[e2e] TCP Framing

Joe Touch touch at ISI.EDU
Mon Mar 26 13:03:06 PST 2001


Ramesh Shankar wrote:
> 
> The fairness issue is an interesting angle and seems relevant only when
> bandwidth is really limited or from an ISP perspective (perhaps). This
> angle is similar to the "fair share scheduling" approach used in time
> sharing UNIX systems. This issue has been discussed in the following
> Ph.D. thesis:
> 
> V. N. Padmanabhan
> Ph.D. Dissertation
> Computer Science Division, University of California at Berkeley, USA
> September 1998
> (Also published as Technical Report UCB/CSD-98-1016.)
> 
> http://www.research.microsoft.com/~padmanab/phd-thesis.html

FWIW, RFC2140 (April 1997) speaks directly to the issue of how sharing
is compliant with TCP and is an extension of T/TCP concepts.

Fairness can be completely decoupled from the number of connections
between two hosts. 

Joe

> >> David P. Reed wrote:
> >>
> >>> Why not use multiple TCP connections
> >>
> >> Two reasons: (1) fairness (2) slow start/congestion avoidance.
> >> Fairness: If I use "n" TCP connections for a single flow because I have
> >> three logical streams that I want to be processed out-of-order with
> >> respect to one another, then I am getting "n" times greater a share of
> >> the bandwidth on congested links that I should reasonably be entitled
> >> to.
> >
> >
> > This begs the question: what are you reasonably entitled to?
> >
> > If you have three logically separate streams which can be processed
> > out-of-order, I would have thought there is a case to be made that those
> > are three essentially independent streams (which just happen to be between
> > the same end-nodes), and so together they deserve three times the
> > bandwidth of a single stream.
> >
> > Damon Wischik.



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