[ntp:questions] National time standard differences

cc cjcrickmar at googlemail.com
Tue Feb 9 13:58:47 UTC 2010


On 9 Feb, 13:44, Joseph Gwinn <joegw... at comcast.net> wrote:
> In article <c2bcn.37983$Ym4.23... at text.news.virginmedia.com>,
>  "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.  
>
> The wide area networks used for international connections are typically
> SONET rings, which are inherently asymmetrical.  
>
> As one works around a ring, the poll response time is constant (being
> the perimeter of the ring), while the out and back times vary with
> position on the ring with respect to the server one is polling.
>
> Joe Gwinn

Thanks.

ChrisC.




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