From: ccie zeng (ccie.candidate@gmail.com)
Date: Mon May 23 2005 - 01:42:00 GMT-3
Thanks Sean:
So basically you were saying it should use be6000 in CB policing, is that right?
how about CAR, how does the new QOS book say?
Thanks again
Zeng
On 5/22/05, Sean C <Upp_and_Upp@hotmail.com> wrote:
> Hi Zeng,
>
> I believe you are looking at the DQOS book - ISBN# 1-58720-058-9
> Bruce is referring to the new QoS book - ISDN# 1-58720-124-0
>
> Both books are authored by Odom and Cavanaugh. The book Bruce is referring
> to is the 2nd edition of the book you are referencing.
>
> Please note - in the 1st edition & the 2nd edition - both books use the same
> example
> 1st edition - pg393
> 2nd edition - pg387
> -all traffic policed at 96kbps
> -Bc of 1 second's worth of traffic allowed
> -Be of 0.5 second's worth of traffic is allowed
> -traffic that violates is dropped
> -traffic that exceeds the contract is marked down to DSCP Be
> -traffic that conforms to the contract is forwarded with no re-marking.
>
> but the solutions and accompanying explanation are not the same:
> 1st edition (pg 393-4):
> police cir 96000 bc 12000 be 18000.......
> "The excess burst configuration parameter actually defines the Bc and Be
> value combined, in bytes. So, the value is configured at 18000, which is
> 6000 bytes more than Bc."
> 2nd edition (pg 388-9:)
> police cir 96000 bc 12000 be 6000....
> "The excess-burst configuration parameter is 6000 bytes, or half of Bc."
>
> To further complicate the issue - in the 2nd edition, the 1st sentence on pg
> 389 actually looks like if was copy and pasted from the 1st edition by
> stating 'police cir 96000 bc 12000 be 18000...' even though the example on
> pg 388 uses 'be 6000'
>
> Interestingly, the 1st edition's errata does not address this. And it does
> not appear there is an errata for the 2nd edition yet.
> HTH (if it doesn't confuse you),
> Sean
>
> ----- Original Message -----
> From: "ccie zeng" <ccie.candidate@gmail.com>
> To: "Andrew B. Caslow" <abcaslow@netmasterclass.net>
> Cc: "simon hart" <simon.hart@btinternet.com>; <ccielab@groupstudy.com>
> Sent: Sunday, May 22, 2005 2:48 PM
> Subject: Re: Bc and Be
>
>
> > Hi Andrew:
> > according to pg,393 in DQOS book, it says all traffic is policed at
> > 96kbps,
> > Bc of 1 seconds worth of traffic is allowed(12000bytes), Be of 0.5
> > seconds worth of traffic is allowed(6000bytes), Then when you look at
> > the configuration at next page, you will see it configure be as 18000,
> > not 6000.
> >
> > Did I misunderstood your statement?
> > Thanks
> > Zeng
> >
> >
> > On 5/22/05, Andrew B. Caslow <abcaslow@netmasterclass.net> wrote:
> >> Simon,
> >>
> >> Regarding the CB-police command, the Bc and Be create two separate and
> >> distinct token buckets. You can have a Be that is equal to or even less
> >> than
> >> the Bc and you will still be able to have an excess burst. This is
> >> central
> >> to the operation of the single-rate three-color-marker. If you have the
> >> Wendell Odom book, check out pages pp 388-393. He has a couple of
> >> examples
> >> where Be is set to a value less than Bc. Odom also has a nice summary on
> >> CB-Police parameters on pp. 405-406.
> >>
> >> I hope all is well.
> >>
> >> -Bruce
> >>
> >> -----Original Message-----
> >> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> >> simon hart
> >> Sent: Sunday, May 22, 2005 4:40 AM
> >> To: ccie zeng; Cisco certification
> >> Subject: RE: Bc and Be
> >>
> >> Zeng,
> >>
> >> You are right. If you configure both bc and be to the same value there
> >> is
> >> no extended burst. In order to achieve your stated goal, then bc 1000
> >> and
> >> be 2000 would be correct.
> >>
> >> Be careful when using these police commands, I would recommend that you
> >> always use the ? prompt to determine whether you need to enter bits or
> >> bytes.
> >>
> >> Also the relationship between bc and be is different when using Traffic
> >> shaping. When traffic shaping any value of be will be the absolute value
> >> of
> >> the burst.
> >>
> >> HTH
> >>
> >> Simon
> >>
> >> -----Original Message-----
> >> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> >> ccie zeng
> >> Sent: 22 May 2005 09:30
> >> To: Cisco certification
> >> Subject: Bc and Be
> >>
> >>
> >> Hi:
> >> Could anyone clarify to me, when I asked to configure normal burst
> >> size 1000 bytes, and excess burst size 1000 bytes for CAR or CB
> >> policing, should I configure like this ".....bc 1000 be 2000" or just
> >> "...bc 1000 be 1000".
> >>
> >> Based on my understanding if Be is configured as 1000, then there is
> >> no excess burst, is that right?
> >>
> >> Thanks
> >> Zeng
> >>
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