**Session Date/Time:** 08 Nov 2022 09:30

# spring

## Summary
The SPRING working group meeting covered a range of topics, including MPLS Network Action, interlayer network programming with SRv6, BFD encapsulation, network slicing, SR policy MTU, SRv6/MPLS interworking, and multicast VPN service in native IPv6 networks. Discussions focused on technical details, applicability, and potential areas for improvement. Several documents were presented, and the working group discussed potential adoption of some.

## Key Discussion Points
*   **MPLS Network Action:** The scope, encoding, and backward compatibility of the MPLS Network Action header were discussed. Concerns around the combination of different modes and the number of special-purpose labels needed were raised.
*   **Interlayer Network Programming:** The use cases for SRv6 in interlayer network programming, specifically for IP/Optical and IP/MTN integration, were presented. Concerns about layer 2 encapsulation and the necessity of a new behavior vs. existing n.X were discussed.
*   **BFD Encapsulation:** Two modes of BFD packet encapsulation (transport and tunnel) for SRv6 policies were presented. Questions arose regarding the necessity of these two modes and whether BFD encapsulation should differ from payload encapsulation. A suggestion was made to consolidate BFD-related documents in SPRING.
*   **Hierarchical IGF Network Slices:** A segment routing-based solution for hierarchical ITF network slices was presented. Questions were raised regarding its informational nature, its compatibility with other hierarchy management methods, and potential IPR disclosures.
*   **SR Policy MTU:** The need for an SR Policy MTU (SRP MTU) definition was reiterated, and potential caveats related to TI-LFA computation, SRv6 encapsulation, and Binding SID path computation were discussed.
*   **SRv6/MPLS Interworking:** Interworking procedures between SRv6 and MPLS domains were presented, including transport and service interworking. Questions focused on deployment and operational aspects as well as clarification of the roles of PCEP and BGP.
*   **SR Policy Group:** The concept of an SR Policy Group was presented, generating discussion on its purpose, location in the network (head-end vs. controller), and potential standardisation benefits.
*   **Network Resource Programming with SRv6:** A new SRv6 endpoint behavior (n.NRP) for associating traffic with specific network resources was proposed. Questions centered on how this relates to existing queuing mechanisms.
*   **Multicast VPN service in Native IPv6 Network:** A new segment type (endpoint nVPN) for multicast VPN in native IPv6 networks was proposed. Questions addressed its applicability to different mvpn scenarios and its conformity to existing mvpn procedures.

## Decisions and Action Items
*   **SR Education Segments:** The working group plus code on SR education segments will be started again pending the inclusion of implementation section.
*   **BFD Documents:** Suggestion to consider consolidating the five distinct BFD documents into a single document with specific examples for each technology.
*   **SR Policy MTU:** Asked for the work group adoption on the draft.
*   **SRv6/MPLS Interworking:** The authors will consider the operational aspects, cooperation with stateful inter-domain PCs, and how the new behaviors are incorporated into PCEP and BGP.  The authors will work with the co-authors of another transport interworking draft to see how to move forward on similar behaviors.
*   **Multicast VPN service in Native IPv6 Network:** Suggestion to present the draft at the best working group in a future meeting. Authors to clarify applicability and operation of the draft based on the discussion.

## Next Steps
*   Authors to revise their drafts based on the feedback received during the meeting and on the mailing list.
*   Further discussion on the mailing list for more in-depth analysis and to address open questions.
*   The chairs to follow up on the consolidation of the BFD documents.
*   The SPRING working group to continue evaluating drafts for potential adoption.