[ntp:questions] Bizzare half second disagreement between ntp hosts
unruh-spam at physics.ubc.ca
Tue Jan 1 00:26:13 UTC 2008
I have a very weird situation. I am running a GPS PPS (Garmin GPS18LVM)
with a few machines as a backup/initialization.
Sudeenly for about half and hour, my GPS failed for some reason ( still do
not know what was wrong since it had come back on air by the time I noticed
something wrong). Every hour I run a ntpq -p just to check that my gps is
on air. I got this report.
remote refid st t when poll reach delay offset jitter
xtick.usask.ca .GPS. 1 u 1003 1024 377 44.954 0.213 480.149
+sanrail.com 220.127.116.11 2 u 993 1024 377 1.486 -479.03 479.917
+raptor.tera-byt 18.104.22.168 2 u 322 1024 377 17.295 -480.35 0.766
*zeus.yocum.org 22.214.171.124 2 u 390 1024 377 70.415 -481.02 1.230
SHM(0) .PPS. 0 l 1415 16 0 0.000 -0.002 0.001
Now I believe the tick.usask.ca result, since all of the machines which use
mine as a source suddenly noticed a .48 second jump when my GPS failed. But
why in the world would three systems all suddenly be out by .48 sec?
Doing a peers on them, one has a GPS as its source, one a .WWVB. and one an
.ACTS. Why should all three suddenly be out by half a second?
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