[ntp:questions] Clock time synchronization of four computers
David J Taylor
david-taylor at blueyonder.co.uk.invalid
Mon Jul 9 06:51:40 UTC 2012
"Nazmul Islam" wrote in message
news:CAFtrfEZN5mhQ_bOdEG5KZ7L2kGA5s6NgsmFBHYkSmxxm9GF5rQ at mail.gmail.com...
>
> Hello,
>
> I have not used ntp processing before. I apologize in advance if my
> questions seem too novice.
>
> I am trying to synchronize the clocks of four computers. The timing does
> not have to be accurate but they have to be sync'd with each other. An
> error tolerance of 10-20 ms is acceptable. The computers are connected to
> the servers.
=============================================
In addition to Paul Kennedy's suggestion, you can make one or two computers
stratum 1 servers by adding a low-cost GPS device. These have serial RS-232
output which can be parallel connected to two PCs (on the PC's data input
and DCD lines), making two of the 4 PCs stratum-1 servers. You can peer the
two PCs with each other, and make these two PCs servers for the remaining
two. With a simple line driver you could likely connect all four PCs to the
GPS source. All PCs should also retain several Internet servers for backup.
I have descriptions of a couple of low-cost GPS devices on my Web site:
http://www.satsignal.eu/ntp/FreeBSD-GPS-PPS.htm
http://www.satsignal.eu/ntp/Sure-GPS.htm
The performance I get (using Windows) is shown here:
http://www.satsignal.eu/mrtg/performance_ntp.php
Cheers,
David
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