Users Guide
wred ecn
To indicate network congestion, rather than dropping packets, use explicit congestion notication (ECN).
S3048–ON
Syntax
wred ecn
To stop marking packets, use the no wred ecn command.
Defaults none
Command Modes CONFIGURATION (conf-qos-policy-out)
Command History
This guide is platform-specic. 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
9.8(0.0P5) Introduced on the S4048-ON.
9.8(0.0P2) Introduced on the S3048-ON.
9.7(0.0) Introduced on the S6000-ON.
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 trac 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
congured 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 congured on the router.
Related Commands
wred-prole — creates a WRED prole and name that prole.
1250
Quality of Service (QoS)