Simple Shared Shaping For Triple-Play Networks; Figure 18: Simple Shared Shaping Over Atm - 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

Simple Shared Shaping for Triple-Play Networks

Figure 18: Simple Shared Shaping over ATM

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If you are configuring VP shared shaping, configure shared shaping on the best-effort
scheduler node for the VP. Shaping the best-effort scheduler node for the VP has the
effect of shaping all the VC best-effort queues for that VP. This enables you to retain the
advantages of per-VC queuing in the hierarchical scheduler.
If you are configuring VC shared shaping and the SAR is operating in low-CDV mode, we
recommend you configure the shared-shaping rate on the best-effort scheduler node
for the VP or VC. The router sets the SAR shaper for the VC or VP to match the
shared-shaping rate on VC and VP nodes in the hierarchical scheduler; this is usually the
desired behavior. A shared shaper configured on the best-effort queue does not trigger
the matching shaper in the SAR.
Simple shared shaping enables you to shape the logical interface to a single rate for
triple-play networks.
In Figure 18 on page 76, the AF traffic-class group contains the video traffic class. The EF
traffic-class group contains the voice traffic class. The best-effort and
better-than-best-effort traffic classes remain outside any traffic-class group. Because
the voice, video, and data queues are stacked in separate scheduler hierarchies, you must
use the shared shaper to shape the logical interface aggregate to a single rate.
In this example, VC 1 is configured for voice and data. VC 2 is configured for data and
video. VC 3 is configured for data, voice, and video. The shared shaper is configured on
the best-effort node or queue for VC 1; the corresponding voice queue for VC 1 shares the
configured rate.
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