Miguel Gonçalves wrote:
Hi Dave!
2011/10/14 Miguel Gonçalves<[email protected]>:
tock# /usr/local/bin/ntpq -p -c as
remote refid st t when poll reach delay offset jitter
==============================================================================
oGPS_NMEA(0) .GPS. 0 l 5 16 377 0.000 -0.004 0.004
*ntp-p1.obspm.fr .TS-3. 1 u 54 64 377 50.254 -1.269 7.885
+ptbtime1.ptb.de .DCFa. 1 u 59 64 377 69.087 -0.863 11.519
+ntp1.oma.be .PPS. 1 u 64 64 377 60.841 1.052 8.067
+canon.inria.fr .GPSi. 1 u 58 64 377 54.529 -2.730 9.511
-ntp1.nl.uu.net .PPS. 1 u 54 64 377 58.920 3.072 1.294
ind assid status conf reach auth condition last_event cnt
===========================================================
1 64946 974a yes yes none pps.peer sys_peer 4
2 64947 963a yes yes none sys.peer sys_peer 3
3 64948 9424 yes yes none candidate reachable 2
4 64949 9424 yes yes none candidate reachable 2
5 64950 9424 yes yes none candidate reachable 2
6 64951 9324 yes yes none outlyer reachable 2
The NMEA clock is being selected as a PPS peer and it was (last_event)
a sys_peer. At the moment an Internet server is the PPS peer.
When fiddling with another machine with a GPS clock last night I found
out this morning that the clock was being considered a false tick:
tock# ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
xGPS_NMEA(0) .GPS. 0 l 3 16 377 0.000 -0.003 0.001
I decided to use NMEA for second numbering and the PPS driver for the
PPS. I found out that the NMEA clock was showing a lot of jitter so
NTP couldn't use NMEA for second numbering and was thus marking it as
false ticker. So I added
tos mindist 0.25
to ntp.conf and it is now
tock# ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
*GPS_NMEA(0) .GPS. 0 l 9 16 377 0.000 -9.147 8.775
oPPS(0) .PPS. 0 l 8 16 377 0.000 0.001 0.002
I did the same on the other machine (the one I reported earlier and
that is a pool server) and I am getting the expected behaviour:
tick# ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
oGPS_NMEA(0) .GPS. 0 l 9 16 377 0.000 0.000 0.004
+ntp-p1.obspm.fr .TS-3. 1 u 4 64 377 44.041 1.249 3.316
+ptbtime1.ptb.de .DCFa. 1 u 11 64 377 67.837 0.566 3.670
-ntp1.oma.be .PPS. 1 u 9 64 377 53.601 4.567 5.302
+canon.inria.fr .GPSi. 1 u 11 64 377 44.790 1.415 1.406
+ntp1.nl.uu.net .PPS. 1 u 13 64 377 58.364 3.385 142.094
By the way, why are servers that use GPSi or PPSa as the refid? I
searched the archives and couldn't find an answer.
The refid is an arbitrary set of up to 4 ascii characters, each driver
has a default name, but this can be easily overridden:
fudge x.x.x.x refid 'XYZ'
Terje
--
- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"
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