Reference Guide

Version Description
9.3.0.0 Introduced on the S6000 and Z9000 platforms
Usage Information If the average queue size is more than the maximum threshold of WRED, the
packet is dropped. If the average queue size is between the minimum and
maximum threshold values, the decision to drop or queue the packet is taken
based on the packet drop probability. The probability that a packet is dropped
depends on the minimum threshold, maximum threshold, and mark probability
denominator.
Example
Dell(conf-qos-policy-out)# wred weight 5
wred ecn
To indicate network congestion without dropping packets, use explicit congestion notification (ECN).
C9000 Series
Syntax
wred ecn
To stop marking packets, use the no wred ecn command.
Defaults none
Command Modes QOS-POLICY-OUT mode
Command History
This guide is platform-specific. For command information about other platforms,
refer to the relevant Dell Networking OS Command Line Reference Guide.
The following is a list of the Dell Networking OS version history for this command.
Version Description
9.9(0.0) Introduced on the C9010.
9.2(1.0) Introduced on the Z9500.
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
scenarios can occur:
• If the transmission endpoints are ECN-capable and traffic is congested, and the
WRED algorithm determines that the packet should have been dropped based
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Quality of Service (QoS)