ASDF

Summary

The ASDF Working Group held its sixth interim meeting of the year. The session focused on status updates for the Network Parameter IP Association (NIPC) and Semantic Definition Format (SDF) protocol mapping specifications, followed by detailed presentations and discussions on active working group drafts: draft-ietf-asdf-digital-twin and draft-ietf-asdf-sdf-nonaffordance. Key outcomes included plans to revive the expired SDF Relation specification and a proposal to separate runtime representations from draft-ietf-asdf-sdf-nonaffordance into the general SDF Instance Information specification.

Key Discussion Points

1. Protocol Mapping and NIPC Status Updates

Current Status: Rohit Mohan announced the publication of SDF Protocol Mapping (v12) and NIPC (v22).
Key Updates:
- Incorporated a pull request from Ari Keränen providing guidance on handling SDF maps with protocol mappings.
- Added a new Zigbee event type in both drafts, establishing a new IANA registration.
- Added an implementation section to the protocol mapping draft containing two Cisco implementations.
AD Review: The drafts are currently awaiting AD review by Chidambaram. Because the updates were published after the review process started, Ari Keränen suggested that the chairs notify the AD about these minor, non-normative updates. Lorenzo Corneo agreed to send this heads-up.
Tooling Implementation: Rohit Mohan asked if Ari Keränen's SDF editor tool should be listed in the implementation section. Ari Keränen clarified that the tool's server is currently down for maintenance and the tool has not yet been updated to support the protocol mapping specification, so it does not need to be mentioned in the draft.

2. Digital Twin Modeling

Presentation: Hyunjeong Lee presented updates for draft-ietf-asdf-digital-twin based on the slide deck SDF modeling for Digital Twin (v05).
Key Revision Updates:
- Clarified in Section 5 that the current protocol mapping specification formally defines mappings for BLE and Zigbee, while other protocols listed in Table 2 (such as MQTT, CoAP, HTTP, WebSocket) serve as applicable examples for digital twin implementations.
- Refined protocol binding examples for BLE (using service ID and characteristic ID) to align with the core protocol mapping work.
- Reorganized Section 5.4 to "QoS considerations," clarifying that QoS levels 0, 1, and 2 are specific to MQTT to prevent them from being seen as general semantics across all protocols.
- Reorganized Section 6 to structure digital twin system examples by domain: Modern, Healthcare, Smart Building, and a new Smart Network system (Section 6.5).
Discussion on QoS: Lorenzo Corneo suggested that in future work, an MQTT protocol mapping could incorporate a specific QoS field within its mapping object.
GitHub Migration: Lorenzo Corneo reminded participants that the digital twin draft is now hosted on GitHub. Rohit Mohan noted that version -05 was not yet uploaded. Hyunjeong Lee agreed to upload it as soon as possible.
Smart Network Use Case: Ari Keränen asked for more background on the new smart network system example. Hyunjeong Lee explained that the use case involves detecting abnormal network device conditions, such as fire or rain, using synchronized digital twin data.
SDF Relation Specification: Lorenzo Corneo noted that the digital twin draft utilizes SDF relations and asked if the expired SDF Relation draft (SDF-Rel) is required to move forward. Hyunjeong Lee confirmed it is necessary. Hyunjeong Lee, Jungha Hong, and Ari Keränen agreed to collaborate to revive and update the SDF Relation specification.
AI Agent Integration: Hyunjeong Lee outlined a potential future direction exploring how AI agents could interact with digital twins for inference, decision-making, and control. Lorenzo Corneo highlighted that this is highly complementary to draft-corneo-t2trg-sdf-coap-agents, which explores embedding AI agent instructions into SDF documents.

3. Non-Affordance Information

Presentation: Jungha Hong presented updates to draft-ietf-asdf-sdf-nonaffordance using the slide deck SDF Extension for Non-Affordance Information.
Key Revision Updates:
- Aligned qualities with RFC 9880.
- Added a formal definition of "SDF context".
- Aligned Section 4.1.3 with draft-ietf-asdf-sdftype-link using the type object and href.
Proposed Structural Changes:
- Jungha Hong proposed focusing draft-ietf-asdf-sdf-nonaffordance strictly on model-level non-affordance (SDF context modeling). She proposed moving the runtime-level messages (context snapshot, identity manifest, and context patch) to the SDF Instance Information draft.
- Lorenzo Corneo, Carsten Bormann, and Ari Keränen strongly supported (+1) this clean separation between model level and runtime instance level.
- Carsten Bormann invited Jungha Hong to provide specific materials and text to integrate into the next update of the instance information draft before the next face-to-face meeting.
- Jungha Hong also proposed simplifying Section 4.1.3 by removing it as a standalone subsection and keeping it as a basic example of external resource links using draft-ietf-asdf-sdftype-link.
CDDL Definition: Rohit Mohan asked if there is a formal CDDL definition for the SDF context. Jungha Hong stated that the next revision will include a dedicated, formal definition and semantics section with CDDL.

4. Other Business (AOB)

Model and Tooling Repository: Bart Brinckman shared that they developed a tool that automatically generates Zigbee and BLE SDF models directly from device GAP/attribute tables. He proposed establishing a collaborative repository and web space (e.g., sdf.wiki) to share open-source tools and generated models. Ari Keränen and Lorenzo Corneo welcomed the work but suggested that model curation and marketing are best coordinated through OneDM (One Data Model) rather than ASDF. Ari Keränen proposed scheduling a dedicated sync-up over Telegram to coordinate a future OneDM meeting.
Working Group Status: Jungha Hong raised a question regarding an email indicating that the ASDF working group might close early next year. Lorenzo Corneo and Ari Keränen reassured the group that the active drafts remain safe. While working groups naturally conclude once chartered milestones are met, there is still active chartered work to complete, and rechartering remains an option if more work is identified.

Decisions and Action Items

Decision: Separate the runtime representation from draft-ietf-asdf-sdf-nonaffordance and merge that material into the SDF Instance Information specification.
Decision: Revive the expired SDF Relation specification (SDF-Rel) to support draft-ietf-asdf-digital-twin.
Action Item: Lorenzo Corneo to contact AD Chidambaram to provide a heads-up on the latest updates to the protocol mapping and NIPC drafts.
Action Item: Hyunjeong Lee to upload draft-ietf-asdf-digital-twin version -05 to the working group's GitHub repository.
Action Item: Jungha Hong to provide Carsten Bormann with runtime specification text from the non-affordance draft to merge into the next update of the SDF Instance Information draft.
Action Item: Lorenzo Corneo, Ari Keränen, Jungha Hong, and Hyunjeong Lee to coordinate offline to revive the SDF Relation specification.
Action Item: Bart Brinckman and Ari Keränen to coordinate over Telegram to schedule a OneDM discussion regarding the model repository and generation tooling.

Next Steps

The next ASDF interim meeting is scheduled to take place in approximately one month, before the upcoming IETF meeting. No ASDF session is currently planned to take place on-site in San Francisco.

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