[ntp:questions] About use of PPS in NTP sync

David Taylor david-taylor at blueyonder.co.uk.invalid
Mon Jun 16 05:19:27 UTC 2014


On 16/06/2014 04:29, jthulard at gmail.com wrote:
> Hello,
> I'm looking for a way to speed up the ntp convergence of a system which would be restarted after several days being off. Does the use of PPS improve this convergence time ?
> This is local configuration, with one LAN and one NTP server, with about 30 NTP clients.
>
> Thank you.
> JT

How accurate are you wanting the system to appear?  Fractions of a 
second?  Milliseconds?  Microseconds?  I run with maxpoll 32 seconds on 
my clients connected to a local server, and they converge very rapidly 
(it takes a short time to get within a few milliseconds, which is their 
ultimate offset range).  The GPS/PPS servers are quickly within a 
millisecond (say the few minutes it might take GPS to sync if it's been 
off for a long time and has to download full ephemeris data), but might 
take an hour or three for them to reach their ultimate microsecond-level 
offset.

-- 
Cheers,
David
Web: http://www.satsignal.eu



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