NTP

Summary

The NTP working group meeting provided updates on various drafts, including the status of NTPv5, which has resolved its remaining open issues from the requirements document. A significant discussion revolved around the separation of the NTPv5 protocol from its time synchronization algorithms, with a new algorithms draft noted. Concerns were raised regarding broader community engagement for NTPv5. Updates were also given on NTS for PTP, NTS for Enabling Pools, and initial feedback was shared on the Time Synchronization over QUIC draft. The 1588 working group's progress on NTS for PTP and the new Client Server PTP (CSPTP) was also reviewed, noting potential alignment of CSPTP's security with NTP's NTS.

Key Discussion Points

Document Status Review:
- draft-ietf-ntp-ntp-over-ptp: Currently in IETF Last Call (ISG review). This document also arose as a topic in the 1588 WG regarding new client-server PTP work.
- RFC 9535 (Interleave Modes) and RFC 9536 (Updating NTP Registries) were published earlier this year and are now complete.
NTPv5 (draft-ietf-ntp-ntpv5):
- Tal presented an update on the latest revision, primarily covering editorial changes and the resolution of five remaining open issues from the expired requirements document. This involved either determining requirements were unnecessary or adding clarifying text to the NTPv5 specification (e.g., client IP address refresh). The document is now considered aligned with the previous requirements.
- Discussion on Algorithm Separation:
  - The chair asked if a formal consensus call was needed regarding the separation of the time synchronization algorithms from the NTPv5 protocol, distinguishing them from NTS cryptographic algorithms. Concern was raised about potential "malpractice" to publish the protocol without associated algorithms.
  - Participants noted that separation was part of the document when it was accepted as a WG document, and a general IETF trend supports separating algorithms (e.g., due to post-quantum considerations). Tal highlighted that PTP took a similar approach.
  - It was noted that Sarah had published an ntpv5-algorithms document (which the chair and others had not previously noted). The sense of those present was that publishing the core protocol separately from the time synchronization algorithms was an acceptable approach.
- Discussion on Broader Community Engagement:
  - The chair expressed concern about the current working group's size and whether it adequately represents the broader NTPv5 community, citing a commercial vendor's reported lack of interest.
  - Tal suggested bringing this question up at the next IETF meeting when more implementers might be present.
NTS for PTP (draft-ietf-ntp-nts-for-ptp):
- No substantive progress was reported due to the author's absence.
- Discussions are ongoing within the 1588 working group, with a possibility of a small design team meeting later in the year to help resolve issues. Review of the draft is encouraged.
NTS for Enabling Pools (draft-ietf-ntp-nts-for-pools):
- No document updates were reported.
- The author received Ayiana grant funding to stand up servers and will provide a report at the next WG meeting.
- The document is proposed as an experimental RFC, and review is encouraged.
Time Synchronization over QUIC (draft-ietf-ntp-time-sync-over-quic):
- The author was unable to attend.
- Initial feedback indicated concerns about the draft's motivation, with some participants questioning its necessity given that NTS already addresses similar goals, and characterizing it as a "well-meaning but poor draft."
1588 Working Group Update:
- NTS over PTP (current 2019 standard): There are ongoing efforts and challenges in integrating NTS as a key management scheme, with extensive work to resolve identified issues.
- Client Server PTP (CSPTP, 1588.1):
  - This new work aims to provide NTP-like functionality with hardware timestamp access.
  - An initial proposal exists for both the protocol and its security mechanism. The intent is for CSPTP's security to be integrated directly into the protocol, similar to NTPv5.
  - It is anticipated that NTS for CSPTP could look very similar to NTP's NTS, potentially requiring no enhancements to existing IETF NTS specifications, unlike the challenges with NTS over PTP (2019). This work is still in early stages.

Decisions and Action Items

Decision: A formal consensus call on separating the NTPv5 protocol from time synchronization algorithms is not immediately required, given past working group sentiment and the publication of an algorithms draft (draft-ietf-ntp-ntpv5-algorithms).
Action Item (Chair): Seek clarification from the author of draft-ietf-ntp-time-sync-over-quic regarding the document's motivation and scope.
Action Item (Working Group): Review draft-ietf-ntp-ntpv5-algorithms on the mailing list to initiate discussion and determine next steps towards a call for adoption.

Next Steps

The working group will not hold a second interim meeting before the November IETF.
The next working group meeting will take place during the IETF 118 meeting week in November.
All working group participants are encouraged to review open documents (including draft-ietf-ntp-nts-for-ptp and draft-ietf-ntp-nts-for-pools) and engage in discussions on the mailing list and via the GitHub repository.
Further discussion on draft-ietf-ntp-ntpv5-algorithms will proceed on the mailing list, with a potential call for adoption if discussions are positive.
The question of broader NTPv5 community engagement will be revisited at the next IETF meeting.

Session Date/Time: 17 Sep 2025 15:00

NTP

Summary

Key Discussion Points

Document Status Review:
- draft-ietf-ntp-ntp-over-ptp: Currently in IETF Last Call (ISG review). This document also arose as a topic in the 1588 WG regarding new client-server PTP work.
- RFC 9535 (Interleave Modes) and RFC 9536 (Updating NTP Registries) were published earlier this year and are now complete.
NTPv5 (draft-ietf-ntp-ntpv5):
- Tal presented an update on the latest revision, primarily covering editorial changes and the resolution of five remaining open issues from the expired requirements document. This involved either determining requirements were unnecessary or adding clarifying text to the NTPv5 specification (e.g., client IP address refresh). The document is now considered aligned with the previous requirements.
- Discussion on Algorithm Separation:
  - The chair asked if a formal consensus call was needed regarding the separation of the time synchronization algorithms from the NTPv5 protocol, distinguishing them from NTS cryptographic algorithms. Concern was raised about potential "malpractice" to publish the protocol without associated algorithms.
  - Participants noted that separation was part of the document when it was accepted as a WG document, and a general IETF trend supports separating algorithms (e.g., due to post-quantum considerations). Tal highlighted that PTP took a similar approach.
  - It was noted that Sarah had published an ntpv5-algorithms document (which the chair and others had not previously noted). The sense of those present was that publishing the core protocol separately from the time synchronization algorithms was an acceptable approach.
- Discussion on Broader Community Engagement:
  - The chair expressed concern about the current working group's size and whether it adequately represents the broader NTPv5 community, citing a commercial vendor's reported lack of interest.
  - Tal suggested bringing this question up at the next IETF meeting when more implementers might be present.
NTS for PTP (draft-ietf-ntp-nts-for-ptp):
- No substantive progress was reported due to the author's absence.
- Discussions are ongoing within the 1588 working group, with a possibility of a small design team meeting later in the year to help resolve issues. Review of the draft is encouraged.
NTS for Enabling Pools (draft-ietf-ntp-nts-for-pools):
- No document updates were reported.
- The author received Ayiana grant funding to stand up servers and will provide a report at the next WG meeting.
- The document is proposed as an experimental RFC, and review is encouraged.
Time Synchronization over QUIC (draft-ietf-ntp-time-sync-over-quic):
- The author was unable to attend.
- Initial feedback indicated concerns about the draft's motivation, with some participants questioning its necessity given that NTS already addresses similar goals, and characterizing it as a "well-meaning but poor draft."
1588 Working Group Update:
- NTS over PTP (current 2019 standard): There are ongoing efforts and challenges in integrating NTS as a key management scheme, with extensive work to resolve identified issues.
- Client Server PTP (CSPTP, 1588.1):
  - This new work aims to provide NTP-like functionality with hardware timestamp access.
  - An initial proposal exists for both the protocol and its security mechanism. The intent is for CSPTP's security to be integrated directly into the protocol, similar to NTPv5.
  - It is anticipated that NTS for CSPTP could look very similar to NTP's NTS, potentially requiring no enhancements to existing IETF NTS specifications, unlike the challenges with NTS over PTP (2019). This work is still in early stages.

Decisions and Action Items

Decision: A formal consensus call on separating the NTPv5 protocol from time synchronization algorithms is not immediately required, given past working group sentiment and the publication of an algorithms draft (draft-ietf-ntp-ntpv5-algorithms).
Action Item (Chair): Seek clarification from the author of draft-ietf-ntp-time-sync-over-quic regarding the document's motivation and scope.
Action Item (Working Group): Review draft-ietf-ntp-ntpv5-algorithms on the mailing list to initiate discussion and determine next steps towards a call for adoption.

Next Steps

The working group will not hold a second interim meeting before the November IETF.
The next working group meeting will take place during the IETF 118 meeting week in November.
All working group participants are encouraged to review open documents (including draft-ietf-ntp-nts-for-ptp and draft-ietf-ntp-nts-for-pools) and engage in discussions on the mailing list and via the GitHub repository.
Further discussion on draft-ietf-ntp-ntpv5-algorithms will proceed on the mailing list, with a potential call for adoption if discussions are positive.
The question of broader NTPv5 community engagement will be revisited at the next IETF meeting.