From: Hobbs (deadheadblues@gmail.com)
Date: Sat Nov 22 2008 - 15:48:37 ARST
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
>
>
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