From: Hobbs (deadheadblues@gmail.com)
Date: Sat Nov 22 2008 - 16:59:54 ARST
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
>>>
>>>
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