From: Chee Chew Leong (cleong3@csc.com)
Date: Tue Oct 10 2006 - 06:15:59 ART
WRED will mark the ECN bit only after min threshold if the packet is ECN
capable which is negotiated between two end hosts. This will notify the
sending host to slow down the transmission.
If the packet is not ECN capable, it will drop as normal WRED behaviour.
"Jung-I Lin" <easyman.lin@gmail.com>
Sent by: nobody@groupstudy.com
10/10/2006 11:06 AM
Please respond to
"Jung-I Lin" <easyman.lin@gmail.com>
To
"CCIE GroupStudy" <ccielab@groupstudy.com>
cc
Subject
Question about WRED with ECN
Hi, Groups
I have a conceptual question in relate to WRED with Explicit Congestion
Notification(ECN).
As far as I understand, wred will drop all subsequent packets if the queue
reach the maximum threshold value.
But from Cisco Docs, I see it has a different beheavior if ECN is enable.
"If the number of packets in the queue is above the maximum
threshold,packets are dropped
based
on the drop probability. This is the identical treatment a packet receives
when WRED is enabled
without ECN configured on the router."
quoted from
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t/122t8/ftwrdecn.htm
I'm little bit confused with this, as you know if ECN is not enable with
WRED, it should drop all the packets if the queue is above the maximum
threshold.
This is "NOT" identical as enable WRED w/o ECN.
Or this is a typo?
Anyone can help clarify this?
TIA.
-- Thanks Best Regards,Jung-I Lin
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