Re: [Linuxptp-users] Want to reduce offset (which is distance dependant) between boundary clocks.

[Richard C. <ric...@gm...>]

On Tue, Jan 19, 2016 at 09:47:40AM +0530, Aniket Hendre wrote:
> Richard I have a server class machine (Dell R720) which is locked to my
> GPS10RBN frequency and time standards unit using Network Time Protocol
> (NTP). Simultaneously I have 1PPS out from GPS10RBN which I have connected
> to my server class machine. NTP daemon has been configured on server class
> machine to use this 1PPS by adding following line in /etc/ntp.conf.
> 
> server 127.127.22.0 minpoll 4 maxpoll 4
> fudge 127.127.22.0 refid PPS flag3 1 flag4 1 time1 -0.060

Do you have a GPS at the master and at the slaves nodes, or only at
the master?
 
> So I do believe that my Dell R720 is now behaving like a PTP grandmaster.
> (correct me if I am wrong).

Well, NTP will correct the Linux system time, but not the time in your
PHC device.

What MAC/PHY hardware are you using?

How have you configured ptp4l and phc2sys on each node?
 
> I am now trying to first synchronise two PHY clock by running ptp4l, where
> I have observed offset changes w.r.t distance.

What do you mean by "observed offset changes"?  Do you mean perhaps
the observed jitter?

ptp4l will always reduce the observed offset to zero, even in the
presence of asymmetry.


Thanks,
Richard