Re: Token buckets question

Token buckets are an aid to understand the process, a model.

When policing, there's really no need to do anything up to the time
you receive a packet. Then, if you remember when was the last time
a packet arrived, you can do the math and "update" token counters.

I guess the main point in that book phrase is to show that you keep
two different counters, as opposed to one.
-Carlos

Jacek @ 12/10/2011 00:22 -0300 dixit:
> Hello Experts,
>
> I have a question, how often tokens are added to token buckets?
> Different docs give different explenations:
>
> 1.
> Cisco book End-to-end QOS network design says:
> "policer has two separate buckets that are filled EACH SECOND with two
> separate token rates."
> If I understand correctly, buckets are refilled only one time per
> second. It does not look very often to me.
>
> 2.
> RFC 2698 ( http://tools.ietf.org/html/rfc2698 ) says: " token count Tc
> is incremented by one CIR times per second up to CBS."
> Does this mean that if CIR=100,000bps then 100 tokens are put into the
> bucket every millisecond ? Just curious, can router count tokens that
> fast ?
>
> Can someone please explain ?
>
> Thanks
>
>
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-- 
Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
Blogs and organic groups at http://www.ccie.net