[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 2.6.22.1-rt9 (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.
http://en.wikipedia.org/wiki/Power_over_Ethernet
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:
https://buy.garmin.com/shop/shop.do?pID=223&pvID=796
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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