[ntp:questions] What level of timesynch error is typical on Win XP?
Joseph Gwinn
joegwinn at comcast.net
Fri Oct 22 11:37:51 UTC 2010
In article <i9r6cb$627$1 at news.eternal-september.org>,
"David J Taylor" <david-taylor at blueyonder.co.uk.invalid> wrote:
> "Joseph Gwinn" <joegwinn at comcast.net> wrote in message
> news:joegwinn-EE48FD.22434621102010 at news.giganews.com...
> > In article <i9pkvb$dc6$1 at news.eternal-september.org>,
> > "David J Taylor" <david-taylor at blueyonder.co.uk.invalid> wrote:
> []
> >> You might consider providing a local, more precise NTP server with
> >> something like a small, fan-less Intel Atom system running FreeBSD and
> >> synched across the network to your GPS time server. You might be able
> >> to
> >> keep a small box like that in a more temperature controlled
> >> environment,
> >> but even without it might provide a way of smoothing out any jitter due
> >> to
> >> your remote connection to the GPS server.
> >
> > I'm not convinced that this would help. NTP reports a round trip time
> > of slightly more than 2 mS, which is very close to the two milliseconds
> > that ping sees, so it seems unlikely that the time server or intervening
> > network is the root cause.
> []
> > Joe Gwinn
>
> No, I wasn't convinced either - hence it was just a suggestion. On the
> systems here, though, the NTP delay shows around 0.25-0.75 msec to the LAN
> servers.
I must say that I don't know why ping sees 2 milliseconds, which did
seem high, but I also don't know the physical location of the
timeserver, or how many hops (and firewalls) it takes to get there.
I'll have to explore it with traceroute.
But the 2 ms RT time explains only a millisecond or so of timesync
error, leaving much error to be explained. Research continues.
Joe Gwinn
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