Re: [Linuxptp-users] phc2sys: Bouncing Back and Forth Between Master and Slave
PTP IEEE 1588 stack for Linux
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From: Richard C. <ric...@gm...> - 2015-09-16 17:59:28
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On Wed, Sep 16, 2015 at 04:17:55PM +0000, Harold Lapprich wrote: > In a current design using PTP IEEE-1588 (linuxptp) for clock > synchronization one of the systems continues to bounce back and > forth from master to slave and vice versa and the other systems > maintain original master and slave status determined some time > ago. From my understanding the hierarchy is created and updated > automatically by the best master clock (BMC) algorithm that runs on > every clock ( or PTP IEEE-1588 system), so is this a case where one > system determines it should be the master and then drops back to > slave (is this correct operation, if not is there some attribute > setting for minimizing the occurrence)? Yes, the BMC determines the role of each port automatically. And no, there is no attribute to prevent the role changing. This is supposed to happen if the GM goes missing, for example. You *can* influence the timing of the BMC using logAnnounceInterval and announceReceiptTimeout. See the ptp4l man page for details. Richard |