[time-nuts] Legal Time dissemination

Chris Albertson albertson.chris at gmail.com
Tue May 28 11:11:27 EDT 2013

The "stratum 2" servers are by definition not connected to GPS.  They get
their time from some other NTP server that is connected to an authoritative
clock which may or may not be GPS.    It looks like the "red server" has
rather smooth swings over around a "handful" of milliseconds.   This is to
be excepted.  It is within the normal range of what NTP does.  Perhaps it
is a Windows PC running in some room where the temperature changes and the
network that connects it to the strum 1 server is loaded.  I don't know but
a handful of milliseconds is in the normal range.  Yes it could be better.

Also the curve is somewhat smooth.  It does not look like noise from a busy
network.  It looks like their server really is moving around.

On Tue, May 28, 2013 at 4:52 AM, Miguel Barbosa Gonçalves <m at mbg.pt> wrote:

> Hi!
> Lately I've been using the two stratum 2 servers our national observatory
> provides to the public mainly as backup for my GPS based local NTP servers.
> I've always found odd that one of them exhibited an erratic behaviour when
> compared to the other one.
> I decided to use ntpdate on one of my stratum 1 machines (Trimble
> AcutimeGold in position hold mode; looking at my loopstats file my
> clock is always
> within 5 us of UTC) against these 2 servers every minute for a while and
> plotted the results. Offset is in seconds and time is UTC.
> I am on a fibre asymmetrical connection 100 Mbps/25 Mbps. The offsets for
> the best behaved server are expected but... the other server?
> After gathering enough data I'll contact them as ask what is the problem
> with the server...
> Opinions?
> Regards,
> Miguel
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Chris Albertson
Redondo Beach, California

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