Re: calculating burst size for "mls qos aggregate-policer" on

anybody?

On Thu, Apr 15, 2010 at 4:00 PM, Persio Pucci <persio_at_gmail.com> wrote:

> hi folks,
>
> I am trying to determine burst sizes for policies to be used on a Cat6500
> using mls qos aggregate-policer, but I am not confident on the numbers I am
> getting.
>
> For instance, for a 1mbps (1024000bps) policy, I would use a CIR of 1024000
> bps. The Cat6500 literature (
> http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SXF/native/configuration/guide/qos.html#wp1726251) says
> that the Tc is 1/4000sec (0.25ms). For that Tc, I would have to use:
>
> CIR=Bc/Tc
>
> 1024000=Bc/(1/4000)
>
> Bc=1024000*(1/4000)
>
> Bc=256
>
>
> That being 256 bits. Considering the normal burst size field asks for a
> value in bytes, that makes 256/8=32 bytes, making my config line:
>
> mls qos aggregate-policer 1mbps 1024000 32 32 conform-action transmit
>> exceed-action drop violate-action drop
>
>
> The burst value does not sound reasonable for me. Wanted to check with you
> guys if I am missing something here.
>
> Persio

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Received on Mon Apr 19 2010 - 15:19:11 ART