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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 IDR Y. Liu 3 Internet-Draft S. Peng 4 Intended status: Standards Track ZTE 5 Expires: 4 September 2022 3 March 2022 7 Advertising SID Algorithm Information in BGP 8 draft-peng-idr-segment-routing-te-policy-attr-02 10 Abstract 12 This document proposes extensions of BGP and defines some new Segment 13 Types with algorithm information to meet more requirements when 14 delivering SR Policy via BGP. 16 Status of This Memo 18 This Internet-Draft is submitted in full conformance with the 19 provisions of BCP 78 and BCP 79. 21 Internet-Drafts are working documents of the Internet Engineering 22 Task Force (IETF). Note that other groups may also distribute 23 working documents as Internet-Drafts. The list of current Internet- 24 Drafts is at https://datatracker.ietf.org/drafts/current/. 26 Internet-Drafts are draft documents valid for a maximum of six months 27 and may be updated, replaced, or obsoleted by other documents at any 28 time. It is inappropriate to use Internet-Drafts as reference 29 material or to cite them other than as "work in progress." 31 This Internet-Draft will expire on 4 September 2022. 33 Copyright Notice 35 Copyright (c) 2022 IETF Trust and the persons identified as the 36 document authors. All rights reserved. 38 This document is subject to BCP 78 and the IETF Trust's Legal 39 Provisions Relating to IETF Documents (https://trustee.ietf.org/ 40 license-info) in effect on the date of publication of this document. 41 Please review these documents carefully, as they describe your rights 42 and restrictions with respect to this document. Code Components 43 extracted from this document must include Revised BSD License text as 44 described in Section 4.e of the Trust Legal Provisions and are 45 provided without warranty as described in the Revised BSD License. 47 Table of Contents 49 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 50 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 51 3. New Segment Types for SR-MPLS Adjacency with optional 52 Algorithm . . . . . . . . . . . . . . . . . . . . . . . . 3 53 3.1. Type M: IPv4 Address + Local Interface ID with optional 54 Algorithm . . . . . . . . . . . . . . . . . . . . . . . . 3 55 3.2. Type N: IPv4 Local and Remote addresses with optional 56 Algorithm . . . . . . . . . . . . . . . . . . . . . . . . 4 57 3.3. Type O: IPv6 Address + Interface ID for local and remote 58 pair with optional Algorithm related SID for SR MPLS . . 5 59 3.4. Type P: IPv6 Local and Remote addresses with optional 60 Algorithm for SR MPLS . . . . . . . . . . . . . . . . . . 6 61 4. New Segment Types for SID only, with optional Algorithm . . . 7 62 4.1. Type L: MPLS SID only, with optional Algorithm . . . . . 7 63 4.2. Type Q: SRv6 SID only, with optional Algorithm . . . . . 8 64 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 65 6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 66 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 67 7.1. Normative References . . . . . . . . . . . . . . . . . . 9 68 7.2. Informative References . . . . . . . . . . . . . . . . . 9 69 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 71 1. Introduction 73 Segment Routing (SR) [RFC8402] allows a headend node to steer a 74 packet flow along any path. [I-D.ietf-spring-segment-routing-policy] 75 details the concepts of SR Policy and steering into an SR Policy. 76 These apply equally to the MPLS and IPv6 data plane instantiations of 77 Segment Routing with their respective representations of segments as 78 SR-MPLS SID and SRv6 SID as described in [RFC8402]. 80 [I-D.ietf-idr-segment-routing-te-policy] specifies the way to use BGP 81 to distribute one or more of the candidate paths of an SR Policy to 82 the headend of that policy. It defines a new BGP address family 83 (SAFI), i.e., SR Policy SAFI NLRI. In UPDATE messages of that 84 address family, the NLRI identifies an SR Policy Candidate Path, and 85 the attributes encode the segment lists and other details of that SR 86 Policy Candidate Path. 11 Segment Types (from A to K) are defined to 87 encode SR-MPLS or SRv6 segments. 89 As specified in [I-D.ietf-idr-segment-routing-te-policy], the SR 90 algorithm can be optionally specified for Segment Types C(IPv4 Node 91 and SID), D(IPv6 Node and SID for SR-MPLS), I(IPv6 Node and SID for 92 SRv6), J(IPv6 Node, index for remote and local pair, and SID for 93 SRv6), and K(IPv6 Local/Remote addresses and SID for SRv6). That is, 94 currently the algorithm can be carried along with SR-MPLS prefix SID, 95 SRv6 prefix SID and SRv6 adjacency SID when delivering SR Policy via 96 BGP. 98 This document proposes extensions of BGP and defines some new Segment 99 Types with algorithm information to meet more requirements when 100 delivering SR Policy via BGP. 102 2. Requirements Language 104 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 105 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 106 document are to be interpreted as described in [RFC2119]. 108 3. New Segment Types for SR-MPLS Adjacency with optional Algorithm 110 [I-D.ietf-lsr-algorithm-related-adjacency-sid] complements that 111 besides Prefix-SID, the algorithm can be also included as part of an 112 Adjacency-SID advertisement for SR-MPLS, in scenarios where multiple 113 algorithm share the same link resource. In this case, an SR-MPLS 114 Policy advertised to the headend may also contain algorithm specific 115 Adjacency-SID. 117 This section defines 4 new Segment Sub-TLVs of Segment List Sub-TLV 118 to provide algorithm information for SR-MPLS Adjacency-SID. 120 The processing procedures for SID with algorithm specified in 121 [I-D.ietf-spring-segment-routing-policy] and 122 [I-D.ietf-idr-segment-routing-te-policy] are still applicable for the 123 new segment types. When the algorithm is not specified for the SID 124 types above which optionally allow for it, the headend SHOULD use the 125 Strict Shortest Path algorithm if available; otherwise, it SHOULD use 126 the default Shortest Path algorithm. 128 3.1. Type M: IPv4 Address + Local Interface ID with optional Algorithm 130 The Type M Segment Sub-TLV is similar with existed Type E Segment 131 Sub-TLV, it also encodes an IPv4 node address, a local interface 132 Identifier (Local Interface ID) and an optional SR-MPLS SID, but with 133 additional algorithm information. The format is as follows: 135 0 1 2 3 136 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 1 137 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 138 | Type | Length | Flags | SR Algorithm | 139 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 140 | Local Interface ID (4 octets) | 141 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 142 | IPv4 Node Address (4 octets) | 143 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 144 | SR-MPLS SID (optional, 4 octets) | 145 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 147 Where: 149 Type: TBD1 151 SR Algorithm: 1 octet specifying SR Algorithm as described in section 152 3.1.1 in [RFC8402] when A-Flag as defined in section 2.4.4.2.12 153 [I-D.ietf-idr-segment-routing-te-policy] is present. SR Algorithm is 154 used by SRPM as described in section 4 in 155 [I-D.ietf-spring-segment-routing-policy]. When A-Flag is not 156 encoded, this field SHOULD be set to zero on transmission and MUST be 157 ignored on receipt. 159 Other fields have the same meaning as the existing Type E Segment 160 Sub-TLV. 162 3.2. Type N: IPv4 Local and Remote addresses with optional Algorithm 164 The Type N Segment Sub-TLV is similar with existed Type F Segment 165 Sub-TLV, it also encodes an adjacency local address, an adjacency 166 remote address and an optional SR-MPLS SID, but with additional 167 algorithm information. The format is as follows: 169 0 1 2 3 170 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 1 171 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 172 | Type | Length | Flags | SR Algorithm | 173 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 174 | Local IPv4 Address (4 octets) | 175 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 176 | Remote IPv4 Address (4 octets) | 177 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 178 | SR-MPLS SID (optional, 4 octets) | 179 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 181 Where: 183 Type: TBD2 185 SR Algorithm: 1 octet specifying SR Algorithm as described in section 186 3.1.1 in [RFC8402] when A-Flag as defined in section 2.4.4.2.12 187 [I-D.ietf-idr-segment-routing-te-policy] is present. SR Algorithm is 188 used by SRPM as described in section 4 in 189 [I-D.ietf-spring-segment-routing-policy]. When A-Flag is not 190 encoded, this field SHOULD be set to zero on transmission and MUST be 191 ignored on receipt. 193 Other fields have the same meaning as existed Type F Segment Sub-TLV. 195 3.3. Type O: IPv6 Address + Interface ID for local and remote pair with 196 optional Algorithm related SID for SR MPLS 198 The Type O Segment Sub-TLV is similar with existed Type G Segment 199 Sub-TLV, it also encodes an IPv6 Link Local adjacency with IPv6 local 200 node address, a local interface identifier (Local Interface ID), IPv6 201 remote node address , a remote interface identifier (Remote Interface 202 ID) and an optional SR-MPLS SID, but with additional algorithm 203 information. The format is as follows: 205 0 1 2 3 206 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 1 207 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 208 | Type | Length | Flags | SR Algorithm | 209 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 210 | Local Interface ID (4 octets) | 211 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 212 // IPv6 Local Node Address (16 octets) // 213 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 214 | Remote Interface ID (4 octets) | 215 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 216 // IPv6 Remote Node Address (16 octets) // 217 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 218 | SR-MPLS SID (optional, 4 octets) | 219 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 221 Where: 223 Type: TBD3 224 SR Algorithm: 1 octet specifying SR Algorithm as described in section 225 3.1.1 in [RFC8402] when A-Flag as defined in section 2.4.4.2.12 226 [I-D.ietf-idr-segment-routing-te-policy] is present. SR Algorithm is 227 used by SRPM as described in section 4 in 228 [I-D.ietf-spring-segment-routing-policy]. When A-Flag is not 229 encoded, this field SHOULD be set to zero on transmission and MUST be 230 ignored on receipt. 232 Other fields have the same meaning as existed Type G Segment Sub-TLV. 234 3.4. Type P: IPv6 Local and Remote addresses with optional Algorithm 235 for SR MPLS 237 The Type P Segment Sub-TLV is similar with existed Type H Segment 238 Sub-TLV, it also encodes an adjacency local address, an adjacency 239 remote address and an optional SR-MPLS SID, but with additional 240 algorithm information. The format is as follows: 242 0 1 2 3 243 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 1 244 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 245 | Type | Length | Flags | SR Algorithm | 246 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 247 // Local IPv6 Address (16 octets) // 248 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 249 // Remote IPv6 Address (16 octets) // 250 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 251 | SR-MPLS SID (optional, 4 octets) | 252 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 254 Where: 256 Type: TBD4 258 SR Algorithm: 1 octet specifying SR Algorithm as described in section 259 3.1.1 in [RFC8402] when A-Flag as defined in section 2.4.4.2.12 260 [I-D.ietf-idr-segment-routing-te-policy] is present. SR Algorithm is 261 used by SRPM as described in section 4 in 262 [I-D.ietf-spring-segment-routing-policy]. When A-Flag is not 263 encoded, this field SHOULD be set to zero on transmission and MUST be 264 ignored on receipt. 266 Other fields have the same meaning as existed Type H Segment Sub-TLV. 268 4. New Segment Types for SID only, with optional Algorithm 270 Segment Sub-TLV for Type A defined in section 2.4.4.2.1 271 [I-D.ietf-idr-segment-routing-te-policy] carries only the SID 272 information in the form of MPLS Label. Segment Sub-TLV for Type B 273 defined in section 2.4.4.2.2 [I-D.ietf-idr-segment-routing-te-policy] 274 carries only the SID information in the form of IPv6 address. 276 If the algorithm information is carried along with the SIDs, it's 277 useful in the scenarios below: 279 Scenario 1: The algorithm may be optionally provided to the headend 280 for verification purposes. The headend can check if the SID value 281 and the related algorithm received can be found in its SR-DB if 282 requested to do so. 284 Scenario 2: The headend may not know about the SID-related algorithm 285 especially in the inter-domain scenario. Providing the algorithm 286 information benefits troubleshooting and network management. 288 This section defines 2 new Segment Sub-TLVs of Segment List Sub-TLV 289 to provide algorithm information for SR-MPLS/SRv6 SID. 291 4.1. Type L: MPLS SID only, with optional Algorithm 293 The Type L Segment Sub-TLV is similar with the Type A Segment Sub- 294 TLV, it also encodes a single SR-MPLS SID, but with additional 295 algorithm information. The format is as follows: 297 0 1 2 3 298 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 1 299 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 300 | Type | Length | Flags | SR Algorithm | 301 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 302 | Label | TC |S| TTL | 303 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 305 Where: 307 Type: TBD5 309 SR Algorithm: 1 octet specifying SR Algorithm as described in section 310 3.1.1 in [RFC8402] when A-Flag as defined in section 2.4.4.2.12 311 [I-D.ietf-idr-segment-routing-te-policy] is present. When A-Flag is 312 not encoded, this field SHOULD be set to zero on transmission and 313 MUST be ignored on receipt. 315 Other fields have the same meaning as Type A Segment Sub-TLV. 317 4.2. Type Q: SRv6 SID only, with optional Algorithm 319 The Type Q Segment Sub-TLV is similar with existed Type B Segment 320 Sub-TLV, it also encodes a single SRv6 SID, but with additional 321 algorithm, endpoint behavior and SID strucutre information. The 322 format is as follows: 324 0 1 2 3 325 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 1 326 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 327 | Type | Length | Flags | SR Algorithm | 328 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 329 // SRv6 SID (16 octets) // 330 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 331 // SRv6 Endpoint Behavior and SID Structure (optional) // 332 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 334 Where: 336 Type: TBD6 338 Length is variable. 340 SR Algorithm: 1 octet specifying SR Algorithm as described in section 341 3.1.1 in [RFC8402] when A-Flag as defined in section 2.4.4.2.12 342 [I-D.ietf-idr-segment-routing-te-policy] is present. When A-Flag is 343 not encoded, this field SHOULD be set to zero on transmission and 344 MUST be ignored on receipt. 346 Other fields have the same meaning as the Type B Segment Sub-TLV. 348 5. IANA Considerations 350 This document requests codepoint allocations for new Segment Sub-TLVs 351 in the "SR Policy List Sub-TLVs" registry. 353 Value Description Reference 354 ------------------------------------------------------------------------ 355 TBD1 Type L MPLS Algorithm related SID sub-TLV This document 356 TBD2 Type M IPv4 Node, index and Algorithm related This document 357 SID sub-TLV 358 TBD3 Type N IPv4 Local/Remote addresses and Algorithm This document 359 related SID sub-TLV 360 TBD4 Type O IPv6 Node, index for remote and local pair This document 361 and Algorithm related SID for SR-MPLS sub-TLV 362 TBD5 Type P IPv6 Local/Remote addresses and Algorithm This document 363 related SID sub-TLV 364 TBD6 Type Q SRv6 Algorithm related SID sub-TLV This document 365 6. Security Considerations 367 Procedures and protocol extensions defined in this document do not 368 affect the security considerations discussed in 369 [I-D.ietf-idr-segment-routing-te-policy]. 371 7. References 373 7.1. Normative References 375 [I-D.ietf-idr-segment-routing-te-policy] 376 Previdi, S., Filsfils, C., Talaulikar, K., Mattes, P., 377 Jain, D., and S. Lin, "Advertising Segment Routing 378 Policies in BGP", Work in Progress, Internet-Draft, draft- 379 ietf-idr-segment-routing-te-policy-14, 10 November 2021, 380 . 383 [I-D.ietf-spring-segment-routing-policy] 384 Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and 385 P. Mattes, "Segment Routing Policy Architecture", Work in 386 Progress, Internet-Draft, draft-ietf-spring-segment- 387 routing-policy-18, 17 February 2022, 388 . 391 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 392 Requirement Levels", BCP 14, RFC 2119, 393 DOI 10.17487/RFC2119, March 1997, 394 . 396 7.2. Informative References 398 [I-D.ietf-lsr-algorithm-related-adjacency-sid] 399 Peng, S., Chen, R., Talaulikar, K., and P. Psenak, 400 "Algorithm Related IGP-Adjacency SID Advertisement", Work 401 in Progress, Internet-Draft, draft-ietf-lsr-algorithm- 402 related-adjacency-sid-02, 18 January 2022, 403 . 406 [I-D.ietf-lsr-flex-algo] 407 Psenak, P., Hegde, S., Filsfils, C., Talaulikar, K., and 408 A. Gulko, "IGP Flexible Algorithm", Work in Progress, 409 Internet-Draft, draft-ietf-lsr-flex-algo-18, 25 October 410 2021, . 413 [I-D.ietf-lsr-isis-srv6-extensions] 414 Psenak, P., Filsfils, C., Bashandy, A., Decraene, B., and 415 Z. Hu, "IS-IS Extensions to Support Segment Routing over 416 IPv6 Dataplane", Work in Progress, Internet-Draft, draft- 417 ietf-lsr-isis-srv6-extensions-18, 20 October 2021, 418 . 421 [I-D.ietf-lsr-ospfv3-srv6-extensions] 422 Li, Z., Hu, Z., Cheng, D., Talaulikar, K., and P. Psenak, 423 "OSPFv3 Extensions for SRv6", Work in Progress, Internet- 424 Draft, draft-ietf-lsr-ospfv3-srv6-extensions-03, 19 425 November 2021, . 428 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 429 (IPv6) Specification", STD 86, RFC 8200, 430 DOI 10.17487/RFC8200, July 2017, 431 . 433 [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., 434 Decraene, B., Litkowski, S., and R. Shakir, "Segment 435 Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, 436 July 2018, . 438 [RFC8660] Bashandy, A., Ed., Filsfils, C., Ed., Previdi, S., 439 Decraene, B., Litkowski, S., and R. Shakir, "Segment 440 Routing with the MPLS Data Plane", RFC 8660, 441 DOI 10.17487/RFC8660, December 2019, 442 . 444 [RFC8665] Psenak, P., Ed., Previdi, S., Ed., Filsfils, C., Gredler, 445 H., Shakir, R., Henderickx, W., and J. Tantsura, "OSPF 446 Extensions for Segment Routing", RFC 8665, 447 DOI 10.17487/RFC8665, December 2019, 448 . 450 [RFC8666] Psenak, P., Ed. and S. Previdi, Ed., "OSPFv3 Extensions 451 for Segment Routing", RFC 8666, DOI 10.17487/RFC8666, 452 December 2019, . 454 [RFC8667] Previdi, S., Ed., Ginsberg, L., Ed., Filsfils, C., 455 Bashandy, A., Gredler, H., and B. Decraene, "IS-IS 456 Extensions for Segment Routing", RFC 8667, 457 DOI 10.17487/RFC8667, December 2019, 458 . 460 [RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J., 461 Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header 462 (SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020, 463 . 465 Authors' Addresses 467 Yao Liu 468 ZTE 469 Nanjing 470 China 471 Email: liu.yao71@zte.com.cn 473 Shaofu Peng 474 ZTE 475 Nanjing 476 China 477 Email: peng.shaofu@zte.com.cn