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) draft-cheng-spring-ipv6-msr-design-consideration-00 Abstract This document discusses the design consideration of IPv6 source routing multicast solution. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 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. Cheng, et al. Expires January 13, 2022 [Page 1] 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 carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as 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 document. Cheng, et al. Expires January 13, 2022 [Page 2] Internet-Draft Design Consideration of MSR6 July 2021 2. Design Consideration Firstly, MSR6 needs to support the basic multicast functionalities, including: 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 Engineering. o SRv6([RFC8986]) SRv6 has advantages in indicating explicit paths, which brings convenience for unicast TE and FRR. MSR6 TE should refer to the Cheng, et al. Expires January 13, 2022 [Page 3] 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), IOAM.etc. 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. Cheng, et al. Expires January 13, 2022 [Page 4] 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 RFC. 5. Security Considerations 6. Acknowledgements 7. Normative References [I-D.dong-6man-enhanced-vpn-vtn-id] 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. [I-D.geng-spring-sr-redundancy-protection] Geng, X., Chen, M., and F. Yang, "Segment Routing for Redundancy Protection", draft-geng-spring-sr-redundancy- protection-02 (work in progress), February 2021. [I-D.geng-spring-srv6-for-detnet] Geng, X., Li, Z., and M. Chen, "SRv6 for Deterministic Networking (DetNet)", draft-geng-spring-srv6-for-detnet-01 (work in progress), July 2020. [I-D.ietf-idr-sr-policy-path-mtu] 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. Cheng, et al. Expires January 13, 2022 [Page 5] Internet-Draft Design Consideration of MSR6 July 2021 [I-D.ietf-ippm-ioam-data] Brockners, F., Bhandari, S., and T. Mizrahi, "Data Fields for In-situ OAM", draft-ietf-ippm-ioam-data-12 (work in progress), February 2021. [I-D.ietf-spring-srv6-path-segment] 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. [I-D.ietf-teas-ietf-network-slices] 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. [I-D.li-6man-e2e-ietf-network-slicing] 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. [I-D.li-apn-framework] 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. [I-D.srcompdt-spring-compression-requirement] 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, . Cheng, et al. Expires January 13, 2022 [Page 6] 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, . [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 Cheng, et al. Expires January 13, 2022 [Page 7] 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 Cheng, et al. Expires January 13, 2022 [Page 8]