From: Tim (ccie2be@nyc.rr.com)
Date: Mon Sep 12 2005 - 10:54:04 GMT-3
Stefan,
Have a look at this link:
http://www.cisco.com/warp/public/105/priorityvsbw.html
Based on my read of this doc, it seems more and more to me that having both
the bandwidth and the priority command for the same class of traffic doesn't
make sense.
My reasoning is as follows:
During periods of congestion, the bandwidth and priority commands have
different and mutually exclusive behaviors. Based on this doc, the
bandwidth command allows traffic to exceed the allocated rate but the
priority command does not. Since both can't be true at the same time for
the same traffic, it seems to me both commands shouldn't not be configured
for the same traffic class.
Another difference is that the priority command is used for the purpose of
reducing latency and jitter. It fulfills this function by having priority
access to the hardware queue which is a fifo queue. This doc isn't clear on
exactly what that means but I take it to mean that if there's any traffic in
the priority queue, it will get serviced first (moved to the h/w queue) up
to point of the specified rate. Unlike the legacy priority-list and
priority-group feature, the MQC priority command won't starve the other
queue's.
I'd like to hear from others and either have my thinking confirmed or
corrected.
HTH, Tim
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Stefan Grey
Sent: Sunday, September 11, 2005 10:36 PM
To: jenseike@start.no; ccielab@groupstudy.com
Subject: RE: SV: Qos question (bandwidth,police).
Hi,
Thank you very much for your reply and for the link. But there is explained
just how the police and bandwidth commands are used separetely but not
together. I just need to find the difference between:
1.
policy-map LIMIT
class web
police 100000 conform-action transmit exceed action drop.
and
2.
policy-map LIMIT
class web
bandwidth 100
police 100000 conform-action transmit exceed action drop.
Could anybody tell something?? Because I don't see any. As I think during
the congestions both configs don't let traffic to be more than 100 M and
when there is no congestion there are no limiting in both case. Thanks.
>From: "Jens Petter Eikeland" <jenseike@start.no>
>Reply-To: "Jens Petter Eikeland" <jenseike@start.no>
>To: "'Stefan Grey'" <examplebrain@hotmail.com>, <ccielab@groupstudy.com>
>Subject: SV: Qos question (bandwidth,police).
>Date: Sun, 11 Sep 2005 23:28:21 +0200
>
>Hi ,
>
>I am sure you will get a better understanding of this two technologies by
>reading findings yourselfe
>
>Here is a some good documents covering both technologies very vel
>
>http://www.cisco.com/en/US/tech/tk543/tk545/tech_design_guides_list.html
>
>Answer to your question is to use the policing command and conform it to
>100
>meg as in your example
>
>Jens Petter
>
>
>
>-----Opprinnelig melding-----
>Fra: nobody@groupstudy.com [mailto:nobody@groupstudy.com] Pe vegne av
>Stefan
>Grey
>Sendt: 11. september 2005 23:02
>Til: ccielab@groupstudy.com
>Emne: Qos question (bandwidth,police).
>
>It is needed to limit the input of some WEB traffic to 100 Megabyte.
>
>I saw such config in the book:
>policy-map LIMIT
>class web
>bandwidth 100
>police 100000 conform-action transmit exceed action drop.
>
>Whe could the bandwidth here be used. Whey to command are used together
>here.
>
>As I know police is really limiting traffic to 100 Mb. But bandwidth is for
>custom queuing.
>Could anybody comment this configuration???? What would be the difference
>between this config with or without bandwidth command.
>
>Thanks.
>
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