[ntp:questions] National time standard differences
joegwinn at comcast.net
Tue Feb 9 13:44:43 UTC 2010
In article <c2bcn.37983$Ym4.23174 at text.news.virginmedia.com>,
"David J Taylor"
<david-taylor at blueyonder.delete-this-bit.and-this-part.co.uk.invalid>
> > 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
> 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.
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