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From: tcp-ip@ucbvax.ARPA
Newsgroups: fa.tcp-ip
Subject: Re: Speaking of 4.2 time programs
Message-ID: <7842@ucbvax.ARPA>
Date: Wed, 5-Jun-85 16:02:07 EDT
Article-I.D.: ucbvax.7842
Posted: Wed Jun  5 16:02:07 1985
Date-Received: Thu, 6-Jun-85 06:09:02 EDT
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Organization: University of California at Berkeley
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From: Jeff Mogul <mogul@Navajo>

     It would be a useful
    and positively fascinating exercise to adapt these algorithms to real
    Internet dynamics using UDP for coarse tracking and ICMP timestamps for
    fine synchronization. Someone out there should cop a Master's thesis for
    going after this one with hammer and tongs.

Someone already has copped a PhD thesis for devising some very
elegant algorithms to maintain distributed clocks even when
some clocks are lying.  See Keith Marzullo's thesis "Maintaining
the Time in a Distributed System" (Stanford, 1983).  His
implementation used Pup rather than IP protocols, but I think the
mapping is obvious.  Keith's address is Marzullo.PA@Xerox.

Also see Gusella and Zatti, "TEMPO: Time Services for the
Berkeley Local Network", Berkeley EECS report # UCB/CSD 83/163,
which presents a simpler, although in my opinion inferior, algorithm
using UDP.  I can't tell if they got a thesis out of this one or not.