RE: Priority Queuing question

From: simon hart (simon@harttel.com)
Date: Mon Nov 14 2005 - 14:12:10 GMT-3


Hi Bob,

Understood and agreed. It polices under congestion conditions

Simon

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of Bob
Sinclair
Sent: 14 November 2005 16:23
To: simon hart; ccielab@groupstudy.com
Subject: Re: Priority Queuing question

Simon,

Perhaps I misunderstood your comment, but just to be clear: the MQC
priority
command will police prioritized flows only under conditions of congestion.
But the flows will take all the bandwidth they require otherwise. As long
as
the bandwidth is available, the priority command does not police. If you
want to set a hard cap on prioritized traffic, you will need to add a police
command. Some (othterwise) very good documentation is wrong on this point.
Try labbing it up.

HTH,

Bob Sinclair
CCIE #10427, CCSI 30427
www.netmasterclass.net

  ----- Original Message -----
  From: simon hart
  To: steven richards ; ccielab@groupstudy.com
  Sent: Monday, November 14, 2005 10:37 AM
  Subject: RE: Priority Queuing question

  Hi Steven,

  The commands below will guarantee 128kbps and no more, there is no burst
  above 128kbps.

  The priority command has two functions, one is to prioritise the packets
  assigned to this queue, that is they will be the first out of the
interface.
  The second function is to police the packets to the bandwidth required.

  Now the show policy map

  Bandwidth 128 (kbps) Burst 3200 (Bytes)

  is showing you what the committed burst rate is, not the excess burst.

  MQC tc in this scenario defaults to 200ms, therefore 128000 *.2 = 25600.
  Convert to bytes 25600 /8 = 3200 bytes. Therefore for each 200ms, the
  policer will allow 25600 bits to be sent, and thus 128kbps no more no less

  HTH

  Simon

  -----Original Message-----
  From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
  steven richards
  Sent: 14 November 2005 04:34
  To: ccielab@groupstudy.com
  Subject: Priority Queuing question

    Hello,

  I am trying to use priority queueing beacuse I am interested in
guarenteing
  a certain amount of bandwidth, withought going over the guereenteed
  bandwidth. One thing I noticed is that with configuring priority queueing
  there appears to be a burst automatically configured. Is there a way to
just
  configure priority queueing withought that autoconfugred burst ?

    Thanks,

  R2#show policy-map interface e0/0
  Ethernet0/0

    Service-policy output: QOS

      Class-map: PREC2 (match-all)
        0 packets, 0 bytes
        5 minute offered rate 0 bps, drop rate 0 bps
        Match: ip precedence 2
        Queueing
          Strict Priority
          Output Queue: Conversation 264
          Bandwidth 128 (kbps) Burst 3200 (Bytes) <----- Burst
automatically
  configured ?
          (pkts matched/bytes matched) 0/0
          (total drops/bytes drops) 0/0

  _________________________________________________________________
  Express yourself instantly with MSN Messenger! Download today - it's FREE!
  http://messenger.msn.click-url.com/go/onm00200471ave/direct/01/

  _______________________________________________________________________
  Subscription information may be found at:
  http://www.groupstudy.com/list/CCIELab.html
  --
  No virus found in this incoming message.
  Checked by AVG Free Edition.
  Version: 7.1.362 / Virus Database: 267.13.0/167 - Release Date: 11/11/2005

  --
  No virus found in this outgoing message.
  Checked by AVG Free Edition.
  Version: 7.1.362 / Virus Database: 267.13.0/167 - Release Date: 11/11/2005

  _______________________________________________________________________
  Subscription information may be found at:
  http://www.groupstudy.com/list/CCIELab.html



This archive was generated by hypermail 2.1.4 : Thu Dec 01 2005 - 09:12:06 GMT-3