**Session Date/Time:** 22 May 2024 14:00

# [ROLL](../wg/roll.html)

## Summary

The ROLL Working Group held an interim meeting to discuss the status of several drafts. Key updates were provided for `draft-ietf-roll-rnfd`, `draft-ietf-roll-enrollment-priority`, `draft-ietf-roll-mopex`, and `draft-ietf-roll-n-extensions`. The working group decided to initiate Working Group Last Calls for `rnfd` and `enrollment-priority`. Discussions also centered on specific technical challenges and proposals for `mopex` and `n-extensions`. Aris Katsilidis was welcomed as a new co-chair for the working group.

## Key Discussion Points

*   **Welcome New Co-Chair:** Aris Katsilidis was welcomed as a new co-chair for the ROLL WG.
*   **draft-ietf-roll-rnfd (Fast Border Router Detection in RPL):**
    *   Conrad presented a recap of `rnfd`, which aims to address slow DoDAC root (ALR) crash detection in RPL, preventing network instability and loops.
    *   The mechanism involves "Sentinel" nodes (DoDAC root neighbors) monitoring root status and "Acceptor" nodes propagating observations. A new option in DIO/DIS messages is used for Sentinels to exchange link status.
    *   Version 03 of the draft was published, addressing four in-depth reviews (SVR Anand, Mar Cars, Victoria from Routing Directorate, Chris L. from Security Directorate).
    *   Major changes in v03 include:
        *   Addition of Section 1.3 discussing alternative solutions to ALR crashes.
        *   Introduction of mechanisms to increase confidence in individual decisions during the verification phase (e.g., limiting transitions for unstable links).
        *   Clarification of root node behavior regarding CFRC bit length changes.
        *   Extraction of `rnfd-cfrc-saturation-threshold` as an explicit constant and reordering of other constants.
    *   Anand and Cars confirmed their remarks were addressed. One minor comment from Cars regarding the `suspicion-growth-threshold` remains and will be addressed in a future version.
*   **draft-ietf-roll-enrollment-priority:**
    *   Michael indicated that version 11 of the draft was published, addressing two outstanding reviews (Dave Thaler, Rat). He believes it is ready for Working Group Last Call. Aris plans to review it as well.
*   **draft-ietf-roll-mopex (Mode of Operation Extension for RPL):**
    *   Dominique discussed the current state of the draft, noting a recent proposal from Pascal.
    *   The draft currently suggests that reusing old MOP values (0-6) within the `mopex` field implies an "improved" or "augmented" behavior for those modes, with specifics to be defined later.
    *   Pascal's proposal suggests that if an old MOP value (0-6) is present *and* the `mopex` field exists, the `mopex` field could be used to indicate a version (e.g., V0, V1, V2) of that particular old MOP.
    *   This proposal was seen as potentially intricate and complex, raising concerns about parsing ambiguity and maintaining simplicity.
*   **draft-ietf-roll-n-extensions:**
    *   Aris provided an update, noting that the draft has been delayed.
    *   A significant discussion point is a proposal from Pascal to make the draft more generic and objective-function-agnostic. Currently, the draft extends `MRHOF` functionality. The proposal is to rewrite it as an orthogonal add-on for any objective function, making it more modular and potentially shorter. This requires further design work.
*   **Next Interim Meeting:** The WG is considering scheduling the next interim meeting in September, with a doodle poll to be sent out for availability.
*   **IETF Participation:** The WG does not plan to participate in the upcoming IETF meeting but aims to participate in the November IETF meeting.

## Decisions and Action Items

*   **Decision:** The Working Group will initiate a Working Group Last Call for `draft-ietf-roll-rnfd` (version 03) by email today, for a duration of two weeks.
*   **Decision:** The Working Group will initiate a Working Group Last Call for `draft-ietf-roll-enrollment-priority` (version 11) immediately after the `rnfd` Working Group Last Call concludes.
*   **Action Item:** Michael (shepherd for `rnfd`) will review the shepherd write-up to ensure it is up to date.
*   **Action Item:** Conrad will address the remaining minor comment from Mar Cars regarding the `suspicion-growth-threshold` in `rnfd` version 04, possibly alongside any comments from the WG Last Call.
*   **Action Item:** Dominique will reach out to Pascal on the mailing list to request further elaboration on his suggestion for using the `mopex` field as a version indicator for existing MOP values.
*   **Action Item:** Aris will work on proposing a revised, more generic version of `draft-ietf-roll-n-extensions` that is objective-function-agnostic, and present it to the WG. If not feasible, the draft will revert to its `MRHOF`-dependent approach.
*   **Action Item:** The chairs will send out a doodle poll to schedule the next interim meeting in September.

## Next Steps

*   The working group will proceed with the two scheduled Working Group Last Calls.
*   The discussions and proposals for `mopex` and `n-extensions` will continue, aiming to resolve open technical questions and advance these drafts.
*   The chairs will coordinate the next interim meeting and future IETF participation.