Ciao Cluadio,
I try to answer to your questions:
· The Linux kernel supports PTP since version 3.0 but Red Hat has
backported this support into 2.6 starting from RHEL 6.4. For your information
I’m using RHEL 6.5 with and Intel i350 without issues.
· Correct me if I’m wrong but, as far as I know, one of the most
important difference between PTPd and linuxptp is that the first one doesn’t
support HW timestamping like the second one does. This was true almost in
earlier version. I heard that there were some plan to add HW timestamp support
into PTPd but I don’t know which is the status….
· Regarding your synchronization issues with ptp4l and phc2sys
sincerely I don’t know… For me works fine, I think that more details/logs are
needed.
Sincerely
William
From: Claudio Scordino [mailto:clau...@evidence.eu.com]
Sent: 18 January 2016 10:22
To: linuxptp-devel@lists.sourceforge.net
Subject: [Linuxptp-devel] Use of PTP on CentOS 6
I need to create a reliable and accurate synchronization between two CentOS 6
machines connected through a direct Ethernet connection.
I've seen that on Linux several implementation of the IEEE 1588 Precision Time
Protocol (PTP)<https://en.wikipedia.org/wiki/Precision_Time_Protocol> exist:
* PTPd<http://ptpd.sourceforge.net>:
* Apparently, this is the original implentation
* Apparently, it is still maintained<http://www.github.com/ptpd/ptpd>
* PTPd2<http://ptpd2.sourceforge.net>:
* A new version meant to supersede the previous implementation
* Apparently unmaintained
* For CentOS 6, available only in the EPEL repositories
* PTPv2d<http://code.google.com/p/ptpv2d>:
* A further implementation
* Unmaintained as well
* linuxptp<http://linuxptp.sourceforge.net>:
* A specific implementation for Linux
* Maintained
* Available on the CentOS repositories
* Suggested by the RedHat documentation for both RedHat
6<https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/ch-Configuring_PTP_Using_ptp4l.html>
and RedHat
7<https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/System_Administrators_Guide/sec-Using_PTP.html>
My questions follow:
* Why does the RedHat documentation suggest the use of
linuxptp<https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Deployment_Guide/s1-Installing_PTP.html>
for RedHat 6 (based on Linux kernel 2.6) despite the linuxptp documentation
says that a Linux kernel version 3.0 or newer is
needed<http://linuxptp.sourceforge.net/> ?
* Which are differences between PTPd2 and Linuxptp in terms of reliability
and timing accuracy ?
* Why when I run ptp4l and phc2sys, the machines do not synchronize
immediately and often need me to start/stop the services several times or
manually change system time through date to make the machine synchronize ?
Many thanks and best regards.
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