Questions tagged [ptp]

Precision Time Protocol is used to synchronize clocks with sub-microsecond accuracy.

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Is PTP really more precise than NTP? If so, why?

I have read quite a bit about NTP and PTP time keeping protocols. While many sources claim that PTP is more precise than NTP for that type of granularity - the reason is not as clear. Why can't NTP be ...
Palace Chan's user avatar
3 votes
3 answers
5k views

Why PTP uses Sync-followup pairs?

The PTP (Precision Time Protocol), uses Sync message then Follow-up message, as described in the article "Understanding the IEEE 1588 Precision Time Protocol". I don't understand why do we need ...
Yousf's user avatar
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2 votes
1 answer
2k views

Is there a way to disable Precision Time Protocol (PTP) on Intel I211 Gigabit w/igb driver?

I have an ASUS Pro WS X570-ACE motherboard, with AMD Ryzen 5700G, with on-board Intel I211 Ethernet, running driver igb ver. 5.11.0-27. This also has a Realtek onboard Ethernet, but that is disabled ...
NoRainDropsInTheSky's user avatar
2 votes
1 answer
1k views

PTP support for RTL8125B-CG NIC in Ubuntu 20.04

I have an RTL8125B-CG NIC which, from what I gather from their product page, has hardware support for PTP. However, sudo ethtool -T does not detect any HW timestamping capabilities. I've tried with ...
eirik-ff's user avatar
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1 vote
2 answers
623 views

PTP (or NTP) and Domain Controller clock sync

We need a high precision (1ms) clock synchronization across multiple machines which are part of the domain. The idea is to use a PTP solution. Is it possible to setup a computer which is part of the ...
Kimi's user avatar
  • 213
1 vote
1 answer
4k views

Packets difference between PTP and gPTP

I'm trying to understand few things about gPTP (IEEE 802.1AS). I am using the open source implementation by AVnu (https://github.com/AVnu/gptp). I looking on the packets using Wireshark, and they ...
Shir's user avatar
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1 vote
1 answer
7k views

ptp time synchronization on centos6/rhel

I need to setup time synchronization using PTP (precision time protocol). I'll get server address. I found ptpd server (version 2.1). I created startup files in /etc/init.d. But wondering what options ...
sashk's user avatar
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1 vote
1 answer
1k views

Ignore chrony source with obviously wrong time

I have a robot and am using timemaster to start chrony and add a PTP source from my GPS. When I start the robot inside where it can't get a satellite fix, the GPS claims it is January 5th, 1980. As a ...
cmshowers's user avatar
1 vote
1 answer
664 views

Incorrect PTP timestamps [closed]

I have trouble syncing to Linux systems using PTP. Setup: Two PCBs with a BegleCore module and a DP83640 PHY are connected with each other over Ethernet. One board should act as the PTP master, the ...
11011100's user avatar
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1 vote
0 answers
575 views

Retrieving the current PTP settings of an Ubuntu machine

I have an Ubuntu machine (18.04) with PTPd installed. I want to write a script that can determine what PTP settings have been set previously. Specifically, I want to find information on the master PTP ...
Eliezer Miron's user avatar
1 vote
0 answers
512 views

Network cards supporting PTP one-step-sync

We currently want to setup a PTP Grandmaster using ptp4linux on a Linux host. The slave devices rely on PTP one-step-sync but we haven't found any purchaseable network card on the marked which has ...
Tik0's user avatar
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1 vote
0 answers
371 views

How to configure a redundant PTP server

I have a Sonoma GPS time server and a server, which should synchronise itself to the GPS clock, and serve as a fallback option. The time should be synchronised using PTP (Precision-Time-Protocol). ...
Michael's user avatar
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0 votes
3 answers
343 views

No info found about `ethtool -T` output?

Nowhere I can find such info, to interpret the following number: PTP Hardware Clock: 1 Most documentation I can find (e.g. from RedHat it shows 0). What does it mean?
jaques-sam's user avatar
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124 views

How to Configure IPTABLES to allow PTP sync behind a bridge firewall

We have a Fedora machine with eth0(ip:10.321.xx)connected to intranet. The same machine has a eth1 with a few more linux boxes connected in a 192.xx network. on the 10.321.xx n/w there is a PTP server....
user3051505's user avatar
0 votes
0 answers
1k views

Use of PTPd on RedHat/CentOS

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 ...
Claudio's user avatar
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