On Mon, Aug 17, 2015 at 02:14:36PM +0000, Harold Lapprich wrote: > "If you run ptp4l on all your systems, and each one also running > phc2sys, it will: > > on system which is "master" > > phc2sys will drive the ptp4l hw clock based on local time > > ptp4l will sync time out the network using PTP > > on systems which are not master > > ptp4l will sync time in from network to hw clock > > phc2sys will sync hw clock to CLOCK_REALTIME. > > But if you want to also use NTP as a clock source, then you need to use > timemaster, as otherwise phc2sys and ntpd will interfere with each other."
Strictly speaking you just need to configure phc2sys to use the NTP SHM servo to feed chronyd/ntpd so they can select the best source or combine multiple sources and synchronize the clock. That's how phc2sys is configured by timemaster. Do you need NTP as a time source? Or just serve time over NTP? The former conflicts with your requirement to allow ptp4l to be a master as phc2sys would need to be the process that synchronizes the clock and not chronyd/ntpd. If you just need to serve NTP, you can configure chronyd/ntpd to not synchronize the clock and keep phc2sys in the control of the clock. > So when NTP is to be the clock source (and vice versa) then 'timermaster' is > needed because phc2sys and ntpd will interfere with one another. Now the > problem is GrandMaster failure, if I understand you correctly when another > PTP system on the network becomes the GrandMater 'timemaster' will NOT > automatically reconfigure and start using NTP as the clock source (using > timemaster to start PTP configuration on all systems on the PTP network)? The problem is that when phc2sys is configured to feed chronyd/ntpd, it is not able to synchronize the PTP clock in the reverse direction when ptp4l is master. > If this is the case then one would have to have another application running > in the background to detect the switch, create the appropriate 'timemaster' > configuration file and start? There is currently no way to configure timemaster to serve local time over PTP. phc2sys would need to allow that first. -- Miroslav Lichvar ------------------------------------------------------------------------------ _______________________________________________ Linuxptp-users mailing list Linuxptp-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-users