From: Chris Lewis (chrlewiscsco@gmail.com)
Date: Mon Jul 17 2006 - 22:44:50 ART
Yes,
This is easy to test. Setup a shaping policy, then do an extended ping
through the shaper with zero interpacket delay, then look at teh line rate
displayed via the show interface serial0/0, or whaterver interface the
shapiong is on and you will see tah the rate achieved over time equals Be
plus Bc sent every time interval.
Chris
On 7/16/06, Kay D <krsna83@gmail.com> wrote:
>
> Thaanks ,so shape peak would send Be bits irrespective of the credit .
>
> Kay
>
>
> On 7/16/06, Chris Lewis <chrlewiscsco@gmail.com> wrote:
> >
> > If you define a Be value, shape average will allow traffic in addition
> > to Bc if credit has built up. Bc (if used fully) allows the shaper to
> > transmit at CIR, so in the case described above, shape average does allow
> > excess traffic as long as Be has a non zero value.
> >
> > Chris
> >
> >
> > On 7/16/06, Kay D < krsna83@gmail.com> wrote:
> > >
> > > Hi ,
> > > Still confused with whether "shape average " would allow
> > > excess traffic if credits are available or does it send only in the first
> > > interval . Please confirm and i can have a good sleep :)
> > >
> > > TIA
> > > Kay D
> > >
> > > On 7/12/06, Montgomery, Jerry < jerry.montgomery@eds.com> wrote:
> > > >
> > > > 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 2.5Mbps?
> > > > 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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