From: Mike Kraus \(mikraus\) (mikraus@cisco.com)
Date: Thu Jul 05 2007 - 15:40:00 ART
As a correction/clarification, Antonio correctly pointed out to me that
the frame-relay congestion commands are intended to be used on the
Frame-Relay DCE side (switch).
So, assuming you mean to use the TCP ECN capabilities, you need to use
the WRED ECN feature. If you are just looking to control the FECN/BECN
behavior in Frame-Relay, then use the frame-relay congestion management
commands. It's probably inappropriate to compare them in the way done
so below, since you are going to be doing them at different times for
different reasons.
I apologize for any confusion, and thank Antonio for pointing this out!
Thanks,
Mike
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Mike Kraus (mikraus)
Sent: Thursday, July 05, 2007 11:38 AM
To: darth router; ccielab@groupstudy.com
Subject: RE: ECN with congestion threshold
Note from the command reference:
The frame-relay congestion threshold ecn command applies only to
default FIFO traffic-shaping queues.
One ECN threshold applies to all traffic on a traffic-shaping queue.
You cannot configure separate thresholds for committed and excess
traffic.
However, if you do it at the interface level using frame-relay
congestion-management works differently:
Frame Relay congestion management is supported only when the interface
is configured with class-based weighted fair queuing (WFQ).
And, then you can have different threshold for committed and excess:
interface serial1
encapsulation frame-relay
frame-relay congestion-management
threshold ecn be 0
threshold ecn bc 20
threshold de 40
This is important because:
"When the output interface queue reaches or exceeds the ECN excess
threshold, all Frame Relay DE bit packets on all PVCs crossing that
interface will be marked with FECN or BECN, depending on their direction
of travel. When the queue reaches or exceeds the ECN committed
threshold, all Frame Relay packets will be marked with FECN or BECN." -
Frame Relay Configuration guide.
Lastly, with random-detect ecn, you are also enabling WRED in the
process, and doesn't really directly relate to DE (unless matching on
fr-de in your class). Not saying this is good/bad, just different.
So, assuming it doesn't matter what queuing strategy is employed, and
you don't care explicitly about how committed vs. excess/DE traffic is
treated, then yes, I'd say it wouldn't matter.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
darth router
Sent: Thursday, July 05, 2007 6:53 AM
To: ccielab@groupstudy.com
Subject: ECN with congestion threshold
Do these two commands (FRTS and MQC) behave the same way?
frame-relay congestion threshold ecn 70
OR
Router(config)# *policy-map pol1*
Router(config-pmap)# *class class-default* Router(config-pmap)#
*bandwidth per 70*
Router(config-pmap-c)# *random-detect*
Router(config-pmap-c)# *random-detect ecn*
or would I need to shape on the MQC version to get the desired effect of
using ECN once the bandwidth threshold is hit? I am thinking they are
the same, but just want to make sure.
DR
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