[LinuxPPS] offsets

[Udo van den Heuvel]

Hello,

A similar event:

GPS loses reception. PPS is lost.
PPS is gained when reception returns.
But my GPS is not chosen:

# ntpq -pn
     remote           refid      st t when poll reach   delay   offset
jitter
==============================================================================
 127.127.1.0     .LOCL.          10 l   42   64  377    0.000    0.000
 0.001
x127.127.20.0    .GPS.            0 l   14   16  377    0.000  -172.01
 0.990
+194.109.22.18   194.109.20.18    3 u   85  128  377    7.542    0.775
 0.265
-213.84.46.114   130.149.17.8     2 u   56  128  377   15.483   -2.626
 0.230
-87.233.14.148   17.72.133.45     3 u   72  128  377    8.614    1.034
 0.654
-80.69.93.212    158.43.128.66    4 u   27  128  377    8.206    2.188
 1.768
*213.239.154.12  193.190.230.65   2 u   77  128  377    8.752   -0.829
 0.353
-81.20.144.10    81.20.144.33     5 u   84  128  377   46.217    3.047
 3.566
-81.169.180.26   192.53.103.108   2 u   48  128  377   23.644   -7.888
 3.995
+81.2.209.38     147.231.100.5    3 u   69  128  377   36.520    0.058
 0.294

Although there is:

# Garmin GPS 18 LVC w/ PPS
#
server 127.127.20.0 prefer minpoll 4
fudge 127.127.20.0 flag3 1 flag2 0 time1 0.000

(note the prefer)


How come?
How can I avoid this?
Is this a LinuxPPS issue? (don't think so)
Issue for ntpd?

Udo



Udo van den Heuvel wrote:
> Hello,
> 
> Today I built ntp4.2.4p4 from the Fedora 9 repo for my updated Fedora 8
> box. I noticed after installing and starting this 4.2.4.p4 that the
> *remote* offsets were all in the 170-180 ms range. Normally *all*
> offsets are less than 20 ms, except when a remote host is off.
> After reinstalling the old (4.2.4p2) version behaviour returned to normal.
> 
> What would cause this situation? (160+ ms difference between local and
> remote)
> 
> (this is with the latest LinuxPPS and Garmin GPS-18 LVC)
> 
> Now:
> 
> # ntpq -pn
>      remote           refid      st t when poll reach   delay   offset
> jitter
> ==============================================================================
>  127.127.1.0     .LOCL.          10 l   32   64  377    0.000    0.000
>  0.001
> +127.127.20.0    .GPS.            0 l    5   16  377    0.000   10.894
>  0.217
> o127.127.22.0    .PPS.            0 l   10   16  377    0.000   10.901
>  0.218
> -194.109.22.18   193.67.79.202    2 u   36   64  377    8.049   16.175
>  0.613
> -213.84.46.114   192.87.106.2     2 u   16   64  377   15.823   15.511
>  0.604
> +80.85.129.25    130.235.20.3     3 u   59   64  377   11.185   11.535
>  0.786
> -81.171.100.41   66.187.224.4     2 u   11   64  377    8.301   13.687
>  1.182
> -81.171.44.131   193.79.237.14    2 u   64   64  377    8.376   12.329
>  0.484
> -88.191.32.45    88.191.254.7     3 u   32   64  377   24.176   12.925
>  0.718
> -83.243.84.13    131.234.137.23   2 u   31   64  377   15.195   21.860
>  1.546
> 
> Wrong:
> 
> # ntpq -pn
>      remote           refid      st t when poll reach   delay   offset
> jitter
> ==============================================================================
>  127.127.1.0     .LOCL.          10 l   14   64   77    0.000    0.000
>  0.001
> *127.127.20.0    .GPS.            0 l   15   16  377    0.000   18.850
>  2.440
>  127.127.22.0    .PPS.            0 l    -   16    0    0.000    0.000
>  0.001
> -194.109.22.18   193.67.79.202    2 u   54   64   77    7.712  187.631
>  6.844
> +213.84.46.114   192.87.106.2     2 u   34   64   77   15.324  185.215
>  6.117
> -80.85.129.25    130.235.20.3     3 u   43   64   77   11.387  171.763
> 12.705
> -81.171.100.41   66.187.224.4     2 u   12   64   77    8.518  189.615
>  7.808
> +81.171.44.131   131.188.3.221    2 u   61   64   77    8.524  180.844
> 10.188
> -88.191.32.45    88.191.254.7     3 u    4   64  177   24.023  181.464
>  6.884
> -83.243.84.13    131.234.137.23   2 u   17   64   77   15.247  185.467
>  6.801
> 
> 
> 
> 
> 
> Udo
> 
> _______________________________________________
> LinuxPPS mailing list
> LinuxPPS at ml.enneenne.com
> http://ml.enneenne.com/cgi-bin/mailman/listinfo/linuxpps
> Wiki: http://wiki.enneenne.com/index.php/LinuxPPS_support
> 
> 
>