linuxptp-users

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

[shashank v. <sha...@gm...>]

Hello experts,
I need to configure PTP with linux bonding.

I can see it is supported in active-passive configuration.

I have following queries related to functioning of PTP with active-passive
bonding:

   - Will passive/standby slave PHC synchronize itself with active slave
   PHC when active-passive NIC ports are on different PHCs?
   - Does the passive NIC port's PHC is ready to take-over when the current
   active slave NIC goes down or does this require the passive NIC's PHC to
   synchronize first?


Thanks and regards
Shashank Varshney

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

[Miroslav L. <mli...@re...>]

On Mon, Apr 10, 2023 at 10:49:45PM +0530, shashank varshney wrote:
> I have following queries related to functioning of PTP with active-passive
> bonding:
> 
>    - Will passive/standby slave PHC synchronize itself with active slave
>    PHC when active-passive NIC ports are on different PHCs?

No, phc2sys doesn't know about the other interfaces in the bond.

>    - Does the passive NIC port's PHC is ready to take-over when the current
>    active slave NIC goes down or does this require the passive NIC's PHC to
>    synchronize first?

The latter. It's not a seamless switch.

-- 
Miroslav Lichvar

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

[shashank v. <sha...@gm...>]

Hi Miroslav,
I Hope you are doing well and thanks a lot for the response.

I was looking at Xillinx sfptpd utility and the following is the working
mechanism of PTP over the Linux bonded interfaces:

https://docs.xilinx.com/r/en-US/ug1602-ptp-user/PTP-over-Bonded-Interfaces

*PTP over Bonded Interfaces*

*sfptpd supports PTP packets over bonded interfaces in an active/standby
mode. In addition, sfptpd also supports bonding over LACP (802.3ad)
bonding.*

*Bonding of interfaces on supported adapters employs the Linux bonding
driver. Multiple ports can be included into a single bond where one port is
selected as the active interface and all others are standby.*

   - *sfptpd will detect which port is active and which ports are passive
   in the bond.*
   - *sfptpd will discipline the high precision clock on the active port’s
   network adapter.*
   - *sfptpd will discipline the clocks of passive ports from the active
   adapter’s clock.*
   - *Via the bonding driver you can select the active port (and therefore
   clock).*
   - *A bond can include non-PTP capable ports on a supported adapter.*

   *sfptpd will switch to software time-stamping when a non-hardware
   time-stamping port becomes active.*
   - *A bond can include third party ports .*

   *sfptpd will switch to software time-stamping when a third party port
   becomes active.*
   - *A bond can include any number of ports.*


 *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?*

Thanks and regards
Shashank Varshney

On Tue, Apr 11, 2023 at 12:50 PM Miroslav Lichvar <mli...@re...>
wrote:

> On Mon, Apr 10, 2023 at 10:49:45PM +0530, shashank varshney wrote:
> > I have following queries related to functioning of PTP with
> active-passive
> > bonding:
> >
> >    - Will passive/standby slave PHC synchronize itself with active slave
> >    PHC when active-passive NIC ports are on different PHCs?
>
> No, phc2sys doesn't know about the other interfaces in the bond.
>
> >    - Does the passive NIC port's PHC is ready to take-over when the
> current
> >    active slave NIC goes down or does this require the passive NIC's PHC
> to
> >    synchronize first?
>
> The latter. It's not a seamless switch.
>
> --
> Miroslav Lichvar
>
>

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

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

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

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

[shashank v. <sha...@gm...>]

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.

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.

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.


Thanks and regards
Shashank Varshney


On Sun, Apr 16, 2023 at 8:40 PM Richard Cochran <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
>

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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