From: darth router (darklordrouter@gmail.com)
Date: Sat Nov 22 2008 - 17:16:32 ARST
That's the way it works.
Would be nice if someone was to exactly explain why cisco created that
command and did it that way. I think it has to do with an arrangement with
your provider. Say, they guarantee you a rate of 512, but allow you a peak
rate of 1024, but if there is congestion, they will be able to drop that 2nd
512 of data. Regardless, your sending 1024 per interval. So depending on how
you marked your traffic, certain classes in that first 512 would be safe,
and anything else would be fair game for the service provider bit bucket in
case of congestion.
On Sat, Nov 22, 2008 at 9:59 AM, Hobbs <deadheadblues@gmail.com> wrote:
> Anyways, after all that yes I agree with your solution. I wonder what the
> experts think...
>
> On Sat, Nov 22, 2008 at 11:51 AM, Hobbs <deadheadblues@gmail.com> wrote:
>
> > Ok. I think I understand this a little better. Whether you configure
> "peak"
> > or "average" the following value is still always CIR. This will always be
> > the "average rate". You target rate will be set using default values if
> you
> > do not specify a Be. And it appears Be = Bc by default.
> >
> > R3(config-pmap-c)#shape ?
> > average configure token bucket: CIR (bps) [Bc (bits) [Be
> > (bits)]], send out Bc only per interval
> > peak configure token bucket: CIR (bps) [Bc (bits) [Be
> > (bits)]], send out Bc+Be per interval
> >
> > So if you want a peak rate of 512000, there are multiple things you can
> > configure since you are sending Bc+Be every interval. In fact you can:
> >
> > 1) set peak to 512000, Bc to 5120, Be of 0
> > 2) set peak to 384000, Bc to 3840, Be to 1280
> > 3) set peak to 256000, Bc to 2560, Be to 2560
> >
> > All of these (and many more combinations) set target rate to 512000.
> >
> > So if you are not asked to specify Bc or Be and can use any values for
> > them, there are many correct answers :)
> >
> >
> > On Sat, Nov 22, 2008 at 10:48 AM, Hobbs <deadheadblues@gmail.com> wrote:
> >
> >> I have noticed that too. When you configure shape peak, your target rate
> >> is doubled. In you example it is 1024000bps, but nowhere did you
> configure
> >> that. I don't really understand why that is...anybody? I have tested in
> my
> >> lab with shape peak 128000. It configures target rate to 256000, and I
> am
> >> able to push about ~240 traffic (not exactly 256 for some reason)
> through
> >> the interface.
> >>
> >>
> >> On Sat, Nov 22, 2008 at 6:00 AM, Huan Pham <pnhuan@yahoo.com> wrote:
> >>
> >>> Hi,
> >>>
> >>> I posted a similar question few months ago, and I got a very good
> answer
> >>> from Narbik. I also believe his answer is right.
> >>>
> >>> http://www.groupstudy.com/archives/ccielab/200806/msg01899.html
> >>>
> >>> However, today, I came accross an example in DOC CD, which left me
> >>> wondering, whether DOC CD example is wrong or not. I did come accross
> few
> >>> wrong example in the Doc CD before, and I believe this one is another
> one.
> >>>
> >>> Really need your opinion on this, to clear things up.
> >>>
> >>> Here's the link to the DOC CD:
> >>>
> >>>
> >>>
> http://www.cisco.com/en/US/docs/ios/qos/command/reference/qos_s1.html#wp1014690
> >>>
> >>> shape
> >>>
> >>> To specify average or peak rate traffic shaping, use the shape command
> in
> >>> class-map configuration mode. To remove traffic shaping, use the no
> form of
> >>> this command.
> >>>
> >>> shape {average | peak} cir [bc] [be]
> >>>
> >>> =================================================================
> >>>
> >>> The following example uses peak rate shaping to ensure a bandwidth of
> 300
> >>> kbps but allow throughput up to 512 kbps if enough bandwidth is
> available on
> >>> the interface:
> >>>
> >>> bandwidth 300
> >>> shape peak 512000
> >>>
> >>> =================================================================
> >>>
> >>>
> >>> In my opinion, this configuration will give a peak rate of 1024K,
> instead
> >>> of 512K.
> >>>
> >>> here's the config, and what the show policy interface output:
> >>>
> >>>
> >>> Rack1R1#
> >>> class-map match-all WWW
> >>> match protocol http
> >>>
> >>> policy-map SHAPE
> >>> class WWW
> >>> bandwidth 300
> >>> shape peak 512000
> >>>
> >>> interface Serial0/0
> >>> service-policy output SHAPE
> >>>
> >>> Rack1R1#sh policy-map interface
> >>> Serial0/0
> >>> Service-policy output: SHAPE
> >>> Class-map: WWW (match-all)
> >>> 0 packets, 0 bytes
> >>> 5 minute offered rate 0 bps, drop rate 0 bps
> >>> Match: protocol http
> >>> Queueing
> >>> Output Queue: Conversation 265
> >>> Bandwidth 300 (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)
> >>> 1024000/512000 3200 12800 12800 25 3200
> >>> Adapt Queue Packets Bytes Packets Bytes Shaping
> >>> Active Depth Delayed Delayed Active
> >>> - 0 0 0 0 0 no
> >>> Class-map: class-default (match-any)
> >>> 1 packets, 13 bytes
> >>> 5 minute offered rate 0 bps, drop rate 0 bps
> >>> Match: any
> >>>
> >>>
> >>> I think the solution should be, following. Any opinion please?
> >>>
> >>> bandwidth 300
> >>> shape peak 300000 37500 26500
> >>>
> >>> Rack1R1#show policy-map interface
> >>> Serial0/0
> >>> Service-policy output: SHAPE
> >>> Class-map: WWW (match-all)
> >>> 0 packets, 0 bytes
> >>> 5 minute offered rate 0 bps, drop rate 0 bps
> >>> Match: protocol http
> >>> Queueing
> >>> Output Queue: Conversation 265
> >>> Bandwidth 300 (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)
> >>> 512000/300000 8000 37500 26500 125 8000
> >>> Adapt Queue Packets Bytes Packets Bytes Shaping
> >>> Active Depth Delayed Delayed Active
> >>> - 0 0 0 0 0 no
> >>> Class-map: class-default (match-any)
> >>> 293 packets, 64409 bytes
> >>> 5 minute offered rate 0 bps, drop rate 0 bps
> >>> Match: any
> >>>
> >>>
> >>> Blogs and organic groups at http://www.ccie.net
> >>>
> >>> _______________________________________________________________________
> >>> Subscription information may be found at:
> >>> http://www.groupstudy.com/list/CCIELab.html
>
>
> Blogs and organic groups at http://www.ccie.net
>
> _______________________________________________________________________
> Subscription information may be found at:
> http://www.groupstudy.com/list/CCIELab.html
Blogs and organic groups at http://www.ccie.net
This archive was generated by hypermail 2.1.4 : Mon Dec 01 2008 - 08:18:31 ARST