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

Detlef Bosau detlef.bosau at web.de
Wed Jul 2 03:10:54 PDT 2008

David P. Reed wrote:
> 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.

So, is this more one of the exercises for a TOEFFL? (Example question: 
What's the meaning of "Mrs. Jones is out of coffee.") Or do we have a 
congestion problem at the coffee machine? And how should we implement a 
"packet drop" then?
> 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.  :-)

O.k., this story circulated here for the little break at 8.15 pm after 
the evening news and the murder story on TV on sunday evening ;-)

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

Hm. The "randomness", which is offen assumed is exactly one of the 
problems in wireless networks and the expectation to find a formula 
which renders a "Bitrate" depending on a "SNR". Particularly noise is 
often highly correlated and symbol drops are anything but "random 
arrival on rare occasions".

Detlef Bosau                          Mail:  detlef.bosau at web.de
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