**Session Date/Time:** 10 Nov 2021 14:30

# roll

## Summary

The roll working group meeting covered the status of active Internet Drafts, with significant discussions on the AODV-RPL mode of operation, a new draft on Multicast Registration in 6lo/roll, and updates on Projection, Failure Detection of the Router, and Enrollment Priority drafts. Key decisions included investigating a change for AODV-RPL's mode of operation to reuse an existing value and adopting the Failure Detection of the Router draft as a working group item.

## Key Discussion Points

*   **Working Group Status and Milestones**:
    *   Two documents (`projection` and `enrollment priority`) are active.
    *   `aodv-rpl` is submitted to the IESG for publication. `moppex-capabilities` was recently submitted.
    *   Milestones related to MOPEX and Capabilities need updating. MOPEX is considered closer to Working Group Last Call (WGLC) with only one open action item, while Capabilities is more complex.
    *   A new version of `storing-root` is available for review and consideration as a work item.
    *   Authors were encouraged to check and close/update open tickets on GitHub.
*   **AODV-RPL Mode of Operation Discussion**:
    *   The current `aodv-rpl` draft uses Mode of Operation (MO) 5. Discussion revolved around reusing MO 4 from RFC 6997 (P2P-RPL) instead, to conserve MO values.
    *   RFC 6997 is experimental and not widely implemented (known implementation in RIOT OS only).
    *   The question of whether `aodv-rpl` should obsolete `p2p-rpl` (RFC 6997) was raised. Obsoleting would require clarifying that implementations cannot coexist and updating any RFCs that reference RFC 6997 (e.g., RFC 8773).
    *   If obsoleted, the process would involve examining the scope of changes to `aodv-rpl` and potentially pulling it back from IESG review.
    *   There was a general consensus among participants to lean towards reusing MO 4 and obsoleting RFC 6997, provided the scope of work is manageable.
*   **Multicast Registration in 6lo/roll**:
    *   Pascal Thubert introduced a new draft extending RFC 8505 (6LoWPAN ND registration) for multicast and anycast addresses, providing an operation in RPL (non-storing mode) to transport these addresses.
    *   This aims to remove the need for MLD in constrained devices, particularly for Wi-SUN applications.
    *   The 6LR would handle ingress replication for multicast and select one 6LR for anycast.
    *   The draft introduces new flags in the RPL Target Option for anycast and multicast.
    *   Backward compatibility for existing RPL deployments (Map 1) was discussed.
    *   Concerns were raised about the interaction with PIM and the potential impact on MLD standardization efforts. It was suggested to inform the PIM working group.
    *   The possibility of splitting the document into separate 6lo and roll components was also discussed to facilitate broader review and adoption.
*   **Projection (`draft-ietf-roll-rpl-optimizations`)**:
    *   The draft is now at revision 21, having undergone significant revisions based on a detailed review by Talos.
    *   Changes include a simpler introduction, a new Section 3 for domain context and requirements, extended projected DAO sections, and a larger Section 6 for protocol operation details, including maintenance.
    *   The document now explicitly states its applicability beyond IoT use cases (e.g., ANIMA).
    *   The authors feel it's ready for WGLC, pending additional reviews.
*   **Failure Detection of the Router (`draft-ietf-roll-rpl-rnv`)**:
    *   Conrad presented updates to the draft, addressing comments on floating products, virtual DAG routes, sentinel selection, and adding an activation/deactivation mechanism.
    *   Discussion highlighted the problem's complexity (classical Byzantine general problem) and the critical need for rapid root failure detection.
    *   The working group recognized the problem statement as important and the draft as a suitable starting point for a solution.
*   **Enrollment Priority (`draft-ietf-roll-rpl-enrollment-priority`)**:
    *   Conrad proposed two approaches: "global" (total congestion control/load balancing) and "flexible" (no clear use case identified yet).
    *   The authors haven't fully discussed the proposed use cases or the core mechanism (e.g., whether priority values are modified down the DAG).
    *   Pascal noted that Wi-SUN has an operational need for this draft, emphasizing that if the priority value set by the root is propagated unchanged, it is perfectly workable.
    *   More reviews are needed, and a new revision is expected from the authors.

## Decisions and Action Items

*   **AODV-RPL Mode of Operation**:
    *   **Decision**: The working group leans towards moving `aodv-rpl` to use Mode of Operation 4 (MO=4) from RFC 6997 and consequently obsoleting RFC 6997. This decision is contingent on the outcome of further investigation into the scope of changes.
    *   **Action**: Alvaro to examine the scope of changes required for `aodv-rpl` and any related RFCs (e.g., RFC 8773) that would be impacted by obsoleting RFC 6997. This includes determining if the document needs to be pulled back from the IESG queue.
    *   **Action**: A GitHub issue will be created to track documents that reference RFC 6997.
    *   **Action**: A final call for strong objections regarding the reuse of MO=4 will be made on the mailing list.
*   **Multicast Registration**:
    *   **Action**: Pascal Thubert to send an email to the PIM mailing list to make them aware of the `multicast-registration` draft and its implications for MLD.
    *   **Action**: The chairs will coordinate with the 6lo chairs to ensure appropriate working group last call procedures are followed, especially if the document contains significant RPL elements.
*   **Failure Detection of the Router**:
    *   **Decision**: Adopt `draft-ietf-roll-rpl-rnv` as a working group item. There were no strong objections raised during the meeting, and consensus was reached on the problem statement's importance.
    *   **Action**: Confirm the adoption of `draft-ietf-roll-rpl-rnv` via the mailing list.
*   **Enrollment Priority**:
    *   **Action**: Authors of `draft-ietf-roll-rpl-enrollment-priority` to discuss the proposed use cases and core mechanism, and post a new revision by the end of the month.
    *   **Action**: New reviews are required for the updated draft.
*   **General**:
    *   **Action**: Authors of MOPEX and Capabilities to provide appropriate dates for milestone updates. MOPEX is targeted for WGLC soon.
    *   **Action**: Authors are encouraged to review their open tickets on GitHub and close/update them as appropriate.

## Next Steps

*   The working group will await the investigation results for AODV-RPL's MO change and subsequent process.
*   Continued engagement with the PIM WG regarding the multicast registration draft.
*   The `failure-detection-of-the-router` draft will proceed as a working group item.
*   A new revision of the `enrollment-priority` draft is expected, followed by further reviews.
*   The `projection` draft is ready for WGLC once additional reviews are completed.