First: Thanks for the extensive responses, not exactly common on some
mailing lists :)

2018-03-06 18:53 GMT+01:00 Richard Cochran <>:
> It really isn't rocket science.  Here is an (untested) awk script that
> accepts responses from exactly one port:

My issue is a bit different from the script solution (and I'm not 100% sure
the script is robust to my issue):
I currently fork and execv pmc once, creating pipes for stdin, out and err.
On a regular interval, I send 'GET WHATEVER_DATA_SET' to stdin and wait for
to respond (wait for '{Identity} RESPONSE MANAGEMENT WHATEVER_DATA_SET').
But if the single device only querys every 5 seconds and another pmc on the
net sends GET requests with boundary hops > 0, the stdout will deliver a
lot of messages that might not contain what I want.
If I always take the first correct response - Identity pair, I will soon
only read outdated data.
Considering what mess we created here in the network by just having 5-10
devices missusing pmc, stdout was a constant stream of unwanted data.

> Using UDS is not part of 1588.  The UDS client has no 1588 port ID at
> all.  Therefore, we set the source port ID to zero.
Understood, expected something like this.

> I don't really see the need, as you can filter the pmc output fairly
> easily.
See above, I have to disagree on the "easy" part.

> A fully featured PTP network monitoring program is really a
> new feature for future development.
More of a "local only" option for pmc.

> I don't think your network setup is very common.  Normally, you would
> have just one PC sending monitoring requests into the network, not
> dozens.
Normally -> You know these "Users", don't you? ;)

> > b) is there a reason not
> > to use IP_MULTICAST_LOOP on the IPv4 port for pmc?
> Actually, that won't work the way that you would want it to.  The
> transmitted frames from pmc will be looped back, but the multicast
> responses from ptp4l will not.
True :/

Best regards, Olli
Check out the vibrant tech community on one of the world's most
engaging tech sites,!
Linuxptp-users mailing list

Reply via email to