[ntp:questions] Re: Sufficient # servers to sync to

David L. Mills mills at udel.edu
Sat Mar 19 18:19:54 UTC 2005


It's not true for three servers. Assuming one is falseticker, the other 
two cannot from a majority clique in the voting process. You need at 
least three alleged truechimers for that. I hesitate to cite Leslie 
Lamport, the source of the Byzantine Generals problem, on which this 
algorithm is based, but the paper is among the citations at 


David Schwartz wrote:
> "David L. Mills" <mills at udel.edu> wrote in message 
> news:d1g1af$o27$1 at dewey.udel.edu...
>>When I say "vote", what I mean is that a majority vote among three of the 
>>four servers is possible in order to declare the fourth a traitor. All 
>>this says is the three servers are truechimers and the fourt is a 
>>falseticker. The "vote" is not for the winner, it's for the loser.
>     Certainly the same would be true for three servers if one were way off 
> and the other two were in agreement. The two accurate ones would vote for 
> the one that's off to lose. Whoever the one that was off voted for, it would 
> only have one vote to the screwed up server's two votes.
>     DS

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