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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-26) exists of draft-ietf-6man-segment-routing-header-02 == Outdated reference: A later version (-25) exists of draft-ietf-isis-segment-routing-extensions-09 == Outdated reference: A later version (-15) exists of draft-ietf-spring-segment-routing-09 Summary: 0 errors (**), 0 flaws (~~), 4 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group S. Previdi, Ed. 3 Internet-Draft L. Ginsberg 4 Intended status: Standards Track C. Filsfils 5 Expires: May 18, 2017 Cisco Systems, Inc. 6 November 14, 2016 8 Segment Routing IPv6 Prefix-SID 9 draft-previdi-isis-ipv6-prefix-sid-03 11 Abstract 13 This document defines the Segment Routing IPv6-Prefix-SID sub-TLV. 14 This new sub-TLV allows to specify which of the prefixes advertised 15 by a node are to be used as Segment Routing Identifiers (SID) for the 16 IPv6 data plane. 18 Requirements Language 20 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 21 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 22 document are to be interpreted as described in RFC 2119 [RFC2119]. 24 Status of This Memo 26 This Internet-Draft is submitted in full conformance with the 27 provisions of BCP 78 and BCP 79. 29 Internet-Drafts are working documents of the Internet Engineering 30 Task Force (IETF). Note that other groups may also distribute 31 working documents as Internet-Drafts. The list of current Internet- 32 Drafts is at http://datatracker.ietf.org/drafts/current/. 34 Internet-Drafts are draft documents valid for a maximum of six months 35 and may be updated, replaced, or obsoleted by other documents at any 36 time. It is inappropriate to use Internet-Drafts as reference 37 material or to cite them other than as "work in progress." 39 This Internet-Draft will expire on May 18, 2017. 41 Copyright Notice 43 Copyright (c) 2016 IETF Trust and the persons identified as the 44 document authors. All rights reserved. 46 This document is subject to BCP 78 and the IETF Trust's Legal 47 Provisions Relating to IETF Documents 48 (http://trustee.ietf.org/license-info) in effect on the date of 49 publication of this document. Please review these documents 50 carefully, as they describe your rights and restrictions with respect 51 to this document. Code Components extracted from this document must 52 include Simplified BSD License text as described in Section 4.e of 53 the Trust Legal Provisions and are provided without warranty as 54 described in the Simplified BSD License. 56 Table of Contents 58 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 59 2. IPv6 Prefix SID . . . . . . . . . . . . . . . . . . . . . . . 2 60 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 61 4. Security Considerations . . . . . . . . . . . . . . . . . . . 4 62 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 63 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 64 6.1. Normative References . . . . . . . . . . . . . . . . . . 4 65 6.2. Informative References . . . . . . . . . . . . . . . . . 5 66 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 68 1. Introduction 70 With Segment Routing (SR)[I-D.ietf-spring-segment-routing], a node 71 steers a packet through an ordered list of instructions, called 72 segments. Segments are identified through Segment Identifiers (SIDs) 73 that are advertised by routing protocols. The IS-IS extensions for 74 SR information advertisement are defined in 75 [I-D.ietf-isis-segment-routing-extensions]. 77 Segment Routing can be directly applied to the IPv6 data plane 78 through the use of the Segment Routing Header defined in 79 [I-D.ietf-6man-segment-routing-header]. 81 When applied to the IPv6 data plane, the SID is represented by an 82 IPv6 address. This document defines a new IS-IS Prefix sub-TLV where 83 information related to the IPv6 address used as SR IPv6 SID is 84 conveyed. 86 2. IPv6 Prefix SID 88 When SR is applied to the IPv6 data plane, Segment Identifiers (SIDs) 89 are IPv6 addresses. In a router, it is desirable to identify which 90 of the local prefixes can be used as SIDs. Also, and in order to 91 provide the same functionalities defined in 92 [I-D.ietf-spring-segment-routing] and according to 93 [I-D.ietf-isis-segment-routing-extensions], a new sub-TLV is defined: 94 the IPv6-Prefix-SID sub-TLV. 96 The IPv6-Prefix-SID sub-TLV is attached to an IPv6 prefix advertised 97 by a node and MAY be present in any of the following TLVs: 99 TLV-236 (IPv6) defined in [RFC5308]. 101 TLV-237 (MT-IPv6) defined in [RFC5120]. 103 The IPv6-Prefix-SID sub-TLV is optional, MAY appear only once for a 104 given prefix and has the following format: 106 0 1 2 3 107 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 1 108 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 109 | Type | Length | Flags | 110 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 111 | Algorithm | // 112 +-+-+-+-+-+-+-+-+ Sub-TLVs // 113 // // 114 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 116 where: 118 Type: To be assigned by IANA (suggested value 5). 120 Length: 3 + length of sub-TLVs. 122 Flags: 2 octet field of flags. None of them is defined at this 123 stage. 125 Algorithm: as defined in 126 [I-D.ietf-isis-segment-routing-extensions]. 128 Sub-TLVs: additional information encoded into the IPv6-Prefix-SID 129 Sub-TLV. Currently, no sub-TLVs are defined yet. 131 A prefix with an attached IPv6-Prefix-SID sub-TLV is defined as an 132 SR-IPv6 Prefix SID. If the prefix is to be used as a Node-SID 133 (according to [I-D.ietf-isis-segment-routing-extensions]) then the 134 following applies: 136 o The IPv6 prefix MUST be advertised with the IPv6-Prefix-SID sub- 137 TLV attached. 139 o The Extended Reachability Attribute Flags sub-TLV defined in 140 [RFC7794] MUST be attached to the prefix and the N-flag MUST be 141 set. 143 When a router has attached an IPv6-Prefix-SID sub-TLV to a prefix, it 144 implies that the router supports the Segment Routing Header (SRH, 145 defined in [I-D.ietf-6man-segment-routing-header] and its associated 146 procedures for packets destined to the advertised prefix. 148 A router receiving an IPv6-Prefix-SID from a remote node and with an 149 algorithm value that such remote node has not advertised in the SR- 150 Capability sub-TLV (as defined in 151 [I-D.ietf-isis-segment-routing-extensions]) MUST ignore the IPv6- 152 Prefix-SID sub-TLV. 154 3. IANA Considerations 156 This document makes the following registrations in the "sub-TLVs for 157 TLV 135, 235, 236 and 237" registry. 159 Type: TBD (suggested value 5) 161 Description: IPv6 Prefix Segment Identifier 163 TLV 135: no 165 TLV 235: no 167 TLV 236: yes 169 TLV 237: yes 171 Reference: This document (Section 2) 173 4. Security Considerations 175 This document doesn't introduce new security considerations. 177 5. Acknowledgements 179 The authors would like to thank Nagendra Kumar for his review of this 180 document. 182 6. References 184 6.1. Normative References 186 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 187 Requirement Levels", BCP 14, RFC 2119, 188 DOI 10.17487/RFC2119, March 1997, 189 . 191 [RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi 192 Topology (MT) Routing in Intermediate System to 193 Intermediate Systems (IS-ISs)", RFC 5120, 194 DOI 10.17487/RFC5120, February 2008, 195 . 197 [RFC5308] Hopps, C., "Routing IPv6 with IS-IS", RFC 5308, 198 DOI 10.17487/RFC5308, October 2008, 199 . 201 [RFC7794] Ginsberg, L., Ed., Decraene, B., Previdi, S., Xu, X., and 202 U. Chunduri, "IS-IS Prefix Attributes for Extended IPv4 203 and IPv6 Reachability", RFC 7794, DOI 10.17487/RFC7794, 204 March 2016, . 206 6.2. Informative References 208 [I-D.ietf-6man-segment-routing-header] 209 Previdi, S., Filsfils, C., Field, B., Leung, I., Linkova, 210 J., Aries, E., Kosugi, T., Vyncke, E., and D. Lebrun, 211 "IPv6 Segment Routing Header (SRH)", draft-ietf-6man- 212 segment-routing-header-02 (work in progress), September 213 2016. 215 [I-D.ietf-isis-segment-routing-extensions] 216 Previdi, S., Filsfils, C., Bashandy, A., Gredler, H., 217 Litkowski, S., Decraene, B., and j. jefftant@gmail.com, 218 "IS-IS Extensions for Segment Routing", draft-ietf-isis- 219 segment-routing-extensions-09 (work in progress), October 220 2016. 222 [I-D.ietf-spring-segment-routing] 223 Filsfils, C., Previdi, S., Decraene, B., Litkowski, S., 224 and R. Shakir, "Segment Routing Architecture", draft-ietf- 225 spring-segment-routing-09 (work in progress), July 2016. 227 Authors' Addresses 229 Stefano Previdi (editor) 230 Cisco Systems, Inc. 231 Via Del Serafico, 200 232 Rome 00142 233 Italy 235 Email: sprevidi@cisco.com 236 Les Ginsberg 237 Cisco Systems, Inc. 238 US 240 Email: ginsberg@cisco.com 242 Clarence Filsfils 243 Cisco Systems, Inc. 244 Brussels 245 BE 247 Email: cfilsfil@cisco.com