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Versions: 00 01                                                         
Network Working Group                                           W. Cheng
Internet-Draft                                              China Mobile
Intended status: Informational                                 G. Mishra
Expires: January 13, 2022                                   Verizon Inc.
                                                                   Z. Li
                                                     Huawei Technologies
                                                                 A. Wang
                                                           China Telecom
                                                                  Z. Qin
                                                            China Unicom
                                                                  C. Fan
                                                    New H3C Technologies
                                                           July 12, 2021

      Design Consideration of IPv6 Multicast Source Routing (MSR6)


   This document discusses the design consideration of IPv6 source
   routing multicast solution.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in RFC 2119 [RFC2119].

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on January 13, 2022.

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Internet-Draft        Design Consideration of MSR6             July 2021

Copyright Notice

   Copyright (c) 2021 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Design Consideration  . . . . . . . . . . . . . . . . . . . .   3
   3.  Conclusion  . . . . . . . . . . . . . . . . . . . . . . . . .   5
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   5
   7.  Normative References  . . . . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   Multicast could provide efficient P2MP service without bandwidth
   waste.  The increasing amount of live video traffic in the network
   bring new requirements for multicast solutions.  The existing
   multicast solutions request multicast tree-building on control plane
   and maintaining end-to-end tree state per flow, which impacts router
   state capacity and network convergence time.  There has been a lot of
   work in IETF to simplify service deployment, in which Source Routing
   is a very important technology, including SRv6, BIER, etc.  Source
   routing is able to reduce the state of intermediate nodes and
   indicate multicast forwarding in the ingress nodes, which could
   simplify multicast deployment.  Source routing requires sufficient
   flexibility on the forwarding plane and IPv6 has the advantage with
   good scalability.  Therefore, it is important to simplify multicast
   deployment and meet high quality service requirements with IPv6
   Source Routing based multicast.

   This document discusses the design consideration of IPv6 multicast
   source routing (MSR6) solution.  The definition of the new IPv6
   multicast source routing solution is out of the scope of this

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Internet-Draft        Design Consideration of MSR6             July 2021

2.  Design Consideration

   Firstly, MSR6 needs to support the basic multicast functionalities,

   o  P2MP Forwarding: replicate and forward multicast packet to the
      next replication nodes;

   o  Multicast Flow Overlay: multicast service, such as MVPN

   o  P2MP OAM functions: Ping/Traceroute/BFD

   In addition to this, it is necessary for MSR6 to meet the need of
   high quality service with high reliability, including:

   o  Traffic Engineering: explicit path specification to satisfy
      different kinds of requirements

   o  FRR

   o  E2E Protection

   o  Advanced network measurement functions, including: performance
      measurement and In-situ Flow Information Telemetry, which is the
      basis for traffic engineering and high quality transport service.

   The IPv6 multicast source routing should take use of the advantages
   of source routing to reduce the state of the network as much as
   possible.  That is, it should satisfy the above requirements with
   high scalability.

   However, MSR6 is not about starting from scratch.  The existing IETF
   work should be reused as much as possible:

   o  BIER

   Bit Index Explicit Replication (BIER) defined in [RFC8279] is an
   architecture providing optimal multicast forwarding without requiring
   intermediate routers to maintain any per-flow state by using a
   multicast-specific BIER header.  BIER use bitstring in the BIER
   header to indicate leaf nodes which gives an efficient solution for
   Best Effort multicast flow without the requirement of Traffic

   o  SRv6([RFC8986])

   SRv6 has advantages in indicating explicit paths, which brings
   convenience for unicast TE and FRR.  MSR6 TE should refer to the

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Internet-Draft        Design Consideration of MSR6             July 2021

   experience of SRv6.  In addition, SRv6 provides flexible path
   programming capability with the definition of different type of
   segments.  MSR6 could make use the of existing segments in the design
   of TE/FRR . For example, path segment
   ([I-D.ietf-spring-srv6-path-segment]) could help to enhance the
   performance measurement capability.  In the meantime, SRv6
   compression ([I-D.srcompdt-spring-compression-requirement]) is under
   discussion to reduce encapsulation overhead, which could also be
   reused by MSR6.

   o  The existing and ongoing IPv6 extensions

   1) Existing functionalities including fragmentation and security

   Multicast packets need to be fragmented and secured as they pass
   through the IPv6 network.  This can be done using IPv6 Fragmentation
   and ESP(Encapsulating Security Payload) defined in [RFC8200].  Work
   about Path MTU [I-D.ietf-idr-sr-policy-path-mtu] which supports
   fragmentation, is also under discussion.  All these existing work
   should be reused in the MSR6.

   2) New network functionalities based on the ongoing IPv6 Extensions,
   including Network Slicing, Deterministic Networking(DetNet),

   Network slicing ([I-D.ietf-teas-ietf-network-slices]) and DetNet
   ([RFC8655]) are being introduced to satisfy the quality service
   requirements of critical services.  IOAM ([I-D.ietf-ippm-ioam-data])
   is also introduced to implement in-situ network measurement.  IPv6
   data plane is being used to support network slicing
   ([I-D.li-6man-e2e-ietf-network-slicing] and
   [I-D.dong-6man-enhanced-vpn-vtn-id]), Detnet
   ([I-D.geng-spring-srv6-for-detnet] and
   [I-D.geng-spring-sr-redundancy-protection]), IOAM
   ([I-D.ietf-ippm-ioam-data]), etc.  Multicast service can also benefit
   from these new network functionalities to improve quality of service.
   MSR6 could reuse the ongoing work based on IPv6 extensions to
   implement the functionalities for multicast services.

   3) Future possible work based on IPv6 extensions, including
   Application Aware Network (APN)

   APN ([I-D.li-apn-framework]) is used to provide more granular
   services, which can use IPv6 extension header to carry APN
   information for the purpose of steering traffic, etc.  MSR6 can
   combine with APN to map the traffic to different Network-based
   multicast services/functionalities according to the APN information
   in the IPv6 data plane.

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Internet-Draft        Design Consideration of MSR6             July 2021

   4) MSR6 is also supposed to be started at the Host based on IPv6

   In [RFC8754], it is supposed that a host can originate the IPv6
   source routing packet.  MSR6 should take use of the native IPv6
   design and support originating the IPv6 packet by the host.

3.  Conclusion

   A new IPv6 multicast source routing solution is requested based on
   the design consideration listed above.

4.  IANA Considerations

   This document makes no request of IANA.

   Note to RFC Editor: this section may be removed on publication as an

5.  Security Considerations

6.  Acknowledgements

7.  Normative References

              Dong, J., Li, Z., Xie, C., and C. Ma, "Carrying Virtual
              Transport Network Identifier in IPv6 Extension Header",
              draft-dong-6man-enhanced-vpn-vtn-id-03 (work in progress),
              February 2021.

              Geng, X., Chen, M., and F. Yang, "Segment Routing for
              Redundancy Protection", draft-geng-spring-sr-redundancy-
              protection-02 (work in progress), February 2021.

              Geng, X., Li, Z., and M. Chen, "SRv6 for Deterministic
              Networking (DetNet)", draft-geng-spring-srv6-for-detnet-01
              (work in progress), July 2020.

              Li, C., Zhu, Y., Sawaf, A. E., and Z. Li, "Segment Routing
              Path MTU in BGP", draft-ietf-idr-sr-policy-path-mtu-02
              (work in progress), November 2020.

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Internet-Draft        Design Consideration of MSR6             July 2021

              Brockners, F., Bhandari, S., and T. Mizrahi, "Data Fields
              for In-situ OAM", draft-ietf-ippm-ioam-data-12 (work in
              progress), February 2021.

              Li, C., Cheng, W., Chen, M., Dhody, D., and R. Gandhi,
              "Path Segment for SRv6 (Segment Routing in IPv6)", draft-
              ietf-spring-srv6-path-segment-00 (work in progress),
              November 2020.

              Farrel, A., Gray, E., Drake, J., Rokui, R., Homma, S.,
              Makhijani, K., Contreras, L. M., and J. Tantsura,
              "Framework for IETF Network Slices", draft-ietf-teas-ietf-
              network-slices-00 (work in progress), April 2021.

              Li, Z. and J. Dong, "Encapsulation of End-to-End IETF
              Network Slice Information in IPv6", draft-li-6man-e2e-
              ietf-network-slicing-00 (work in progress), April 2021.

              Li, Z., Peng, S., Voyer, D., Li, C., Liu, P., Cao, C.,
              Ebisawa, K., Previdi, S., and J. N. Guichard,
              "Application-aware Networking (APN) Framework", draft-li-
              apn-framework-02 (work in progress), February 2021.

              Cheng, W., Xie, C., Bonica, R., Dukes, D., Li, C., Shaofu,
              P., and W. Henderickx, "Compressed SRv6 SID List
              Requirements", draft-srcompdt-spring-compression-
              requirement-06 (work in progress), March 2021.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,

   [RFC8200]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", STD 86, RFC 8200,
              DOI 10.17487/RFC8200, July 2017,

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Internet-Draft        Design Consideration of MSR6             July 2021

   [RFC8279]  Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
              Przygienda, T., and S. Aldrin, "Multicast Using Bit Index
              Explicit Replication (BIER)", RFC 8279,
              DOI 10.17487/RFC8279, November 2017,

   [RFC8296]  Wijnands, IJ., Ed., Rosen, E., Ed., Dolganow, A.,
              Tantsura, J., Aldrin, S., and I. Meilik, "Encapsulation
              for Bit Index Explicit Replication (BIER) in MPLS and Non-
              MPLS Networks", RFC 8296, DOI 10.17487/RFC8296, January
              2018, <https://www.rfc-editor.org/info/rfc8296>.

   [RFC8655]  Finn, N., Thubert, P., Varga, B., and J. Farkas,
              "Deterministic Networking Architecture", RFC 8655,
              DOI 10.17487/RFC8655, October 2019,

   [RFC8663]  Xu, X., Bryant, S., Farrel, A., Hassan, S., Henderickx,
              W., and Z. Li, "MPLS Segment Routing over IP", RFC 8663,
              DOI 10.17487/RFC8663, December 2019,

   [RFC8754]  Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J.,
              Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
              (SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020,

   [RFC8986]  Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer,
              D., Matsushima, S., and Z. Li, "Segment Routing over IPv6
              (SRv6) Network Programming", RFC 8986,
              DOI 10.17487/RFC8986, February 2021,

Authors' Addresses

   Weiqiang Cheng
   China Mobile

   Email: chengweiqiang@chinamobile.com

   Gyan Mishra
   Verizon Inc.

   Email: gyan.s.mishra@verizon.com

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Internet-Draft        Design Consideration of MSR6             July 2021

   Zhenbin Li
   Huawei Technologies

   Email: lizhenbin@huawei.com

   Aijun Wang
   China Telecom

   Email: wangaj3@chinatelecom.cn

   Zhuangzhuang Qin
   China Unicom

   Email: qinzhuangzhuang@chinaunicom.cn

   Chi Fan
   New H3C Technologies

   Email: fanchi@h3c.com

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