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Reduction in the Reserved Bandwidth Based on the Leaky Bucket

IP.com Disclosure Number: IPCOM000110844D
Original Publication Date: 1994-Jan-01
Included in the Prior Art Database: 2005-Mar-26
Document File: 2 page(s) / 55K

Publishing Venue

IBM

Related People

Roginsky, AL: AUTHOR

Abstract

High-speed network protocols may provide a bandwidth guarantee to every transport connection. An assumption is usually made that each source is of an on/off type, with a known peak rate R, an "on" probability &rho., and a mean burst rate b. The other parameters that affect the bandwidth are the intermediate nodes' buffer sizes and the target data loss probability &epsilon..

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Reduction in the Reserved Bandwidth Based on the Leaky Bucket

      High-speed network protocols may provide a bandwidth guarantee
to every transport connection.  An assumption is usually made that
each source is of an on/off type, with a known peak rate R, an "on"
probability &rho., and a mean burst rate b.  The other parameters
that affect the bandwidth are the intermediate nodes' buffer sizes
and the target data loss probability &epsilon..

      In reality, however, a network does not see a source as an
"on/off" device, since the data are filtered through the leaky
bucket.  (The first definition of a leaky bucket was given in
lbracket 1 rbracket.  Numerous other papers examined various
properties of a leaky bucket, as well as its advantages and
disadvantages.)  The source has three different rates: R - the peak
rate, &gamma.  - the speed at which the leaky bucket produces the
green bits, and 0.  This parameter &gamma.  and the new shape of the
data stream were not previously taken into account when calculating
the reserved bandwidth.

      An equivalent capacity of the source is defined to be the link
speed that guarantees the desired loss probability &epsilon..  In
high-speed networks the bandwidth may be reserved according to the
calculated equivalent capacity lbracket 2 rbracket.  One way the
equivalent capacity of  n  independent sources can be calculated is:

  c % equals % M % + % alpha Sigma ' ,'
where

  M % equals % sum from j=1 to n of mj

  '       is the combined mean rate,'

  Sigma sup 2 % equals % sum from j=1 to n of sigma j sup 2

  '       is the variance of the combined process'
and

  alpha % equals % sqrt <2ln 1 over epsilon % - % ln(2 pi)> ' .'

      For each individual source, the variance is given by sigma sup
2 equals R sup...