Re: [Linuxptp-users] ptp4l passive phc synchronization with active phc in linux bonding

[Johannes Z. <j....@pe...>]

Hi Shashank,

On 6/6/23 08:51, shashank varshney wrote:
> Hi Richard/Miroslav,
> Hope you are doing good.
> 
> As mentioned, PTP switchover from one NIC port to another is not seamless when 
> ports belong to different NICs with different hardware clocks.


if the different ports of your endpoint are taking part in the same PTP domain 
and if they are synchronized there should be little or no offset. Why not using 
2 different NICs and having 2 daemons sync to the network? I don't quite get 
why you would even want to run PTP over LACP or something alike (using LACP in 
Realtime Network with tight timing budgets is asking for trouble anyway...).

Maybe I entirely miss your point, but from reading this thread, I'd recommend 
to review your system design.

> 
> I am looking to utilize PTP for very time sensitive use cases like 5G wireless, 
> stock markets, etc. which desire High Availability and redundancy at NIC port 
> level while utilizing PTP.

You probably want to look a bit closer on PCR/FRER for data transport, the 
different ports of your talker/listener devices can take part in a single 
(g)PTP domain.

> 
> This is going to be a significant use case if we would like to move to open 
> sourced environment and LinuxPTP is going to have significant role to play to 
> achieve this aspect.
> 
> Can someone help me with getting this functionality of seamless switchover by 
> synchronizing Active Port PHC with PTP GM and then synchronizing system clock 
> and standby PHCs with active PHC?
>
> PS: I am not from development background so it will be difficult to develop 
> this functionality from my end. So need community help to get this functionality.
>


This is not quite how the opensource community works - we can give you pointers 
and discuss the technical background, but you will probably not find anyone who 
does the implementation _for_ you, at least not for free.
You can either participate in the effort yourself or hire someone to do it, 
there is quite a lot of companies as well as well as freelance individual 
contributors with tons of expertise in PTP.

Best regards
Johannes

> 
> Thanks and regards
> Shashank Varshney
> 
> 
> On Sun, Apr 16, 2023 at 8:40 PM Richard Cochran <ric...@gm... 
> <mailto:ric...@gm...>> wrote:
> 
>     On Sun, Apr 16, 2023 at 01:54:20PM +0530, shashank varshney wrote:
> 
>      > *sfptpd supports PTP packets over bonded interfaces in an active/standby
>      > mode. In addition, sfptpd also supports bonding over LACP (802.3ad)
>      > bonding.*
> 
>     Looks like sfptpd is a hacked version of the old ptpd program.  If
>     that works for you, then great.
> 
>      >  *Is there any plan to include a similar kind of working mechanism for PTP
>      > over Linux Bonding for seamless switchover in case of failure of
>      > active-slave port to passive-slave port when both slaves are on different
>      > NICs with different PHCs?*
> 
>     I'm not aware of any plan for that.  If you feel like adding it, then
>     we'll look forward to your patches on the list...
> 
>     Thanks,
>     Richard
> 
> 
> 
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