[e2e] 10% packet loss stops TCP flow
jnc at mercury.lcs.mit.edu
Fri Feb 25 15:08:10 PST 2005
> From: Jonathan Stone <jonathan at dsg.stanford.edu>
>> T retransmissions .. given that it has N total segments to transmit,
>> .. Pc = f(Pp, T, N), where Pc is the probability of the successful
>> completion of the tranmssion, and Pp is the probability of the loss of
>> any individual packet.
> Are you deliberately tempting your readers to fall into the fallacy of
> assuming packet loss is statistically independent, and thus of assuming
> Poisson behaviour of packets in the Internet?
Well, it depends on what's causing the packet loss, doesn't it? E.g. if it's
congestion, yes there is a chance it will be non-random (although it will
depend on what drop algorithm the switches/routers are using). However, if
it's a lossy radio link, it might be fairly well random.
May I also note that Pc calculated by the simplistic formula I point toward is
actually something of an *upper* bound, and any deviation away from perfect
randomness in packet dropping will *reduce* it. (If the losses are not evenly
randomly distributed, then the probability of the loss of the T retransmission
of a given packet needed to kill the connection is even *higher* than the Pp^T
you get with a random model, no?)
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