From: Elias Chari (elias.chari@gmail.com)
Date: Thu Jun 29 2006 - 10:30:46 ART
Andy,
It is when you configure shape peak 96000 (not average) that you get upto
192k.
If not specified bc and be default to the same value, then peak = 2*CIR as
per the formula. Also if only cir and bc are specified the bc value is used
for be
Rack1R1#sh policy-map int s0/1
Serial0/1
Service-policy output: testB
Class-map: testB (match-all)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: any
Queueing
Output Queue: Conversation 265
Bandwidth 84 (kbps) Max Threshold 64 (packets)
(pkts matched/bytes matched) 0/0
(depth/total drops/no-buffer drops) 0/0/0
Traffic Shaping
Target/Average Byte Sustain Excess Interval Increment
Rate Limit bits/int bits/int (ms) (bytes)
*192000/96000 1992 7968 7968 83 1992*
Adapt Queue Packets Bytes Packets Bytes Shaping
Active Depth Delayed Delayed Active
- 0 0 0 0 0 no
Class-map: class-default (match-any)
0 packets, 0 bytes
5 minute offered rate 0 bps, drop rate 0 bps
Match: any
On 6/29/06, Anderson Mota Alves <mota_anderson@hotmail.com> wrote:
>
> Hi Petr,
>
> Based on your explanation below it's more clear to me that you cannot mix
> "priority" and "shape" because one is for policing and the other for
> shaping purposes.
>
> But I've been seaching in cisco webpage and from the link below it says:
>
> You can specify two types of traffic shaping; average rate shaping and
> peak rate shaping. Average rate shaping limits the transmission rate to
> the CIR. Using the CIR ensures that the average amount of traffic being
> sent conforms to the rate expected by the network.
>
> Peak rate shaping configures the router to send more traffic than the
> CIR. To determine the peak rate, the router uses the following formula:
>
> peak rate = CIR(1 + Be / Bc)
>
> http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_command_reference_chapter09186a0080087f34.html#wp1077189
>
>
> But how do I know that configuring the "shape average 96000" I can send
> traffic up to 192 kbps?
>
> Thanks,
>
> Andy
>
> --------------------------------------------------------------------
>
> From: "Petr Lapukhov" <petr@internetworkexpert.com>
> To: "Anderson Mota Alves" <mota_anderson@hotmail.com >,
> <ccielab@groupstudy.com>
> Subject: Re: Doubt in QoS
> Date: Thu, 29 Jun 2006 14:42:55 +0400
> >The first one seems to be "almost" correct:
> >
> >You shape (limit) traffic up to 96kbit here - the only problem
> >is "peak" keyword. This configuration actually permits you to send
> >traffic up to 192kbit by default. So I would better do something
> >like:
> >
> >...
> >class CRITICAL
> > shape average 96000
> > bandwidth 84
> >...
> >
> >This way you guarantee 84k in case of congestion,
> >and limit flow up to 96k in any case.
> >
> >As for your second example - you can not mix priority and bandwidth:
> >
> >R6(config-pmap-c)#priority 64
> >R6(config-pmap-c)#bandwidth 92
> >Must remove priority configuration from this class first.
> >
> >Also remember that you cannot mix "priority" and "shape",
> >and dont forget that "priority" actually police your traffic in
> >case of congestion.
> >
> >Finally, you may choose "police" instead of "shape", with
> >your first example. The decision should depend on task wording.
> >
> >HTH
> >---
> >Petr Lapukhov, CCIE #16379
> >petr@internetworkexpert.com
> >
> >Internetwork Expert, Inc.
> >http://www.InternetworkExpert.com <http://www.internetworkexpert.com/>
> >Toll Free: 877-224-8987
> >Outside US: 775-826-4344
> >
> >----- Original Message ----- From: "Anderson Mota Alves"
> ><mota_anderson@hotmail.com>
> >To: <ccielab@groupstudy.com>
> >Sent: Thursday, June 29, 2006 2:16 PM
> >Subject: Doubt in QoS
> >
> >
> >>Hi gurus, The question I need to complish is the following:
> >>
> >>Which configuration provides the mission-critical traffic class
> >>with a
> >>minimum
> >>
> >>bandwidth guarantee of 84 kbps and a maximum upper bandwidth limit
> >>of 96
> >>
> >>kbps?
> >>
> >>I think I have to solution for this one but I'm not sure if I'm
> >>right:
> >>
> >>policy-map shape
> >>class mission-critical
> >>bandwidth 84
> >>shape peak 96000
> >>
> >>or
> >>
> >>policy-map shape
> >>class mission-critical
> >>priority 64
> >>bandwidth 96
> >>
> >>Could anyone tell me which one I could use? Also I don't know if in
> >>order
> >>to use the shape peak I need to first configure the shape cir ir
> >>order to
> >>make sure that this will be the peak above the Cir.
> >>
> >>Thanks
> >>
> >>_______________________________________________________________________
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