Re: [Ntp] NTP over PTP

Miroslav Lichvar <> Wed, 30 June 2021 10:19 UTC

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Date: Wed, 30 Jun 2021 12:18:58 +0200
From: Miroslav Lichvar <>
To: Doug Arnold <>
Cc: Heiko Gerstung <>, "" <>
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Subject: Re: [Ntp] NTP over PTP
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On Tue, Jun 29, 2021 at 05:10:02PM +0000, Doug Arnold wrote:
> PTP with embedded NTP messages would not be accepted by the equipment vendors who make PTP capable devices, and not be accepted by network operators who deploy PTP.

Do you speak for all vendors and operators?

> Even when the PTP ATHENTICATION TLV was defined people were concerned about making PTP messages longer.  The NTP messages would be redundant information that adds no value, accept for the attached ICV.  So why not just add the ICV and skip the NTP message.

Yes, you can do that, but you will not get all of the security of
NTS4NTP, which some people here seem to be interested in. You can
think of the NTP TLV as an authentication TLV that provides you with
that. It has to be longer as it contains the keys.

> However some industries are wedded to unicast PTP.  Telecom is heavily invested in PTP for wireless back haul timing.  The investment is in their standards, in product development and network deployment.

I'm somewhat familiar with the ongoing efforts in the telecom
industry. From what I understand, they are not going to use unicast
PTP in the new-generation networks. It's only for the older
generations as it cannot meet the new requirements. They need full
on-path support (i.e. G.8275.1) and in some cases even SyncE. Please
correct me if I'm wrong.

> Their contributions to the definition of NTPv4 were rejected, 

This is the interesting part for me. Is the discussion archived

Miroslav Lichvar