Session Date/Time: 20 Aug 2025 07:00

ASDF

Summary

This interim meeting focused on aligning the instance-information and sdf-non-affordance drafts by introducing a common concept of "SDF context." The new draft-rohit-asdf-protocol-mappings was introduced, with a proposal to fast-track its adoption, pending a discussion on its name to avoid confusion with existing documents. Significant updates were made to the NIPY draft, including a new approach to problem types and refinements to extension mechanisms. The group also decided on a new process for reviewing NIPY issues and scheduled the next interim.

Key Discussion Points

Administrative

Note-taking: Ari volunteered to take notes.
Agenda Review: An item was added to discuss instance-information in the context of sdf-non-affordance. Updates from Junga and Yan were also requested.
Note Well Reminder: Standard IETF policies apply, the meeting is recorded, and participants should adhere to the code of conduct.
Working Group Document Updates:
- A new draft, draft-rohit-asdf-protocol-mappings, has been posted, co-authored by Rohit, S.B., and the Chair. This draft aims to standardize SDF protocol mappings, likely via a registry, to enable interaction with external ecosystems (e.g., Bluetooth, Zigbee, HTTP).
- The digital-twin and sdf-non-affordance drafts were formally adopted as working group documents.
- NIPY has posted several new versions addressing various issues.

Instance Information & SDF Non-Affordance Alignment

Yan presented on the conceptual conflict between the instance-information and sdf-non-affordance drafts, which was previously discussed in Madrid.
A potential alignment using SDF context as a common concept was proposed.
The instance-information draft has already been updated to use SDF context, replacing previous $context and offdevice property concepts, and this update works well.
There's a need for "litmus tests" to guide when to use SDF property versus SDF context.
Junga confirmed plans to update the sdf-non-affordance draft to incorporate the SDF context keyword.
The authors of the relevant documents will collaborate to ensure alignment, particularly in examples, acknowledging that this might take time due to availability.

SDF Protocol Mappings Draft (`draft-rohit-asdf-protocol-mappings`)

Rohit introduced the new draft, which was split from the NIPY document. It consolidates protocol mapping-related text and adds examples for protocols like CoAP (using CDDL) and HTTP. The NIPY draft now normatively references this new document.
Carsten emphasized the usefulness of the document and proposed an accelerated process for making it a working group document, given its origin from an existing work item. He anticipated minimal controversy.
Carsten also raised concerns about potential confusion due to naming, noting that the existing sdf-mapping document uses "map" differently. He suggested working on a paragraph to explain how the two documents combine rather than compete. He also suggested a broader review of terminology related to "map" or "mapping" across the working group.
The Chair agreed to fast-track the adoption process with Michael but noted the importance of agreeing on a clear, descriptive name before formal adoption to avoid year-long confusion.

NIPY Updates

Bart proposed a new process for NIPY issue review: for clearly solved issues, he will email the list for a week-long review period, only bringing complex or contentious issues to interim meetings. This was agreed upon.
Issues closed:
- 149 (Query parameters percent encoded): All reserved characters are now percent-encoded (in draft-12).
- 146 (Remove 'manage' keyword): The "manage" keyword was removed, and "connection" is now part of the regular path (e.g., connections). (Note: a typo in the description was noted).
- 145 (Protocol mapping to separate draft): Done, now draft-rohit-asdf-protocol-mappings.
- 143 (MQTT client object to boolean): Changed from an empty object to a boolean, as discussed in Madrid.
- 141 (URI template for API paths): Updated for /connection and query parameters.
- 150 (Inconsistencies in example): Fixed JSON pointer URL inconsistencies (SDF thing vs. SDF object).
- 128 (Supporting write and read in a single value): Updated to support different content types and introduced a new nipy+json media type for JSON-formatted bodies. Text regarding "raw binary data" was clarified to mean "the actual representation as such."
Issues Open (requiring further action/discussion):
- 139 (Problem Types):
  - NIPY now uses its own problem types and a new dedicated registry, moving away from HTTP problem types and removing the NIPY prefix.
  - Carsten noted this establishes a precedent for allocating code points in a similar namespace to RFC 9457 (HTTP Problem Details). He recommended involving IANA and the working group that developed RFC 9457 (HTTPAPI) to ensure proper registry management.
  - Draft-12 already incorporates these changes. Bart will initiate contact with the HTTPAPI list, referencing the current draft.
- 136 (Limitations on extensions):
  - The draft's text describing the reasons for extensions (e.g., "complex set of NIPY operations," "more efficiently") was discussed for being potentially too restrictive.
  - Discussion on the SHOULD requirement for extensions to leverage the /extensions path element. Carsten argued that a SHOULD would "never pass" and suggested changing it to MUST to ensure collision-free naming.
  - The group agreed to change SHOULD to MUST.
  - Further discussion is needed on mechanisms for managing extension names (IANA registry, domain names for vendor-specific extensions) and how these would be reflected in URI templates.
- 50 (Action without binary data):
  - An inconsistency in Draft-12 was noted: extensions/manage/transmit should be extensions/ID/transmit or similar, as "manage" was removed from the general path structure.
  - The specific issue about "request body can contain binary data" was not clearly reflected in the current text or PR, suggesting a possible incorrect PR link or unaddressed change. This issue remains open for re-evaluation.

Decisions and Action Items

Decision: The instance-information and sdf-non-affordance drafts will align using the SDF context keyword.
Decision: NIPY issue review process will be streamlined: Bart will email the list with proposed closed issues for review, and only complex issues will be discussed in meetings.
Decision: NIPY Problem Types: The group will pursue creating a NIPY-specific problem types registry.
Decision: NIPY Extensions: The SHOULD for using the /extensions/{extension-name} path element will be changed to MUST.
Action Item: Junga and Yan to update the sdf-non-affordance draft to use SDF context.
Action Item: Authors of instance-information and sdf-non-affordance to collaborate on aligning documents and examples, including developing litmus tests for SDF property vs. SDF context.
Action Item: Chairs (with Rohit) to fast-track the adoption process for draft-rohit-asdf-protocol-mappings.
Action Item: Before draft-rohit-asdf-protocol-mappings adoption, the WG will agree on a descriptive name to avoid conflict with sdf-mapping.
Action Item: Bart to draft an email to the HTTPAPI working group and IANA regarding the NIPY problem types registry, referencing the current draft-ietf-asdf-nipy.
Action Item: Bart (and the WG) to clarify the intended types of NIPY extensions, how they should be registered/named (e.g., IANA, domain names for vendor-specific), and how such naming reflects in URI templates, updating issue 136.
Action Item: Bart to re-evaluate and address issue 50 regarding "Action without binary data" and the inconsistency in the extensions/manage/transmit path in Draft-12.

Next Steps

Next Interim Meeting: September 24th, 1 hour earlier than today's slot (9:00 Helsinki time / 8:00 Central European Time). The Chair will request the slot.