[ntp:questions] PPS indication in ntpq

Miguel Gonçalves mail at miguelgoncalves.com
Tue Aug 2 20:56:25 UTC 2011


Hello all!

I recently installed a Garmin 18 LVC in the roof of my company. The
configuration for a FreeBSD 7.4 machine is as follows:

server 127.127.20.1 mode 2 prefer minpoll 4 iburst
fudge 127.127.20.1 flag1 1 flag2 0 flag3 1

server ntp02.oal.ul.pt iburst noselect
server ntp04.oal.ul.pt iburst noselect

statsdir        /var/log/ntp/
filegen clockstats      file clockstats type day        enable
filegen peerstats       file peerstats  type day        enable
filegen loopstats       file loopstats  type day        enable
statistics clockstats peerstats loopstats
logfile /var/log/ntp/messages

driftfile /etc/ntp.drift

I get this:

tick# ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*GPS_NMEA(1)     .GPS.            0 l   17   16  377    0.000    0.003   0.004
 ntp02.oal.ul.pt 194.117.9.129    2 u  157  256  377   15.469   -1.038  12.814
 ntp04.oal.ul.pt 194.117.9.138    2 u  150  256  377   15.660    0.266  44.672

Yet, on another FreeBSD 7.4 machine where I have a Sure GPS board with
the following configuration:

server 127.127.20.1 mode 18 minpoll 4 prefer
fudge 127.127.20.1 flag1 1 flag2 0 flag3 1 time2 0.400

server ntp02.oal.ul.pt iburst noselect
server ntp04.oal.ul.pt iburst noselect

statsdir        /var/log/ntp/
filegen clockstats      file clockstats type day        enable
filegen peerstats       file peerstats  type day        enable
filegen loopstats       file loopstats  type day        enable
statistics clockstats peerstats loopstats
logfile /var/log/ntp/messages

driftfile /etc/ntp/ntp.drift

I get this

tock# ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
oGPS_NMEA(1)     .GPS.            0 l    9   16  377    0.000    0.220   0.077
 ntp02.oal.ul.pt 194.117.9.129    2 u   36   64   77   16.633    0.416   0.898
 ntp04.oal.ul.pt 194.117.9.138    2 u   39   64   77   16.910    0.721   1.373

The high offset for the GPS clock is because I just restarted the ntp
daemon and it takes a while to lock.

Why one shows the GPS clock sync status with a o and another with the
more common *?

Can anyone help me please?

Thanks!



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