[e2e] Why do we need TCP flow control (rwnd)?

David P. Reed dpreed at reed.com
Tue Jul 1 06:26:25 PDT 2008

Michael Scharf wrote:
> BTW: I wonder how all those TCP simulators out there address this
> problem.
Trivial arrival models:  e.g. the wondrous Poisson model, with all its 
huge flaws of assuming that the sender will keep banging away despite 
getting no app-layer results.

This is awful: most predictions of "congestion collapse" (though not 
all) were created by mindlessly presuming Poisson arrival.  No human 
that I know of *ever* generates a Poisson distribution.   We use them on 
student problem sets because they are analytically easy, not because 
they are realistic in any way.   Then a whole generation of theory 
students grow up thinking that network traffic is best thought of as 
Poisson.  And they dominate the conversation, blasting out any more 
thoughtful approaches by generating minimum publishable units and 
reviewing each others' papers as if they were problem sets to be graded.

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