6LO

Summary

The 6LO Working Group met at IETF 125 to review the status of its active drafts and discuss recent progress. The session included reports on two newly published RFCs (RFC 9926 and RFC 9927) and technical presentations on path-aware addressing, SCHC compression over IEEE 802.15.4, optical wireless communications, and updates to IPv6 over MS/TP. A significant portion of the meeting was dedicated to a technical debate regarding the necessity of the Generic Address Assignment Option (GAO) versus existing DHCPv6 mechanisms.

Key Discussion Points

1. Chairs' Introduction and Document Status

Presenter: Carles Gomez Slides: 6lo chairs introduction

New RFCs: The group celebrated the publication of RFC 9926 (Prefix Registration for IPv6 Neighbor Discovery) and RFC 9927 (Fixing the C Flag in the Extended Address Registration Option (EARO)).
Publication Requests: AD review is pending for the PASA and GAO documents. Erik Kline (AD) noted that reviews are expected by the end of next week to progress toward IETF Last Call.

2. Path-Aware Semantic Addressing (PASA) and Generic Address Assignment Option (GAO)

Presenter: Luigi Iannone Slides:

Path-Aware Semantic Addressing (PASA) for Low power and Lossy Networks
Generic Address Assignment Option for 6LoWPAN Neighbor Discovery
Technical Discussion: Lorenzo Colitti raised concerns regarding GAO, arguing it duplicates existing DHCPv6 functionality. He noted that DHCPv6 can be used as a one-hop protocol without the overhead described in the draft.
Rebuttal: Luigi Iannone and Adnan (via draft updates) argued that GAO is more efficient within the 6LoWPAN ND framework, avoiding broadcast and centralized architecture constraints.
AD Perspective: Erik Kline (AD) stated that the burden is on the proponents to justify a new mechanism when an existing one (DHCPv6) might suffice. He emphasized that the IETF should avoid creating multiple ways to do the same thing unless there is a substantial benefit.
Coordination: Shweta Bhandari (6man Chair) and Carles Gomez agreed to continue coordination between the 6man and 6lo working groups to address these concerns.

3. Transmission of SCHC-compressed packets over IEEE 802.15.4

Presenter: Carles Gomez Draft: draft-ietf-6lo-schc-15dot4 Slides: Transmission of SCHC-compressed packets over IEEE 802.15.4 networks

Updates: Version 12 incorporates feedback from Esco Dijk, including a more flexible definition of 6LoWPAN nodes (6LN) and alignment with new SCHC architecture terminology.
PRO Mode: The Pointer-based Route-Over (PRO) mode was updated to allow routers access to ECN bits for congestion signaling.
Open Issue: A challenge remains regarding the address residue length field (0-127 range) when the residue is 128 bits. The authors are considering focusing the field on the IID part.

4. Transmission of IPv6 Packets over Short-Range Optical Wireless Communications (OWC)

Presenter: Young-hwan Choi Draft: draft-ietf-6lo-owc Slides: Transmission of IPv6 Packets over SR OWCs

Updates: Version 06 focused on Section 7 (Security Considerations). It incorporates high-level risk considerations (signal leakage, jamming) and references IEEE 802.15.7 MAC security services for mitigation.

5. Update of RFC 8163 (IPv6 over MS/TP)

Presenter: Kerry Lynn Draft: draft-ietf-6lo-rfc8163-bis Slides: Update of RFC 8163

Objective: To obsolete RFC 8163 with updated terminology (inclusive language) and corrected references.
SCHC Integration: Kerry Lynn inquired about adding optional SCHC compression support. Carles Gomez suggested referencing draft-ietf-6lo-owc for a similar implementation approach.
Implementation: Kerry Lynn plans a reference implementation, potentially using the Zephyr RTOS.

Decisions and Action Items

GAO/PASA: The AD (Erik Kline) will conduct a formal review of the GAO and PASA drafts by the end of next week.
Coordination: 6man chairs will solicit feedback from their working group regarding the GAO mechanism to ensure there is no unnecessary protocol fragmentation.
SCHC Terminology: Authors of draft-ietf-6lo-schc-15dot4 will continue to monitor the SCHC working group's design team for further terminology stabilization.

Next Steps

draft-ietf-6lo-schc-15dot4: Authors will resolve the PRO mode address residue length issue and seek implementation feedback before requesting a Working Group Last Call.
draft-ietf-6lo-rfc8163-bis: Kerry Lynn will investigate the feasibility of adding optional SCHC support and begin work on a reference implementation.

Automatic IETF Minutes

6LO