SPRING WG W. Cheng Internet-Draft China Mobile Intended status: Standards Track Changwang. Lin Expires: October 25, 2022 H3C Corporation L. Gong China Mobile April 25, 2022 Encoding Network Slice Identification for SRv6 draft-cheng-spring-srv6-encoding-network-sliceid-03 Abstract This document describe a method to encode network slicing identifier within SRv6 domain. 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 October 25, 2022. 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. Cheng, et al. Expires October 25, 2022 [Page 1] Internet-Draft Encoding Network Slice Identification April 2022 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 2. Slice Identifier . . . . . . . . . . . . . . . . . . . . . . 2 3. SLID Assignment . . . . . . . . . . . . . . . . . . . . . . . 2 4. Per-Slice Forwarding . . . . . . . . . . . . . . . . . . . . 3 5. Backward Compatibility . . . . . . . . . . . . . . . . . . . 3 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 7.1. Normative References . . . . . . . . . . . . . . . . . . 4 7.2. Informative References . . . . . . . . . . . . . . . . . 4 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction SRv6 Network Programming[RFC8986] enables the creation of overlays with underlay optimization to be deployed in an SR domain[RFC8402]. As defined in [RFC8754], all inter-domain packets are encapsulated for the part of the packet journey that is within the SR domain. The outer IPv6 header [RFC8200] is originated by a node of the SR domain and is destined to a node of the SR domain. This document describes a novel method to encode slice identifier in the outer IPv6 header of an SR domain. Unlike other proposed methods before, which will bring side effects on existed functions, by encoding network slicing identifier in the source IPv6 address of the outer header, this method avoids the drawbacks which previous proposals incur. 1.1. 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]. 2. Slice Identifier Slice identifier (SLID) is a 16-bit Identifier which uniquely defines a slicing of the network in the specified SR domain. 3. SLID Assignment When SR domain enables network slicing, the ingress PE should reserve 16 least significant bits in its locater for slicing use. When a packet enters the SR domain from an ingress PE, the ingress PE encapsulates the packet in an outer IPv6 header and optional SRH as defined in [RFC8754]. The ingress PE MAY also classify the packet into a slice and set the slice identifier as follows: Cheng, et al. Expires October 25, 2022 [Page 2] Internet-Draft Encoding Network Slice Identification April 2022 o Set the SPI bit (SLID Presence Indicator) in the Traffic Class field of the outer IPv6 header. o Write this SLID in the 16 least significant bits of source address of the outer IPv6 header. 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Version| SPI Bit | Flow Label | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Payload Length | Next Header | Hop Limit | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Source Address + | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | SLID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | | + Destination Address + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ The choice of the SPI bit from within the IPv6 Traffic Class field is a domain-wide configuration and is outside the scope of this document. 4. Per-Slice Forwarding Any router within the SR domain that forwards a packet with SPI bit set uses the SLID to select a slice and apply per-slice policies. 5. Backward Compatibility PE routers that do not set the SPI bit do not enable the SLID semantic of the IPv6 source address bits. Hence, SLID-aware routers would not attempt to classify these packets into a slice. Any router that does not process the SPI nor the SLID forwards packets as usual. Cheng, et al. Expires October 25, 2022 [Page 3] Internet-Draft Encoding Network Slice Identification April 2022 6. Acknowledgements The authors would like to thank AAAA, BBBB and CCCC for their insightful feedback on this document. 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC8986] Filsfils, C., Camarillo, P., Leddy, J., Voyer, D., Matsushima, S., and Z. Li, Segment Routing over IPv6 (SRv6) Network Programming, RFC 8986, DOI 10.17487/RFC8986, February 2021, . [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., Decraene, B., Litkowski, S., and R. Shakir, "Segment Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, July 2018, . [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, . 7.2. Informative References [RFC8200] Deering, S., and Hinden, D., "Internet Protocol, Version 6 (IPv6) Specification", RFC 8200, DOI 10.17487/RFC8200, July 2017, . Authors' Addresses Weiqiang Cheng China Mobile Beijing China Email: chengweiqiang@chinamobile.com Changwang Lin H3C Corporation Beijing China Email: linchangwang.04414@h3c.com Liyan Gong China Mobile Beijing China Email: gongliyan@chinamobile.com Cheng, et al. Expires October 25, 2022 [Page 4] Internet-Draft Encoding Network Slice Identification April 2022