[time-nuts] Divide by five ->Ensemble

Bob Camp kb8tq at n1k.org
Mon Nov 10 07:14:55 EST 2014

> On Nov 10, 2014, at 1:59 AM, Poul-Henning Kamp <phk at phk.freebsd.dk> wrote:
> --------
> In message <4CDC0090-DD4B-4380-ACC1-40A80D3BC20C at n1k.org>, Bob Camp writes:
>> Hi
>> Here’s what I’m saying:
>> The NTP algorithm as it is written and as it is implemented results
>> in an output clock that does *not* improve when a number of very
>> good clocks are being used [...]
> The crucial word here is "good clocks".
> A "good clock" in NTP is nearby and because it is nearby, the chances
> of several of them overlapping is usually not high enough for any
> clock combining to happen.

Yes, in normal NTP land it’s  not in any way worth worrying about. 
> The NTP algorithms were built for 10-100msec packet delays, not
> low microsecond packet delays.

NTP is designed to do something very different.


> -- 
> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
> phk at FreeBSD.ORG         | TCP/IP since RFC 956
> FreeBSD committer       | BSD since 4.3-tahoe    
> Never attribute to malice what can adequately be explained by incompetence.

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