From: Chris Lewis (chrlewiscsco@gmail.com)
Date: Thu Jun 29 2006 - 13:13:42 ART
Just a note of caution here. The shaper can only utilize the Be tokens if
credit has been built up, meaning that the shaper has been transmitting at
below CIR for a period of time. Be does not allow you to constantly transmit
at a rate above CIR, it is only available if traffic has dropped below CIR.
Over time, you should still acerage out at CIR.
Chris
On 6/29/06, Elias Chari <elias.chari@gmail.com> wrote:
>
> 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
> > >>
> >
> >>_______________________________________________________________________
> > >>Subscription information may be found at:
> > >>http://www.groupstudy.com/list/CCIELab.html
> >
> > _______________________________________________________________________
> > Subscription information may be found at:
> > http://www.groupstudy.com/list/CCIELab.html
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
This archive was generated by hypermail 2.1.4 : Sat Jul 01 2006 - 07:57:34 ART