Dell PowerEdge FN I/O Module Command Line Reference Guide 9.10(0.0)

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wred ecn

To indicate network congestion, rather than dropping packets, use explicit congestion notification (ECN).

Syntax

wred ecn

To stop marking packets, use the no wred ecn command.

Defaults

none

Command Modes

CONFIGURATION (conf-qos-policy-out)

Supported Modes

Full–Switch

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 FN IOM.
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 traffic 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 configured 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 configured on the router.

Related Commands

wred-profile — creates a WRED profile and name that profile.