From: Bob Sinclair (bsin@cox.net)
Date: Sun Jul 18 2004 - 20:41:48 GMT-3
Andy,
Cisco's implementation of WFQ is IP Precedence - aware. Not sure how it
relates to tail drop, though Odom is usually pretty reliable. Here is a
link to more on the WFQ algorithm:
http://www.cisco.com/warp/public/732/Tech/wfq/
Bob Sinclair
CCIE #10427, CISSP, MCSE
www.netmasterclass.net
----- Original Message -----
From: "Andy Mrozek" <AndyMrozek@yahoo.com>
To: <ccielab@groupstudy.com>
Sent: Sunday, July 18, 2004 5:13 PM
Subject: WFQ Clarification
> Question : Does WFQ -- queuing tool -- act on previously marked layer 3
> headers such as DSCP / Ip Prec
>
> Info Source: In Dqos cisco press book there is the the following quote on
> page 257 : " WFQ differs from PQ and CQ in several significant ways. The
> first and most obvious difference is that WFQ does not allow
classification
> options to be configured. WFQ classifies packets based on flows. A "Flow"
> consists of all packets that have the same source / destination port
numbers
> " end quote.... But then in the table on page 272 where it lists the
> charachteristics of WFQ functions and features it states this : "
> Classifies without configuration , based on source / Destination IP
address
> / port / protocol type (udp/tcp) and TOS. And says it has a modified tail
> drop . Drop policy..
>
>
> I am trying to determine what " Modified Tail Drop" means in the context
of
> Dqos book on page 272 .. And say I mark via CB marking a flow to Critical
> Accounting webserver at 10.10.10.10 and set all packets with IP
destination
> in them with "Critical" IP prec ... Will WFQ look at this flow differently
> than a flow that has the same volume say to a web server that is marked "
> Routine" ????
>
> Thanks
>
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