paul wrote: > Hi All, I'm new to NTP, glad to meet you here. > > I did some experiments to test NTP performance on WINNT. In an > isolated network, two machines are inter connnected with a switcher. > Machine A is configure as a stratum 12 NTP server, using lcl as > reference clock; machine B is sychronized to machine A. Then, 'ntpq - > p' is performed on machine B every 16 seconds. The output of ntpq is > cooked by a python script and offset field is recorded to log file. > After about 2 hours, I check the log file and found the offset value > is 4 ~ 8 ms. Is this normal? I mean if things are properly done, how > small the offset I can expect? Thanks. > > The OS is Windows XP Pro SP3 and NTP software is 4.2.4-p7 from > mainberg.
Paul, For comparison, I have the performance of a mixture of Windows systems running a mixture of NTP versions plotter here: http://www.satsignal.eu/mrtg/daily_ntp.html The Windows XP system synced to a local stratum-1 clock is Narvik, showing an offset of within 1.5ms, but that is with a poll interval clamped to 64s. The best is the system Feenix with a local GPS serial and PPS reference clock (but no temperature control) where the offset is within about 0.2ms, and the worst the Windows Vista system Gemini which has a DVB/USB data reception system capturing about 20GB/day, but clobbering the offset with transient peaks of at least 50ms. "How long is a piece of string...." comes to mind! Cheers, David _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
