Richard B. Gilbert wrote: > Noob wrote: > >> 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. >> >> http://www.heoldesign.com/index.php?id=58 > > That link takes me to a page advertising THREE products! Which one did > you have in mind?
The HEOL-T101 (with a Fast Ethernet port). >> 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! Cool. (I'll give RFC 4330 a look.) >> What kind of accuracy may I expect? > > These devices should be accurate to within the range of 25 to 100 > nanoseconds. The spec seems to mention +/- 40 ns. > The limiting factor will be the jitter introduced while > getting the time into your computer. I plan to connect my box to the time server using a cross-over cable. (My box has 4 Ethernet ports, I will devote one to NTP traffic.) The RTT is very stable at 80-85 µs. > 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. I thought the error was on the order of half the RTT, i.e. I could hope for 40-50 µs in my situation? Regards. _______________________________________________ questions mailing list questions@lists.ntp.org https://lists.ntp.org/mailman/listinfo/questions
