[ntp:questions] Win7: ntpd adjusting time backwards

David Lord snews at lordynet.org
Tue Dec 11 14:20:34 UTC 2012


David Taylor wrote:
> On 10/12/2012 21:18, David Woolley wrote:
>> Jeroen Mostert wrote:
>>
>>>>
>>> For what it's worth, after all of that, the offset is steadily
>>> zigzagging between 27 and 41 ms, which I'm guessing is about the best
>>> you can hope for on a Windows machine with Internet sync. There have
>>> not been any major time step adjustments.
>>
>> Offsets should be scattered around zero.  If they are all the same sign,
>> something is wrong.
> 
> What happens if the link to the Internet is rather asymmetrical?  For 
> example, here I am stuck with 30 Mb/s down, but only 3 Mb/s up.
> 
> I also note that with my PCs being stratum-1 servers or synced to local 
> stratum-1, there is an offset to the WAN servers of some number of 
> milliseconds, typically between +3 ms and +6 ms, but the LAN servers 
> have a near zero average offset.


Here just now I have only MSF stratum-1 which from loop_summary
is varying widely, over last 7 days from 61+/-1070 rms=266
to 2251+/-4282 rms=527. ADSL is about 12 Mbps down, 1200 kbps up.
Other server 21+/-598 rms=166 to 177+/-794 rms=368. During that
period NetBSD kernel and userland have been updated on both
servers involving 2-3 reboots.

The different down/up latency gets lost in the noise. I should
have GPS+PPS reconnected next week but don't remember that
showing any significant offset from the server with only internet
ntp sources.

David





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