Hi there! I have been quite a time nut for a while but recently I bought a GPS 18 LVC from Garmin and wired it up according to one of the many tutorials around the Internet. I have a static IP and if this works out OK I am thinking about opening my NTP port to the world. :-)
I am using FreeBSD 7.4 with a PPS_SYNC kernel and the GPS is connected to COM1. I am getting this tick# ntpq -p remote refid st t when poll reach delay offset jitter ============================================================================== *GPS_NMEA(1) .GPS. 0 l 11 16 377 0.000 0.007 0.004 +rustime01.rus.u .PPS. 1 u 38 64 377 59.228 1.422 1.749 -ptbtime2.ptb.de .PTB. 1 u 27 64 377 61.864 -2.420 0.922 +canon.inria.fr .GPSi. 1 u 37 64 377 44.454 1.346 0.728 and I think it's quite good but the problem is that my NTP daemon is hammering the other servers on the configuration file. As I don't want to get banned from using these servers I would like some opinions regarding my config file: tick# cat /etc/ntp.conf server 127.127.20.1 mode 2 prefer minpoll 4 fudge 127.127.20.1 flag1 1 flag3 1 refid GPS server rustime01.rus.uni-stuttgart.de server ptbtime2.ptb.de server canon.inria.fr 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 Any ideas? I have another machine that is physically close to this one I and got the PPS signal from the GPS connected to the DCD line of the COM port also. I intend to discipline the local clock with the PPS. I am numbering the seconds using stratum 1 servers. Here's the configuration: tock# cat /etc/ntp.conf server 127.127.22.1 minpoll 4 fudge 127.127.22.1 flag3 1 stratum 0 server rustime01.rus.uni-stuttgart.de prefer server ptbtime2.ptb.de prefer server canon.inria.fr prefer 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 The idea behind this is that if the server with the GPS is turned off for maintenance I will still have the other machine getting the PPS and the seconds from public NTP servers. Is this configuration correct? By the way, on this second machine I get tock# ntpq -p remote refid st t when poll reach delay offset jitter ============================================================================== oPPS(1) .PPS. 0 l 14 16 377 0.000 -0.004 0.002 +rustime01.rus.u .PPS. 1 u 175 1024 377 59.726 1.577 0.143 +ptbtime2.ptb.de .PTB. 1 u 170 1024 377 62.099 -1.806 0.165 +canon.inria.fr .GPSi. 1 u 493 1024 37 44.637 1.385 0.794 This one is polling the Internet servers every 1024 seconds. Why doesn't the other? One final question... Is 1ms difference from stratum 1 close servers (36ms) normal? For me it's quite good. Can it be better? stratum 1, precision -18, leap 00, trust 000 refid [PPS], delay 0.03641, dispersion 0.00078 transmitted 4, in filter 4 reference time: d1dba30e.893d3d9b Thu, Jul 28 2011 9:57:50.536 originate timestamp: d1dba34e.8d92e2b2 Thu, Jul 28 2011 9:58:54.553 transmit timestamp: d1dba34e.8a966c79 Thu, Jul 28 2011 9:58:54.541 filter delay: 0.03818 0.03641 0.03738 0.04140 0.00000 0.00000 0.00000 0.00000 filter offset: 0.002177 0.001189 0.001666 0.003551 0.000000 0.000000 0.000000 0.000000 delay 0.03641, dispersion 0.00078 offset 0.001189 28 Jul 09:58:54 ntpdate[4779]: adjust time server 193.136.250.246 offset 0.001189 sec Sorry for the large amount of questions but any help would be appreciated. Thanks! Cheers, Miguel _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions