**Session Date/Time:** 27 Jan 2026 15:00 # [SCHC](../wg/schc.html) ## 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.