Session Date/Time: 27 Jan 2026 15:00

SCHC

Summary

This interim meeting focused on status updates for various working group documents, a decision regarding the physical IETF 119 meeting in Shenzhen, and a presentation on the SCHC context, compression, and fragmentation over networks prone to disruption draft. Following the presentation and discussion, the working group agreed to initiate a Working Group Last Call for this document, with an extended review period. Progress on a related Forward Error Correction (FEC) draft was also discussed, with plans for a mailing list adoption call.

Key Discussion Points

Meeting Logistics: Low attendance noted. Standard IETF Notwell reminder issued.
IETF 119 Shenzhen Meeting:
- A poll of the mailing list indicated no participants planned to attend IETF 119 physically.
- Given the lack of physical attendance interest, the working group agreed not to hold a physical SCHC meeting in Shenzhen.
Document Status Updates:
- draft-ietf-schc-icmpv6: Still expired. Authors requested to publish a new version to proceed with Working Group Last Call.
- draft-ietf-schc-8824-update: Working Group Last Call is ongoing with a deadline of February 10. Reviews are highly encouraged due to the document's size.
- Protocol Numbers Draft: Outstanding issues remain regarding UDP port assignments, as identified in early reviews. Authors are expected to address these.
- SCHICLET Document: Received good support on the mailing list and has been adopted. The Chair requested the co-chair to publish it as a draft-ietf. (Note: A tooling issue temporarily misrouted the draft to 6lowpan).
Presentation: "SCHC Context, Compression and Fragmentation over Networks Prone to Disruption" (draft-ietf-schc-fragmentation-disruption) by Rodrigo
- Problem Statement: The draft addresses challenges for SCHC in environments with interruptions or long delays (e.g., 3GPP zero-energy devices, direct-to-satellite scenarios).
- Proposed Solutions:
  - SCHC Proxy: Introduces a new network element that requests retransmissions locally before forwarding fragments to the SCHC receiver, similar to a Performance Enhancing Proxy (PEP).
  - Forward Error Correction (FEC): The SCHC sender applies channel coding to fragments. This allows the receiver to reconstitute lost fragments without retransmission, up to a certain threshold.
- Related Draft: The author highlighted draft-rodrigo-schc-fec-fragmentation, which further develops the FEC mechanism and presents a new fragmentation mode supporting channel coding.
- Readiness for Working Group Last Call: The authors believe the draft is ready for WG Last Call.
- Discussion on Implementation: The FEC mechanism has a running code and experiments, which will be valuable for the shepherd review. The proxy solution is considered less novel, not requiring specific implementation evidence.
- Standard Track vs. Informational: The authors clarified that draft-ietf-schc-fragmentation-disruption is intended as an informational document, presenting solutions and ideas. The detailed FEC protocol specification will be in the separate FEC draft, which is aimed at standard track.
- Dependency on FEC Draft: A discussion ensued regarding the referencing of the FEC draft from the fragmentation-disruption draft.
  - Currently, the FEC draft is not adopted, so any reference must be informational.
  - If the FEC draft were to be normatively referenced in fragmentation-disruption, the latter's publication would be blocked until the FEC draft also reached RFC status (cluster publication).
  - The authors will discuss offline whether to pursue a normative or informational reference once the FEC draft is adopted.
SCHC FEC Fragmentation Draft (draft-rodrigo-schc-fec-fragmentation):
- This draft was recently published, following recommendations from the previous interim to make the FEC mode more generic (not limited to DTS/IoT-to-satellite).
- The Chair plans to poll the mailing list for working group adoption of this draft.

Decisions and Action Items

Decision: The SCHC Working Group will not hold a physical meeting at IETF 119 in Shenzhen.
Action Item (Alexander): Post a message to the SCHC mailing list to confirm the decision not to hold a physical meeting in Shenzhen and solicit any objections.
Decision: Initiate a Working Group Last Call for draft-ietf-schc-fragmentation-disruption.
Decision: The Working Group Last Call for draft-ietf-schc-fragmentation-disruption will have an extended review period, concluding at the end of February, to accommodate ongoing reviews for draft-ietf-schc-8824-update.
Action Item (Rodrigo and co-authors of draft-ietf-schc-fragmentation-disruption): Discuss offline and decide whether the related FEC draft (draft-rodrigo-schc-fec-fragmentation) will be referenced as normative or informational in draft-ietf-schc-fragmentation-disruption once the FEC draft is adopted.
Action Item (Authors of draft-ietf-schc-icmpv6): Publish a refreshed version of the draft to enable the start of a Working Group Last Call.
Action Item (Authors of Protocol Numbers Draft): Address the outstanding UDP port issues identified in earlier reviews.
Action Item (Alexander): Publish the adopted SCHICLET document as a draft-ietf.
Action Item (Rodrigo and co-authors of draft-rodrigo-schc-fec-fragmentation): Post to the SCHC mailing list regarding the status and readiness of the FEC draft for working group adoption.
Action Item (Chair): Following the authors' mailing list post, poll the SCHC mailing list for working group adoption of draft-rodrigo-schc-fec-fragmentation.

Next Steps

Reviewers are encouraged to prioritize the ongoing Working Group Last Call for draft-ietf-schc-8824-update and prepare for the upcoming Working Group Last Call for draft-ietf-schc-fragmentation-disruption.
The working group will continue to push for adoption of draft-rodrigo-schc-fec-fragmentation.
The next SCHC interim meeting is scheduled in two weeks.