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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) -- Unexpected draft version: The latest known version of draft-ietf-ospf-mt-ospfv3 is -03, but you're referring to -04. == Outdated reference: draft-ietf-ospf-ospfv3-segment-routing-extensions has been published as RFC 8666 Summary: 0 errors (**), 0 flaws (~~), 2 warnings (==), 4 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group A. Lindem 3 Internet-Draft A. Roy 4 Updates: 5340, 5838 (if approved) Cisco Systems 5 Intended status: Standards Track D. Goethals 6 Expires: July 28, 2018 Nokia 7 V. Reddy Vallem 9 F. Baker 10 January 24, 2018 12 OSPFv3 LSA Extendibility 13 draft-ietf-ospf-ospfv3-lsa-extend-22.txt 15 Abstract 17 OSPFv3 requires functional extension beyond what can readily be done 18 with the fixed-format Link State Advertisement (LSA) as described in 19 RFC 5340. Without LSA extension, attributes associated with OSPFv3 20 links and advertised IPv6 prefixes must be advertised in separate 21 LSAs and correlated to the fixed-format LSAs. This document extends 22 the LSA format by encoding the existing OSPFv3 LSA information in 23 Type-Length-Value (TLV) tuples and allowing advertisement of 24 additional information with additional TLVs. Backward compatibility 25 mechanisms are also described. 27 This document updates RFC 5340, "OSPF for IPv6", and RFC 5838, 28 "Support of Address Families in OSPFv3" by providing TLV-based 29 encodings for the base OSPFv3 unicast support and OSPFv3 address 30 family support. 32 Status of This Memo 34 This Internet-Draft is submitted in full conformance with the 35 provisions of BCP 78 and BCP 79. 37 Internet-Drafts are working documents of the Internet Engineering 38 Task Force (IETF). Note that other groups may also distribute 39 working documents as Internet-Drafts. The list of current Internet- 40 Drafts is at http://datatracker.ietf.org/drafts/current/. 42 Internet-Drafts are draft documents valid for a maximum of six months 43 and may be updated, replaced, or obsoleted by other documents at any 44 time. It is inappropriate to use Internet-Drafts as reference 45 material or to cite them other than as "work in progress." 47 This Internet-Draft will expire on July 28, 2018. 49 Copyright Notice 51 Copyright (c) 2018 IETF Trust and the persons identified as the 52 document authors. All rights reserved. 54 This document is subject to BCP 78 and the IETF Trust's Legal 55 Provisions Relating to IETF Documents 56 (http://trustee.ietf.org/license-info) in effect on the date of 57 publication of this document. Please review these documents 58 carefully, as they describe your rights and restrictions with respect 59 to this document. Code Components extracted from this document must 60 include Simplified BSD License text as described in Section 4.e of 61 the Trust Legal Provisions and are provided without warranty as 62 described in the Simplified BSD License. 64 Table of Contents 66 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 67 1.1. Requirements notation . . . . . . . . . . . . . . . . . . 4 68 1.2. OSPFv3 LSA Terminology . . . . . . . . . . . . . . . . . 4 69 2. OSPFv3 Extended LSA Types . . . . . . . . . . . . . . . . . . 4 70 3. OSPFv3 Extended LSA TLVs . . . . . . . . . . . . . . . . . . 5 71 3.1. Prefix Options Extensions . . . . . . . . . . . . . . . . 6 72 3.1.1. N-bit Prefix Option . . . . . . . . . . . . . . . . . 6 73 3.2. Router-Link TLV . . . . . . . . . . . . . . . . . . . . . 7 74 3.3. Attached-Routers TLV . . . . . . . . . . . . . . . . . . 8 75 3.4. Inter-Area-Prefix TLV . . . . . . . . . . . . . . . . . . 9 76 3.5. Inter-Area-Router TLV . . . . . . . . . . . . . . . . . . 10 77 3.6. External-Prefix TLV . . . . . . . . . . . . . . . . . . . 11 78 3.7. Intra-Area-Prefix TLV . . . . . . . . . . . . . . . . . . 12 79 3.8. IPv6 Link-Local Address TLV . . . . . . . . . . . . . . . 13 80 3.9. IPv4 Link-Local Address TLV . . . . . . . . . . . . . . . 14 81 3.10. IPv6-Forwarding-Address Sub-TLV . . . . . . . . . . . . . 15 82 3.11. IPv4-Forwarding-Address Sub-TLV . . . . . . . . . . . . . 15 83 3.12. Route-Tag Sub-TLV . . . . . . . . . . . . . . . . . . . . 16 84 4. OSPFv3 Extended LSAs . . . . . . . . . . . . . . . . . . . . 16 85 4.1. OSPFv3 E-Router-LSA . . . . . . . . . . . . . . . . . . . 16 86 4.2. OSPFv3 E-Network-LSA . . . . . . . . . . . . . . . . . . 18 87 4.3. OSPFv3 E-Inter-Area-Prefix-LSA . . . . . . . . . . . . . 19 88 4.4. OSPFv3 E-Inter-Area-Router-LSA . . . . . . . . . . . . . 20 89 4.5. OSPFv3 E-AS-External-LSA . . . . . . . . . . . . . . . . 21 90 4.6. OSPFv3 E-NSSA-LSA . . . . . . . . . . . . . . . . . . . . 22 91 4.7. OSPFv3 E-Link-LSA . . . . . . . . . . . . . . . . . . . . 23 92 4.8. OSPFv3 E-Intra-Area-Prefix-LSA . . . . . . . . . . . . . 25 93 5. Malformed OSPFv3 Extended LSA Handling . . . . . . . . . . . 26 94 6. LSA Extension Backward Compatibility . . . . . . . . . . . . 26 95 6.1. Full Extended LSA Migration . . . . . . . . . . . . . . . 26 96 6.2. Extended LSA Sparse-Mode Backward Compatibility . . . . . 27 97 6.3. LSA TLV Processing Backward Compatibility . . . . . . . . 27 98 7. Security Considerations . . . . . . . . . . . . . . . . . . . 28 99 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28 100 8.1. OSPFv3 Extended-LSA TLV Registry . . . . . . . . . . . . 28 101 8.2. OSPFv3 Extended-LSA sub-TLV Registry . . . . . . . . . . 29 102 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 30 103 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 30 104 10.1. Normative References . . . . . . . . . . . . . . . . . . 30 105 10.2. Informative References . . . . . . . . . . . . . . . . . 30 106 Appendix A. Appendix A - Global Configuration Parameters . . . . 31 107 Appendix B. Appendix B - Area Configuration Parameters . . . . . 31 108 Appendix C. Acknowledgments . . . . . . . . . . . . . . . . . . 31 109 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 32 111 1. Introduction 113 OSPFv3 requires functional extension beyond what can readily be done 114 with the fixed-format Link State Advertisement (LSA) as described in 115 RFC 5340 [OSPFV3]. Without LSA extension, attributes associated with 116 OSPFv3 links and advertised IPv6 prefixes must be advertised in 117 separate LSAs and correlated to the fixed-format LSAs. This document 118 extends the LSA format by encoding the existing OSPFv3 LSA 119 information in Type-Length-Value (TLV) tuples and allowing 120 advertisement of additional information with additional TLVs. 121 Backward compatibility mechanisms are also described. 123 This document updates RFC 5340, "OSPF for IPv6", and RFC 5838, 124 "Support of Address Families in OSPFv3" by providing TLV-based 125 encodings for the base OSPFv3 support [OSPFV3] and OSPFv3 address 126 family support [OSPFV3-AF]. 128 A similar extension was previously proposed in support of multi- 129 topology routing. Additional requirements for OSPFv3 LSA extension 130 include source/destination routing, route tagging, and others. 132 A final requirement is to limit the changes to OSPFv3 to those 133 necessary for TLV-based LSAs. For the most part, the semantics of 134 existing OSPFv3 LSAs are retained for their TLV-based successor LSAs 135 described herein. Additionally, encoding details, e.g., the 136 representation of IPv6 prefixes as described in section A.4.1 in RFC 137 5340 [OSPFV3], have been retained. This requirement was included to 138 increase the expedience of IETF adoption and deployment. 140 The following aspects of OSPFv3 LSA extension are described: 142 1. Extended LSA Types 144 2. Extended LSA TLVs 145 3. Extended LSA Formats 147 4. Backward Compatibility 149 1.1. Requirements notation 151 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 152 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 153 "OPTIONAL" in this document are to be interpreted as described in BCP 154 14 [RFC2119] [RFC8174] when, and only when, they appear in all 155 capitals, as shown here. 157 1.2. OSPFv3 LSA Terminology 159 The TLV-based OSPFv3 LSAs described in this document will be referred 160 to as Extended LSAs. The OSPFv3 fixed-format LSAs [OSPFV3] will be 161 referred to as Legacy LSAs. 163 2. OSPFv3 Extended LSA Types 165 In order to provide backward compatibility, new LSA codes must be 166 allocated. There are eight fixed-format LSAs defined in RFC 5340 167 [OSPFV3]. For ease of implementation and debugging, the LSA function 168 codes are the same as the fixed-format LSAs only with 32, i.e., 0x20, 169 added. The alternative to this mapping was to allocate a bit in the 170 LS Type indicating the new LSA format. However, this would have used 171 one half the LSA function code space for the migration of the eight 172 original fixed-format LSAs. For backward compatibility, the U-bit 173 MUST be set in LS Type so that the LSAs will be flooded by OSPFv3 174 routers that do not understand them. 176 LSA function code LS Type Description 177 ---------------------------------------------------- 178 33 0xA021 E-Router-LSA 179 34 0xA022 E-Network-LSA 180 35 0xA023 E-Inter-Area-Prefix-LSA 181 36 0xA024 E-Inter-Area-Router-LSA 182 37 0xC025 E-AS-External-LSA 183 38 N/A Unused (Not to be allocated) 184 39 0xA027 E-Type-7-LSA 185 40 0x8028 E-Link-LSA 186 41 0xA029 E-Intra-Area-Prefix-LSA 188 OSPFv3 Extended LSA Types 190 3. OSPFv3 Extended LSA TLVs 192 The format of the TLVs within the body of the extended LSAs is the 193 same as the format used by the Traffic Engineering Extensions to OSPF 194 [TE]. The variable TLV section consists of one or more nested 195 Type/Length/Value (TLV) tuples. Nested TLVs are also referred to as 196 sub-TLVs. The format of each TLV is: 198 0 1 2 3 199 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 1 200 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 201 | Type | Length | 202 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 203 | Value... | 204 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 206 TLV Format 208 The Length field defines the length of the value portion in octets 209 (thus, a TLV with no value portion would have a length of 0). The 210 TLV is padded to 4-octet alignment; padding is not included in the 211 length field (so a 3-octet value would have a length of 3, but the 212 total size of the TLV would be 8 octets). Nested TLVs are also 213 32-bit aligned. For example, a 1-byte value would have the length 214 field set to 1, and 3 octets of padding would be added to the end of 215 the value portion of the TLV. 217 This document defines the following top-level TLV types: 219 o 0 - Reserved 221 o 1 - Router-Link TLV 223 o 2 - Attached-Routers TLV 225 o 3 - Inter-Area Prefix TLV 227 o 4 - Inter-Area Router TLV 229 o 5 - External Prefix TLV 231 o 6 - Intra-Area Prefix TLV 233 o 7 - IPv6 Link-Local Address TLV 235 o 8 - IPv4 Link-Local Address TLV 236 Additionally, this document defines the following sub-TLV types: 238 o 0 - Reserved 240 o 1 - IPv6 Forwarding Address sub-TLV 242 o 2 - IPv4 Forwarding Address sub-TLV 244 o 3 - Route Tag sub-TLV 246 In general, TLVs and sub-TLVs MAY occur in any order and the 247 specification should define whether the TLV or sub-TLV is required 248 and the behavior when there are multiple occurrences of the TLV or 249 sub-TLV. While this document only describes the usage of TLVs and 250 Sub-TLVs, Sub-TLVs may be nested to any level as long as the Sub-TLVs 251 are fully specified in the specification for the subsuming Sub-TLV. 253 For backward compatibility, an LSA is not considered malformed from a 254 TLV perspective unless either a required TLV is missing or a 255 specified TLV is less than the minimum required length. Refer to 256 Section 6.3 for more information on TLV backward compatibility. 258 3.1. Prefix Options Extensions 260 The prefix options are extended from Appendix A.4.1.1 [OSPFV3]. The 261 applicability of the LA-bit is expanded and it SHOULD be set in 262 Inter-Area-Prefix-TLVs and MAY be set in External-Prefix-TLVs when 263 the advertised host IPv6 address, i.e., PrefixLength = 128, is an 264 interface address. In RFC 5340, the LA-bit is only set in Intra- 265 Area-Prefix-LSAs (Section 4.4.3.9 in [OSPFV3]). This will allow a 266 stable address to be advertised without having to configure a 267 separate loopback address in every OSPFv3 area. 269 3.1.1. N-bit Prefix Option 271 Additionally, the N-bit prefix option is defined. The figure below 272 shows the position of the N-bit in the prefix options (pending IANA 273 allocation). This corresponds to the value 0x20. 275 0 1 2 3 4 5 6 7 276 +--+--+--+--+--+--+--+--+ 277 | | | N|DN| P| x|LA|NU| 278 +--+--+--+--+--+--+--+--+ 280 The Prefix Options field 282 The N-bit is set in PrefixOptions for a host address 283 (PrefixLength=128) that identifies the advertising router. While it 284 is similar to the LA-bit, there are two differences. The advertising 285 router MAY choose NOT to set the N-bit even when the above conditions 286 are met. If the N-bit is set and the PrefixLength is NOT 128, the 287 N-bit MUST be ignored. Additionally, the N-bit is propagated in the 288 PrefixOptions when an OSPFv3 Area Border Router (ABR) originates an 289 Inter-Area-Prefix-LSA for an Intra-Area route which has the N-bit set 290 in the PrefixOptions. Similarly, the N-bit is propagated in the 291 PrefixOptions when an OSPFv3 NSSA ABR originates an E-AS-External-LSA 292 corresponding to an NSSA route as described in section 3 of RFC 3101 293 ([NSSA]). The N-bit is added to the Inter-Area-Prefix-TLV 294 (Section 3.4), External-Prefix-TLV (Section 3.6), and Intra-Area- 295 Prefix-TLV (Section 3.7). The N-bit is useful for applications such 296 as identifying the prefixes corresponding to Node Segment Identifiers 297 (SIDs) in Segment Routing [SEGMENT-ROUTING]. 299 3.2. Router-Link TLV 301 The Router-Link TLV defines a single router link and the field 302 definitions correspond directly to links in the OSPFv3 Router-LSA, 303 section A.4.3, [OSPFV3]. The Router-Link TLV is only applicable to 304 the E-Router-LSA (Section 4.1). Inclusion in other Extended LSAs 305 MUST be ignored. 307 0 1 2 3 308 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 1 309 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 310 | 1 (Router-Link) | TLV Length | 311 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 312 | Type | 0 | Metric | 313 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 314 | Interface ID | 315 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 316 | Neighbor Interface ID | 317 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 318 | Neighbor Router ID | 319 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 320 . . 321 . sub-TLVs . 322 . . 323 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 325 Router-Link TLV 327 3.3. Attached-Routers TLV 329 The Attached-Routers TLV defines all the routers attached to an 330 OSPFv3 multi-access network. The field definitions correspond 331 directly to content of the OSPFv3 Network-LSA, section A.4.4, 332 [OSPFV3]. The Attached-Routers TLV is only applicable to the E- 333 Network-LSA (Section 4.2). Inclusion in other Extended LSAs MUST be 334 ignored. 336 0 1 2 3 337 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 1 338 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 339 | 2 (Attached-Routers) | TLV Length | 340 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 341 | Adjacent Neighbor Router ID | 342 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 343 . . 344 . Additional Adjacent Neighbors . 345 . . 346 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 348 Attached-Routers TLV 350 There are two reasons for not having a separate TLV or sub-TLV for 351 each adjacent neighbor. The first is to discourage using the E- 352 Network-LSA for more than its current role of solely advertising the 353 routers attached to a multi-access network. The router's metric as 354 well as the attributes of individual attached routers should be 355 advertised in their respective E-Router-LSAs. The second reason is 356 that there is only a single E-Network-LSA per multi-access link with 357 the Link State ID set to the Designated Router's Interface ID and, 358 consequently, compact encoding has been chosen to decrease the 359 likelihood that the size of the E-Network-LSA will require IPv6 360 fragmentation when advertised in an OSPFv3 Link State Update packet. 362 3.4. Inter-Area-Prefix TLV 364 The Inter-Area-Prefix TLV defines a single OSPFV3 inter-area prefix. 365 The field definitions correspond directly to the content of an OSPFv3 366 IPv6 Prefix as defined in Section A.4.1, [OSPFV3] and an OSPFv3 367 Inter-Area-Prefix-LSA, as defined in section A.4.5, [OSPFV3]. 368 Additionally, the PrefixOptions are extended as described in 369 Section 3.1. The Inter-Area-Prefix TLV is only applicable to the E- 370 Inter-Area-Prefix-LSA (Section 4.3). Inclusion in other Extended 371 LSAs MUST be ignored. 373 0 1 2 3 374 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 1 375 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 376 | 3 (Inter-Area Prefix) | TLV Length | 377 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 378 | 0 | Metric | 379 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 380 | PrefixLength | PrefixOptions | 0 | 381 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 382 | Address Prefix | 383 | ... | 384 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 385 . . 386 . sub-TLVs . 387 . . 388 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 390 Inter-Area Prefix TLV 392 3.5. Inter-Area-Router TLV 394 The Inter-Area-Router TLV defines a single OSPFv3 Autonomous System 395 Boundary Router (ASBR) reachable in another area. The field 396 definitions correspond directly to the content of an OSPFv3 Inter- 397 Area-Router-LSA, as defined in section A.4.6, [OSPFV3]. The Inter- 398 Area-Router TLV is only applicable to the E-Inter-Area-Router-LSA 399 (Section 4.4). Inclusion in other Extended LSAs MUST be ignored. 401 0 1 2 3 402 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 1 403 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 404 | 4 (Inter-Area Router) | TLV Length | 405 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 406 | 0 | Options | 407 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 408 | 0 | Metric | 409 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 410 | Destination Router ID | 411 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 412 . . 413 . sub-TLVs . 414 . . 415 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 417 Inter-Area Router TLV 419 3.6. External-Prefix TLV 421 The External-Prefix TLV defines a single OSPFv3 external prefix. 422 With the exception of omitted fields noted below, the field 423 definitions correspond directly to the content of an OSPFv3 IPv6 424 Prefix as defined in Section A.4.1, [OSPFV3] and an OSPFv3 AS- 425 External-LSA, as defined in section A.4.7, [OSPFV3]. The External- 426 Prefix TLV is only applicable to the E-AS-External-LSA (Section 4.5) 427 and the E-NSSA-LSA (Section 4.6). Additionally, the PrefixOptions 428 are extended as described in Section 3.1. Inclusion in other 429 Extended LSAs MUST be ignored. 431 0 1 2 3 432 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 1 433 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 434 | 5 (External Prefix) | TLV Length | 435 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 436 | |E| | | Metric | 437 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 438 | PrefixLength | PrefixOptions | 0 | 439 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 440 | Address Prefix | 441 | ... | 442 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 443 . . 444 . sub-TLVs . 445 . . 446 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 448 External Prefix TLV 450 In the External-Prefix TLV, the optional IPv6/IPv4 Forwarding Address 451 and External Route Tag are now sub-TLVs. Given the Referenced LS 452 type and Referenced Link State ID from the AS-External-LSA have never 453 been used or even specified, they have been omitted from the External 454 Prefix TLV. If there were ever a requirement for a referenced LSA, 455 it could be satisfied with a sub-TLV. 457 The following sub-TLVs are defined for optional inclusion in the 458 External Prefix TLV: 460 o 1 - IPv6 Forwarding Address sub-TLV (Section 3.10) 462 o 2 - IPv4 Forwarding Address sub-TLV (Section 3.11) 464 o 3 - Route Tag sub-TLV (Section 3.12) 466 3.7. Intra-Area-Prefix TLV 468 The Intra-Area-Prefix TLV defines a single OSPFv3 intra-area prefix. 469 The field definitions correspond directly to the content of an OSPFv3 470 IPv6 Prefix as defined in Section A.4.1, [OSPFV3] and an OSPFv3 Link- 471 LSA, as defined in section A.4.9, [OSPFV3]. The Intra-Area-Prefix 472 TLV is only applicable to the E-Link-LSA (Section 4.7) and the E- 473 Intra-Area-Prefix-LSA (Section 4.8). Additionally, the PrefixOptions 474 are extended as described in Section 3.1. Inclusion in other 475 Extended LSAs MUST be ignored. 477 0 1 2 3 478 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 1 479 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 480 | 6 (Intra-Area Prefix) | TLV Length | 481 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 482 | 0 | Metric | 483 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 484 | PrefixLength | PrefixOptions | 0 | 485 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 486 | Address Prefix | 487 | ... | 488 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 489 . . 490 . sub-TLVs . 491 . . 492 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 494 Intra-Area Prefix TLV 496 3.8. IPv6 Link-Local Address TLV 498 The IPv6 Link-Local Address TLV is to be used with IPv6 address 499 families as defined in [OSPFV3-AF]. The IPv6 Link-Local Address TLV 500 is only applicable to the E-Link-LSA (Section 4.7). Inclusion in 501 other Extended LSAs MUST be ignored. 503 0 1 2 3 504 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 1 505 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 506 | 7 (IPv6 Local-Local Address) | TLV Length | 507 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 508 | | 509 +- -+ 510 | | 511 +- IPv6 Link-Local Interface Address -+ 512 | | 513 +- -+ 514 | | 515 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 516 . . 517 . sub-TLVs . 518 . . 519 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 521 IPv6 Link-Local Address TLV 523 3.9. IPv4 Link-Local Address TLV 525 The IPv4 Link-Local Address TLV is to be used with IPv4 address 526 families as defined in [OSPFV3-AF]. The IPv4 Link-Local Address TLV 527 is only applicable to the E-Link-LSA (Section 4.7). Inclusion in 528 other Extended LSAs MUST be ignored. 530 0 1 2 3 531 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 1 532 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 533 | 8 (IPv4 Local-Local Address) | TLV Length | 534 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 535 | IPv4 Link-Local Interface Address | 536 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 537 . . 538 . sub-TLVs . 539 . . 540 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 542 IPv4 Link-Local Address TLV 544 3.10. IPv6-Forwarding-Address Sub-TLV 546 The IPv6 Forwarding Address TLV has identical semantics to the 547 optional forwarding address in section A.4.7 of [OSPFV3]. The IPv6 548 Forwarding Address TLV is applicable to the External-Prefix TLV 549 (Section 3.6). Specification as a sub-TLV of other TLVs is not 550 defined herein. The sub-TLV is optional and the first specified 551 instance is used as the Forwarding Address as defined in [OSPFV3]. 552 Instances subsequent to the first MUST be ignored. 554 The IPv6 Forwarding Address TLV is to be used with IPv6 address 555 families as defined in [OSPFV3-AF] It MUST be ignored for other 556 address families. The IPv6 Forwarding Address TLV length must meet 557 minimum length (16 octets) or it will be considered malformed as 558 described in Section 6.3. 560 0 1 2 3 561 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 1 562 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 563 | 1 - Forwarding Address | sub-TLV Length | 564 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 565 | | 566 +- -+ 567 | | 568 +- Forwarding Address -+ 569 | | 570 +- -+ 571 | | 572 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 574 IPv6 Forwarding Address TLV 576 3.11. IPv4-Forwarding-Address Sub-TLV 578 The IPv4 Forwarding Address TLV has identical semantics to the 579 optional forwarding address in section A.4.7 of [OSPFV3]. The IPv4 580 Forwarding Address TLV is The IPv4 Forwarding Address TLV is 581 applicable to the External-Prefix TLV (Section 3.6). Specification 582 as a sub-TLV of other TLVs is not defined herein. The sub-TLV is 583 optional and the first specified instance is used as the Forwarding 584 Address as defined in [OSPFV3]. Instances subsequent to the first 585 MUST be ignored. 587 The IPv4 Forwarding Address TLV is to be used with IPv4 address 588 families as defined in [OSPFV3-AF] It MUST be ignored for other 589 address families. The IPv4 Forwarding Address TLV length must meet 590 minimum length (4 octets) or it will be considered malformed as 591 described in Section 6.3. 593 0 1 2 3 594 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 1 595 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 596 | 2 - Forwarding Address | sub-TLV Length | 597 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 598 | Forwarding Address | 599 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 601 IPv4 Forwarding Address TLV 603 3.12. Route-Tag Sub-TLV 605 The optional Route Tag sub-TLV has identical semantics to the 606 optional External Route Tag in section A.4.7 of [OSPFV3]. The Route 607 Tag sub-TLV is applicable to the External-Prefix TLV (Section 3.6). 608 Specification as a sub-TLV of other TLVs is not defined herein. The 609 sub-TLV is optional and the first specified instance is used as the 610 Route Tag as defined in [OSPFV3]. Instances subsequent to the first 611 MUST be ignored. 613 The Route Tag TLV length must meet minimum length (4 octets) or it 614 will be considered malformed as described in Section 6.3. 616 0 1 2 3 617 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 1 618 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 619 | 3 - Route Tag | sub-TLV Length | 620 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 621 | Route Tag | 622 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 624 Route Tag Sub-TLV 626 4. OSPFv3 Extended LSAs 628 This section specifies the OSPFv3 Extended LSA formats and encoding. 629 The Extended OSPFv3 LSAs corresponded directly to the original OSPFv3 630 LSAs specified in [OSPFV3]. 632 4.1. OSPFv3 E-Router-LSA 634 The E-Router-LSA has an LS Type of 0xA021 and has the same base 635 information content as the Router-LSA defined in section A.4.3 of 636 [OSPFV3]. However, unlike the existing Router-LSA, it is fully 637 extendable and represented as TLVs. 639 0 1 2 3 640 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 1 641 +-+-+-+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 642 | LS Age |1|0|1| 0x21 | 643 +-+-+-+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 644 | Link State ID | 645 +-+-+-+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 646 | Advertising Router | 647 +-+-+-+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 648 | LS Sequence Number | 649 +-+-+-+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 650 | LS Checksum | Length | 651 +-+-+-+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 652 | 0 |Nt|x|V|E|B| Options | 653 +-+-+-+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 654 . . 655 . TLVs . 656 . . 657 +-+-+-+--+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 659 Extended Router-LSA 661 Other than having a different LS Type, all LSA Header fields are the 662 same as defined for the Router-LSA. Initially, only the top-level 663 Router-Link TLV Section 3.2 is applicable and an E-Router-LSA may 664 include multiple Router-Link TLVs. Like the existing Router-LSA, the 665 LSA length is used to determine the end of the LSA including TLVs. 666 Depending on the implementation, it is perfectly valid for an E- 667 Router-LSA to not contain any Router-Link TLVs. However, this would 668 imply that the OSPFv3 router doesn't have any adjacencies in the 669 corresponding area and is forming an adjacency or adjacencies over 670 unnumbered link(s). Note that no E-Router-LSA stub link is 671 advertised for an unnumbered link. 673 4.2. OSPFv3 E-Network-LSA 675 The E-Network-LSA has an LS Type of 0xA022 and has the same base 676 information content as the Network-LSA defined in section A.4.4 of 677 [OSPFV3]. However, unlike the existing Network-LSA, it is fully 678 extendable and represented as TLVs. 680 0 1 2 3 681 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 1 682 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 683 | LS Age |1|0|1| 0x22 | 684 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 685 | Link State ID | 686 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 687 | Advertising Router | 688 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 689 | LS Sequence Number | 690 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 691 | LS Checksum | Length | 692 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 693 | 0 | Options | 694 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 695 . . 696 . TLVs . 697 . . 698 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 700 E-Network-LSA 702 Other than having a different LS Type, all LSA Header fields are the 703 same as defined for the Network-LSA. Like the existing Network-LSA, 704 the LSA length is used to determine the end of the LSA including 705 TLVs. Initially, only the top-level Attached-Routers TLV Section 3.3 706 is applicable. If the Attached-Router TLV is not included in the E- 707 Network-LSA, it is treated as malformed as described in Section 5. 708 Instances of the Attached-Router TLV subsequent to the first MUST be 709 ignored. 711 4.3. OSPFv3 E-Inter-Area-Prefix-LSA 713 The E-Inter-Area-Prefix-LSA has an LS Type of 0xA023 and has the same 714 base information content as the Inter-Area-Prefix-LSA defined in 715 section A.4.5 of [OSPFV3]. However, unlike the existing Inter-Area- 716 Prefix-LSA, it is fully extendable and represented as TLVs. 718 0 1 2 3 719 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 1 720 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 721 | LS Age |1|0|1| 0x23 | 722 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 723 | Link State ID | 724 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 725 | Advertising Router | 726 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 727 | LS Sequence Number | 728 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 729 | LS Checksum | Length | 730 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 731 . . 732 . TLVs . 733 . . 734 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 736 E-Inter-Area-Prefix-LSA 738 Other than having a different LS Type, all LSA Header fields are the 739 same as defined for the Inter-Area-Prefix-LSA. In order to retain 740 compatibility and semantics with the current OSPFv3 specification, 741 each Inter-Area-Prefix LSA MUST contain a single Inter-Area Prefix 742 TLV. This will facilitate migration and avoid changes to functions 743 such as incremental SPF computation. 745 Like the existing Inter-Area-Prefix-LSA, the LSA length is used to 746 determine the end of the LSA including TLV. Initially, only the top- 747 level Inter-Area-Prefix TLV (Section 3.4) is applicable. If the 748 Inter-Area-Prefix TLV is not included in the E-Inter-Area-Prefix-LSA, 749 it is treated as malformed as described in Section 5. Instances of 750 the Inter-Area-Prefix TLV subsequent to the first MUST be ignored. 752 4.4. OSPFv3 E-Inter-Area-Router-LSA 754 The E-Inter-Area-Router-LSA has an LS Type of 0xA024 and has the same 755 base information content as the Inter-Area-Router-LSA defined in 756 section A.4.6 of [OSPFV3]. However, unlike the Inter-Area-Router- 757 LSA, it is fully extendable and represented as TLVs. 759 0 1 2 3 760 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 1 761 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 762 | LS Age |1|0|1| 0x24 | 763 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 764 | Link State ID | 765 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 766 | Advertising Router | 767 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 768 | LS Sequence Number | 769 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 770 | LS Checksum | Length | 771 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 772 . . 773 . TLVs . 774 . . 775 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 777 E-Inter-Area-Router-LSA 779 Other than having a different LS Type, all LSA Header fields are the 780 same as defined for the Inter-Area-Router-LSA. In order to retain 781 compatibility and semantics with the current OSPFv3 specification, 782 each Inter-Area-Router LSA MUST contain a single Inter-Area Router 783 TLV. This will facilitate migration and avoid changes to functions 784 such as incremental SPF computation. 786 Like the existing Inter-Area-Router-LSA, the LSA length is used to 787 determine the end of the LSA including TLV. Initially, only the top- 788 level Inter-Area-Router TLV (Section 3.5) is applicable. If the 789 Inter-Area-Router TLV is not included in the E-Inter-Area-Router-LSA, 790 it is treated as malformed as described in Section 5. Instances of 791 the Inter-Area-Router TLV subsequent to the first MUST be ignored. 793 4.5. OSPFv3 E-AS-External-LSA 795 The E-AS-External-LSA has an LS Type of 0xC025 and has the same base 796 information content as the AS-External-LSA defined in section A.4.7 797 of [OSPFV3]. However, unlike the existing AS-External-LSA, it is 798 fully extendable and represented as TLVs. 800 0 1 2 3 801 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 1 802 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 803 | LS Age |1|1|0| 0x25 | 804 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 805 | Link State ID | 806 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 807 | Advertising Router | 808 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 809 | LS Sequence Number | 810 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 811 | LS Checksum | Length | 812 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 813 . . 814 . TLVs . 815 . . 816 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 818 E-AS-External-LSA 820 Other than having a different LS Type, all LSA Header fields are the 821 same as defined for the AS-External-LSA. In order to retain 822 compatibility and semantics with the current OSPFv3 specification, 823 each LSA MUST contain a single External Prefix TLV. This will 824 facilitate migration and avoid changes to OSPFv3 processes such as 825 incremental SPF computation. 827 Like the existing AS-External-LSA, the LSA length is used to 828 determine the end of the LSA including sub-TLVs. Initially, only the 829 top-level External-Prefix TLV (Section 3.6) is applicable. If the 830 External-Prefix TLV is not included in the E-External-AS-LSA, it is 831 treated as malformed as described in Section 5. Instances of the 832 External-Prefix TLV subsequent to the first MUST be ignored. 834 4.6. OSPFv3 E-NSSA-LSA 836 The E-NSSA-LSA will have the same format and TLVs as the Extended AS- 837 External-LSA Section 4.5. This is the same relationship as exists 838 between the NSSA-LSA defined in section A.4.8 of [OSPFV3], and the 839 AS-External-LSA. The NSSA-LSA will have type 0xA027 which implies 840 area flooding scope. Future requirements may dictate that supported 841 TLVs differ between the E-AS-External-LSA and the E-NSSA-LSA. 842 However, future requirements are beyond the scope of this document. 844 4.7. OSPFv3 E-Link-LSA 846 The E-Link-LSA has an LS Type of 0x8028 and will have the same base 847 information content as the Link-LSA defined in section A.4.9 of 848 [OSPFV3]. However, unlike the existing Link-LSA, it is extendable 849 and represented as TLVs. 851 0 1 2 3 852 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 1 853 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 854 | LS Age |1|0|0| 0x28 | 855 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 856 | Link State ID | 857 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 858 | Advertising Router | 859 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 860 | LS Sequence Number | 861 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 862 | LS Checksum | Length | 863 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 864 | Rtr Priority | Options | 865 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 866 . . 867 . TLVs . 868 . . 869 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 871 E-Link-LSA 873 Other than having a different LS Type, all LSA Header fields are the 874 same as defined for the Link-LSA. 876 Only the Intra-Area-Prefix TLV (Section 3.7), IPv6 Link-Local Address 877 TLV (Section 3.8), and IPv4 Link-Local Address TLV (Section 3.9) are 878 applicable to the E-Link-LSA. Like the Link-LSA, the E-Link-LSA 879 affords advertisement of multiple intra-area prefixes. Hence, 880 multiple Intra-Area Prefix TLVs (Section 3.7) may be specified and 881 the LSA length defines the end of the LSA including all TLVs. 883 A single instance of the IPv6 Link-Local Address TLV (Section 3.8) 884 SHOULD be included in the E-Link-LSA. Instances following the first 885 MUST be ignored. For IPv4 address families as defined in 886 [OSPFV3-AF], this TLV MUST be ignored. 888 Similarly, only a single instance of the IPv4 Link-Local Address TLV 889 (Section 3.9) SHOULD be included in the E-Link-LSA. Instances 890 following the first MUST be ignored. For OSPFv3 IPv6 address 891 families as defined in [OSPFV3-AF], this TLV SHOULD be ignored. 893 If the IPv4/IPv6 Link-Local Address TLV corresponding to the OSPFv3 894 Address Family is not included in the E-Link-LSA, it is treated as 895 malformed as described in Section 5. 897 Future specifications may support advertisement of routing and 898 topology information for multiple address families. However, this is 899 beyond the scope of this document. 901 4.8. OSPFv3 E-Intra-Area-Prefix-LSA 903 The E-Intra-Area-Prefix-LSA has an LS Type of 0xA029 and has the same 904 base information content as the Intra-Area-Prefix-LSA defined in 905 section A.4.10 of [OSPFV3] except for the Referenced LS Type. 906 However, unlike the Intra-Area-Prefix-LSA, it is fully extendable and 907 represented as TLVs. The Referenced LS Type MUST be either an E- 908 Router-LSA (0xA021) or an E-Network-LSA (0xA022). 910 0 1 2 3 911 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 1 912 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 913 | LS Age |1|0|1| 0x29 | 914 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 915 | Link State ID | 916 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 917 | Advertising Router | 918 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 919 | LS Sequence Number | 920 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 921 | LS Checksum | Length | 922 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 923 | 0 | Referenced LS Type | 924 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 925 | Referenced Link State ID | 926 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 927 | Referenced Advertising Router | 928 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 929 . . 930 . TLVs . 931 . . 932 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 934 E-Intra-Area-Prefix-LSA 936 Other than having a different LS Type, all LSA Header fields are the 937 same as defined for the Intra-Area-Prefix-LSA. 939 Like the Intra-Area-Prefix-LSA, the E-Intra-Area-Link-LSA affords 940 advertisement of multiple intra-area prefixes. Hence, multiple 941 Intra-Area Prefix TLVs may be specified and the LSA length defines 942 the end of the LSA including all TLVs. 944 5. Malformed OSPFv3 Extended LSA Handling 946 Extended LSAs that have inconsistent length or other encoding errors, 947 as described herein, MUST NOT be installed in the Link State 948 Database, acknowledged, or flooded. Reception of malformed LSAs 949 SHOULD be counted and/or logged for examination by the administrator 950 of the OSPFv3 Routing Domain. Note that for the purposes of length 951 validation, a TLV or Sub-TLV should not be considered invalid unless 952 the length exceeds the length of the LSA or does not meet the minimum 953 length requirements. This allows for Sub-TLVs to be added as 954 described in Section 6.3. 956 Additionally, an LSA MUST be considered malformed if it does not 957 include all of the required TLVs and Sub-TLVs. 959 6. LSA Extension Backward Compatibility 961 In the context of this document, backward compatibility is solely 962 related to the capability of an OSPFv3 router to receive, process, 963 and originate the TLV-based LSAs defined herein. Unrecognized TLVs 964 and sub-TLVs are ignored. Backward compatibility for future OSPFv3 965 extensions utilizing the TLV-based LSAs is out of scope and must be 966 covered in the documents describing those extensions. Both full and, 967 if applicable, partial deployment SHOULD be specified for future TLV- 968 based OSPFv3 LSA extensions. 970 6.1. Full Extended LSA Migration 972 If ExtendedLSASupport is enabled Appendix A, OSPFv3 Extended LSAs 973 will be originated and used for the SPF computation. Individual OSPF 974 Areas can be migrated separately with the Legacy AS-External LSAs 975 being originated and used for the SPF computation. This is 976 accomplished by enabled AreaExtendedLSASupport Appendix B. 978 An OSPFv3 routing domain or area may be non-disruptively migrated 979 using separate OSPFv3 instances for the extended LSAs. Initially, 980 the OSPFv3 instances with ExtendedLSASupport will have a lower 981 preference, i.e., higher administrative distance, than the OSPFv3 982 instances originating and using the Legacy LSAs. Once the routing 983 domain or area is fully migrated and the OSPFv3 Routing Information 984 Bases (RIB) have been verified, the OSPFv3 instances using the 985 extended LSAs can be given preference. When this has been completed 986 and the routing within the OSPF routing domain or area has been 987 verified, the original OSPFv3 instance using Legacy LSAs can be 988 removed. 990 6.2. Extended LSA Sparse-Mode Backward Compatibility 992 In this mode, OSPFv3 will use the Legacy LSAs for the SPF computation 993 and will only originate extended LSAs when LSA origination is 994 required in support of additional functionality. Furthermore, those 995 extended LSAs will only include the top-level TLVs (e.g., Router-Link 996 TLVs or Inter-Area TLVs) which require further specification for that 997 new functionality. However, if a top-level TLV is advertised, it 998 MUST include required Sub-TLVs or it will be considered malformed as 999 described in Section 5. Hence, this mode of compatibility is known 1000 as "sparse-mode". The advantage of sparse-mode is that functionality 1001 utilizing the OSPFv3 extended LSAs can be added to an existing OSFPv3 1002 routing domain without the requirement for migration. In essence, 1003 this compatibility mode is very much like the approach taken for 1004 OSPFv2 [OSPF-PREFIX-LINK]. As with all the compatibility modes, 1005 backward compatibility for the functions utilizing the extended LSAs 1006 must be described in the IETF documents describing those functions. 1008 6.3. LSA TLV Processing Backward Compatibility 1010 This section defines the general rules for processing LSA TLVs. To 1011 ensure compatibility of future TLV-based LSA extensions, all 1012 implementations MUST adhere to these rules: 1014 1. Unrecognized TLVs and sub-TLVs are ignored when parsing or 1015 processing Extended-LSAs. 1017 2. Whether or not partial deployment of a given TLV is supported 1018 MUST be specified. 1020 3. If partial deployment is not supported, mechanisms to ensure the 1021 corresponding feature are not deployed MUST be specified in the 1022 document defining the new TLV or sub-TLV. 1024 4. If partial deployment is supported, backward compatibility and 1025 partial deployment MUST be specified in the document defining the 1026 new TLV or sub-TLV. 1028 5. If a TLV or Sub-TLV is recognized but the length is less than the 1029 minimum, then the LSA should be considered malformed and it 1030 SHOULD NOT be acknowledged. Additionally, the occurrence SHOULD 1031 be logged with enough information to identify the LSA by type, 1032 originator, and sequence number and the TLV or Sub-TLV in error. 1033 Ideally, the log entry would include the hexadecimal or binary 1034 representation of the LSA including the malformed TLS or Sub-TLV. 1036 6. Documents specifying future TLVs or Sub-TLVs MUST specify the 1037 requirements for usage of those TLVs or Sub-TLVs. 1039 7. Future TLV or Sub-TLVs must be optional. However, there may be 1040 requirements for Sub-TLVs if an optional TLV is specified. 1042 7. Security Considerations 1044 In general, extendible OSPFv3 LSAs are subject to the same security 1045 concerns as those described in RFC 5340 [OSPFV3]. Additionally, 1046 implementations must assure that malformed TLV and sub-TLV 1047 permutations do not result in errors that cause hard OSPFv3 failures. 1049 If there were ever a requirement to digitally sign OSPFv3 LSAs as 1050 described for OSPFv2 LSAs in RFC 2154 [OSPF-DIGITAL-SIGNATURE], the 1051 mechanisms described herein would greatly simplify the extension. 1053 8. IANA Considerations 1055 This specification defines nine OSPFv3 Extended LSA types as 1056 described in Section 2. These are added the existing OSPFv3 LSA 1057 Function Codes registry. 1059 The specification defines a new code point for the N-bit in the 1060 OSPFv3 Prefix-Options registry. The value 0x20 is suggested. 1062 This specification also creates two registries OSPFv3 Extended-LSAs 1063 TLVs and sub-TLVs. The TLV and sub-TLV code-points in these 1064 registries are common to all Extended-LSAs and their respective 1065 definitions must define where they are applicable. 1067 8.1. OSPFv3 Extended-LSA TLV Registry 1069 The OSPFv3 Extended-LSA TLV registry defines top-level TLVs for 1070 Extended-LSAs and should be placed in the existing OSPFv3 IANA 1071 registry. 1073 Nine values are allocated by this specification: 1075 o 0 - Reserved 1077 o 1 - Router-Link TLV 1079 o 2 - Attached-Routers TLV 1081 o 3 - Inter-Area Prefix TLV 1083 o 4 - Inter-Area Router TLV 1085 o 5 - External Prefix TLV 1086 o 6 - Intra-Area Prefix TLV 1088 o 7 - IPv6 Link-Local Address TLV 1090 o 8 - IPv4 Link-Local Address TLV 1092 Types in the range 9-32767 are allocated via IETF Consensus or IESG 1093 Approval. 1095 Types in the range 32768-33023 are for experimental use; these will 1096 not be registered with IANA, and MUST NOT be mentioned by RFCs. 1098 Types in the range 33024-45055 are to be assigned on a First-Come- 1099 First-Serve (FCFS) basis. 1101 Types in the range 45056-65535 are not to be assigned at this time. 1102 Before any assignments can be made in the 33024-65535 range, there 1103 MUST be an IETF specification that specifies IANA Considerations that 1104 covers the range being assigned. 1106 8.2. OSPFv3 Extended-LSA sub-TLV Registry 1108 The OSPFv3 Extended-LSA sub-TLV registry defines sub-TLVs at any 1109 level of nesting for Extended-LSAs and should be placed in the 1110 existing OSPFv3 IANA registry. 1112 Four values are allocated by this specification: 1114 o 0 - Reserved 1116 o 1 - IPv6 Forwarding Address sub-TLV 1118 o 2 - IPv4 Forwarding Address sub-TLV 1120 o 3 - Route Tag sub-TLV 1122 Types in the range 4-32767 are allocated via IETF Consensus or IESG 1123 Approval. 1125 Types in the range 32768-33023 are for experimental use; these will 1126 not be registered with IANA, and MUST NOT be mentioned by RFCs. 1128 Types in the range 33024-45055 are to be assigned on a First-Come- 1129 First-Serve (FCFS) basis. 1131 Types in the range 45056-65535 are not to be assigned at this time. 1132 Before any assignments can be made in the 33024-65535 range, there 1133 MUST be an IETF specification that specifies IANA Considerations that 1134 covers the range being assigned. 1136 9. Contributors 1138 Contributors' Addresses 1140 Sina Mirtorabi 1141 Cisco Systems 1142 170 Tasman Drive 1143 San Jose, CA 95134 1144 USA 1145 Email: sina@cisco.com 1147 10. References 1149 10.1. Normative References 1151 [NSSA] Murphy, P., "The OSPF Not-So-Stubby Area (NSSA) Option", 1152 RFC 3101, January 2003. 1154 [OSPFV3] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF 1155 for IPv6", RFC 5340, July 2008. 1157 [OSPFV3-AF] 1158 Lindem, A., Mirtorabi, S., Roy, A., Barnes, M., and R. 1159 Aggarwal, "Support of Address Families in OSPFv3", 1160 RFC 5838, April 2010. 1162 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1163 Requirement Levels", RFC 2119, March 1997. 1165 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1166 2119 Key Words", RFC 8174, May 2017. 1168 [TE] Katz, D., Yeung, D., and K. Kompella, "Traffic Engineering 1169 Extensions to OSPF", RFC 3630, September 2003. 1171 10.2. Informative References 1173 [MT-OSPFV3] 1174 Mirtorabi, S. and A. Roy, "Multi-topology routing in 1175 OSPFv3 (MT-OSPFV3)", draft-ietf-ospf-mt-ospfv3-04.txt 1176 (work in progress), January 2008. 1178 [OSPF-DIGITAL-SIGNATURE] 1179 Murphy, S., Badger, M., and B. Wellington, "OSPF with 1180 Digital Signatures", RFC 2154, June 1997. 1182 [OSPF-PREFIX-LINK] 1183 Psenak, P., Gredler, H., Shakir, R., Henderickx, W., 1184 Tantsura, J., and A. Lindem, "OSPF Prefix/Link 1185 Attributes", RFC 7684, December 2015. 1187 [SEGMENT-ROUTING] 1188 Psenak, P., Previdi, S., Filsfils, C., Gredler, H., 1189 Shakir, R., Henderickx, W., and J. Tantsura, "OSPFv3 1190 Extensions for Segment Routing", draft-ietf-ospf-ospfv3- 1191 segment-routing-extensions-10.txt (work in progress), July 1192 2016. 1194 Appendix A. Appendix A - Global Configuration Parameters 1196 The global configurable parameter ExtendedLSASupport is added to the 1197 OSPFv3 protocol. If ExtendedLSASupport is enabled, the OSPFv3 Router 1198 will originate OSPFv3 Extended LSAs and use the LSAs for the SPF 1199 computation. If ExtendedLSASupport is not enabled, a subset of 1200 OSPFv3 Extended LSAs may still be originated and used for other 1201 functions as described in Section 6.2. 1203 Appendix B. Appendix B - Area Configuration Parameters 1205 The area configurable parameter AreaExtendedLSASupport is added to 1206 the OSPFv3 protocol. If AreaExtendedLSASupport is enabled, the 1207 OSPFv3 Router will originate link and area OSPFv3 Extended LSAs and 1208 use the LSAs for the SPF computation. Legacy AS-Scoped LSAs will 1209 still be originated and used for the AS External LSA computation. If 1210 AreaExtendedLSASupport is not enabled a subset of OSPFv3 link and 1211 area Extended LSAs may still be originated and used for other 1212 functions as described in Section 6.2. 1214 For regular areas, i.e., areas where AS scoped LSAs are flooded, 1215 disabling AreaExtendedLSASupport for a regular OSPFv3 area (not a 1216 Stub or NSSA area) when ExtendedLSASupport is enabled is 1217 contradictory and SHOULD be prohibited by the implementation. 1219 Appendix C. Acknowledgments 1221 OSPFv3 TLV-based LSAs were first proposed in "Multi-topology routing 1222 in OSPFv3 (MT-OSPFv3)" [MT-OSPFV3]. 1224 Thanks for Peter Psenak for significant contributions to the backward 1225 compatibility mechanisms. 1227 Thanks go to Michael Barnes, Mike Dubrovsky, Anton Smirnov, and Tony 1228 Przygienda for review of the draft versions and discussions of 1229 backward compatibility. 1231 Thanks to Alan Davey for review and comments including the suggestion 1232 to separate the extended LSA TLV definitions from the extended LSAs 1233 definitions. 1235 Thanks to David Lamparter for review and suggestions on backward 1236 compatibility. 1238 Thanks to Karsten Thomann, Chris Bowers, Meng Zhang, and Nagendra 1239 Kumar for review and editorial comments. 1241 Thanks to Alia Atlas for substantive Routing Area Director (AD) 1242 comments prior to IETF last call. 1244 Thanks to Alvaro Retana and Suresh Krishna for substantive comments 1245 during IESG Review. 1247 Thanks to Mehmet Ersue for OPS Directorate review. 1249 The RFC text was produced using Marshall Rose's xml2rfc tool. 1251 Authors' Addresses 1253 Acee Lindem 1254 Cisco Systems 1255 301 Midenhall Way 1256 Cary, NC 27513 1257 USA 1259 Email: acee@cisco.com 1261 Abhay Roy 1262 Cisco Systems 1263 170 Tasman Drive 1264 San Jose, CA 95134 1265 USA 1267 Email: akr@cisco.com 1268 Dirk Goethals 1269 Nokia 1270 Copernicuslaan 50 1271 Antwerp 2018 1272 Belgium 1274 Email: dirk.goethals@nokia.com 1276 Veerendranatha Reddy Vallem 1277 Bangalore 1278 India 1280 Email: vallem.veerendra@gmail.com 1282 Fred Baker 1283 Santa Barbara, California 93117 1284 USA 1286 Email: FredBaker.IETF@gmail.com