[ntp:questions] National time standard differences

cc cjcrickmar at googlemail.com
Tue Feb 9 11:08:43 UTC 2010


On 9 Feb, 10:46, "David J Taylor" <david-tay... at blueyonder.delete-this-
bit.and-this-part.co.uk.invalid> wrote:
> > I've setup an NTP server in the south east asia region synchonising
> > with regional NTP servers as well as a couple of servers I am
> > responsible for in the US.
>
> > remote        st t when poll reach   delay   offset  jitter
> > ==============================================
> > +Japan         1 u  454 1024  377   87.402   -0.560   0.056
> > *Japan         1 u  476 1024  377   87.277   -0.810   1.542
> > -NorthAmerica  2 u  427 1024  377  285.387  -17.741   5.084
> > -NorthAmerica  2 u  429 1024  377  307.208  -17.061   0.083
>
> > Is the above delta seen between Japanese and North American time
> > sources purely the delta between the outbound / return network path or
> > something else?
>
> > Chris
>
> Chris,
>
> Most likely asymmetrical paths, yes.  To answer your implied question, it
> is most /unlikely/ that the USA National Time is 17 milliseconds away from
> Japan National Time, if that's what you were thinking.  National time
> differences are likely to be microseconds or less, I believe.
>
> Cheers,
> David

I wouldn't have thought so either and given that they all trace back
to GPS it isn't likely either but it made me consider the natioanal
security / financial implications of setting your national clock 10ms
ahead of where everyone else thinks it is.

Chris.




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