From: Salau, Yemi (yemi.salau@siemens.com)
Date: Tue May 13 2008 - 13:08:21 ART
Calm down dear, it's only a commercial!
normal burst is really the amount of traffic in bytes, that can pass
through a time interval measured in seconds.
CIR is traffic rate in bits that can pass through in a time interval of
a second
so NB = CIR * 1.5
NB(byte) = CIR (bps) * 1.5
NB(byte) = CIR (bits per second) * 1.5
You have to convert bits to byte at this stage to make the equation
balanced
NB(byte) = CIR({1/8}bytes per second) * 1.5
so at this stage, CIR is in bytes per second as opposed to initial stage
when it was bits per second. if you had used the first stage, then the
value of NB will be in bits. and we both know Cisco router accepts byte
values for normal bursts.
This is so that at the end of the day, you have to speak the IOS
language. calculate NB in bytes as opposed to bits that normal CIR gives
you.
Many Thanks
Yemi Salau
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
CCIE3000
Sent: Tuesday, May 13, 2008 4:11 PM
To: Josh Covarrubias
Cc: ccieking@gmail.com; ccielab@groupstudy.com
Subject: Re: rate-limit help
Could somebody elaborate on
normal burst = configured rate * (1 byte)/(8 bits) * 1.5 seconds
I don't understand the (1 byte)/ (8 bits) bit.
okay, I know there are 8 bits to a byte but I just can't work out
exactly
what is meant by the equation.
Sorry to sound dumb but it's just going over my head.
On 4/26/08, Josh Covarrubias <shmokin@gmail.com> wrote:
>
> Hey Richard,
>
>
> From the following link:
>
>
http://www.cisco.com/en/US/docs/ios/12_3t/qos/command/reference/qos_q1gt
.html#wp1080850
>
>
> Policing Traffic with CAR
>
> CAR embodies a rate-limiting feature for policing traffic. When
policing
> traffic with CAR, Cisco recommends the following values for the normal
and
> extended burst parameters:
>
> normal burst = configured rate * (1 byte)/(8 bits) * 1.5 seconds
>
> extended burst = 2 * normal burst
>
> With the listed choices for parameters, extensive test results have
shown
> CAR to achieve the configured rate. If the burst values are too low,
then
> the achieved rate is often much lower than the configured rate.
>
>
> HTH
> Regards,
>
> Josh
>
> On 4/26/08, ccieking@gmail.com <ccieking@gmail.com> wrote:
> >
> > Hi experts
> >
> > Would you please explain about ratelimit CIR Bc Be (in CAR) how to
> > calculate
> > the values and same in frame-relay
> > I have been waiting for this help from CCIE Masters Mr.Brian Dennis,
> > Mr.Brian
> > McGahan
> >
> > Regards
> > Richard
> >
> >
> > Pass the CCIE in six weeks, Guaranteed!
> > http://www.certscience.com/CCIE
> >
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