[ntp:questions] ntp-dev: PPS is a falseticker?
mike cook
michael.cook at sfr.fr
Sat Jun 14 16:52:40 UTC 2014
Le 14 juin 2014 à 16:56, Rob a écrit :
>
>> By the way, you can have more than one server marked prefer.
>
> So the solution is to mark everything but the PPS server marked prefer?
> What is the value of that?
The documentation, although a bit long in the tooth, does not recommend multiple preferred peers:-
"While the rules do not forbid it, it does not seem useful to designate more than one peer as preferred, since the additional complexities to mitigate among them do not seem justified from on-air experience."
Let's see what happens:-
# muon stratum1 gps ref
server 192.168.1.4 iburst minpoll 4 maxpoll 4 prefer
# laurelineA GPS sync'd NTP server
server 192.168.1.23 iburst minpoll 4 maxpoll 6 prefer
# raspberry pi net sync'd NTP server
server 192.168.1.15 iburst minpoll 4 maxpoll 6 prefer
restart ntpd and let the dust settle:
Sat Jun 14 18:30:56 CEST 2014
remote refid st t when poll reach delay offset jitter
=========================================================
o127.127.22.1 .PPS1. 0 l 14 16 377 0.000 -0.004 0.008
+192.168.1.4 .PPS1. 1 u 11 16 377 0.874 0.047 0.010
+192.168.1.23 .GPS. 1 u 10 16 377 0.549 0.054 0.051
*192.168.1.15 192.168.1.23 2 u 9 16 377 0.918 0.498 0.056
now pull 192.168.1.15.
Sat Jun 14 18:36:37 CEST 2014
remote refid st t when poll reach delay offset jitter
=========================================================
o127.127.22.1 .PPS1. 0 l 2 16 377 0.000 -0.006 0.008
*192.168.1.4 .PPS1. 1 u 15 16 377 0.881 0.044 0.017
+192.168.1.23 .GPS. 1 u 15 16 377 0.552 0.053 0.008
192.168.1.15 192.168.1.23 2 u 158 16 0 0.914 0.422 0.052
192.168.1.4 gets selected and we still have PPS.
So while not being categoric about it, it looks like assigning multiple prefer peers may have some merit.
Mike
>
> _______________________________________________
> questions mailing list
> questions at lists.ntp.org
> http://lists.ntp.org/listinfo/questions
More information about the questions
mailing list