From: Edwards, Andrew M (andrew.m.edwards@boeing.com)
Date: Mon Sep 19 2005 - 17:27:38 GMT-3
Good luck Leigh!
To those of us that are QOS challenged, myself included, I'd like to
request one more bit of information regarding the MQC answer and an
alternative thought to see if there really is a difference.
Without having IE workbook I've got some variables, but here goes.
If it said convert to MQC:
rate-limit input access-group 101 128000 2000 2000 conform-action
transmit exceed-action set-prec-transmit 0
My first thought is this:
class-map match-all ACL101
match ip access 101
policy-map QOS
class ACL101
police 128000 2000 2000 conform transmit exceed set-prec-tra 0
int xxx
service in QOS
service out QOS
My reasoning is that I am not doing 2 rate policing (CIR and PIR). In
fact there is no bursting.
I believe above would be correct as well.
In fact, I think police bps bc be .... Is equivalent to police cir bc be
Its only when you explicitly need a two rate policer, or you need to
support extended bursting that you would definitely choose cir/pir
police option.
Anyone else have a different view?
Andy
-----Original Message-----
From: Leigh Harrison [mailto:ccileigh@gmail.com]
Sent: Monday, September 19, 2005 9:26 AM
To: simon hart
Cc: Group Study
Subject: Re: QOS IE Workbook Lab 13 Q.9.1
All,
Having had a damn good read through the doc CD, I'd like to retract my
earlier mail, and class my writing as total crap!!
Wish me luck on Thursday....
LH
simon hart wrote:
>Hi All,
>
>I would welcome comments on this task within the IE workbook. I think
>that the question and answer may be incorrect,
>
>The task itself is to change various CAR statements into MQC. The
>problem I see here is that CAR and MQC have different policing
>algorithms and thus to mimic each statement is extremely diffilcult.
>
>One is asked to achieve the following
>
>rate-limit input access-group 101 128000 2000 2000 conform-action
>transmit exceed-action set-prec-transmit 0
>
>The answer given for the MQC statement is as follows
>
>police cir 128000 bc 2000 be 2000
>conform-action transmit
>exceed-action set-prec-transmit 0
>
>Now I believe this answer to be wrong for the following reasons. When
>the bc and be are equal within CAR there is no burst, thus no exceed
>action. Although the CLI for CAR will accept the 'exceed-action
>set-prec-transmit 0' there is in fact no burst and thus no exceed
>action. However when entering the command within MQC we have a problem
>if we mimic the CAR statements. Because MQC uses a single rate three
>colour marker it has two discrete token buckets. By setting bc and be
>we are setting the values for each token bucket and hence enabling an
>exceed action. Therefore we are allowing a burst action that will set
>the precedence of 0, however the CAR statement does not allow that.
>
>I believe the correct answer would be
>
>police cir 128000 bc 2000
>conform-action transmit
>exceed-action drop
>
>
>One is also asked to perform the following
>
>rate-limit input access-group 102 256000 4000 8000 conform-action
>transmit exceed-action set-prec-transmit 0
>
>The answer given for this in MQC is:
>
>police cir 256000 bc 4000 be 8000
>conform-action transmit
>exceed-action set-prec-transmit 0
>
>For similar reasons that I gave above I believe that this answer is
>also incorrect. I believe that the correct answer should be
>
>police cir 256000 bc 4000 be 4000
>conform-action transmit
>exceed-action set-prec-transmit 0
>violate-action drop
>
>The CAR statement implies a burst of 4000 (the difference between 4000
>and 8000), therefore within MQC bc and be should be 4000 a piece. In
>addition one has to create a violate-action otherwise the circuit will
>never be limited to an average of 256000 as the exceed action will be
>used on all out of contract traffic.
>
>Other views most welcome
>
>Simon Hart
>
>
>
>
>--
>No virus found in this outgoing message.
>Checked by AVG Anti-Virus.
>Version: 7.0.344 / Virus Database: 267.11.1/104 - Release Date:
>16/09/2005
>
>_______________________________________________________________________
>Subscription information may be found at:
>http://www.groupstudy.com/list/CCIELab.html
This archive was generated by hypermail 2.1.4 : Sun Oct 02 2005 - 14:40:15 GMT-3