**Session Date/Time:** 24 Feb 2022 15:00

# [CORE](../wg/core.html)

## Summary

This interim meeting covered updates on active working group documents: `coreconf`, `href`, and `coral`. Significant progress was reported on `coreconf` regarding YANG SID file support and a new path forward with yangcatalog.org. The `coap-attacks` draft was formally split, with the CORE WG focusing on attacks against CoAP, and a call for adoption was initiated. Bill Sylvarajan presented the latest revision of `conditional-attributes`, leading to discussions on attribute definition and a potential registry. Finally, Kristian Kißling led a discussion on `transport indication`, outlining a proposed mechanism for advertising resources accessible via both CoAP and CoAP+TCP, and clarifying open issues.

## Key Discussion Points

*   **coreconf Update**:
    *   A recent meeting with YANG SIBO authors and area directors discussed yangcatalog.org support for SID files.
    *   The outcome will be written into a substantial pull request for the `coreconf` document, likely necessitating another Last Call (possibly an IETF Last Call).
    *   A suggestion was made to remove the normative reference from `yang-sibo` to `coreconf`, which did not meet outright disagreement.
    *   yangcatalog.org has agreed to support server-side SID, addressing IANA's budget limitations.
*   **href and coral Updates**:
    *   `href`: Implementations are still being adjusted, a process taking longer than anticipated due to time constraints. An aspirational goal is a revision for IETF 113 that can be considered for Working Group Last Call.
    *   `coral`: No specific updates were reported, though work is ongoing.
*   **coap-attacks Document**:
    *   Following discussions at the previous interim, the `coap-attacks` draft has been formally split.
    *   The CORE WG document now focuses on attacks *against* CoAP.
    *   Parts related to attacks *using* CoAP (e.g., amplification, formerly section 3) have been moved to a separate document in T2TRG.
*   **conditional-attributes Presentation**:
    *   Bill Sylvarajan presented draft-sylvarajan-core-conditional-attributes-02, submitted prior to the meeting.
    *   Feedback was incorporated, and three GitHub issues were closed.
    *   The `band` attribute's value was changed from a boolean to a query parameter whose presence indicates its use, with further discussion on handling explicit values (e.g., `band=0` or `band=1`).
    *   The need for a clearer definition of "attributes" (query parameters used in a specific way) was discussed, possibly through a new section that could be referenced by other documents.
    *   Text on proxies was updated to "should use" Max-Age in security considerations.
    *   The idea of a conditional attributes registry was introduced to map parameter names, prompting discussion on whether it should be specific to conditional attributes or a more general attributes registry, potentially extending the existing Resource Directory attribute registry.
*   **transport indication Discussion**:
    *   Kristian Kißling presented a proposal for a mechanism to reconcile CoAP servers having resources accessible via both CoAP and CoAP+TCP, allowing clients to switch.
    *   The proposal leverages existing link format resource announcements, adding a statement that co-hosted resources are available via a proxy (e.g., `coap+tcp://address`).
    *   Three key clarification points from reviews were discussed:
        1.  **URI Aliasing**: The mechanism, particularly when omitting the `Proxy-URI` option, might appear as URI aliasing on the wire, but server and client are aware of the original URI. This should be viewed as a form of compression or context introduction rather than true aliasing. Security considerations should address this.
        2.  **URI for Proxy Identification**: Using URIs like `coap+tcp://address` to identify a proxy mechanism, distinct from a resource at that host's root. The document could introduce a concept of "proxy described by URI" with a narrow scope.
        3.  **Use of `hosts` Relation**: The `hosts` relation (RFC 6690) is used to group resources on the same device, providing an indirection to associate them with a proxy advertised for the device's root (`/`). Discussion touched on different interpretations of the `hosts` relation, with the proposal leaning on RFC 6690's definition of an implied relation.
    *   There was general agreement that this work is important for fulfilling a long-standing promise to support multiple transports in CoAP.

## Decisions and Action Items

*   **Decision**: The `coreconf` document will have a pull request incorporating discussion on yangcatalog.org support for SID files.
*   **Decision**: The `coap-attacks` draft in CORE WG will focus on attacks *against* CoAP, with other aspects moved to T2TRG.
*   **Action Item**: A two-week call for adoption will be started on the mailing list for the `coap-attacks` draft as an informational document in the CORE WG.
*   **Action Item**: Bill Sylvarajan (conditional-attributes) to produce a new revision incorporating comments from the meeting (e.g., on attribute definition and registry).
*   **Action Item**: Bill Sylvarajan (conditional-attributes) to present the updated draft at IETF 113, aiming for WG Last Call readiness.
*   **Action Item**: Kristian Kißling (transport indication) to produce a new revised version of the draft addressing the three clarification points and present it at IETF 113.
*   **Action Item**: Bill Sylvarajan and Kristian Kißling to discuss offline the potential for a more general attribute registry and its relation to the Resource Directory's attribute registry.

## Next Steps

*   The CORE WG will hold another interim meeting next week (Wednesday, F-15 UTC).
*   All active document authors are encouraged to prepare updates for presentation at the IETF 113 two-hour session.