[Linuxptp-users] PMC differences between udp and UDS

[Ledda William EXT]

Dear all,
I would know about the difference behaviour of pmc when launched on the ethernet interface or on the UDS. Suppose that I would get the PORT_DATA_SET of the local port. To do this I run pmc as follow:

$ sudo -E ./pmc -b 0 -i eth1 "GET PORT_DATA_SET"
sending: GET PORT_DATA_SET
008063.fffe.db5d80-1 seq 0 RESPONSE MANAGEMENT PORT_DATA_SET
portIdentity 008063.fffe.db5d80-1
portState INITIALIZING
logMinDelayReqInterval 3
peerMeanPathDelay 0
logAnnounceInterval 1
announceReceiptTimeout 3
logSyncInterval 0
delayMechanism 1
logMinPdelayReqInterval 0
versionNumber 2
008063.fffe.db5d80-2 seq 0 RESPONSE MANAGEMENT PORT_DATA_SET
portIdentity 008063.fffe.db5d80-2
portState MASTER
logMinDelayReqInterval 3
peerMeanPathDelay 0
logAnnounceInterval 1
announceReceiptTimeout 3
logSyncInterval 0
delayMechanism 1
logMinPdelayReqInterval 0
versionNumber 2
...

$ sudo -E ./pmc -b 0 -u "GET PORT_DATA_SET"
sending: GET PORT_DATA_SET
00106f.fffe.223fc9-1 seq 0 RESPONSE MANAGEMENT PORT_DATA_SET
portIdentity 00106f.fffe.223fc9-1
portState SLAVE
logMinDelayReqInterval 3
peerMeanPathDelay 0
logAnnounceInterval 1
announceReceiptTimeout 3
logSyncInterval 0
delayMechanism 1
logMinPdelayReqInterval 0
versionNumber 2

Using the ethernet interface I get the port dataset of all ports of the Boundary Clock where my local port is connected, but not the port dataset of the local port. Using UDS I get the port dataset of the local port but not of the boundary clock. Is there any special reason about this difference? Am I doing something wrong? It is a matter of standard or simply an implementation detail? I was using version 1.3 but I have seen it is the same on 1.6.

Thank you all

William

[Richard Cochran]

Post by Ledda William EXT
Using the ethernet interface I get the port dataset of all ports of
the Boundary Clock where my local port is connected, but not the
port dataset of the local port. Using UDS I get the port dataset of
the local port but not of the boundary clock. Is there any special
reason about this difference?

When you send out through the Ethernet interface, the local port does
not receive the message, and even if it did, it cannot reply to
itself. So, to get local status, use the UDS method.

If you use '-b 1' with the UDS option, then ptp4l will forward the
message, and you should see replies from your BC as well.

HTH,
Richard

[Ledda William EXT]

Thank you Richard now it is everything more clear, and yes I have noted that using '-b 1' over UDS I get the replies from BC as well. I was curious about the different response between the two cases.

Cheers
William


-----Original Message-----
From: Richard Cochran [mailto:***@gmail.com]
Sent: 11 April 2016 20:33
To: Ledda William EXT
Cc: linuxptp-***@lists.sourceforge.net
Subject: Re: [Linuxptp-users] PMC differences between udp and UDS

Post by Ledda William EXT
Using the ethernet interface I get the port dataset of all ports of
the Boundary Clock where my local port is connected, but not the port
dataset of the local port. Using UDS I get the port dataset of the
local port but not of the boundary clock. Is there any special reason
about this difference?

When you send out through the Ethernet interface, the local port does not receive the message, and even if it did, it cannot reply to itself. So, to get local status, use the UDS method.

If you use '-b 1' with the UDS option, then ptp4l will forward the message, and you should see replies from your BC as well.

HTH,
Richard