[ntp:questions] Server offset included in served time?
david at ex.djwhome.demon.co.uk.invalid
Tue Sep 16 07:32:49 UTC 2008
> Mike K Smith <mks-usenet at dsl.pipex.com> writes:
>> So I can't plot the offsets in the loopstats file to show how accurate
>> the time was on an NTP client over a period of time?
> That is the best estimate that you have. Alternatively buy a GPS hook it up
> and measure the offset against that.
But, if you use individual measurements, you will get a figure that,
most of the time, is several times the true error and not necessarily in
the right direction.
What you can do, is to use some hindsight, and make a slightly better
estimate of the true time by combining offsets from both before and
after the time the local clock was read. That gives you an advantage
during startup and after transients, but, in the steady state, the local
clock time is going to be the same as such an enhanced statistic.
In the steady state, all you can really deduce from the offsets is the
amount of noise in the measurements. You can then expect the amount of
noise in the local clock time to be several times less.
More information about the questions