Re: [Linuxptp-users] List of Boundary clocks

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

On Thu, Apr 04, 2013 at 01:04:49PM +0200, Mozhdeh Kamel wrote:
> 
> Actually I am going to design a network to run the PTP protocol(with BC).
> But the main problem for me is I don't access to real hardware. I though
> maybe using a PC with several network card (HW time stamping) would help.
> But, share clock is another problem!!!

With a small modification to ptp4l, you might be able to use multiple,
separate PCI cards together as a BC. We just need to disable* the check
in ptp4l that makes sure all the PHC clocks are the save. For example:

port1 eth0 /dev/ptp0 - ptp4l controls this clock, port connected to GM
port2 eth1 /dev/ptp1 - phc2sys instance 1 slaves this clock to /dev/ptp0
port3 eth2 /dev/ptp2 - phc2sys instance 2 slaves this clock to /dev/ptp0

In order to test how well phc2sys synchronizes the internal clocks,
you could run three separate ptp4l instances, one per port, and
connect all the ports to the same master through a switch. If you set
the ptp4l "free running" option on ports 2 and 3, then you can measure
the time error between the phc2sys servo and the PTP network time.

What PTP hardware do you have to choose from?
 
> Now, I am thinking of possibility to use of virtual switch, router and NIC
> .. Is anyone have experience of it?? Is it possible?

I am not sure what you mean by "virtual" here.

HTH,
Richard

* Or you could use a Linux kernel version before 3.5, without
  ETHTOOL_GET_TS_INFO support.