Session Date/Time: 18 Dec 2024 15:00

CORE

Summary

This interim meeting of the CORE Working Group covered a packed agenda, including an in-depth discussion on transport indication concepts, updates on the status of group communication and CORE-CLAR documents, an IPR-related discussion concerning DNS over CoAP, and proposals for a new resource type and fixes to CoAP content format registration. The group also discussed consolidating its wiki content on the IETF Community Wiki. Key decisions included proceeding with a second Working Group Last Call for Group COMIS, adopting the content format registration draft, and delaying the DNS over CoAP Working Group Last Call to allow for IPR due diligence.

Key Discussion Points

Transport Indication Concepts:
- Christian presented on CoAP+something URI schemes, arguing for a more flexible approach akin to HTTP/2 and HTTP/3.
- The current draft treats alternate transports as proxies, using has-proxy link relations.
- SVCB records (RFC 9460) were proposed as a robust mechanism for service binding, supporting priorities, hostnames, ports, and ALPN.
- A significant gap was identified regarding IP literals, which lack sufficient information for complex connection establishments, especially with multiple transports or future protocols like CoAP over QUIC. The document acknowledges this gap but proposes deferring a detailed solution.
- Discussion arose on whether to have a dedicated _coap SVCB-style DNS RR or use a generic _coap underscore name with an SVCB record.
- The question of registering ALPN for unencrypted protocols or introducing a new SVCB parameter for non-ALPN protocols was also raised.
- The concept of a "link" encompassing a URI and other necessary connection information (address records, TLSA, SVCB parameters) was discussed as a way to unify URI schemes like CoAP and CoAPs when SVCB information is available.
CORE-CLAR Update:
- PR #40 was merged into draft-ietf-core-clar-01, which now includes the content from the PR and updated references.
- The document is considered ready for reference by other drafts, such as DNS over CoAP.
Group COMIS Status:
- A second Working Group Last Call is planned due to significant changes following earlier reviews, with Christian's comments already incorporated into draft-ietf-core-group-comis-12.
- The document size has been reduced, and it is considered to have converged.
DL LPN Status:
- The intended status for DL LPN was changed from Standard Track to Informational, as it primarily concerns an IANA registration.
- New milestones are under review, targeting a publication deadline of February 2025.
DNS over CoAP - IPR Discussion:
- Carsten highlighted an IPR disclosure related to a patent impacting DNS over CoAP.
- Working group members were strongly encouraged to consult legal counsel regarding the patent claims to determine implementability for their organizations.
- The goal is to ensure informed feedback during the upcoming Working Group Last Call, rather than just general support or non-support.
New Resource Type for SRP:
- Esco proposed registering a core.srp resource type within the DNS over CoAP document, enabling CoAP-based Service Registration Protocol (SRP) updates.
- The proposal highlighted SRP's use of DNS encoding and its potential utility for devices like Matter over Thread.
- Concerns were raised about whether DNS update mechanisms have been thoroughly considered within the existing DNS over CoAP framework and if there are any current implementations.
- The potential for delays if significant new work is required was acknowledged, with an option to defer SRP to a separate document if necessary.
Fixing CoAP Content Format Registration:
- A new draft was presented to address issues with the First-Come-First-Served (FCFS) assignment of CoAP content format numbers (10,000+ range), which allows registration of non-existent media types.
- The proposal introduces updated procedures:
  - Simple FCFS for registrations without parameters or content coding, verified by IANA against existing media types.
  - Lightweight expert review for registrations with parameters and/or content coding to check for correctness (e.g., valid parameters, known content codings, no duplicates).
- The draft has undergone multiple rounds of review and is considered to be in good shape.
CORE Wiki Migration:
- The working group discussed migrating content from the existing CORE GitHub Wiki to the IETF Community Wiki to consolidate information.
- Esco demonstrated an initial update to the IETF Community Wiki with current CORE content and a proposed structure including links to data tracker, external tools, a section on core registries (e.g., experimental content ID ranges), and a page for known URIs used by SDOs (e.g., KNX).
- A preference for Markdown formatting was expressed for ease of collaboration.

Decisions and Action Items

Transport Indication: The document will move forward with the SVCB approach. Further discussion is needed on specific SVCB parameters (dedicated _coap RR vs. generic _coap underscore name, ALPN for unencrypted vs. new SVCB parameter). The issue of IP literals will be acknowledged in the document but deferred for a detailed solution. Christian will clarify the "set of things you need to start having a connection."
CORE-CLAR: The working group will review the diff of draft-ietf-core-clar-01 and submit comments/issues/PRs. (Carsten)
Group COMIS: A second Working Group Last Call will be initiated in early January, with a proposed deadline around January 8th. Carsten will conduct a shepherd check during this period. (Marco, Carsten)
DNS over CoAP - IPR: The Working Group Last Call for DNS over CoAP will be delayed until January to allow members to conduct due diligence regarding the IPR disclosure. (Marco, Carsten)
New Resource Type (SRP): Esco will investigate in more detail how DNS updates and SRP specifics align with the existing DNS over CoAP framework, including potential implementation aspects. A PR on GitHub for a concrete proposal is encouraged for quick integration if feasible. (Esco)
Fixing CoAP Content Format Registration: The draft will be officially adopted by the working group. A GitHub repository will be set up for the adopted version, and Carsten's pending PR will be applied directly to it. (Marco, Carsten, Esco, Thomas)
CORE Wiki Migration: The working group supports migrating content to the IETF Community Wiki. Chairs and interested members (Christian, Ken) will review existing content in both the IETF Wiki and the GitHub Wiki to consolidate and update it. (Esco, Christian, Ken)

Next Steps

Transport Indication: Continued discussion on the mailing list regarding the specific SVCB options and parameters, and Christian will work on clarifying the comprehensive set of information needed for connection establishment.
CORE-CLAR: Review draft-ietf-core-clar-01 and provide feedback.
Group COMIS: Prepare for the second Working Group Last Call in early January.
DNS over CoAP - IPR: Working group members to perform IPR due diligence in preparation for the delayed Working Group Last Call in January.
New Resource Type (SRP): Esco to present findings on SRP integration with DNS over CoAP, potentially via a GitHub PR.
Fixing CoAP Content Format Registration: Set up GitHub repo for the adopted draft and apply pending updates.
CORE Wiki Migration: Chairs and other interested parties will collaborate on reviewing and consolidating wiki content on the IETF Community Wiki.

The next interim meetings are scheduled for January 15th, and then every other Wednesday at the same time.