[Linuxptp-users] PTP Slave to Master Signaling

[Rohit Borse]

Hi,


In PTP protocol specification, I found Signaling message, which can be sent when PTP slave is Synchronized to PTP Master.


In linuxptp-1.3 stack, Is there any message to notify PTP

Synchronization Status (i.e.Synchronization lost) from PTP Slave to PTP Master or any command/message can be sent from PTP Master to Slave to check PTP Synchronization status?


Thanks and Regards,

Rohit Borse

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[Richard Cochran]

Post by Rohit Borse
In PTP protocol specification, I found Signaling message, which can
be sent when PTP slave is Synchronized to PTP Master.

Yes, there is a "Signaling" message in 1588, but it is not used in
that way.

Post by Rohit Borse
In linuxptp-1.3 stack, Is there any message to notify PTP
Synchronization Status (i.e.Synchronization lost) from PTP Slave to
PTP Master or any command/message can be sent from PTP Master to
Slave to check PTP Synchronization status?

To monitor synchronization status, use the "pmc" program.

HTH,
Richard

[Richard Cochran]

From PTP Master side code, can we know the PTP clock time status of
Remote Slave node using programmatic approach rather than using pmc
command.

If you don't want to use the pmc program, then you can send the
appropriate management messages directly. See pmc_common.h and
pmc_common.c for an example.

eg. If master A needs that clock time of master A is not in sync
with clock time of slave B, to send some signal to any dependent
module which would be helpful.

That is not the way it works. If node A wants information about node
B, then node A must request it. For your case, this implies that A
will poll the state of B.

So how master A can know if PTP time of slave B is not in sync/or in
sync.

1. Send the "GET PORT_DATA_SET" request and check that portState is SLAVE.
2. Send the "GET CURRENT_DATA_SET" request and check offsetFromMaster.

Currently we are planning to decide if Maser clock is not in sync
with slave Clock, if pDelayReq message is not sent by Slave for some
defined timeout. Is this suitable logic?

No, that won't work at all. The delay requests are sent periodically,
regardless of the synchronization status.

Cheers,
Richard