[ntp:questions] Fwd: [ntpwg] RFC 5905 on Network Time Protocol Version 4: Protocol and Algorithms Specification

Richard B. Gilbert rgilbert88 at comcast.net
Fri Jun 25 02:05:27 UTC 2010

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.

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.

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