[ntp:questions] NTP.ORG MEINBERG KEEP TIME ACCURATE to 10MS

unruh unruh at invalid.ca
Tue Nov 13 23:48:01 UTC 2012


On 2012-11-13, gbusenberg at yahoo.com <gbusenberg at 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.

??? Maybe more information would be good. I easily get 20 microseconds
(not milliseconds) on a lan from a server (GPS PPS Stratum 1) on that same lan.

I cannot see how, even if you try really really hard, you could get 10
milliseconds. 

>
> 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

Get rid of the last two lines. Not sure why the first is there either. 


>
> 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.

It is really hard to get 10ms-- that is so bad that it would take a
special genius to do it:-)

Give us more information, including how you are concluding that you are
only getting 400ms. (Note that ntpd will step if the time is 128ms out.
Ie, that is considered to be so horrible that slewing the clock is
pointless.)




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