Subject: Re: Selection of Tspec parameters

From: Mark W Garrett <[email-masked]>
Date: Tue, 10 Jun 1997 10:48:04 -0400 (EDT)

> My question relates to the token bucket parameters of the Tspec.
 > The values of the bucket depth b and of the token bucket rate r  
 > are not unique of course. One can find "infinite" (b,r) pairs
 > that give valid envelopes for the sender's traffic.

I did a little work related to this a while ago.  One thing we found
was that the tradeoff between R and B is very sharp, so there is
a "optimal" (or very preferable) region.  Away from this region,
it costs a lot of R to gain a little in B and vice versa.

To see an example of this R vs B curve for some VBR video trace data, please
see Garrett, Willinger, "Analysis, Modeling and Generation of
Self-Similar VBR Video Traffic", Sigcomm'94 (fig 14).

-Mark

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