[ntp:questions] Keeping NTP Honest Redux

Evandro Menezes evandro at mailinator.com
Mon Nov 9 20:49:06 UTC 2009

On Nov 9, 9:21 am, "David J Taylor" <david-tay... at blueyonder.not-this-
bit.nor-this.co.uk.invalid> wrote:
> Here's the offset:
>  http://www.satsignal.eu/ntp/2009-11-07-08-09-Narvik_offset-tod.png
> and here's the rate:
>  http://www.satsignal.eu/ntp/2009-11-07-08-09-Narvik_frequency-tod.png
> where values for the last two and half days have been overlaid against
> time-of-day.

I think that we can all agree that these charts indicate that the
variation is due to temperature variations.  Given that, they also
indicate that NTP, as is, is too slow to react to temperature
variations, taking something like 8 to 10h to compensate for them,
even at 64s sampling period, it seems.  The reference stratum 1
server, Feenix, seems to suffer from the same temperature-induced
daily accuracy variations.

Unfortunately, Mills will probably deny that this is an issue and will
probably refuse revisions to his algorithm.  If this is the case,
perhaps it's time to add another algorithm alongside Mill's and let to
the user whether he prefers Mill's algorithm or an alternative.  Which
alternative I have no idea, but I'd sure like to decide what's good
for me, not Mills.


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