[ntp:questions] Synchronize clocks without a reference clock

Richard B. gilbert rgilbert88 at comcast.net
Sat Mar 31 17:27:45 UTC 2007


Hal Murray wrote:
>>Well, I was mainly thinking of the case where you have orphan mode set
>>up as a fallback to external servers - then the drift value that has
>>been calculated while external servers were reachable is a good "quality
>>indicator". But I assume the non-"masters" in an orphan-only setup
>>calculate a drift relative to the "master" - in that case, if you're
>>happy with the drift of the "master", you will be least unhappy if the
>>host with the lowest drift relative to the departed "master" is chosen
>>as the new "master".
> 
> 
> The value of drift doesn't have any correlation to goodness.
> 
> What you want is best stability.  What is the peak-peak value
> of the drift measured over several days?  Or something like that.
> 

I don't think that is correct.  No single value of "drift" tells you 
anything about stability.  It only tells you the frequency error of the 
uncorrected clock.  A time history of drift MIGHT tell you something 
about stability.




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