Session Date/Time: 06 Nov 2025 22:00

6LO

Summary

The 6LO Working Group met to discuss the status and next steps for several drafts, including updates on Path-Aware Semantic Addressing (PASA) and Generic Address Assignment Option (GAO), the transmission of SHIC compressed packets over IEEE 802.15.4 networks, and IPv6 over Optical Wireless Communication (OWC). A significant portion of the meeting was dedicated to a new proposal for updating RFC 8163 (IPv6 over MSTP) to align with updated terminology and address potential modernizations.

Key Discussion Points

Chairs' Introduction and Document Status

Logistics: Carlos Gomez (Chair) welcomed attendees, noted Shretta Mandari (Chair) was remote, and Eric Vink (AD) was responsible. Lauren volunteered as minute-taker, with collaborative minutes via HedgeDoc encouraged. Mitecho sign-in for in-person attendees was emphasized for queue management and blue sheets.
Notewell: Reminder of IETF policies regarding professional conduct, IPR, and working group guidelines.
Agenda: The proposed agenda included presentations on PASA, GAO, SHIC over 15.4, IPv6 over OWC (two related drafts), and an update to RFC 8163.
Document Status:
- RFC Editor Queue: Two documents are in the RFC Editor queue: "IPv6 and the Prefix Registration" and "Fixing the C-flag in EARO."
- Working Group Documents:
  - PASA for LLNs: Ready for IESG submission, currently held pending GAO's readiness.
  - GAO: Passed Working Group Last Call (WGLC), updated after Shepherd review, and progressing towards Shepherd write-up.
  - SHIC Compressed Packets over 15.4: Updated since the last IETF.
  - IPv6 over OWC: Updated since the last IETF.

Path-Aware Semantic Addressing (PASA) for LLNs and Generic Address Assignment Option (GAO)

Presenter: Luigi Iannone
PASA (draft-ietf-6lo-pasa-08):
- Two minor updates since the last meeting, primarily to align examples with GAO option format changes.
- The document remains stable and is considered ready for IESG submission, awaiting GAO.
GAO (draft-ietf-6lo-gao-13):
- Two revisions since the last meeting, addressing WGLC comments (Pascal) and Shepherd review (Carlos Gomez).
- Terminology: Reverted "ratification" to "registration" to clarify implicit vs. explicit registration. Implicit registration occurs when the node accepts an offered address/prefix; explicit registration involves a separate phase using existing mechanisms.
- Prefix Support: The GAO option format was extended with a prefix length field to support prefix assignment, not just addresses. Requesting a prefix/address can specify a target prefix.
- Optimizations: Clarified existing text on piggybacking the GAO option in other messages, such as link-local address registration exchanges or router solicitations, to reduce message overhead.
Next Steps: Carlos Gomez (Shepherd) will publish the Shepherd write-up for GAO and then slightly update the PASA write-up. Both documents will then be jointly submitted to the IESG.

Transmission of SHIC Compressed Packets over IEEE 802.15.4 Networks

Presenter: Carlos Gomez
Draft Status: Presenting version 11, which incorporates feedback from the last IETF.
Main Goal: Enable SHIC as an alternative header compression technique for IPv6 and application-layer protocols (e.g., CoAP/UDP) over IEEE 802.15.4 networks, potentially offering greater compression than 6LoWPAN.
Protocol Stacks:
- Main Protocol Stack: Only SHIC is used for header compression, supporting different SHIC strata for CoAP secured by DTLS or OSCORE.
- Transition Protocol Stack (TPS): Allows continued use of 6LoWPAN for IP header compression while introducing SHIC for UDP and CoAP.
- Multiple SHIC Strata: Illustrated using separate SHIC strata for UDP, CoAP, and CoAP inner headers (when OSCORE is used).
Discussion on UDP/CoAP Strata: Eric Vink questioned the necessity of separate SHIC strata for UDP and CoAP if not secured. Christian suggested a scenario where a border router decompresses UDP, sending it to an internet server, while a different application on the host decompresses CoAP. Carlos noted a single stratum for UDP and CoAP is possible.
SHIC Stratum Header Formats: Detailed formats for SHIC stratum headers for UDP (protocol ID 17), CoAP (port number for CoAP), and CoAP inner (OSCORE option number 9), with mechanisms for full alighting (zero bits over the air).
Routing Modes (Appendices): Provided analysis and examples for three routing modes in multi-hop networks:
- Straightforward Route-Over (SRO): Best for small, static networks (e.g., small home/office).
- Tunnel-Based Route-Over (TRO): Best for networks with dominant upwards traffic, often with RPL (e.g., smart grid).
- Pointer-Based Route-Over (PRO): Does not require RPL, better for significant non-upwards traffic (e.g., larger home networks).
Minor Points and Terminology:
- Coexistence: Addressed concerns about 6LoWPAN-only and SHIC-only nodes: no confusion risk due to different 6LoWPAN dispatch types. Full handling of coexistence deferred to a separate draft due to complexity.
- Terminology "Single Endpoint Networks": Alexander suggested "single endpoint node networks" for clarity. Carlos noted alignment with the evolving SHIC architecture draft (draft-ietf-lwig-shic-architecture) is crucial.
Esco's Review Comments:
- Hybrid Approaches: Consider explicitly mentioning hybrid routing approaches.
- 6LBR as Source/Destination: Emphasize scenarios where 6LBRs are direct sources or final destinations of data.
- ECN Bit Handling: Clarify whether intermediate routers can change ECN bits in TRO and PRO modes; if not, decide whether to modify formats (potentially impacting compression) to support this.
- "6LN as LEAF" Consistency: Double-check the consistent use of "6LN" across the document, as it can be a host or router.
- PRO Address Length Field: Ensure the address length field in PRO can identify both full compression (zero) and no compression (128).
- SHIC Architecture Alignment: Actively monitor and align with the latest SHIC architecture draft's terminology (e.g., "SHIC control header," "SHIC data," "SHIC datagram"). Strong consensus to adopt these three terms immediately.
Future Considerations:
- SHIC DTLS Compression: Esco noted previous work on DTLS header compression with SHIC, suggesting potential future exploration (outside this draft).
- Matter Protocol: Alexander raised whether SHIC could benefit the Matter application layer and its security protocols, given it's not CoAP. This remains an open question for community interest.
Next Steps: Address review comments, align terminology, complete examples, and potentially request working group last call soon.

Transmission of IPv6 Packets over Short Range Optical Wireless Communication (OWC)

Presenter: Yongan Choi
Draft Status: Version 05 submitted since IETF 117.
Changes: Primarily editorial, aimed at unifying and clarifying the text in IETF RFC style. Improved motivation in Section 1 and logical flow in Section 4. No technical changes.
Security Considerations: Currently marked as TBD in this draft. Munan Choi is developing a separate individual draft focused solely on security considerations for IPv6 over OWC. These are expected to be integrated into Yongan Choi's draft later.
Request: Call for reviews from the working group.

Security Considerations for IPv6 over OWC

Presenter: Munan Choi
Progress: Initial draft introduced at IETF 121. Version 03 for this meeting.
Changes in v03: Removed "data integrity" section (merged with other parts), added "interpurious and jamming" as a new security consideration.
Key Characteristics of OWC: Highlighted characteristics from Yongan Choi's draft (visible light, short-range, bidirectional, LoS/non-LoS, data rate variation, energy efficiency, secure communication features) as the basis for security analysis.
Security Risks: Identified 12 security risk factors specific to OWC (e.g., eavesdropping, data interception, authentication, DoS). Categorized these into main security considerations.
Mapping Table: Presented a table mapping OWC characteristics to specific security considerations.
Future Plans:
- Refine cause and impact relationships in the mapping table.
- Update current security considerations based on refined analysis.
- Propose the updated content as a candidate for Section 7 of Yongan Choi's IPv6 over OWC working draft.
Discussion:
- Link-Layer Security: Esco suggested mentioning if IEEE standards for OWC define link-layer security, and its implications (e.g., point-to-point links vs. key management difficulties).
- Lightweight Security: Esco also suggested considering lightweight security methods like OSCORE, particularly for constrained systems and CoAP.
Next Steps: Plan to generate a new revision (04) and announce it on the mailing list to request comments and feedback from the working group.

Update to RFC 8163 (IPv6 over MSTP)

Presenter: Kerry Lynn
Motivation: Open-source implementation interest and harmonization of terminology with the latest ASHRAE BACnet standard. RFC 8163 (6loBAC) defines IPv6 over MSTP (Multi-drop Serial Bus Token Passing, formerly Master-Slave Token Passing).
Proposed Changes:
- Terminology Harmonization: Update "Master-Slave Token Passing" to "Multi-drop Serial Bus Token Passing." Change "master node" to "managed node" and "slave node" to "subordinate node," aligning with the 2024 BACnet specification.
- Errata/References: Fix errata in example code, update references.
- Co-authors: Moved original co-authors to acknowledgments due to their unavailability for edits.
Key Question: How should these changes be incorporated? Via errata, obsoleting, or a new document? Also, should the working group consider a broader modernization review (e.g., privacy, compression)?
Discussion on Update Mechanism:
- Eric Vink (AD): Recommended obsoleting RFC 8163 with a new document, citing it as a cleaner approach. Noted that the administrative effort for obsoleting vs. updating is similar.
- Carlos Gomez (Chair): Agreed that obsoleting would require following the standard adoption process for a new working group document.
- Esco: Supported obsoleting to reflect updated terminology and potential other fixes in the base BACnet spec.
- Robin (BACnet Community): Strongly supported obsoleting the entire document to create one clean, updated RFC, especially given the extensive changes in the 2024 BACnet specification. Also emphasized the need to change the outdated language.
Authorship: Eric Vink strongly suggested that previous authors be listed as "contributors" rather than just in "acknowledgments," as they wrote significant portions of the original document. Kerry accepted this advice.
Future Work: Alexander asked if there would be interest in using SHIC for compression of encapsulated data within MSTP. Kerry stated this would be a working group decision if the document is adopted.
BACnet Sync: Tim Winters and Dave Robb confirmed coordination on BACnet spec changes for the update.
Next Steps: A formal call for adoption for Kerry's draft will be issued on the mailing list.

Decisions and Action Items

Decision: The draft-ietf-6lo-pasa and draft-ietf-6lo-gao drafts will be jointly submitted to the IESG after the Shepherd write-ups are finalized.
- Action: Carlos Gomez (Shepherd) to finalize and publish Shepherd write-ups for draft-ietf-6lo-pasa and draft-ietf-6lo-gao, then prepare them for IESG submission.
Decision: The new draft proposed by Kerry Lynn will obsolete RFC 8163.
- Action: Chairs to issue a formal call for adoption on the 6LO mailing list for Kerry Lynn's draft to obsolete RFC 8163.
Action: Carlos Gomez (author of draft-ietf-6lo-shic-over-15-4) to:
- Re-evaluate the necessity of separate UDP and CoAP SHIC strata in certain transition protocol stacks.
- Address all comments from Esco's review.
- Align terminology with the latest draft-ietf-lwig-shic-architecture, specifically updating "SHIC stratum header" to "SHIC control header," "SHIC payload" to "SHIC data," and "SHIC packet" to "SHIC datagram."
- Complete examples in Appendix A.
Action: Munan Choi (author of draft-choi-6lo-ipv6-owc-security-considerations) to:
- Announce the next revision on the mailing list to request comments.
- Incorporate feedback regarding existing link-layer security standards for OWC and the potential use of lightweight security methods like OSCORE.
Action: Yongan Choi (author of draft-choi-6lo-ipv6-over-owc) to incorporate the security considerations from Munan Choi's draft into a future version of his document.

Next Steps

The 6LO Working Group will proceed with the IESG submission of the PASA and GAO drafts.
A formal call for adoption for the RFC 8163 update draft will be initiated on the mailing list.
Authors of the SHIC over 15.4 and IPv6 over OWC drafts will continue to address comments, refine content, and align with related architectural documents, aiming for future working group last calls.