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6LO

Summary

The 6LO Working Group (WG) met during IETF 126. The session covered working group document updates, leadership changes, and technical discussions on semantic addressing, Neighbor Discovery address assignment options, and Static Context Header Compression (SCHC) integrations across various link layers.

An important leadership update was announced: Laurent Toutain will join Carles Gomez and Shwetha Bhandari as the third co-chair of the 6LO working group.

Key drafts discussed included the Path-Aware Semantic Addressing (PASA) draft, the Generic Address Assignment Option (GAAO) draft, draft-ietf-6lo-schc-15dot4, draft-ietf-6lo-owc, and draft-ietf-6lo-rfc8163-bis.

Key Discussion Points

1. Introduction and Administration

• Presenter: Carles Gomez
• Slide Deck: 6lo chairs introduction
• Notes: Carles Gomez opened the meeting, presented the Note Well, and detailed the status of current working group documents.
• Leadership Update: Responsible Area Director Éric Vyncke announced that Laurent Toutain has accepted the role of the third co-chair for the 6LO working group.

2. Path-Aware Semantic Addressing (PASA) for Low power and Lossy Networks

• Presenter: Luigi Iannone
• Slide Deck: Path-Aware Semantic Addressing (PASA) for Low power and Lossy Networks
• Discussion:
  • Since the last IETF, two revisions were published to address reviews by Hong Yang and Éric Vyncke. Changes included terminology improvements, algorithm clarifications, and security considerations based on RFC 4443 (ICMPv6 error handling).
  • Use Cases Section: Éric Vyncke suggested moving the extensive use cases section to an appendix to make the document lighter. Luigi agreed to this change.
  • Intended Status (Proposed Standard vs. Experimental): Reviews raised concerns that the technology might be too disruptive/new for a Proposed Standard. Éric Vyncke suggested that changing the status to Experimental would ease the IESG evaluation process. Laurent Toutain noted that changing to Experimental requires defining the concrete experiment and its intended outcomes in the document. Luigi agreed and indicated that an internal implementation is ongoing.

3. Generic Address Assignment Option (GAAO) for 6LoWPAN Neighbor Discovery

• Presenter: Luigi Iannone
• Slide Deck: Generic Address Assignment Option for 6LoWPAN Neighbor Discovery
• Discussion:
  • Two revisions were submitted to address reviews. Appendix C was added to provide a comparison between GAAO and DHCPv6 tailored for 6LoWPAN deployments, including rapid commit options.
  • Efficiency Concerns: Laurent Toutain pointed out that the current introduction asserts DHCPv6 is inefficient, but Appendix C suggests DHCPv6 with rapid commit is almost as efficient, except for multi-link packet propagation. He suggested updating the introduction to reflect this and explaining why alternative designs (such as restricting DHCPv6 packet scope) were not pursued. Luigi Iannone agreed that efficiency is highly topology-dependent and agreed to refine the wording.
  • Alternative Deployment Experiences: Esco Dijk shared that a previous 6LoWPAN mesh network deployment had defined a unicast-based DHCPv6 operation to circumvent multicast inefficiencies, though it was not widely deployed due to SLAAC. Esco offered to send this reference to the authors.
  • Alexander Pelov encouraged the working group to perform additional reviews to help refine the scope and wording.

4. Transmission of SCHC-Compressed Packets over IEEE 802.15.4 Networks

• Presenter: Carles Gomez
• Slide Deck: Transmission of SCHC-compressed packets over IEEE 802.15.4 networks
• Draft Reference: draft-ietf-6lo-schc-15dot4
• Discussion:
  • The latest version (v13) addresses outstanding comments from Esco Dijk regarding the Pointer-Based Route-Over (PRO) mode.
  • To resolve an encoding limitation of the Address Residue Length field (which needs to represent values from 0 to 128), the field size was reduced from 7 bits to 5 bits. It now maps values indirectly using a lookup table in Appendix C based on typical prefix sizes.
  • Normative Content: Éric Vyncke strongly advised moving this lookup table from Appendix C into the main body of the document because appendices are considered non-normative by default. Carles agreed to move it.
  • SCHC Architecture Alignment: Carles noted that version 06 of the SCHC Architecture draft introduced terminology changes (e.g., "control header", "instance" vs. "session"). The authors plan to align the terminology in the 15.4 draft with these updates. Alexander Pelov confirmed that the SCHC WG will coordinate with the authors to ensure a smooth transition.
  • Once the terminology is updated and the table is relocated, the document will be ready for Working Group Last Call (WGLC), which will also be shared with the SCHC working group.

5. Transmission of IPv6 Packets over Short-Range OWC

• Presenter: Younghwan Choi
• Slide Deck: Transmission of IPv6 Packets over Short-Range OWC
• Draft Reference: draft-ietf-6lo-owc
• Discussion:
  • Version 07 updates focus entirely on Section 5 (Internet connectivity scenarios). Figures 7 and 8 were updated to better represent the unique directional propagation characteristics of Optical Wireless Communication (OWC).
  • The concept of Optical Transmission Range (OTR) was introduced to clarify the connectivity boundaries.
  • Alexander Pelov noted that the document is concise and well-written but requested more working group reviews before scheduling WGLC.

6. RFC 8163 Bis Status Report

• Presenter: Carles Gomez (on behalf of Kerry Lynn)
• Slide Deck: 8163 bis
• Draft Reference: draft-ietf-6lo-rfc8163-bis
• Discussion:
  • The draft has not been updated since the last meeting, but the author is currently developing an implementation testbed using Nordic devices running Riot OS and Linux hosts. The next draft revision will feature an "Implementation Status" section.
  • SCHC Implementation Support: The author is seeking assistance with implementing optional SCHC header compression for MS/TP networks.
  • Coordination: Alexander Pelov and Éric Vyncke advised that the author should send a request for assistance to the SCHC working group mailing list. Laurent Toutain offered to investigate if students at IMT Atlantique could assist with this implementation effort.

Decisions and Action Items

1. Leadership Change: Laurent Toutain is officially appointed as the third co-chair of the 6LO Working Group.
2. PASA Draft Status: The authors will move the use cases section to an appendix, change the intended status from Proposed Standard to Experimental, and add text defining the experiment and its goals.
3. GAAO Draft Wording: The authors will update the introduction to clarify that DHCPv6 efficiency is topology-dependent, align the introduction with Appendix C, and add references to the unicast-based DHCPv6 deployment scenario suggested by Esco Dijk.
4. draft-ietf-6lo-schc-15dot4 Table Relocation: The authors must move the lookup table for indirect address residue length encoding from Appendix C to the main normative body of the draft.
5. draft-ietf-6lo-schc-15dot4 Terminology Alignment: The authors will update the draft's terminology to align with version 06 of the SCHC Architecture draft.
6. draft-ietf-6lo-rfc8163-bis SCHC Implementation Support: Kerry Lynn to send an email to the SCHC WG mailing list requesting collaboration/support for implementing SCHC on the MS/TP testbed.

Next Steps

1. draft-ietf-6lo-schc-15dot4 WGLC: Once terminology alignment and table relocation are complete, the chairs will initiate a WGLC, cross-posting it to the SCHC WG.
2. draft-ietf-6lo-owc WGLC: The authors aim to gather final community feedback and target WGLC early next year (2024).
3. PASA/GAAO IESG Review: The authors will finalize updates addressing Éric Vyncke's AD reviews. Éric Vyncke will resume the IESG review cycle once the new revisions are submitted.

Related Documents

draft-ietf-6lo-owc, draft-ietf-6lo-rfc8163-bis, draft-ietf-6lo-schc-15dot4