure HAR, the changes take place immediately. When
you disable HAR, the scheduler node's previous weight is restored.
Figure 10 on page 54 shows an application of HAR for VC nodes. In the example, VCs,
which are configured for HAR, are stacked over virtual path (VP) nodes. The VP nodes
are in turn stacked over an OC-3 ATM port. Each VC has a best-effort data queue, which
currently has an assured rate of 20 Kbps. The VCs share equal portions of their parent
VP's bandwidth. However, when the video queue is added to VC2, HAR enables VC2's
share of the VP bandwidth to increase in proportion to the 1-Mbps video queue that was
created. The bandwidth of sibling VC nodes, which have only a data queue, is decreased
in equal proportions.

Figure 10: Hierarchical Assured Rate

Configuring an Assured Rate for a Scheduler Node or Queue on page 54
Configuring the HRR Weight for a Scheduler Node or Queue on page 56
You can configure the effective weight of the scheduler node or queue by configuring a
static assured rate or a hierarchical assured rate (HAR). HAR dynamically adjusts the
available bandwidth for a scheduler node based on the creation and deletion of other
scheduler nodes.
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