Re: [Ntp] ntp-over-ptp concerns

[Doug Arnold <[e-mail]>]

I agree with Rodney.  The ntp-over-ptp mechanism might not need all of the things that I listed, but PTP requires them.  I would also support Rodney's proposal for NTP over CSPTP.

In principle, one will be able to do with CSPTP what one can do with NTP.   However, I have heard from a lot of people who are used to NTP and prefer to work with it, so there is likely that there would be interest in NTP over CSPTP.

Doug


________________________________
From: Rodney Cummings <[e-mail]>
Sent: Tuesday, March 12, 2024 7:42 PM
To: NTP WG <[e-mail]>; Doug Arnold <[e-mail]>
Subject: ntp-over-ptp concerns

Hello IETF NTP WG,

Possibly similar to Doug Arnold's comments, as an individual, I have three strong objections to draft-ietf-ntp-over-ptp-02.

1. The draft violates the IETF NTP WG charter. The draft does not enhance NTP. The draft specifies a TLV to enhance PTP. Therefore, the project should have been proposed in the IEEE 1588 Working Group.

2. The protocol specified in the draft uses two IEEE 1588 message formats, and therefore the protocol advertises itself as conformant to the IEEE 1588 standard. The protocol is not conformant to IEEE 1588, in that it ignores most requirements of that standard. This sort of disregard for IEEE conformance has never been published in the past by IETF. In the past, cooperation between IETF WGs and IEEE WGs has been excellent, and it is important that this cooperation continue.

3. If objection #1 and #2 are ignored, there is the problem that the draft's protocol breaks other conformant PTP Profiles that are running on the same network. Apparently, the draft is attempting to use domainNumber of 123 to isolate itself from other conformant PTP Profiles. This attempt is technically insufficient, because any other conformant PTP Profile is allowed to also use domainNumber 123. If IETF wishes to specify an isolated protocol, IETF must register to obtain an IEEE 1588 sdoId for that purpose, as described in:
   https://standards.ieee.org/products-programs/regauth/sdoid/

I would like to suggest a solution to all three of these problems.

The IEEE 1588 Working Group has recently submitted an IEEE Project Authorization Request (PAR) for IEEE P1588.1, Client Server Precision Time Protocol (CSPTP). The goals for the CSPTP project are to formally specify a simple client/server message exchange, similar to the message exchange described in draft-ietf-ntp-over-ptp-02. CSPTP will meet IEEE conformance and compatibility requirements, including use of sdoId.

IEEE approval of the new PAR for CSPTP is scheduled for May 2024, after which proposals will begin, leading to draft text. If the IEEE 1588 WG and IETF NTP WG cooperate to propose a TLV for CSPTP that encapsulates NTP, the result will effectively be NTP-over-CSPTP. In my view, that sort of IEEE/IETF cooperation is the best approach.

Rodney Cummings