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

John Day day at std.com
Tue Jul 1 10:54:51 PDT 2008

No kidding. There are some textbook authors who have helped with this 
too.  I was shocked to see Stallings say in one of his books, 
something to the effect of 'In the early 90s we discovered network 
traffic wasn't Poisson.'  (!)  We had known *that* since the 70s!!! 
I remember prior to 1976 scouring the literature looking for work 
that was closer to real, i.e. didn't assume Poisson, or would give us 
the tools to get closer to real.

I also think that there has been a lot of sloppy teaching out there. 
Or maybe it is sloppy learning.  The attitude of 'just tell me what I 
need to know to get through this course.'  Well, you need to know the 

Makes you wonder what other misconceptions people are operating under.

Take care,

At 9:26 -0400 2008/07/01, David P. Reed wrote:
>Michael Scharf wrote:
>>BTW: I wonder how all those TCP simulators out there address this
>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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