[time-nuts] NTP stratum 0
M. Warner Losh
imp at bsdimp.com
Sat Jan 14 14:19:51 EST 2006
In message: <000a01c6193a$03346200$0500a8c0 at darius.domain.actdsltmp>
"Bill Hawkins" <bill at iaxs.net> writes:
: Perhaps it needs to be better than a millisecond. I remember an
: NTP accuracy of 100 microseconds, after enough round-trip time
: statistics were gathered. Perhaps the net is noisier now, and
: more uncertain. That certainly characterizes the messages carried
: by the 'net.
My rough and ready rule was based on the 'people noticing and
complaining' standard, which is fairly easy to meet... I base this on
one of our main ntp servers that gets its time from a machine that's
connected to a GPS server, as well as a few ohters and routinely see
remote refid st t when poll reach delay offset jitter
+EnsembleAGPS.ti .GPS. 1 u 160 1024 377 1.200 -4.389 0.072
+tick.usnogps.na .USNO. 1 u 223 1024 377 98.290 2.130 0.646
*india.colorado. .ACTS. 1 u 395 1024 376 61.283 0.514 4.185
: In any event, the noise from the frequency standards should be at
: least a factor of ten smaller than the filtered noise limit of the
: Internet, IMHO.
It should be about a thousand times better...
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