[e2e] TCP 'fast start'

Joe Touch touch at ISI.EDU
Wed Sep 28 16:19:41 PDT 2005

S. Keshav wrote:
> Hi,
>     The idea of using environmental variables to optimize TCP start goes
> back a while. It is particularly useful for short transfers that complete
> before they reach the 'steady-state'. My students and I worked on this in
> 1999. We used Shared Passive Network Discovery, proposed by Seshan, Stemm,
> and Katz to discover connection parameters from a cluster of users to a
> popular destination, say, Yahoo, and used this information to choose initial
> TCP parameters. Though we only did simulations, our results looked pretty
> decent, so maybe Joe, you can actually implement our work :-)

Sharing the state among a set of hosts with similar paths was proposed
in RFC2140 (1997), and some tests based on an implementation were
published in CCR early in 2000:

L. Eggert, J. Heidemann, J. Touch, "Effects of Ensemble-TCP," ACM CCR,
Jan. 2000, pp. 15-29.

This of course is close to what you did in the NOSSDAV paper, as was
cited therein already. The primary difference (AFAICT - I did a very
quick read) is that 2140 shared state among a set, and your work used
state from other nearby connections (that aren't necessarily 'shared'
explicitly) to infer network conditions. Both of which may be useful,
but aren't what ALN does.

ALN uses a lot of external parameters that have nothing per se to do
with networking, e.g., whether it's a national holiday in the country of
one of the endpoints, time of day, etc., and reusing it - perhaps a long
time later, if past experience accuratly predicts patterns of repetition.

I.e., if 3pm on the Wednesday before Thanksgiving in the USA in previous
years was an idle network time (whereas it wouldn't be most other
Wednesdays in general), then this Wed before Thanksgiving at 3pm we
might reuse that information.


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