On Fri, Jan 15, 2016 at 03:51:57PM +0530, aniket wrote: > In my first experiment, master and slave are 2 Km away from each other. > In this case I got offset at slave PHY clock around 50 nano second. > > In second experiment I relocate my slave around 20 Km from master where > I got offset of 150 nano seconds.
So you are checking against GPS, right? > Ideally the offset between PHY clocks should remain constant though we > are varying distance between them (correct me if I am wrong). If the system is properly calibrated, then the offset should be minimal, and the difference in distance should be reflected in the path delay. > Do we need to specify any parameter (which is distance dependant) while > issuing above command? Because there are many PROGRAM AND CLOCK OPTIONS > in ptp4l. Do we need to set any specific option? We do have options to calibrate the system: delayAsymmetry - corrects for any asymmetry between the Rx and Tx paths egressLatency - corrects the transmit latency at the MAC/PHY ingressLatency - corrects the receive latency at the MAC/PHY What you observe sounds like an asymmetry. If it is, then it is surprising to me that the asymmetry grows with distance. Then again, I don't know anything about your equipment, and so maybe this is simply a property of your fibre optic links. HTH, Richard ------------------------------------------------------------------------------ Site24x7 APM Insight: Get Deep Visibility into Application Performance APM + Mobile APM + RUM: Monitor 3 App instances at just $35/Month Monitor end-to-end web transactions and take corrective actions now Troubleshoot faster and improve end-user experience. Signup Now! http://pubads.g.doubleclick.net/gampad/clk?id=267308311&iu=/4140 _______________________________________________ Linuxptp-users mailing list Linuxptp-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linuxptp-users
