[ntp:questions] SNTP server + ntpd 4.2.4 client
Richard B. Gilbert
rgilbert88 at comcast.net
Fri Mar 14 14:44:34 UTC 2008
> I've been running ntpd 4.2.4 to synchronize my system clock using remote
> stratum 2 servers as a reference. (The RTT to these servers is in the
> 30-50 ms range.) The accuracy is in the 1-2 ms range, based on the
> reported offset.
> I've been asked to evaluate the following time server, in order to reach
> a better accuracy than what the current setup provides.
That link takes me to a page advertising THREE products! Which one did
you have in mind?
> (AFAIU, this time server implements SNTP, not the full NTP.)
> The idea would be to put this (stratum 1) time server in the same LAN as
> my box, and add it my ntp.conf. (The RTT on the LAN is on the order of
> 100 µs.)
> Will it work?
It should work.
> Is it a problem that the time server only implements SNTP?
It should not be a problem. The largest difference between NTP and SNTP
is the effort to account for the vagaries of the internet!
> What kind of accuracy may I expect?
These devices should be accurate to within the range of 25 to 100
nanoseconds. The limiting factor will be the jitter introduced while
getting the time into your computer.
A SWAG (Scientific Wild Ass Guess) would be 500 microseconds. By
spending a lot of time and effort you might be able to get something
better than that. The chief difficulty would be measuring and
controlling the delays within the computer.
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