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

David P. Reed dpreed at reed.com
Tue Jul 1 12:31:07 PDT 2008

Humans respond to the network getting slow by going to get coffee.   
Mobs of humans acting independently also respond to slowness by *all* 
getting coffee or doing something else.

It's well known that before Superbowl commercials became more 
interesting than the game, the plumbing systems of cities showed major 
spikes of effluent highly correlated with commercial breaks.  :-)

My general point was not against "random arrivals" but against the 
assumption that those arrivals are independent of service rate changes.

Jim Gettys wrote:
> On Tue, 2008-07-01 at 08:54 -0700, Lachlan Andrew wrote:
>> Greetings David,
>> 2008/7/1 David P. Reed <dpreed at reed.com>:
>>>  No human that I know
>>> of *ever* generates a Poisson distribution.
>> I might be one of the brainwashed, but I think that your (correct)
>> observation misses the point.  An individual human produces one or two
>> connections.  The Poisson process comes from thousands or millions of
>> users each generating their connections independently.
> Heh.
> The individual human pokes a web browser to visit another page.
> Embedded on that page are often tons of images or other objects, not
> necessarily at the same web site.
> So an individual human often initiates anywhere from one, to many, many,
> many TCP connections all at once.
>                           - Jim

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