Version Description
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.
wred weight
Configure the weight factor for computation of average-queue size. This weight value applies to front-
end ports. This mechanism to configure a weight for WRED and ECN functionality for front-end ports is
supported on the S6000 and Z9000 platforms.
S6000
Syntax
[no] wred weight number
Parameters
weight Define the weight factor to be used for computation of the
WRED average-queue size to either enable WRED to discard
packets or cause ECN to mark packets that exceed the
minimum threshold configured. This setting applies to front-
end ports only.
number Enter the weight as a number to be used to calculate the
average-queue size. The range is 1 to 15. The default is 0.
Default The default weight is zero.
1290
Quality of Service (QoS)
