From: Maximus (victorius@gmail.com)
Date: Tue Jun 20 2006 - 11:02:13 ART
so how do i calculate Bc if normal is given ?
is this right bc = normal* 1/8*1.5 ?
On 6/20/06, Chris Lewis <chrlewiscsco@gmail.com> wrote:
>
> There is no need to multiply by 1.5.
>
> Burst can never be expressed as a rate, it can only be expressed as a bit
> or byte value.
>
> The 1.5 figure comes from a general rule of thumb to help calculate the
> size of burst, if you have been given the burst size, it is irrelevant. The
> 1.5 figure is just a generalizationfor giving you a figure that will help
> the policer achieve line rate under normal conditions. If the traffic
> profile of the load offered to the policer differes, the 1.5 figure
> differs. It is probably best just to forget it as i know of only extremely
> rare situations when you need to worry about tuning this.
>
> I believe the original question was either written incorrectly, of the
> person setting the question did not understand policing. Burst should only
> be described as a burst or byte value. The only time you can really use
> burst to define a rate is if you state that credit has been built up, which
> is the only way you can use burst setings in policing.
>
> Chris
>
>
> On 6/20/06, Popgeorgiev Nikolay <nikolay.popgeorgiev@siemens.com > wrote:
> >
> > Koen,
> >
> > Can you explain better why with need to multiply with 1.5 ? I thouth
> > there were some recommendations from cisco about the normal burst and max
> > burst which have something to do with this 1.5 but can't remember well
> > what was it about.
> >
> > I am for solution 2.
> >
> > Best,
> > Nick
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > -----Original Message-----
> > From: Koen Zeilstra [mailto: koen@koenzeilstra.com]
> > Sent: Tuesday, June 20, 2006 2:47 PM
> > To: Maximus
> > Cc: Cisco certification
> > Subject: Re: Doubt in CAR : Rate limit
> >
> > if the b is lowercaps its bits so you should divide by 8. That give's
> > you
> > the burst size per timing interval. Not per second. So you have to
> > convert
> > the bps to a byte per timing interval value. I believe the timing
> > interface for CAR is 1,5. So that makes 300000/8*1,5=56250.
> >
> > -> solution 3.
> >
> > Don't forget the "exceed-action drop".
> >
> > HTH
> >
> > Koen
> >
> > -----------------------
> > Kerr's Three Rules for a Successful College:
> > Have plenty of football for the alumni, sex for the students,
> > and parking for the faculty.
> >
> > On Tue, 20 Jun 2006, Maximus wrote:
> >
> > | ok i am only confused on converting the normal and max burst
> > |
> > | i will give the three kind of answers which i got from pals... can
> > somebody
> > | tell me which one to go forward with..
> > |
> > | Qn again : the requiremenet is "traffic is limited to 8 Mbps, with a
> > normal
> > | burst size of 150kbps and an Max Burst size of 300kbps. traffic that
> > | conforms is sent
> > | with an IP precedence of 5. Traffic that does not conform is dropped.
> > "
> > |
> > | Sol 1 :rate-limit output 8000000 150000 300000 conform-action
> > | set-prec-transmit 5
> > |
> > | Sol 2 :rate-limit output 8000000 18750 37500 conform-action
> > | set-prec-transmit 5
> > |
> > | 150000/8 = 18750
> > | 300000/8 = 37500
> > |
> > | Sol 3 :rate-limit output 8000000 28125 56250 conform-action
> > | set-prec-transmit 5
> > |
> > | (150000/8)*1.5 = 28125
> > | (300000/8)*1.5 = 56250
> > |
> > |
> > | On 6/20/06, Vishal Patel <vpatel@accessproviders.com.au> wrote:
> > |
> > | > In CAR command , the first figure i.e. 8 Mb in your case is in Bits
> > per
> > | seconds.
> > |
> > | Then the second figure is Normal burst which is number of Bytes.
> > |
> > | Then the third value is the Maximum Burst which is number of Bytes.
> > |
> > |
> > |
> > |
> > | -----Original Message-----
> > | From: nobody@groupstudy.com [mailto: nobody@groupstudy.com] On Behalf
> > Of
> > | Maximus
> > | Sent: Tuesday, 20 June 2006 11:21 AM
> > | To: Cisco certification
> > | Subject: Fwd: Doubt in CAR : Rate limit
> > |
> > | sorry made a small typo... this is the exact config i have done
> > |
> > | hie all just a lil confusion
> > |
> > | the requiremenet is "traffic is limited to 8 Mbps, with a normal burst
> > size
> > | of 150kbps and an Max Burst size of 300kbps. traffic that conforms is
> > sent
> > | with an IP precedence of 5. Traffic that does not conform is dropped.
> > "
> > |
> > |
> > | rate-limit output 8000000 150000 300000 conform-action
> > set-prec-transmit 5
> > |
> > | is my config rite ? the confision is in normal n max is it in bytes or
> > | bits...somebody please lead me out...
> > |
> > |
> > | regards,
> > |
> > | Max
> > |
> > |
> > |
> > | --
> > | regards,
> > |
> > | Max
> > |
> > |
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>
-- regards,Max
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