[comp.protocols.time.ntp] xntp, reference clock via dialup modem?

mats@enea.se (Mats Josefsson) (03/20/91)

We have been running xntpd on a number of HP 9000/800
machines for a while. Since we have no connection to the
internet, we have been synchronizing to the builtin clock
on one of our hosts. We are quite happy with the
synchronization, but since the clock drift is about one
second per day we would like to get more precision in the
absolute time keeping.

Through a dialup modem we can reach the Swedish PTT's
cesium clocks which would make it possible to get time
readings to an accuracy of about +/- 20 ms (they say).
Since it's a dialup line we can't expect to have a
continous connection. We must use some type of polling
scheme.

My question is:

	Which is the best way to use this clock source to
	periodically adjust the time of our network of
	machines? 

An absolute accuracy of a few seconds would be sufficient,
we just want to avoid doing the adjustment manually.

Should we poll the cesium clock a few times every
day and set the clock of our current stratum 1 machine
via settimeofday()?
	
Do we have to write our own clock driver? In this case
will it be sufficient to poll the cesium clock just a
few times a day.

Mats Josefsson (mats@enea.se)
Enea Data AB 
Sweden

Mills@udel.edu (03/20/91)

Mats,

You might consider running NTP with timer.unik.no and/or timer.nta.no,
which are primary servers synchronized directly with the Norwegian
cesia and LORAN-C.

Dave