[ee122] MNL not simulating congestion correctly

vern at cs.berkeley.edu vern at cs.berkeley.edu
Tue Nov 27 21:58:35 PST 2007


> >   This seems to be counter-intuitive to the 
> > behavior of an actual congested network, which would drop less packets 
> > if a sender reduced its sending speed.  
> Only if that particular sender was responsible for a significant share 
> of the network's congestion.

Exactly.  While it can be the case that an individual TCP backing off will
by itself lower the drop rate along a path, during situations of high
multiplexing, the actions of an individual won't in fact have discernable
effect by themselves.  (In fact, the notion that the drop rate remains
unchanged as a source varies its rate was a basic part of the deriviation
of the TCP throughput equation.)

		Vern


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