Markdown Version | Session Recording

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.