RE: CEF and QOS

From: Victor Cappuccio (cvictor@protokolgroup.com)
Date: Sat Aug 19 2006 - 01:07:01 ART


Sorry for the spam but Michael, WRED is a Congestion Avoidance tool, that
means, that it would kill randomly queues Traffic ordered by priorities (TOS
of IP / (DSCP or IPP)) by a min/max threshold #todiscard, in case of a
congestion in the interface, this feature would kick in when the Queues (for
example created WFQ / I'm not sure if the Shaping Q also are affected by
RED, my logic says yes, but not have some routers to play today) are
starting to be congested.

There is a Nice RFC to read http://rfc.net/rfc2309.html

-----Mensaje original-----
De: Victor Cappuccio [mailto:cvictor@protokolgroup.com]
Enviado el: Viernes, 18 de Agosto de 2006 11:52 p.m.
Para: 'Michael Stout'; 'masterdt@yahoo.com'; 'ccielab@groupstudy.com'
Asunto: RE: CEF and QOS

Hi Guys, please take a look at this link

http://www.cisco.com/en/US/tech/tk39/tk824/technologies_tech_note09186a00800
94978.shtml

Regards
Victor.-

-----Mensaje original-----
De: nobody@groupstudy.com [mailto:nobody@groupstudy.com] En nombre de
Michael Stout
Enviado el: Viernes, 18 de Agosto de 2006 11:44 p.m.
Para: masterdt@yahoo.com; ccielab@groupstudy.com
Asunto: RE: CEF and QOS

I know of two ways to do wred.
The first, and i believe most preferable is to use MQC.
using wred with class based qos will require cef.
However, i am unable to find that requirement in the docs, currently.

The second is to use wred on the interface.
I don't think the interface method requires cef.

After some deliberation i think wred is a worthwihile queueing strategy
for circuits that experience a high number of output drops.

If anybody knows more about this subject or has used it effectivly in
production environments, I would be greatful to hear your valuable input.

Thank You.
Mike

  --------------------------------------------------------------------

  From: David Timmons <masterdt@yahoo.com>
  Reply-To: David Timmons <masterdt@yahoo.com>
  To: CCIElab <ccielab@groupstudy.com>
  Subject: CEF and QOS
  Date: Wed, 16 Aug 2006 08:51:42 -0700 (PDT)
  Hi,

  Just wondering if we have to worry about turning off CEF to get QOS
  parameters to work properly. For example, if we would like to
  configure explicit congestion notification for WRED, do we have to
  turn off CEF.

  Configuration:
  Policy-map WREDandECN
  class class-default
  bandwidth percent 22
  random-detect
  random-detect ecn

  s0/0
  encapsulation frame-relay
  service-policy out WREDandECN

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