[ntp:questions] SNTP server + ntpd 4.2.4 client

Noob root at localhost.invalid
Tue Mar 18 09:32:28 UTC 2008

Unruh wrote:

> SNTP is a client protocol, not a server, according to RFC.

You keep saying that. Which RFC are you referring to?

> We have absolutely no idea what you are running on all your machines. You
> never told us. This was an assumption based on the weird conditions you
> stated. It really really helps if you give information when you ask for
> help so that the help may actually be helpful. Tell us what your system is,
> what "SNTP program" you are using as the server, what the other client
> machines on the lan are running.

The only client is an x86 PC running Linux (i.e. with 
real-time extensions) and ntpd 4.2.4p0 at 1.1472.

The server is an embedded device (HEOL-T101) with a GPS receiver and a 
Fast Ethernet port. I have no idea what operating system runs on the 
device; there might not even be an OS. The manufacturer claims the 
device implements SNTPv4 instead of the full NTP.

( http://www.heoldesign.com/index.php?id=58 )

I plan to connect the two systems with a cross-over Ethernet cable.
The round-trip time between the two systems would be 80-85 µs.

> If you attach a GPS PPS receiver to one of your boxes (the server) and you
> use a reasonable client then yes you can expect much better than 100 µs
> accuracy on your net-- assuming it is not overloaded and the machines are
> not overloaded with disk activity.

The GPS receiver is inside the embedded device, which will serve time 
over its Ethernet port.

Considering the answers I've been given by you and by others in this 
thread, I believe there is a good chance that the setup outlined above 
will work.

More information about the questions mailing list