On 2010-06-25, Richard B. Gilbert <[email protected]> wrote: > pc wrote: >> At risk of stirring up a hornets' nest: >> >> The RFC unequivocally states that "A primary server is >> synchronized to a reference clock directly traceable to >> UTC." >> >> IMO, that is not a necessary condition. If I have a >> hierarchy of NTP servers and clients with no external >> connection to the Internet and I feed in Northern >> Bongosooziland Spring Time (NBST) at the top of the >> hierarchy, NTP will propagate that time throughout the >> hierarchy. The only condition is that NBST must tick at a >> rate of approximately 1 second per UTC second, otherwise the >> finely-tuned FLL and PLL will not perform optimally. >> >> Many users of this list have a requirement to synchronize a >> number of machines within some user-defined limit, but they >> don't care if they are all offset from UTC by a few minutes. >> Time islands would seem to be a common use-case, and it's my >> opinion that the RFC's assertion that genuine NTP networks >> must be based on UTC is an unnecessary restriction. I >> suggest that the RFC should mention that UTC-based NTP is >> probably the most valuable use-case, and is the only form of >> NTP that should be allowed on the Internet, whilst admitting >> the existence of time islands. >> >> Paul > > There may be people who cannot use UTC or who simply do not care what > time it really is as long as all their clocks agree, but should we care > what they want or what they believe??? > > NTP is about time traceable to UTC and accurate to the extent permitted > by the medium of transmission. >
ntp is not a religion. It is process for synchronizing clocks via the exchange or certain well defined packets. It is also a process for using those packets to discipline the local clock on a computer or other system. If in the future, MTC is defined (Mars Time Coordinate) ntp will work equally well there without UTC. Nor should a new RFC be needed simply to have ntp defined with MTC. Now one might say that "primary" is defined in terms of UTC, and that one should define a new term for MTC (maybe the martian term for primary) but it would seem more sensible to define "primary" as a machine which gets its time from an outside non-NTP source like GPS, UTC, Rubidium clock, radio,.... > I'm not going to send assassins to deal with those who disagree. . . . > > It may also be worth noting that systems following an ultra > accurate/stable source seem to agree with each other more closely than > if the source is afflicted with random phase noise. > > _______________________________________________ questions mailing list [email protected] http://lists.ntp.org/listinfo/questions
