RE: Priority Queuing question

From: simon hart (simon@harttel.com)
Date: Mon Nov 14 2005 - 12:37:37 GMT-3


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



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