Re: [Linuxptp-users] Building a PTP grandmaster with disciplined oscillator

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

On Tue, Mar 08, 2022 at 12:38:46PM +0100, Andre Puschmann wrote:
> Dear all,
> 
> we are trying to build a PTP grandmaster with linuxptp to provide sync
> signals to telco equipment.
> 
> So far we've only used the internal oscillators of the NIC for a bunch of
> cards, Intel based and also Microchip LAN7430.
> 
> I am now looking into disciplining the oscillators with an external PPS
> input to improve frequency stability. The EVB-LAN7430 eval kit has a PPS
> input exposed over a GPIO pin.
> 
> I was wondering if someone has used this successfully at all?

Yes, I would guess so.
 
> In general, what are the steps to set this up? Is this something managed in
> the NIC driver itself or do I have to (permanently) run the `ts2phc` to keep
> to PHC in sync?

You need to run ts2phc or similar.  In general, the NICs are dumb devices.
 
> Are there studies/measurements that compare the stability of such a system
> to e.g. commercial PTP grandmaster solutions?

I haven't seen any.  I've done my own reports showing, for example,
linuxptp + Intel210 + uBlox GPS radio performing comparably to
commercial GM solutions.

However, making a reliable GM product is quite a bit of work.  The PTP
software stack is only one piece of the puzzle.

HTH,
Richard