Command Line Reference Guide

Quality of Service (QoS) | 1225
wred-ecn
Use Explicit Congestion Notification (ECN) to indicate network congestion, rather than dropping
packets.
Syntax
wred-ecn
Use the no wred-ecn command to stop marking packets.
Defaults
No default behavior or values
Command Modes
CONFIGURATION (conf-qos-policy-out)
Command
History
Usage
Information
When wred-ecn is enabled, and the number of packets in the queue is below the minimum threshold,
packets are transmitted per the usual WRED treatment.
When wred-ecn is enabled, and the number of packets in the queue is between the minimum threshold
and the maximum threshold, one of the following three 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 slo transmission
rates.
• If neither endpoint is ECN capable, the packet may be dropped based on the WRED drop
probability. This is the identical treatment that a packet receives when WRED is enabled without
ECN configured on the router.
• If the network is experiencing congestion, the packet is transmitted. No further marking is
required.
When wred-ecn is enabled, packets above the maximum threshold are marked with ECN bits and no
packets are dropped until the queue limit is reached.
Related
Commands
wred-profile
e
Create a WRED profile and name that profile.
Syntax
wred-profile wred-profile-name
To remove an existing WRED profile, use the no wred-profile command.
Parameters
Defaults
The five pre-defined WRED profiles. When a new profile is configured, the minimum and maximum
threshold defaults to predefined wred_ge_g values
Version 8.3.8.0 Introduced on S4810
wred-profile Create a WRED profile and name that profile
wred-profile-name
Enter your WRED profile name in character format (16 character maximum). Or
use one of the pre-defined WRED profile names. You can configure up to 26
WRED profiles plus the 5 pre-defined profiles, for a total of 31 WRED profiles.
Pre-defined Profiles:
wred_drop, wred-ge_y, wred_ge_g, wred_teng_y, wred_teng_g