From: Godswill Oletu (oletu@inbox.lv)
Date: Tue Jul 11 2006 - 17:39:39 ART
Jerry,
To ensure that the light bulb stays ON all the time, remember to pay your
light bills on time.:)
Godswill Oletu
CCIE #16464
>>>
----- Original Message -----
From: "Montgomery, Jerry" <jerry.montgomery@eds.com>
To: "Chris Lewis" <chrlewiscsco@gmail.com>
Cc: <ccielab@groupstudy.com>
Sent: Tuesday, July 11, 2006 4:19 PM
Subject: RE: Shaping Average / Peak vs. Policing
> Chris,
>
> Thanks for the link. The light bulb just came on!!!!
>
> Thanks.
>
>
> Respectfully,
> Jerry Montgomery, CCDP, CCNP, CCDA, & CCNA
>
> -----Original Message-----
> From: Chris Lewis [mailto:chrlewiscsco@gmail.com]
> Sent: Tuesday, July 11, 2006 2:13 PM
> To: Montgomery, Jerry
> Cc: Joe Gagznos; ccielab@groupstudy.com
> Subject: Re: Shaping Average / Peak vs. Policing
>
>
> Please read over the following:
>
> http://www.cisco.com/warp/public/125/traffic_shaping_6151.html
>
> Shape peak does send Bc plus Be at every interval, contrary to my
> initial post.
> If things rae still unclear to you after reading this link, post again.
>
> Cheers
>
> Chris
>
>
> On 7/11/06, Montgomery, Jerry <jerry.montgomery@eds.com> wrote:
> Good morning, Chris,
>
> What is the main difference between shape average and shape peak?
>
> I am trying to answer the following scenario:
>
> Limit all traffic leaving FA0/0 with IP Precedence of 128K. Do not use
> policing or rate-limiting.
>
> Sometimes I convince myself that "shape average 128000 16000 0" is the
> answer (assuming Tc=125ms). And then sometimes I convince myself that
> "shape peak 128000" is the answer (default to Bc and Be).
>
> Any inside as to what the difference between "shape average" and "shape
> peak" are?
>
> Also, can you send me a link regarding Be being sent in addition to Bc
> on the first interval of a second only? I did not find that information
> explicitly stated.
>
> Thanks in advance.
>
> Respectfully,
>
> Jerry Montgomery
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Chris Lewis
> Sent: Wednesday, July 05, 2006 9:27 AM
> To: Joe Gagznos
> Cc: ccielab@groupstudy.com
> Subject: Re: Shaping Average / Peak vs. Policing
>
>
> Shape average does not allow Bc + Be to be sent every interval.
>
> Shape average allows Be to be sent in addition to Bc on the first
> interval of a second only, also the shaper needs to have built up credit
> in previous intervals to use Be. The effect of Be in shape average is to
> allow the shaper to achieve CIR over a long period of time,
> accommodating periods of lull where less than CIR is sent in one second,
>
> with an additional Be amount of data in a later period should the credit
> be available and the shaper needing to send more data.
>
> Chris
>
>
> On 7/4/06, Joe Gagznos < joegagznos@comcast.net> wrote:
>>
>> I am trying to find another way to limit outbound traffic through an
>> interface similar in manner to policing. I understand that
>> functionally the two are different. With shaping you are going to be
>> queuing excess traffic
>> to a predetermined rate where with policing you are going to be
> executing
>> some kind of action on traffic that exceeds the contract (usually
>> dropping).
>>
>> For comparison purposes, I have configured shaping and policing on two
>
>> separate subinterfaces in the following manner:
>>
>> interface Ethernet0/0.1
>> encapsulation dot1Q 10
>> ip address 10.1.1.1 255.255.255.0
>> service-policy output shape
>>
>> interface Ethernet0/0.2
>> encapsulation dot1Q 20
>> ip address 10.1.2.1 255.255.255.0
>> service-policy output police
>>
>> Both interfaces are configured to limit traffic to no more than 2.5
>> Mbps as
>> follows:
>>
>> policy-map police
>> class class-default
>> police 2500000 conform-action transmit exceed-action drop
>>
>> policy-map shape
>> class class-default
>> shape average 2500000
>>
>> What I find is that the shaping interface initializes the parameters
>> as
>> follows:
>>
>> R1#sh policy-map interface e0/0.1
>> Ethernet0/0.1
>>
>> Service-policy output: shape
>>
>> Class-map: class-default (match-any)
>> 19 packets, 1729 bytes
>> 5 minute offered rate 0 bps, drop rate 0 bps
>> Match: any
>> Traffic Shaping
>> Target/Average Byte Sustain
>> Excess Interval Increment
>> Rate Limit bits/int bits/int
> (ms)
>> (bytes)
>> 2500000/2500000 15000 60000 60000 24 7500
>>
>> Adapt Queue Packets Bytes Packets Bytes
> Shaping
>> Active Depth Delayed Delayed Active
>> - 0 19 1729 0 0 no
>>
>> A couple things to note here - Be is initialized to the same value as
>> Bc of 60000 (or 7500 bytes). The byte limit is 15000 bytes, though.
>> This must mean that the byte limit is initialized to Bc+Be=15000.
>> With a 24 ms interval, does this mean that the interface will send 5
>> Mbps (15000 * 8 bits
>> / byte * 1 sec/.024 = 5000000) instead of the contracted 2.5 Mbps?
> If
>> shape average is allowing the interface to transmit Bc+Be each
> interval,
>> then how does this differ from configuring shape peak which
> accomplishes
>> the
>> same thing?
>>
>> With policing it appears that things are much more straightforward.
>>
>> R1#sh policy-map int e0/0.2
>> Ethernet0/0.2
>>
>> Service-policy output: police
>>
>> Class-map: class-default (match-any)
>> 107 packets, 7473 bytes
>> 5 minute offered rate 0 bps, drop rate 0 bps
>> Match: any
>> police:
>> cir 2500000 bps, bc 78125 bytes
>> conformed 63 packets, 4305 bytes; actions:
>> transmit
>> exceeded 0 packets, 0 bytes; actions:
>> drop
>> conformed 0 bps, exceed 0 bps
>>
>> Thanks for any response!
>>
>> Joe Gagznos
>>
>> ______________________________________________________________________
>
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