[cap-talk] "coordinated attack"/generals and TCP
smagi at naasking.homeip.net
Thu Feb 2 19:23:06 EST 2006
Jed at Webstart wrote:
>> > If people are prepared to continue sending messages
>> > indefinitely then they will either end up agreeing
> No. As explained again in my last message, they can
> never agree. They can only choose to act without
> agreement (coordination). The last one to send a
> message is always vulnerable. That is, the last one
> to send a message doesn't know if it arrived.
>> > or sending messages
>> > forever. This is the point of the proof - you can't _guarantee_ an
>> > agreement, but in practice you will often get one.
I think Ben's point is that you can *practically* achieve your goal (eg.
robbing the bank) the majority of the time (the "expected value"), but
as the proof demonstrates, you can't guarantee a 100% success rate.
Thus, "practically" in this case means "statistically".
In other words, if you know 1 out of every 5 of your runners gets nabbed
by the cops, you have a high chance of success if you send out more than
one and assume at least one got through. This assumes they can each take
separate routes though such that the probability of one being nabbed is
independent of the others.
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