Users Guide

Version Description
9.2(1.0) Introduced on the Z9500.
9.0.2.0 Introduced on the S6000.
8.3.19.0 Introduced on the S4820t.
8.3.11.1 Introduced on the Z9000.
8.3.7.0 Introduced on the S4810.
Usage Information
When you enable wred ecn, and the number of packets in the queue is below the minimum threshold, packets
are transmitted per the usual WRED treatment.
When you enable wred ecn, and the number of packets in the queue is between the minimum threshold and the
maximum threshold, one of the following two scenarios can occur:
• If the transmission endpoints are ECN-capable and trac is congested, and the WRED algorithm determines
that the packet should have been dropped based on the drop probability, the packet is transmitted and marked
so the routers know the system is congested and can slow transmission rates.
• If neither endpoint is ECN-capable, the packet may be dropped based on the WRED drop probability. This
behavior is the identical treatment that a packet receives when WRED is enabled without ECN congured on
the router.
When you enable wred ecn, and the number of packets in the queue is above the maximum threshold, packets
are dropped based on the drop probability. This behavior is the identical treatment a packet receives when WRED
is enabled without ECN congured on the router.
Related Commands
• wred-prole — creates a WRED prole and name that prole.
wred weight
Congure the weight factor for computation of average-queue size. This weight value applies to front-end ports. This mechanism to
congure a weight for WRED and ECN functionality for front-end ports is supported on the S6000 and Z9000 platforms.
Syntax
[no] wred weight number
Parameters
weight Dene the weight factor to be used for computation of the WRED average-queue size to
either enable WRED to discard packets or cause ECN to mark packets that exceed the
minimum threshold congured. This setting applies to front-end ports only.
number Enter the weight as a number to be used to calculate the average-queue size. The range
is 1 to 15. The default is 0.
Default The default weight is zero.
Command Modes QOS-POLICY-OUT mode
Command History
Version Description
9.10(0.0) Introduced on the S6100-ON.
1306 Quality of Service (QoS)