DWS/chrony
1
0
Fork 0
mirror of https://gitlab.com/chrony/chrony.git synced 2026-01-20 21:00:20 -05:00
Code Issues Packages Projects Releases Wiki Activity

ntp: update NTP-over-PTP support

Browse Source 
Update the support for NTP over PTP to the latest specification
(currently in the RFC editor queue). Switch the NTP TLV to the
organization-specific TLV using the IANA OUI and assigned TLV
subtype 0x1. The Network Correction extension field has been
assigned type 0x10A. The extfield option accepts F324 as an alias
for 10A to not break existing configurations. Drop the experimental
status.
This commit is contained in:
Miroslav Lichvar
2025-11-26 12:14:08 +01:00
parent 73f6657dfd
commit 007a1ae4fe
12 changed files with 94 additions and 82 deletions
Download Patch File Download Diff File Expand all files Collapse all files

23
doc/faq.adoc
View File

@@ -401,11 +401,12 @@ server ntp.local minpoll 0 maxpoll 0 xleave extfield F323
Since version 4.5, `chronyd` can apply corrections from PTP one-step end-to-end
transparent clocks (e.g. network switches) to significantly improve accuracy of
synchronisation in local networks. It requires the PTP transport to be enabled
by the `ptpport` directive, HW timestamping, and the `extfield F324` option.
For example:
by the `ptpport` directive, `port` option, HW timestamping, and the `extfield
F324` option (in versions 4.5-4.8) or `extfield 10A` option (version 4.9 and
later). For example:
----
server ntp.local minpoll -4 maxpoll -4 xleave extfield F323 extfield F324 port 319
server ntp.local minpoll -4 maxpoll -4 xleave extfield F323 extfield 10A port 319
ptpport 319
hwtimestamp eth0 minpoll -4
----
@@ -668,13 +669,15 @@ packets (enabled by the `hwtimestamp` directive) if the NIC can timestamp other
packets than PTP, which is usually the case at least for transmitted packets.
The `ethtool -T` command can be used to verify the timestamping support.
As an experimental feature added in version 4.2, `chrony` can use PTP as a
transport for NTP messages (NTP over PTP) to enable hardware timestamping on
hardware which can timestamp PTP packets only. It can be enabled by the
`ptpport` directive. Since version 4.5, `chrony` can also apply corrections
provided by PTP one-step end-to-end transparent clocks to reach the accuracy of
ordinary PTP clocks. The application of PTP corrections can be enabled by the
`extfield F324` option.
As an experimental feature added in version 4.2, and fully supported since
version 4.9, `chrony` can use PTP as a transport for NTP messages (NTP over
PTP) to enable hardware timestamping on hardware which can timestamp only PTP
packets. NTP over PTP can be enabled by the `ptpport` directive and setting the
`port` option to the PTP port 319. Since version 4.5, `chrony` can also apply
corrections provided by PTP one-step end-to-end transparent clocks (e.g.
network switches) to reach the accuracy of ordinary PTP clocks. The application
of PTP corrections can be enabled by the `extfield F324` option in versions
before 4.9, or `extfield 10A` in later versions.
=== How can I avoid using wrong PHC refclock?