Reference Guide

Version
8.3.19.0
Introduced on the S4820t.
Version 8.3.11.1 Introduced on the Z9000.
Version 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 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 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.
wred-profile
Create a WRED profile and name the profile.
S4820T
Syntax
wred-profile wred-profile-name
To remove an existing WRED profile, use the no wred-profile command.
Parameters
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 five 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.
Defaults The five pre-defined WRED profiles. When you configure a new profile, the
minimum and maximum threshold defaults to predefined wred_ge_g values.
Quality of Service (QoS)
1377