Configuring Wred; Configuring Wred Through Two Methods; Wred Parameters - 3Com MSR 50 Series Configuration Manual

Configuring WRED

Configuring WRED
through Two Methods

WRED Parameters

Figure 474 Relation between WRED and queue mechanism
Associating WRED with WFQ, the flow-based WRED can be realized. Because
different flow has its own queue during packet classification, the flow with small
traffic always has a short queue length, so the packet dropping probability will be
small. The flow with high traffic will have the longer queue length and will drop
more packets, so we can protect the benefits of the flow with small traffic.
Configure on interface: configure WRED parameters on the interface and
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enable WRED. This configuration applies only on layer 3 router interface.
Configure WRED table: configure WRED table under system view and apply it
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on the interface. This configuration applies only to layer 2 interface cards
having 16 or 24 interfaces.
Pre-define the parameters below before configuring WRED:
Maximum limitation and minimum limitation of queue length: when the
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average queue length is less than the minimum limitation, no packet is
dropped. When average queue length is between maximum limitation and
minimum limitation, the packet will be dropped randomly. The longer the
length of queue, the higher the dropping probability is. When the length of
queue exceeds the maximum limitation, all the incoming packets will be
dropped.
Drop precedence: the parameters referred to when dropping packets are
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defined as follows - 0 is red packet, 1 is yellow packet, and 2 is green packet.
The red packet is dropped by precedence.
Index to calculate average queue length: the larger the index, the more
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sensitive it is to real-time change of queue when calculating the average queue
length.
Configuring WRED 1685