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

David L. Mills mills at udel.edu
Thu Jun 24 17:10:58 UTC 2010


pc,

You completely miss the point. By definition a primary server is 
synchronized to UTC via an external source such as a GPS receiver. By 
definition, it operates at stratum 1. It is indeed possible to operate a 
server with some other reference source, even itself (orphan mode or 
local clock driver) at this or some other stratum, but it is not by 
definition a primary server.

Dave

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
>
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