[ntp:questions] SNTP server + ntpd 4.2.4 client

Noob root at localhost.invalid
Wed Mar 19 09:40:22 UTC 2008

Unruh wrote:

> Noob wrote:
>> Unruh wrote:
>>> SNTP is a client protocol, not a server, according to RFC.
>> You keep saying that. Which RFC are you referring to?

Apparently, you forgot to answer this question ;-)

>> 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.
> Just looked it up. A bit bizarre -- power over the ethernet? The ethernet
> has no power supply capability.

Engineers do all sorts of crazy things.


Anyway, I didn't plan on using that feature.

> The GPS timing claimed is 40ns, but the timestamp is only 10usec. How much
> does this thing cost?

Over 1000 euros (!!) AFAIU.

> Are you really in a situation where this is a better
> solution than say a cheap Garmin 18LVC?

I've already told my boss several times about the GPS18LVC. I'm not 
sure why he ignores my request to test a unit.

Reference to self:

The HEOL-T101 comes with a very stable XO (OCXO perhaps?) accurate 
within +/- 30 ppb. How much does such an XO cost?

Does the GPS18LVC provide an oscillator to serve time even when there 
are not enough satellites in sight?

>> 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.
> You have not told us what the requirements are, so what "will work" is
> is unclear. Yes, I am sure it will discipline your computer's clock.
> probably to better than ms accuracy.

My goal was clearly stated in my original message: Will the new setup 
provide better accuracy than the current setup.

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