Name: Multicast Source Routing over IPv6 (MSR6)

Description

The MSR6 WG focuses on source routing multicast based on native IPv6 (IPv6 and IPv6 extension headers), including Best Effort and Traffic Engineering solutions, which is able to decouple multicast forwarding with per flow status in intermediate nodes, similar as SRv6 for unicast.

There are some multicast scenarios with the following characteristics at the same time, for example multicast for DCN, that can’t be covered well by the existing work in IETF:

1.Large network scale ; BIER/BIER TE defined in BIER WG request bit position allocation for each egress nodes/adjacencies. When the the network scale is large, bitstring length is unacceptable considering the encapsulation expanse.

2.Numerous multicast service; PIM and SR P2MP defined in PIM WG request maintaining per flow status in the intermediate nodes. When the multicast service is numerous, the number of replication status could overload the capability of the intermediate nodes.

3.Small and flexible multicast tree; It is affordable for encapsulation expense to encode a multicast tree in the packet in the ingress node.

Source routing provides the capability to steer a packet though a list of network nodes without maintaining per flow status in intermediate nodes. MSR6 is suitable for these multicast scenarios which request scalability and flexibility.

With the rapid deployment of IPv6, there are some other multicast scenarios carried in IPv6 network request functions provided by IPv6 extension header, including IPsec, network slicing. For example security is one of the fundamental requirements in SD-WAN network. Multicast services for SD-WAN also request encryption. Native IPv6 based multicast solution like MSR6 is suitable for these scenarios.

MSR6 have the following benefits:

1.Source Routing to achieve high scalability.

2.Native IPv6 based design, to reuse functionalities defined in IPv6 extension header and transit through non-MSR6 IPv6 nodes.

The BOF is to discuss the use case, requirements, and potential solutions for MSR6.

Required Details

• Status: WG Forming
• Responsible AD: Alvaro Retana
• BOF proponents: Yisong Liu <liuyisong@chinamobile.com>, Aijun Wang <wangaijun@tsinghua.org.cn>, Xueru Zhang <zhangxr49@chinaunicom.cn>, Huaimo Chen <huaimo.chen@futurewei.com>, Xuesong Geng <gengxuesong@huawei.com>, Changwang Lin <linchangwang.04414@h3c.com>
• Proposed BOF chairs: Weiqiang Cheng <chengweiqiang@chinamobile.com>, Mike McBride <mmcbride7@gmail.com>
• Number of people expected to attend: 100
• Length of session: 2 hours
• Conflicts (whole Areas and/or WGs): SRPING, BIER, 6MAN, PIM, Mboned
• Chair Conflicts: TBD
• Technology Overlap: Segment Routing, Multicast
• Key Participant Conflict: TBD

Agenda

• Administration: Chairs [5 minutes]
• MSR6 Overview/Design Consideration [10 minutes]
• MSR6 Use Case [30 minutes]
• MSR6 BE/TE Potential Solutions [20 minutes]
• MSR6 WG Scope Discussion [10 minutes]
• MSR6 WG Charter Discussion [30 minutes]
• Conclusions and next steps: Chairs and AD [5 minutes]

Links to the mailing list, draft charter if any, relevant Internet-Drafts, etc.

• Mailing List: Not Yet

• Draft charter: https://github.com/MSR6-community/IETF-113-MSR6-BOF-Request/blob/main/BOF%20Charter%20v4.0

• Relevant drafts:

  • Design Considerations:

    • https://datatracker.ietf.org/doc/draft-cheng-spring-ipv6-msr-design-consideration/

  • Proposed Solutions:

    • https://datatracker.ietf.org/doc/draft-lx-msr6-rgb-segment/
    • https://datatracker.ietf.org/doc/draft-xl-msr6-source-segment/
    • https://datatracker.ietf.org/doc/draft-geng-msr6-traffic-engineering/
    • https://datatracker.ietf.org/doc/draft-chen-pim-srv6-p2mp-path/