idnits 2.17.1 draft-mirsky-6man-unified-id-sr-01.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (October 10, 2018) is 2024 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) -- Looks like a reference, but probably isn't: '0' on line 165 == Outdated reference: A later version (-26) exists of draft-ietf-6man-segment-routing-header-14 == Outdated reference: A later version (-18) exists of draft-ietf-idr-bgp-ls-segment-routing-ext-08 == Outdated reference: A later version (-25) exists of draft-ietf-isis-segment-routing-extensions-19 == Outdated reference: A later version (-23) exists of draft-ietf-ospf-ospfv3-segment-routing-extensions-15 == Outdated reference: A later version (-27) exists of draft-ietf-ospf-segment-routing-extensions-25 == Outdated reference: A later version (-22) exists of draft-ietf-spring-segment-routing-mpls-14 Summary: 0 errors (**), 0 flaws (~~), 7 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network G. Mirsky 3 Internet-Draft ZTE Corp. 4 Intended status: Standards Track P. Shaofu 5 Expires: April 13, 2019 ZTE Corporation 6 October 10, 2018 8 Unified Identifier in IPv6 Segment Routing Networks 9 draft-mirsky-6man-unified-id-sr-01 11 Abstract 13 Segment Routing architecture leverages the paradigm of source 14 routing. It can be realized in a network data plane by prepending 15 the packet with a list of instructions, a.k.a. segments. A segment 16 can be encoded as a Multi-Protocol Label Switching (MPLS) label, IPv4 17 address or IPv6 address. Segment Routing can be applied in MPLS data 18 plane by encoding segments in MPLS label stack. It also can be 19 applied to IPv6 data plane by encoding list of segment identifiers in 20 IPv6 Segment Routing Extension Header (SRH). This document extends 21 the use of the SRH to segment identifiers encoded as MPLS label and 22 IPv4 address. 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 https://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 April 13, 2019. 41 Copyright Notice 43 Copyright (c) 2018 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 (https://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 1.1. Conventions used in this document . . . . . . . . . . . . 3 60 1.1.1. Terminology . . . . . . . . . . . . . . . . . . . . . 3 61 1.1.2. Requirements Language . . . . . . . . . . . . . . . . 3 62 2. Segment Routing Extension Header: Benefits and Challenges . . 3 63 3. Support of Multiple SID Lengths in IPv6 Segment Routing 64 Extension Header . . . . . . . . . . . . . . . . . . . . . . 4 65 4. Theory of Operation . . . . . . . . . . . . . . . . . . . . . 5 66 4.1. Egress SR Tunnel Node . . . . . . . . . . . . . . . . . . 5 67 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 68 6. Security Considerations . . . . . . . . . . . . . . . . . . . 5 69 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 5 70 8. Normative References . . . . . . . . . . . . . . . . . . . . 5 71 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 73 1. Introduction 75 Segment Routing architecture [RFC8402] leverages the paradigm of 76 source routing. It can be realized in a network data plane by 77 prepending the packet with a list of instructions, a.k.a. segment 78 identifiers (SIDs). A segment can be encoded as a Multi-Protocol 79 Label Switching (MPLS) label, IPv4 address or IPv6 address. Segment 80 Routing can be applied in MPLS data plane by encoding 20-bits SIDs in 81 MPLS label stack [I-D.ietf-spring-segment-routing-mpls]. It also can 82 be applied to IPv6 data plane by encoding list of 128-bits SIDs in 83 IPv6 Segment Routing Extension Header (SRH) 84 [I-D.ietf-6man-segment-routing-header]. Applicability of 32-bits SID 85 that may represent an IPv4 address has not been defined. 87 SR extensions to Interior Gateway Protocols (IGP), IS-IS 88 [I-D.ietf-isis-segment-routing-extensions], OSPF 89 [I-D.ietf-ospf-segment-routing-extensions], and OSPFv3 90 [I-D.ietf-ospf-ospfv3-segment-routing-extensions], defined how 91 20-bits and 32-bits SIDs advertised and bound to SR objects and/or 92 instructions. Extensions to BGP link-state address family 93 [I-D.ietf-idr-bgp-ls-segment-routing-ext] enabled propagation of 94 segment information of variable length via BGP. 96 This document extends the use of the SRH 97 [I-D.ietf-6man-segment-routing-header] to SIDs encoded as MPLS label 98 and IPv4 address. 100 1.1. Conventions used in this document 102 1.1.1. Terminology 104 SR: Segment Routing 106 SRH: Segment Routing Extension Header 108 MPLS: Multiprotocol Label Switching 110 MPLS-SR: Segment Routing in MPLS 112 SID: Segment Identifier 114 IGP: Interior Gateway Protocol 116 OAM: Operation, Administration and Maintenance 118 TE: Traffic Engineering 120 SRv6: Segment Routing in IPv6 122 1.1.2. Requirements Language 124 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 125 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 126 "OPTIONAL" in this document are to be interpreted as described in BCP 127 14 [RFC2119] [RFC8174] when, and only when, they appear in all 128 capitals, as shown here. 130 2. Segment Routing Extension Header: Benefits and Challenges 132 Many functions related to Operation, Administration and Maintenance 133 (OAM) require identification of the SR tunnel ingress and the path, 134 constructed by segments, between the ingress and the egress SR nodes. 135 Combination of IPv6 encapsulation [RFC8200] and SRH 136 [I-D.ietf-6man-segment-routing-header], referred to as SRv6, comply 137 with this requirements while it is challenging when applying SR in 138 MPLS networks, also referred to as MPLS-SR. 140 On the other hand, the size of IPv6 SID presents a scaling challenge 141 to use topological instructions that define strict explicit traffic 142 engineered (TE) path in combination with service-based instructions. 144 At the same time, that is where MPLS-SR approach provides better 145 results due to smaller SID length. 147 [I-D.bryant-mpls-unified-ip-sr] addresses the scaling challenge by 148 using more compact SID encoding of MPLS-SR. Ability to address OAM 149 challenge characteristic to MPLS-SR is open for investigation. 151 3. Support of Multiple SID Lengths in IPv6 Segment Routing Extension 152 Header 154 In section 3 of [I-D.ietf-6man-segment-routing-header] SRH format has 155 been defined as presented in Figure 1 157 0 1 2 3 158 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 1 159 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 160 | Next Header | Hdr Ext Len | Routing Type | Segments Left | 161 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 162 | Last Entry | Flags | Tag | 163 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 164 | | 165 | Segment List[0] (128 bits IPv6 address) | 166 | | 167 | | 168 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 169 | | 170 | | 171 ... 172 | | 173 | | 174 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 175 | | 176 | Segment List[n] (128 bits IPv6 address) | 177 | | 178 | | 179 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 180 // // 181 // Optional Type Length Value objects (variable) // 182 // // 183 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 185 Figure 1: SRH format 187 This document defines the new field Size in the Flags field, 188 presented in Figure 2, as a two-bits field with the following values: 190 0b00 - 128-bits SID; 191 0b01 - 20-bits SID; 193 0b10 - 32-bits SID 195 0b11 - reserved for future use. 197 When the value of the S field is 0b01, the 20-bit SID is encoded in 198 four octets and occupies the 20 rightmost bits. 200 0 1 2 3 4 5 6 7 201 +-+-+-+-+-+-+-+-+ 202 |U|P|O|A|H| S |U| 203 +-+-+-+-+-+-+-+-+ 205 Figure 2: Flags field format 207 Entries of the segment list in the SRH MUST be of the same length. 209 4. Theory of Operation 211 When the SRH is used to include 20-bits or 32-bits SIDs the ingress 212 and transit nodes of an SR tunnel act as described in Section 5.1 and 213 Section 5.2 of [I-D.ietf-6man-segment-routing-header] respectively. 215 4.1. Egress SR Tunnel Node 217 TBD 219 5. IANA Considerations 221 TBD 223 6. Security Considerations 225 This specification inherits all security considerations of [RFC8402] 226 and [I-D.ietf-6man-segment-routing-header]. 228 7. Acknowledgements 230 TBD 232 8. Normative References 234 [I-D.bryant-mpls-unified-ip-sr] 235 Bryant, S., Farrel, A., Drake, J., and J. Tantsura, "MPLS 236 Segment Routing in IP Networks", draft-bryant-mpls- 237 unified-ip-sr-03 (work in progress), October 2017. 239 [I-D.ietf-6man-segment-routing-header] 240 Filsfils, C., Previdi, S., Leddy, J., Matsushima, S., and 241 d. daniel.voyer@bell.ca, "IPv6 Segment Routing Header 242 (SRH)", draft-ietf-6man-segment-routing-header-14 (work in 243 progress), June 2018. 245 [I-D.ietf-idr-bgp-ls-segment-routing-ext] 246 Previdi, S., Talaulikar, K., Filsfils, C., Gredler, H., 247 and M. Chen, "BGP Link-State extensions for Segment 248 Routing", draft-ietf-idr-bgp-ls-segment-routing-ext-08 249 (work in progress), May 2018. 251 [I-D.ietf-isis-segment-routing-extensions] 252 Previdi, S., Ginsberg, L., Filsfils, C., Bashandy, A., 253 Gredler, H., Litkowski, S., Decraene, B., and J. Tantsura, 254 "IS-IS Extensions for Segment Routing", draft-ietf-isis- 255 segment-routing-extensions-19 (work in progress), July 256 2018. 258 [I-D.ietf-ospf-ospfv3-segment-routing-extensions] 259 Psenak, P., Filsfils, C., Previdi, S., Gredler, H., 260 Shakir, R., Henderickx, W., and J. Tantsura, "OSPFv3 261 Extensions for Segment Routing", draft-ietf-ospf-ospfv3- 262 segment-routing-extensions-15 (work in progress), August 263 2018. 265 [I-D.ietf-ospf-segment-routing-extensions] 266 Psenak, P., Previdi, S., Filsfils, C., Gredler, H., 267 Shakir, R., Henderickx, W., and J. Tantsura, "OSPF 268 Extensions for Segment Routing", draft-ietf-ospf-segment- 269 routing-extensions-25 (work in progress), April 2018. 271 [I-D.ietf-spring-segment-routing-mpls] 272 Bashandy, A., Filsfils, C., Previdi, S., Decraene, B., 273 Litkowski, S., and R. Shakir, "Segment Routing with MPLS 274 data plane", draft-ietf-spring-segment-routing-mpls-14 275 (work in progress), June 2018. 277 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 278 Requirement Levels", BCP 14, RFC 2119, 279 DOI 10.17487/RFC2119, March 1997, 280 . 282 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 283 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 284 May 2017, . 286 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 287 (IPv6) Specification", STD 86, RFC 8200, 288 DOI 10.17487/RFC8200, July 2017, 289 . 291 [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., 292 Decraene, B., Litkowski, S., and R. Shakir, "Segment 293 Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, 294 July 2018, . 296 Authors' Addresses 298 Greg Mirsky 299 ZTE Corp. 301 Email: gregimirsky@gmail.com 303 Peng Shaofu 304 ZTE Corporation 305 No.50 Software Avenue, Yuhuatai District 306 Nanjing 307 China 309 Email: peng.shaofu@zte.com.cn