From: David Timmons (masterdt@yahoo.com)
Date: Mon Jul 03 2006 - 12:49:19 ART
Hi,
I don't think you compute a Tc for policing. I have
not found a link that even talks about the use of Tc
with policing. I'll try to find a link that talks
about the time interval. I do agree that this is the
formula for computing the Tc for shaping.
I wonder if the rate command is from the Car days.
Maybe it has to be in 8k increments? I did see where
it is used for traffic that is sent to the control
plan.
Here is an example. we are told to limit a particular
flow to 8,000 bits/s. We are also told that the we the
flow we are watching is 1024 bytes; however, we would
like to allow for any size packet with a minimum burst
size. What do you think you would list as your
policing statement?
--- Paul Dardinski <pauld@marshallcomm.com> wrote:
> Dave,
>
> From below, tc would be cir=bc/tc, so 8000=12000/tc
> or tc=12000/8000=1.5
> seconds.
>
> Be is totally separate from the equation. The below
> statement would
> allow an excess burst of 16000bps over the same 1.5
> second tc span.
>
> I never received any real answer as to the
> difference of police cir vs
> just police, so I'm assuming they are the
> same.........
>
> -----Original Message-----
> From: David Timmons [mailto:masterdt@yahoo.com]
> Sent: Monday, July 03, 2006 10:58 AM
> To: Paul Dardinski; Cisco certification
> Subject: Re: Police "cir" vs police
>
>
> HI,
>
> I have had the same questions. I am also having
> problems understanding how the Bc is actually
> interpreted. For example, what does this really
> mean?
>
> police cir 8000 bc 1500 be 2000
>
> Do we use the CIR to compute a time interval? Is it
> just 1500 per second? Do we have a way to compute a
> time interval? I have only found a recommended value
> for Bc and Be from Cisco:
> normal burst = configured rate * (1 byte)/(8 bits)
> *
> 1.5 seconds
> extended burst = 2 * normal burst
>
> Many QOS books say that policing does not really use
> Tc the same as in shaping. I just don't understand
> how
> we evaluate the time period for the Bc and Be.
>
>
>
>
> --- Paul Dardinski <pauld@marshallcomm.com> wrote:
>
> > I see the "police cir" command in the cco only
> > occasionally. I can't
> > seem to locate difference between using just
> police
> > command vs police
> > cir (mqc).
> >
> >
> >
> > Any help?
> >
> >
> >
> > PD
> >
> >
>
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