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

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Figure 2: Packets Dropped as Queue Length Increases
WRED is an extension of RED that allows you to assign different RED drop thresholds
to each color of traffic. The router assigns a color to each packet. Committed means
green, conformed means yellow, and exceeded means red. When the queue fills
above the exceeded threshold, the router drops red packets, but still queues yellow
and green packets. When the queue fills above the conformed drop threshold, the
router queues only green packets.
Related Topics
Configuring RED on page 27
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Configuring WRED on page 31
Configuring RED
Each line module supports a default drop profile and 15 configurable drop profiles.
You can configure the default drop profile on all E Series line modules except for the
ES2 10G LM.
To configure RED:
1.
Create a drop profile and enter Drop Profile Configuration mode.
host1(config)# drop-profile internetDropProfile
host1(config-drop-profile)#
You can configure up to 16 drop profiles.
2.
Set the average-length exponent, which specifies the exponent used to weight
the average queue length over time, controlling WRED responsiveness.
host1(config-drop-profile)# average-length-exponent 9
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Specifying an average-length exponent enables the RED average queue length
computation.
Configuring RED
■ 27
Chapter 4: Configuring Dropping Behavior with RED and WRED