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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(See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-31) exists of draft-bonica-6man-comp-rtg-hdr-27 ** Downref: Normative reference to an Experimental draft: draft-bonica-6man-comp-rtg-hdr (ref. 'I-D.bonica-6man-comp-rtg-hdr') -- Possible downref: Non-RFC (?) normative reference: ref. 'ISO10589' ** Obsolete normative reference: RFC 5316 (Obsoleted by RFC 9346) Summary: 2 errors (**), 0 flaws (~~), 2 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 LSR Working Group P. Kaneriya 3 Internet-Draft R. Shetty 4 Intended status: Standards Track S. Hegde 5 Expires: 28 August 2022 R. Bonica 6 Juniper Networks 7 24 February 2022 9 IS-IS Extensions To Support The IPv6 Compressed Routing Header (CRH) 10 draft-bonica-lsr-crh-isis-extensions-06 12 Abstract 14 Source nodes can use the IPv6 Compressed Routing Header (CRH) to 15 steer packets through a specified path. This document defines IS-IS 16 extensions that support the CRH. 18 Status of This Memo 20 This Internet-Draft is submitted in full conformance with the 21 provisions of BCP 78 and BCP 79. 23 Internet-Drafts are working documents of the Internet Engineering 24 Task Force (IETF). Note that other groups may also distribute 25 working documents as Internet-Drafts. The list of current Internet- 26 Drafts is at https://datatracker.ietf.org/drafts/current/. 28 Internet-Drafts are draft documents valid for a maximum of six months 29 and may be updated, replaced, or obsoleted by other documents at any 30 time. It is inappropriate to use Internet-Drafts as reference 31 material or to cite them other than as "work in progress." 33 This Internet-Draft will expire on 28 August 2022. 35 Copyright Notice 37 Copyright (c) 2022 IETF Trust and the persons identified as the 38 document authors. All rights reserved. 40 This document is subject to BCP 78 and the IETF Trust's Legal 41 Provisions Relating to IETF Documents (https://trustee.ietf.org/ 42 license-info) in effect on the date of publication of this document. 43 Please review these documents carefully, as they describe your rights 44 and restrictions with respect to this document. Code Components 45 extracted from this document must include Revised BSD License text as 46 described in Section 4.e of the Trust Legal Provisions and are 47 provided without warranty as described in the Revised BSD License. 49 Table of Contents 51 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 52 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 2 53 3. Advertising The CRH Capability . . . . . . . . . . . . . . . 2 54 4. Advertising Prefix Segment Identifiers . . . . . . . . . . . 3 55 5. Advertising Adjacency Segment Identifiers . . . . . . . . . . 4 56 6. Advertising Adjacency Segment Identifiers Into LANs . . . . . 5 57 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 58 7.1. The CRH Sub-TLV . . . . . . . . . . . . . . . . . . . . . 7 59 7.2. Prefix SID Sub-TLV . . . . . . . . . . . . . . . . . . . 8 60 7.3. Adjacency SID Sub-TLV . . . . . . . . . . . . . . . . . . 8 61 8. Security Considerations . . . . . . . . . . . . . . . . . . . 9 62 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 63 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 64 10.1. Normative References . . . . . . . . . . . . . . . . . . 9 65 10.2. Informative References . . . . . . . . . . . . . . . . . 11 66 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11 68 1. Introduction 70 Source nodes can use the IPv6 Compressed Routing Header (CRH) 71 [I-D.bonica-6man-comp-rtg-hdr] to steer packets through a specified 72 path. This document defines IS-IS extensions that support the CRH. 74 2. Requirements Language 76 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 77 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 78 "OPTIONAL" in this document are to be interpreted as described in BCP 79 14 [RFC2119] [RFC8174] when, and only when, they appear in all 80 capitals, as shown here. 82 3. Advertising The CRH Capability 84 The Router CAPABILITY TLV [RFC7981] MAY contain exactly one CRH sub- 85 TLV. The CRH sub-TLV indicates that the advertising node can process 86 the CRH. 88 The CRH sub-TLV MAY contain sub-sub-TLVs. No sub-sub-TLVs are 89 currently defined. 91 0 1 2 3 92 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 93 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 94 | Type | Length | Max CRH Len | Reserved | 95 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 96 Figure 1: CRH Sub-TLV 98 Figure 1 depicts the CRH sub-TLV. The CRH sub-TLV contains the 99 following fields: 101 * Type: 8 bits. CRH (value TBD by IANA. Suggested value is 30.) 103 * Length: 8 bits. Length of TLV data excluding the TLV header. 104 MUST be equal to 2 plus the length of sub-sub-TLVs (if any). 106 * Max CRH Len: 8 bits. Maximum CRH length supported by the 107 advertising node, measured in 8-octet units, not including the 108 first 8 octets. See Note 1. 110 * Reserved: 8 bits. SHOULD be set to zero by sender. MUST be 111 ignored by receiver. 113 Note 1: According to [RFC8200], all IPv6 Routings header include a 114 "Hdr Ext Len" field. That field specifies the length of the Routing 115 header in 8-octet units, not including the first 8 octets. The same 116 unit of measure was chosen for the "Max CRH Len" field in the CRH 117 sub-TLV. 119 4. Advertising Prefix Segment Identifiers 121 The following TLVs MAY contain one or more Prefix SID sub-TLVs: 123 * TLV-236 (IPv6 IP Reachability) [RFC5308]. 125 * TLV-237 (Multitopology IPv6 IP Reachability) [RFC5120]. 127 The Prefix SID sub-TLV is valid only when its parent TLV specifies a 128 prefix length of 128. In this case, it binds the SID that it 129 contains to the prefix (i.e., IPv6 address) that its parent TLV 130 contains. This information is used to construct the mapping table 131 described in [I-D.bonica-6man-comp-rtg-hdr]. 133 When the parent TLV is propagated across level boundaries, the Prefix 134 SID sub-TLV SHOULD be kept. 136 0 1 2 3 137 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 1 138 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 139 | Type | Length | Reserved | 140 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 141 | SID 142 +-+-+-+-+-+-+-+ 143 Figure 2: Prefix SID sub-TLV 145 Figure 2 depicts the Prefix SID sub-TLV. It contains the following 146 fields: 148 * Type: 8 bits. Prefix SID sub-TLV (Value TBD by IANA. Suggested 149 value is 33.) 151 * Length: 8 bits. Length of TLV data excluding the TLV header, 152 measured in bytes. 154 * Reserved: 16 bits. SHOULD be set to zero by the sender. MUST be 155 ignored by the receiver. 157 * SID - Variable length. Segment Identifier. 159 5. Advertising Adjacency Segment Identifiers 161 The following TLVs can contain one or more Adjacency SID sub-TLVs: 163 * TLV-22 (Extended IS reachability) [RFC5305] 165 * TLV-222 (Multitopology IS) [RFC5120] 167 * TLV-23 (IS Neighbor Attribute) [RFC5311] 169 * TLV-223 (Multitopology IS Neighbor Attribute) [RFC5311] 171 * TLV-141 (inter-AS reachability information) [RFC5316] 173 The Adjacency SID sub-TLV is valid only when its parent TLV also 174 contains an IPv6 Neighbor Address sub-TLVs [RFC6119]. In this case, 175 the SID contained by the Adjacency SID sub-TLV is bound to the IPv6 176 address contained by the IPv6 Neighbor Address sub-TLV. This 177 information is used to construct the mapping table described in 178 [I-D.bonica-6man-comp-rtg-hdr]. 180 0 1 2 3 181 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 1 182 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 183 | Type | Length | Flags | Weight | 184 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 185 | SID 186 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 188 Figure 3: Adjacency SID Sub-TLV 190 Figure 3 depicts the Adjacency SID sub-TLV. It contains the 191 following fields: 193 * Type: 8 bits. Adjacency SID sub-TLV (Value TBD by IANA. 194 Suggested value is 45.) 196 * Length: 8 bits. Length of TLV data excluding the TLV header, 197 measured in bytes. 199 * Flags: 8 bits. See below. 201 * Weight: 8 bits. The value represents the SID weight for the 202 purpose of load balancing. 204 * SID - Variable length. Segment Identifier. 206 0 1 2 3 4 5 6 7 207 +-+-+-+-+-+-+-+-+ 208 |B|S|P| Reserved| 209 +-+-+-+-+-+-+-+-+ 211 Figure 4: Adjacency SID Sub-TLV Flags 213 Figure 4 depicts Adjacency SID Sub-TLV flags. They include the 214 following: 216 * B-Flag: Backup flag. If set, the SID is eligible for protection. 218 * S-Flag:. Set flag. When set, the S-Flag indicates that the SID 219 refers to a set of adjacencies (and therefore MAY be assigned to 220 other adjacencies as well). 222 * P-Flag: Persistent flag. When set, the P-Flag indicates that the 223 SID is persistently allocated, i.e., the SID value remains 224 consistent across router restart and/or interface flap.) 226 6. Advertising Adjacency Segment Identifiers Into LANs 228 In LAN subnetworks, the Designated Intermediate System (DIS) is 229 elected and originates the Pseudonode-LSP (PN-LSP) including all 230 neighbors of the DIS. 232 When the CRH is used, each router in the LAN MAY advertise its 233 Adjacency SIDs of each of its neighbors. Since, on LANs, each router 234 only advertises one adjacency to the DIS (and doesn't advertise any 235 other adjacency), each router advertises the set of Adjacency SIDs 236 (for each of its neighbors) inside a newly defined sub-TLV part of 237 the TLV advertising the adjacency to the DIS (e.g.: TLV-22). 239 The following TLVs can contain one or more LAN Adjacency SID sub- 240 TLVs: 242 * TLV-22 (Extended IS reachability) [RFC5305] 244 * TLV-222 (Multitopology IS) [RFC5120] 246 * TLV-23 (IS Neighbor Attribute) [RFC5311] 248 * TLV-223 (Multitopology IS Neighbor Attribute) [RFC5311] 250 The LAN Adjacency SID sub-TLV binds an IPv6 address to a SID. The 251 sub-TLV contains both the IPv6 address and the SID. This information 252 is used to construct the mapping table described in 253 [I-D.bonica-6man-comp-rtg-hdr]. 255 0 1 2 3 256 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 1 257 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 258 | Type | Length | Flags | Weight | 259 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 261 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 262 | Neighbor System-ID (ID length octets) | 263 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 264 | | 265 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 266 | 267 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 268 | SID 269 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 271 Figure 5: LAN Strictly Routed SID Sub-TLV 273 Figure 5 depicts the Adjacency SID sub-TLV. It contains the 274 following fields: 276 * Type: 8 bits. Adjacency SID sub-TLV (Value TBD by IANA. 277 Suggested value is 46.) 279 * Length: 8 bits. Length of TLV data excluding the TLV header, 280 measured in bytes. 282 * Flags: 8 bits. See below. 284 * Weight: 8 bits. The value represents the SID weight for the 285 purpose of load balancing. 287 * Neighbor System-ID: 6 bytes. IS-IS System-ID of length "ID 288 Length" as defined in [ISO10589]. 290 * SID - Variable length. Segment Identifier. 292 0 1 2 3 4 5 6 7 293 +-+-+-+-+-+-+-+-+ 294 |B|S|P| Reserved| 295 +-+-+-+-+-+-+-+-+ 297 Figure 6: Adjacency SID Sub-TLV Flags 299 Figure 6 depicts Adjacency SID Sub-TLV flags. They include the 300 following: 302 * B-Flag: Backup flag. If set, the SID is eligible for protection. 304 * S-Flag:. Set flag. When set, the S-Flag indicates that the SID 305 refers to a set of adjacencies (and therefore MAY be assigned to 306 other adjacencies as well). 308 * P-Flag: Persistent flag. When set, the P-Flag indicates that the 309 SID is persistently allocated, i.e., the SID value remains 310 consistent across router restart and/or interface flap.) 312 7. IANA Considerations 314 7.1. The CRH Sub-TLV 316 IANA is requested to add a new sub-TLV in the Sub-TLVs for TLV 242 317 (IS-IS Router CAPABILITY TLV) Registry [capreg]. 319 * Value - TBD by IANA. (Suggested value is 30). 321 * Description - CRH 323 This document requests the creation of a new IANA managed registry 324 for sub-sub-TLVs of the CRH sub-TLV. The registration procedure is 325 "Expert Review" as defined in [RFC7370]. Suggested registry name is 326 "sub-sub-TLVs for CRH sub-TLV". No sub- sub-TLVs are defined by this 327 document except for the reserved value. 329 * 0 - Reserved 331 * 1 - 255 Unassigned 333 7.2. Prefix SID Sub-TLV 335 IANA is requested to add a new entry in the Sub-TLVs for TLVs 135, 336 235, 236, and 237 (Extended IP reachability, MT IP. Reach, IPv6 IP. 337 Reach, and MT IPv6 IP. Reach TLVs) Registry [loosereg]. 339 * Value - TBD by IANA. (Suggested value is 33) 341 * Description - Prefix SID 343 * 135 - N 345 * 136 - N 347 * 236 - Y 349 * 237 - Y 351 * Reference - This document. 353 7.3. Adjacency SID Sub-TLV 355 IANA is requested to add the following entries in the Sub-TLVs for 356 TLVs 22, 23, 25, 141, 222, and 223 (Extended IS reachability, IS 357 Neighbor Attribute, L2 Bundle Member Attributes, inter-AS 358 reachability information, MT-ISN, and MT IS Neighbor Attribute TLVs) 359 Registry [strictreg]. 361 The first entry follows: 363 * Value - TBD by IANA (Suggested value is 45). 365 * Description - Adjacency SID 367 * 22 - Y 369 * 23 - Y 371 * 25 - N 373 * 141 - Y 375 * 222 - Y 377 * 223 - Y 379 * Reference - This document. 381 The second entry follows: 383 * Value - TBD by IANA (Suggested value is 46) 385 * Description - LAN Adjacency SID 387 * 22 - Y 389 * 23 - Y 391 * 25 - N 393 * 141 - N 395 * 222 - Y 397 * 223 - Y 399 * Reference - This document. 401 8. Security Considerations 403 Security concerns for IS-IS are addressed in [ISO10589], [RFC5304], 404 and [RFC5310]. 406 9. Acknowledgements 408 Thanks to Ram Santhanakrishnan for his comments on this document. 410 10. References 412 10.1. Normative References 414 [I-D.bonica-6man-comp-rtg-hdr] 415 Bonica, R., Kamite, Y., Alston, A., Henriques, D., and L. 416 Jalil, "The IPv6 Compact Routing Header (CRH)", Work in 417 Progress, Internet-Draft, draft-bonica-6man-comp-rtg-hdr- 418 27, 15 November 2021, . 421 [ISO10589] IANA, "Intermediate system to Intermediate system routing 422 information exchange protocol for use in conjunction with 423 the Protocol for providing the Connectionless-mode Network 424 Service (ISO 8473)", August 1987, . 426 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 427 Requirement Levels", BCP 14, RFC 2119, 428 DOI 10.17487/RFC2119, March 1997, 429 . 431 [RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi 432 Topology (MT) Routing in Intermediate System to 433 Intermediate Systems (IS-ISs)", RFC 5120, 434 DOI 10.17487/RFC5120, February 2008, 435 . 437 [RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic 438 Authentication", RFC 5304, DOI 10.17487/RFC5304, October 439 2008, . 441 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 442 Engineering", RFC 5305, DOI 10.17487/RFC5305, October 443 2008, . 445 [RFC5308] Hopps, C., "Routing IPv6 with IS-IS", RFC 5308, 446 DOI 10.17487/RFC5308, October 2008, 447 . 449 [RFC5310] Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R., 450 and M. Fanto, "IS-IS Generic Cryptographic 451 Authentication", RFC 5310, DOI 10.17487/RFC5310, February 452 2009, . 454 [RFC5311] McPherson, D., Ed., Ginsberg, L., Previdi, S., and M. 455 Shand, "Simplified Extension of Link State PDU (LSP) Space 456 for IS-IS", RFC 5311, DOI 10.17487/RFC5311, February 2009, 457 . 459 [RFC5316] Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in 460 Support of Inter-Autonomous System (AS) MPLS and GMPLS 461 Traffic Engineering", RFC 5316, DOI 10.17487/RFC5316, 462 December 2008, . 464 [RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic 465 Engineering in IS-IS", RFC 6119, DOI 10.17487/RFC6119, 466 February 2011, . 468 [RFC7370] Ginsberg, L., "Updates to the IS-IS TLV Codepoints 469 Registry", RFC 7370, DOI 10.17487/RFC7370, September 2014, 470 . 472 [RFC7981] Ginsberg, L., Previdi, S., and M. Chen, "IS-IS Extensions 473 for Advertising Router Information", RFC 7981, 474 DOI 10.17487/RFC7981, October 2016, 475 . 477 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 478 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 479 May 2017, . 481 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 482 (IPv6) Specification", STD 86, RFC 8200, 483 DOI 10.17487/RFC8200, July 2017, 484 . 486 10.2. Informative References 488 [capreg] IANA, "Sub-TLVs for TLV 242 (IS-IS Router CAPABILITY 489 TLV)", August 1987, . 493 [loosereg] IANA, "Sub-TLVs for TLVs 135, 235, 236, and 237 (Extended 494 IP reachability, MT IP. Reach, IPv6 IP. Reach, and MT IPv6 495 IP. Reach TLVs)", August 1987, 496 . 500 [strictreg] 501 IANA, "Sub-TLVs for TLVs 22, 23, 25, 141, 222, and 223 502 (Extended IS reachability, IS Neighbor Attribute, L2 503 Bundle Member Attributes, inter-AS reachability 504 information, MT-ISN, and MT IS Neighbor Attribute TLVs)", 505 August 1987, . 509 Authors' Addresses 511 Parag Kaneriya 512 Juniper Networks 513 Elnath-Exora Business Park Survey 514 Bangalore 560103 515 Karnataka 516 India 517 Email: pkaneria@juniper.net 518 Rejesh Shetty 519 Juniper Networks 520 Elnath-Exora Business Park Survey 521 Bangalore 560103 522 Karnataka 523 India 524 Email: mrajesh@juniper.net 526 Shraddha Hegde 527 Juniper Networks 528 Elnath-Exora Business Park Survey 529 Bangalore 560103 530 Karnataka 531 India 532 Email: shraddha@juniper.net 534 Ron Bonica 535 Juniper Networks 536 2251 Corporate Park Drive 537 Herndon, Virginia 20171 538 United States of America 539 Email: rbonica@juniper.net