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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(See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-31) exists of draft-bonica-6man-comp-rtg-hdr-22 ** Downref: Normative reference to an Experimental draft: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: March 3, 2021 R. Bonica 6 Juniper Networks 7 August 30, 2020 9 IS-IS Extensions To Support The IPv6 Compressed Routing Header (CRH) 10 draft-bonica-lsr-crh-isis-extensions-03 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 March 3, 2021. 35 Copyright Notice 37 Copyright (c) 2020 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 42 (https://trustee.ietf.org/license-info) in effect on the date of 43 publication of this document. Please review these documents 44 carefully, as they describe your rights and restrictions with respect 45 to this document. Code Components extracted from this document must 46 include Simplified BSD License text as described in Section 4.e of 47 the Trust Legal Provisions and are provided without warranty as 48 described in the Simplified BSD License. 50 Table of Contents 52 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 53 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 2 54 3. Advertising The CRH Capability . . . . . . . . . . . . . . . 2 55 4. Advertising Prefix Segment Identifiers . . . . . . . . . . . 3 56 5. Advertising Adjacency Segment Identifiers . . . . . . . . . . 4 57 6. Advertising Adjacency Segment Identifiers Into LANs . . . . . 6 58 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 59 7.1. The CRH Sub-TLV . . . . . . . . . . . . . . . . . . . . . 7 60 7.2. Prefix SID Sub-TLV . . . . . . . . . . . . . . . . . . . 8 61 7.3. Adjacency SID Sub-TLV . . . . . . . . . . . . . . . . . . 8 62 8. Security Considerations . . . . . . . . . . . . . . . . . . . 9 63 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 9 64 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9 65 10.1. Normative References . . . . . . . . . . . . . . . . . . 9 66 10.2. Informative References . . . . . . . . . . . . . . . . . 11 67 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 69 1. Introduction 71 Source nodes can use the IPv6 Compressed Routing Header (CRH) 72 [I-D.bonica-6man-comp-rtg-hdr] to steer packets through a specified 73 path. This document defines IS-IS extensions that support the CRH. 75 2. Requirements Language 77 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 78 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 79 "OPTIONAL" in this document are to be interpreted as described in BCP 80 14 [RFC2119] [RFC8174] when, and only when, they appear in all 81 capitals, as shown here. 83 3. Advertising The CRH Capability 85 The Router CAPABILITY TLV [RFC7981] MAY contain exactly one CRH sub- 86 TLV. The CRH sub-TLV indicates that the advertising node can process 87 the CRH. 89 The CRH sub-TLV MAY contain sub-sub-TLVs. No sub-sub-TLVs are 90 currently defined. 92 0 1 2 3 93 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 94 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 95 | Type | Length | Max CRH Len | Reserved | 96 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 98 Figure 1: CRH Sub-TLV 100 Figure 1 depicts the CRH sub-TLV. The CRH sub-TLV contains the 101 following fields: 103 o Type: 8 bits. CRH (value TBD by IANA. Suggested value is 30.) 105 o Length: 8 bits. Length of TLV data excluding the TLV header. 106 MUST be equal to 2 plus the length of sub-sub-TLVs (if any). 108 o Max CRH Len: 8 bits. Maximum CRH length supported by the 109 advertising node, measured in 8-octet units, not including the 110 first 8 octets. See Note 1. 112 o Reserved: 8 bits. SHOULD be set to zero by sender. MUST be 113 ignored by receiver. 115 Note 1: According to [RFC8200], all IPv6 Routings header include a 116 "Hdr Ext Len" field. That field specifies the length of the Routing 117 header in 8-octet units, not including the first 8 octets. The same 118 unit of measure was chosen for the "Max CRH Len" field in the CRH 119 sub-TLV. 121 4. Advertising Prefix Segment Identifiers 123 The following TLVs MAY contain one or more Prefix SID sub-TLVs: 125 o TLV-236 (IPv6 IP Reachability) [RFC5308]. 127 o TLV-237 (Multitopology IPv6 IP Reachability) [RFC5120]. 129 The Prefix SID sub-TLV is valid only when its parent TLV specifies a 130 prefix length of 128. In this case, it binds the SID that it 131 contains to the prefix (i.e., IPv6 address) that its parent TLV 132 contains. This information is used to construct the mapping table 133 described in [I-D.bonica-6man-comp-rtg-hdr]. 135 When the parent TLV is propagated across level boundaries, the Prefix 136 SID sub-TLV SHOULD be kept. 138 0 1 2 3 139 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 1 140 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 141 | Type | Length | Reserved | 142 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 143 | SID 144 +-+-+-+-+-+-+-+ 146 Figure 2: Prefix SID sub-TLV 148 Figure 2 depicts the Prefix SID sub-TLV. It contains the following 149 fields: 151 o Type: 8 bits. Prefix SID sub-TLV (Value TBD by IANA. Suggested 152 value is 33.) 154 o Length: 8 bits. Length of TLV data excluding the TLV header, 155 measured in bytes. 157 o Reserved: 16 bits. SHOULD be set to zero by the sender. MUST be 158 ignored by the receiver. 160 o SID - Variable length. Segment Identifier. 162 5. Advertising Adjacency Segment Identifiers 164 The following TLVs can contain one or more Adjacency SID sub-TLVs: 166 o TLV-22 (Extended IS reachability) [RFC5305] 168 o TLV-222 (Multitopology IS) [RFC5120] 170 o TLV-23 (IS Neighbor Attribute) [RFC5311] 172 o TLV-223 (Multitopology IS Neighbor Attribute) [RFC5311] 174 o TLV-141 (inter-AS reachability information) [RFC5316] 176 The Adjacency SID sub-TLV is valid only when its parent TLV also 177 contains an IPv6 Neighbor Address sub-TLVs [RFC6119]. In this case, 178 the SID contained by the Adjacency SID sub-TLV is bound to the IPv6 179 address contained by the IPv6 Neighbor Address sub-TLV. This 180 information is used to construct the mapping table described in 181 [I-D.bonica-6man-comp-rtg-hdr]. 183 0 1 2 3 184 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 1 185 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 186 | Type | Length | Flags | Weight | 187 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 188 | SID 189 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 191 Figure 3: Adjacency SID Sub-TLV 193 Figure 3 depicts the Adjacency SID sub-TLV. It contains the 194 following fields: 196 o Type: 8 bits. Adjacency SID sub-TLV (Value TBD by IANA. 197 Suggested value is 45.) 199 o Length: 8 bits. Length of TLV data excluding the TLV header, 200 measured in bytes. 202 o Flags: 8 bits. See below. 204 o Weight: 8 bits. The value represents the SID weight for the 205 purpose of load balancing. 207 o SID - Variable length. Segment Identifier. 209 0 1 2 3 4 5 6 7 210 +-+-+-+-+-+-+-+-+ 211 |B|S|P| Reserved| 212 +-+-+-+-+-+-+-+-+ 214 Figure 4: Adjacency SID Sub-TLV Flags 216 Figure 4 depicts Adjacency SID Sub-TLV flags. They include the 217 following: 219 o B-Flag: Backup flag. If set, the SID is eligible for protection. 221 o S-Flag:. Set flag. When set, the S-Flag indicates that the SID 222 refers to a set of adjacencies (and therefore MAY be assigned to 223 other adjacencies as well). 225 o P-Flag: Persistent flag. When set, the P-Flag indicates that the 226 SID is persistently allocated, i.e., the SID value remains 227 consistent across router restart and/or interface flap.) 229 6. Advertising Adjacency Segment Identifiers Into LANs 231 In LAN subnetworks, the Designated Intermediate System (DIS) is 232 elected and originates the Pseudonode-LSP (PN-LSP) including all 233 neighbors of the DIS. 235 When the CRH is used, each router in the LAN MAY advertise its 236 Adjacency SIDs of each of its neighbors. Since, on LANs, each router 237 only advertises one adjacency to the DIS (and doesn't advertise any 238 other adjacency), each router advertises the set of Adjacency SIDs 239 (for each of its neighbors) inside a newly defined sub-TLV part of 240 the TLV advertising the adjacency to the DIS (e.g.: TLV-22). 242 The following TLVs can contain one or more LAN Adjacency SID sub- 243 TLVs: 245 o TLV-22 (Extended IS reachability) [RFC5305] 247 o TLV-222 (Multitopology IS) [RFC5120] 249 o TLV-23 (IS Neighbor Attribute) [RFC5311] 251 o TLV-223 (Multitopology IS Neighbor Attribute) [RFC5311] 253 The LAN Adjacency SID sub-TLV binds an IPv6 address to a SID. The 254 sub-TLV contains both the IPv6 address and the SID. This information 255 is used to construct the mapping table described in 256 [I-D.bonica-6man-comp-rtg-hdr]. 258 0 1 2 3 259 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 1 260 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 261 | Type | Length | Flags | Weight | 262 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 264 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 265 | Neighbor System-ID (ID length octets) | 266 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 267 | | 268 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 269 | 270 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 271 | SID 272 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- 274 Figure 5: LAN Strictly Routed SID Sub-TLV 276 Figure 5 depicts the Adjacency SID sub-TLV. It contains the 277 following fields: 279 o Type: 8 bits. Adjacency SID sub-TLV (Value TBD by IANA. 280 Suggested value is 46.) 282 o Length: 8 bits. Length of TLV data excluding the TLV header, 283 measured in bytes. 285 o Flags: 8 bits. See below. 287 o Weight: 8 bits. The value represents the SID weight for the 288 purpose of load balancing. 290 o Neighbor System-ID: 6 bytes. IS-IS System-ID of length "ID 291 Length" as defined in [ISO10589]. 293 o SID - Variable length. Segment Identifier. 295 0 1 2 3 4 5 6 7 296 +-+-+-+-+-+-+-+-+ 297 |B|S|P| Reserved| 298 +-+-+-+-+-+-+-+-+ 300 Figure 6: Adjacency SID Sub-TLV Flags 302 Figure 6 depicts Adjacency SID Sub-TLV flags. They include the 303 following: 305 o B-Flag: Backup flag. If set, the SID is eligible for protection. 307 o S-Flag:. Set flag. When set, the S-Flag indicates that the SID 308 refers to a set of adjacencies (and therefore MAY be assigned to 309 other adjacencies as well). 311 o P-Flag: Persistent flag. When set, the P-Flag indicates that the 312 SID is persistently allocated, i.e., the SID value remains 313 consistent across router restart and/or interface flap.) 315 7. IANA Considerations 317 7.1. The CRH Sub-TLV 319 IANA is requested to add a new sub-TLV in the Sub-TLVs for TLV 242 320 (IS-IS Router CAPABILITY TLV) Registry [capreg]. 322 o Value - TBD by IANA. (Suggested value is 30). 324 o Description - CRH 326 This document requests the creation of a new IANA managed registry 327 for sub-sub-TLVs of the CRH sub-TLV. The registration procedure is 328 "Expert Review" as defined in [RFC7370]. Suggested registry name is 329 "sub-sub-TLVs for CRH sub-TLV". No sub- sub-TLVs are defined by this 330 document except for the reserved value. 332 o 0 - Reserved 334 o 1 - 255 Unassigned 336 7.2. Prefix SID Sub-TLV 338 IANA is requested to add a new entry in the Sub-TLVs for TLVs 135, 339 235, 236, and 237 (Extended IP reachability, MT IP. Reach, IPv6 IP. 340 Reach, and MT IPv6 IP. Reach TLVs) Registry [loosereg]. 342 o Value - TBD by IANA. (Suggested value is 33) 344 o Description - Prefix SID 346 o 135 - N 348 o 136 - N 350 o 236 - Y 352 o 237 - Y 354 o Reference - This document. 356 7.3. Adjacency SID Sub-TLV 358 IANA is requested to add the following entries in the Sub-TLVs for 359 TLVs 22, 23, 25, 141, 222, and 223 (Extended IS reachability, IS 360 Neighbor Attribute, L2 Bundle Member Attributes, inter-AS 361 reachability information, MT-ISN, and MT IS Neighbor Attribute TLVs) 362 Registry [strictreg]. 364 The first entry follows: 366 o Value - TBD by IANA (Suggested value is 45). 368 o Description - Adjacency SID 370 o 22 - Y 371 o 23 - Y 373 o 25 - N 375 o 141 - Y 377 o 222 - Y 379 o 223 - Y 381 o Reference - This document. 383 The second entry follows: 385 o Value - TBD by IANA (Suggested value is 46) 387 o Description - LAN Adjacency SID 389 o 22 - Y 391 o 23 - Y 393 o 25 - N 395 o 141 - N 397 o 222 - Y 399 o 223 - Y 401 o Reference - This document. 403 8. Security Considerations 405 Security concerns for IS-IS are addressed in [ISO10589], [RFC5304], 406 and [RFC5310]. 408 9. Acknowledgements 410 Thanks to Ram Santhanakrishnan for his comments on this document. 412 10. References 414 10.1. Normative References 416 [I-D.bonica-6man-comp-rtg-hdr] 417 Bonica, R., Kamite, Y., Niwa, T., Alston, A., and L. 418 Jalil, "The IPv6 Compact Routing Header (CRH)", draft- 419 bonica-6man-comp-rtg-hdr-22 (work in progress), May 2020. 421 [ISO10589] 422 IANA, "Intermediate system to Intermediate system routing 423 information exchange protocol for use in conjunction with 424 the Protocol for providing the Connectionless-mode Network 425 Service (ISO 8473)", August 1987, . 427 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 428 Requirement Levels", BCP 14, RFC 2119, 429 DOI 10.17487/RFC2119, March 1997, 430 . 432 [RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi 433 Topology (MT) Routing in Intermediate System to 434 Intermediate Systems (IS-ISs)", RFC 5120, 435 DOI 10.17487/RFC5120, February 2008, 436 . 438 [RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic 439 Authentication", RFC 5304, DOI 10.17487/RFC5304, October 440 2008, . 442 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 443 Engineering", RFC 5305, DOI 10.17487/RFC5305, October 444 2008, . 446 [RFC5308] Hopps, C., "Routing IPv6 with IS-IS", RFC 5308, 447 DOI 10.17487/RFC5308, October 2008, 448 . 450 [RFC5310] Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R., 451 and M. Fanto, "IS-IS Generic Cryptographic 452 Authentication", RFC 5310, DOI 10.17487/RFC5310, February 453 2009, . 455 [RFC5311] McPherson, D., Ed., Ginsberg, L., Previdi, S., and M. 456 Shand, "Simplified Extension of Link State PDU (LSP) Space 457 for IS-IS", RFC 5311, DOI 10.17487/RFC5311, February 2009, 458 . 460 [RFC5316] Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in 461 Support of Inter-Autonomous System (AS) MPLS and GMPLS 462 Traffic Engineering", RFC 5316, DOI 10.17487/RFC5316, 463 December 2008, . 465 [RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic 466 Engineering in IS-IS", RFC 6119, DOI 10.17487/RFC6119, 467 February 2011, . 469 [RFC7370] Ginsberg, L., "Updates to the IS-IS TLV Codepoints 470 Registry", RFC 7370, DOI 10.17487/RFC7370, September 2014, 471 . 473 [RFC7981] Ginsberg, L., Previdi, S., and M. Chen, "IS-IS Extensions 474 for Advertising Router Information", RFC 7981, 475 DOI 10.17487/RFC7981, October 2016, 476 . 478 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 479 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 480 May 2017, . 482 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 483 (IPv6) Specification", STD 86, RFC 8200, 484 DOI 10.17487/RFC8200, July 2017, 485 . 487 10.2. Informative References 489 [capreg] IANA, "Sub-TLVs for TLV 242 (IS-IS Router CAPABILITY 490 TLV)", August 1987, . 494 [loosereg] 495 IANA, "Sub-TLVs for TLVs 135, 235, 236, and 237 (Extended 496 IP reachability, MT IP. Reach, IPv6 IP. Reach, and MT IPv6 497 IP. Reach TLVs)", August 1987, 498 . 502 [strictreg] 503 IANA, "Sub-TLVs for TLVs 22, 23, 25, 141, 222, and 223 504 (Extended IS reachability, IS Neighbor Attribute, L2 505 Bundle Member Attributes, inter-AS reachability 506 information, MT-ISN, and MT IS Neighbor Attribute TLVs)", 507 August 1987, . 511 Authors' Addresses 513 Parag Kaneriya 514 Juniper Networks 515 Elnath-Exora Business Park Survey 516 Bangalore, Karnataka 560103 517 India 519 Email: pkaneria@juniper.net 521 Rejesh Shetty 522 Juniper Networks 523 Elnath-Exora Business Park Survey 524 Bangalore, Karnataka 560103 525 India 527 Email: mrajesh@juniper.net 529 Shraddha Hegde 530 Juniper Networks 531 Elnath-Exora Business Park Survey 532 Bangalore, Karnataka 560103 533 India 535 Email: shraddha@juniper.net 537 Ron Bonica 538 Juniper Networks 539 2251 Corporate Park Drive 540 Herndon, Virginia 20171 541 USA 543 Email: rbonica@juniper.net