| Re: [chrony-dev] Frequency transfer in NTP |
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- To: chrony-dev@xxxxxxxxxxxxxxxxxxxx
- Subject: Re: [chrony-dev] Frequency transfer in NTP
- From: Miroslav Lichvar <mlichvar@xxxxxxxxxx>
- Date: Tue, 16 Nov 2021 12:04:42 +0100
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On Thu, Jan 28, 2021 at 03:40:52PM +0100, Miroslav Lichvar wrote:
> I guess most people here don't follow the NTP WG list. There is one
> feature proposed for NTPv5 that I think would make a big difference
> for chrony:
>
> https://fedorapeople.org/~mlichvar/ntp-freq-transfer/
This is now implemented as an experimental feature in the chrony
development branch. It can be enabled by adding "extfield F323" to the
server/peer/pool directive. Beside the new monotonic receive
timestamp, the extension field also contains a higher-resolution
version of the root delay and root dispersion, so clients in local
network can better estimate their maximum error.
In my tests the frequency transfer works well, in both basic and
interleaved modes. It significantly improves stability of the
synchronization. I wish I looked into it sooner.
I hope it will be included in NTPv5 in some form, but that may take
years. The working group still has not reached a consensus on the
requirements for the new protocol. So, at least for now, we have this
experimental extension field in chrony.
--
Miroslav Lichvar
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