[ntp:questions] Re: Clock selection?

David J Taylor david-taylor at blueyonder.co.uk.not-this-bit
Mon Jan 19 09:56:34 UTC 2004

> David,
> Not quite. While the list is ordered by increasing stratum/distance, it
> could be and sometimes happens that the lowest one gets torpedoed as the
> cluster is whittled down. Selection error as defined in the briefings is
> the RMS offset differences between a each survivor and all the others.
> Dave


OK, thanks for that.  So whilst it may all be working as intended, we do
have the original poster's observation that the worst server was
apparently chosen (but of course we didn't see the history of the
algorithm at work that led up to that decision) and my own observation
that if I have a mixture of landline and satellite servers, it seems to be
the satellite servers which are chosen.

May I suggest that if you have a spare box you might like to try a mixture
of same-stratum landline (10-40ms delay) and satellite (>150ms) servers,
see if you get the same effect, and see if it is in accordance with how
the system should work.


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