On 13/11/2012 21:24, gbusenb...@yahoo.com wrote:
I am not sure if this is possible. I have a requirement from a customer that
the time must be within 10ms of the parent server which is on the same LAN. I
have tried several different things without an luck. NTP Time seems to get up
to 400ms with defaults.
I have tried to put the following within my ntp.conf file
tinker panic 0 step .3 stepout 60
driftfile <default>
server 10.1.126.204 iburst minpoll 5
server 127.127.1.0
fudge 127.127.1.0 stratum 12
If it is not possible to do 10ms, then I want to get the time as close as
possible. I really don't know much about NTP. I have tried my best to search
the web as much as possible however most people inclucding myself never use the
tinker other than with panic 0.
An example of what Windows PCs can do is shown here:
http://www.satsignal.eu/mrtg/performance_ntp.php
The top line is a FreeBSD stratum-1 server, to which the other PCs are
synced (Hydra, Narvik, Puffin, Bergen, Ystad). Several of the Windows
PCs have their own GPS/PPS reference clock (Alta, Bacchus, Feenix,
Stamsund).
The secret has been to make a tight connection between the Windows PCs
and the "best available" stratum-1 server by fixing the polling at 32
seconds. In your case, this may correspond to a line like:
server 10.1.126.204 iburst minpoll 5 maxpoll 5
On the basis of a test I tried recently, you might try using a FreeBSD
or Linux-based server to connect to remote server (this could be a
low-cost Raspberry Pi server, possibly with its own GPS), and sync the
Windows PCs tightly to that server. Even using Internet servers I saw
no more than an 5 ms reported offset with such a simple server:
http://www.satsignal.eu/ntp/2012-11-10-11-12-raspi1_ntp-b-day.png
http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html
If you can equip that intermediate server with a GPS/PPS source, so much
the better. You could also consider equipping one or more PCs with
GPS/PPS reference clocks.
You may find my Windows information helpful:
http://www.satsignal.eu/ntp/index.html
--
Cheers,
David
Web: http://www.satsignal.eu
_______________________________________________
questions mailing list
questions@lists.ntp.org
http://lists.ntp.org/listinfo/questions
