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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 SPRING WG W. Cheng 2 Internet-Draft China Mobile 3 Intended status: Standards Track Changwang. Lin 4 Expires: April 24, 2022 H3C Corporation 5 L. Gong 6 China Mobile 7 October 24, 2021 9 Encoding Network Slice Identification for SRv6 10 draft-cheng-spring-srv6-encoding-network-sliceid-02 12 Abstract 14 This document describe a method to encode network slicing identifier 15 within SRv6 domain. 17 Status of This Memo 19 This Internet-Draft is submitted in full conformance with the 20 provisions of BCP 78 and BCP 79. 22 Internet-Drafts are working documents of the Internet Engineering 23 Task Force (IETF). Note that other groups may also distribute 24 working documents as Internet-Drafts. The list of current Internet- 25 Drafts is at https://datatracker.ietf.org/drafts/current/. 27 Internet-Drafts are draft documents valid for a maximum of six months 28 and may be updated, replaced, or obsoleted by other documents at any 29 time. It is inappropriate to use Internet-Drafts as reference 30 material or to cite them other than as "work in progress." 32 This Internet-Draft will expire on April 24, 2022. 34 Copyright Notice 36 Copyright (c) 2021 IETF Trust and the persons identified as the 37 document authors. All rights reserved. 39 This document is subject to BCP 78 and the IETF Trust's Legal 40 Provisions Relating to IETF Documents 41 (https://trustee.ietf.org/license-info) in effect on the date of 42 publication of this document. Please review these documents 43 carefully, as they describe your rights and restrictions with respect 44 to this document. Code Components extracted from this document must 45 include Simplified BSD License text as described in Section 4.e of 46 the Trust Legal Provisions and are provided without warranty as 47 described in the Simplified BSD License. 49 Table of Contents 51 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 52 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 53 2. Slice Identifier . . . . . . . . . . . . . . . . . . . . . . 2 54 3. SLID Assignment . . . . . . . . . . . . . . . . . . . . . . . 2 55 4. Per-Slice Forwarding . . . . . . . . . . . . . . . . . . . . 3 56 5. Backward Compatibility . . . . . . . . . . . . . . . . . . . 3 57 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4 58 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 59 7.1. Normative References . . . . . . . . . . . . . . . . . . 4 60 7.2. Informative References . . . . . . . . . . . . . . . . . 4 61 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4 63 1. Introduction 65 SRv6 Network Programming[RFC8986] enables the creation of overlays 66 with underlay optimization to be deployed in an SR domain[RFC8402]. 68 As defined in [RFC8754], all inter-domain packets are encapsulated 69 for the part of the packet journey that is within the SR domain. The 70 outer IPv6 header [RFC8200] is originated by a node of the SR domain 71 and is destined to a node of the SR domain. 73 This document describes a novel method to encode slice identifier 74 in the outer IPv6 header of an SR domain. Unlike other proposed 75 methods before, which will bring side effects on existed functions, 76 by encoding network slicing identifier in the source IPv6 address of 77 the outer header, this method avoids the drawbacks which previous 78 proposals incur. 80 1.1. Requirements Language 82 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 83 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 84 document are to be interpreted as described in RFC 2119 [RFC2119]. 86 2. Slice Identifier 88 Slice identifier (SLID) is a 16-bit Identifier which uniquely defines 89 a slicing of the network in the specified SR domain. 91 3. SLID Assignment 93 When SR domain enables network slicing, the ingress PE should reserve 94 16 least significant bits in its locater for slicing use. When a 95 packet enters the SR domain from an ingress PE, the ingress PE 96 encapsulates the packet in an outer IPv6 header and optional SRH as 97 defined in [RFC8754]. The ingress PE MAY also classify the packet 98 into a slice and set the slice identifier as follows: 100 o Set the SPI bit (SLID Presence Indicator) in the Traffic Class 101 field of the outer IPv6 header. 103 o Write this SLID in the 16 least significant bits of source address 104 of the outer IPv6 header. 106 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 1 107 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 108 |Version| SPI Bit | Flow Label | 109 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 110 | Payload Length | Next Header | Hop Limit | 111 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 112 | | 113 + + 114 | | 115 + Source Address + 116 | | 117 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 118 | | SLID | 119 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 120 | | 121 + + 122 | | 123 + Destination Address + 124 | | 125 + + 126 | | 127 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 129 The choice of the SPI bit from within the IPv6 Traffic Class field is 130 a domain-wide configuration and is outside the scope of this 131 document. 133 4. Per-Slice Forwarding 135 Any router within the SR domain that forwards a packet with SPI bit 136 set uses the SLID to select a slice and apply per-slice policies. 138 5. Backward Compatibility 140 PE routers that do not set the SPI bit do not enable the SLID 141 semantic of the IPv6 source address bits. Hence, SLID-aware routers 142 would not attempt to classify these packets into a slice. 144 Any router that does not process the SPI nor the SLID forwards 145 packets as usual. 147 6. Acknowledgements 149 The authors would like to thank AAAA, BBBB and CCCC for their 150 insightful feedback on this document. 152 7. References 154 7.1. Normative References 156 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 157 Requirement Levels", BCP 14, RFC 2119, 158 DOI 10.17487/RFC2119, March 1997, 159 . 161 [RFC8986] Filsfils, C., Camarillo, P., Leddy, J., Voyer, D., 162 Matsushima, S., and Z. Li, 163 Segment Routing over IPv6 (SRv6) Network Programming, 164 RFC 8986, DOI 10.17487/RFC8986, February 2021, 165 . 167 [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., 168 Decraene, B., Litkowski, S., and R. Shakir, "Segment 169 Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, 170 July 2018, . 172 [RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J., 173 Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header 174 (SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020, 175 . 177 7.2. Informative References 179 [RFC8200] Deering, S., and Hinden, D., "Internet Protocol, Version 6 180 (IPv6) Specification", RFC 8200, DOI 10.17487/RFC8200, 181 July 2017, . 183 Authors' Addresses 185 Weiqiang Cheng 186 China Mobile 187 Beijing 188 China 190 Email: chengweiqiang@chinamobile.com 192 Changwang Lin 193 H3C Corporation 194 Beijing 195 China 197 Email: linchangwang.04414@h3c.com 199 Liyan Gong 200 China Mobile 201 Beijing 202 China 204 Email: gongliyan@chinamobile.com