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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) ** Obsolete normative reference: RFC 2370 (ref. 'OPAQUE') (Obsoleted by RFC 5250) ** Obsolete normative reference: RFC 2740 (ref. 'OSPFV3') (Obsoleted by RFC 5340) == Outdated reference: A later version (-06) exists of draft-ietf-isis-igp-p2p-over-lan-05 -- Obsolete informational reference (is this intentional?): RFC 3137 (ref. 'STUB') (Obsoleted by RFC 6987) Summary: 3 errors (**), 0 flaws (~~), 2 warnings (==), 8 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group A. Lindem (Editor) 3 Internet-Draft Redback Networks 4 Intended status: Standards Track N. Shen 5 Expires: August 13, 2007 J. Vasseur 6 Cisco Systems 7 R. Aggarwal 8 Juniper Networks 9 S. Shaffer 10 BridgePort Networks 11 February 9, 2007 13 Extensions to OSPF for Advertising Optional Router Capabilities 14 draft-ietf-ospf-cap-10.txt 16 Status of this Memo 18 By submitting this Internet-Draft, each author represents that any 19 applicable patent or other IPR claims of which he or she is aware 20 have been or will be disclosed, and any of which he or she becomes 21 aware will be disclosed, in accordance with Section 6 of BCP 79. 23 Internet-Drafts are working documents of the Internet Engineering 24 Task Force (IETF), its areas, and its working groups. Note that 25 other groups may also distribute working documents as Internet- 26 Drafts. 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 The list of current Internet-Drafts can be accessed at 34 http://www.ietf.org/ietf/1id-abstracts.txt. 36 The list of Internet-Draft Shadow Directories can be accessed at 37 http://www.ietf.org/shadow.html. 39 This Internet-Draft will expire on August 13, 2007. 41 Copyright Notice 43 Copyright (C) The IETF Trust (2007). 45 Abstract 47 It is useful for routers in an OSPFv2 or OSPFv3 routing domain to 48 know the capabilities of their neighbors and other routers in the 49 routing domain. This draft proposes extensions to OSPFv2 and OSPFv3 50 for advertising optional router capabilities. A new Router 51 Information (RI) Link State Advertisement (LSA) is proposed for this 52 purpose. In OSPFv2, the RI LSA will be implemented with a new opaque 53 LSA type ID. In OSPFv3, the RI LSA will be implemented with a new 54 LSA type function code. In both protocols, the RI LSA can be 55 advertised at any of the defined flooding scopes (link, area, or AS). 57 Table of Contents 59 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 60 1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3 61 2. OSPF Router Information (RI) LSA . . . . . . . . . . . . . . . 4 62 2.1. OSPFv2 Router Information (RI) Opaque LSA . . . . . . . . 4 63 2.2. OSPFv3 Router Information (RI) Opaque LSA . . . . . . . . 5 64 2.3. OSPF Router Informational Capabilities TLV . . . . . . . . 6 65 2.4. Assigned OSPF Router Informational Capability Bits . . . . 7 66 2.5. Flooding Scope of the Router Information LSA . . . . . . . 7 67 3. Router Information LSA Opaque Usage and Applicability . . . . 8 68 4. Security Considerations . . . . . . . . . . . . . . . . . . . 9 69 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 70 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 71 6.1. Normative References . . . . . . . . . . . . . . . . . . . 12 72 6.2. Informative References . . . . . . . . . . . . . . . . . . 12 73 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 13 74 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 14 75 Intellectual Property and Copyright Statements . . . . . . . . . . 15 77 1. Introduction 79 It is useful for routers in an OSPFv2 [OSPF] or OSPFv3 [OSPFV3] 80 routing domain to know the capabilities of their neighbors and other 81 routers in the routing domain. This can be useful for both the 82 advertisement and discovery of OSPFv2 and OSPFv3 capabilities. 83 Throughout this document, OSPF will be used when the specification is 84 applicable to both OSPFv2 and OSPFv3. Similarly, OSPFv2 or OSPFv3 85 will be used when the text is protocol specific. 87 OSPF uses the options field in LSAs and hello packets to advertise 88 optional router capabilities. In the case of OSPFv2, all the bits in 89 this field have been allocated and there is no way to advertise new 90 optional capabilities. This document proposes extensions to OSPF to 91 advertise these optional capabilities via opaque LSAs in OSPFv2 and 92 new LSAs in OSPFv3. For existing OSPF capabilities, backward 93 compatibility issues dictate that this advertisement is used 94 primarily for informational purposes. For future OSPF features, this 95 advertisement MAY be used as the sole mechanism for advertisement and 96 discovery. 98 1.1. Requirements notation 100 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 101 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 102 document are to be interpreted as described in [RFC-KEYWORDS]. 104 2. OSPF Router Information (RI) LSA 106 OSPF routers MAY optionally advertise their optional capabilities in 107 a link-scoped, area-scoped, or AS-scoped LSA. For existing OSPF 108 capabilities, this advertisement will be used primarily for 109 informational purposes. Future OSPF features could use the RI LSA as 110 the sole mechanism for advertisement and discovery. The RI LSA will 111 be originated initially when an OSPF router instance is created and 112 whenever one of the advertised capabilities is configured or changed. 114 2.1. OSPFv2 Router Information (RI) Opaque LSA 116 OSPFv2 routers will advertise a link scoped, area-scoped, or AS- 117 scoped Opaque-LSA [OPAQUE]. The OSPFv2 Router Information LSA has an 118 Opaque type of 4 and Opaque ID of 0. 120 0 1 2 3 121 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 1 122 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 123 | LS age | Options | 9, 10 or 11 | 124 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 125 | 4 | 0 | 126 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 127 | Advertising Router | 128 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 129 | LS sequence number | 130 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 131 | LS checksum | length | 132 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 133 | | 134 +- TLVs -+ 135 | ... | 137 OSPFv2 Router Information Opaque LSA 139 The format of the TLVs within the body of an RI LSA is the same as 140 the format used by the Traffic Engineering Extensions to OSPF [TE]. 141 The LSA payload consists of one or more nested Type/Length/Value 142 (TLV) triplets. The format of each TLV is: 144 0 1 2 3 145 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 1 146 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 147 | Type | Length | 148 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 149 | Value... | 150 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 152 TLV Format 154 The Length field defines the length of the value portion in octets 155 (thus a TLV with no value portion would have a length of zero). The 156 TLV is padded to four-octet alignment; padding is not included in the 157 length field (so a three octet value would have a length of three, 158 but the total size of the TLV would be eight octets). Nested TLVs 159 are also 32-bit aligned. For example, a one-byte value would have 160 the length field set to 1, and three octets of padding would be added 161 to the end of the value portion of the TLV. Unrecognized types are 162 ignored. 164 2.2. OSPFv3 Router Information (RI) Opaque LSA 166 The OSPFv3 Router Information LSA has a function code of 12 while the 167 S1/S2 bit are dependent on the desired flooding scope for the LSA. 168 The U bit will be set indicating the OSPFv3 RI LSA should be flooded 169 even if it is not understood. The Link State ID (LSID) value for 170 this LSA is 0. This is unambiguous since an OSPFv3 router will only 171 advertise a single RI LSA per flooding scope. 173 0 1 2 3 174 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 1 175 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 176 | LS age |1|S12| 12 | 177 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 178 | 0 (Link State ID) | 179 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 180 | Advertising Router | 181 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 182 | LS sequence number | 183 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 184 | LS checksum | Length | 185 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 186 | | 187 +- TLVs -+ 188 | ... | 189 OSPFv3 Router Information LSA 191 The format of the TLVs within the body of an RI LSA as defined in 192 Section 2.1 194 When a new Router Information LSA TLV is defined, the specification 195 MUST explicitly state whether the TLV is applicable to OSPFv2 only, 196 OSPFv3 only, or both OSPFv2 and OSPFv3. 198 2.3. OSPF Router Informational Capabilities TLV 200 The first defined TLV in the body of an RI LSA is the Router 201 Informational Capabilities TLV. A router advertising an RI LSA MAY 202 include the Router Informational Capabilities TLV. If included, it 203 MUST be the first TLV in the LSA. Additionally, the TLV MUST 204 accurately reflect the OSPF router's capabilities in the scope 205 advertised. However, the informational capabilities advertised have 206 no impact on the OSPFs operation - they are advertised purely for 207 informational purposes 209 The format of the Router Informational Capabilities TLV is as 210 follows: 212 0 1 2 3 213 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 1 214 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 215 | Type | Length | 216 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 217 | Informational Capabilities | 218 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 220 Type A 16-bit field set to 1. 221 Length A 16-bit field that indicates the length of the value 222 portion in octets and will be a multiple of 4 octets 223 dependent on the number of capabilities advertised. 224 Initially, the length will be 4 denoting 4 octets of 225 informational capability bits. 226 Value A variable length sequence of capability bits rounded 227 to a multiple of 4 octets padded with undefined bits. 228 Initially, there are 4 octets of capability bits. Bits 229 are numbered left-to-right starting with the most 230 significant bit being bit zero. 232 OSPF Router Informational Capabilities TLV 234 The Router Informational Capabilities TLV MAY be followed by optional 235 TLVs that further specify a capability. 237 2.4. Assigned OSPF Router Informational Capability Bits 239 The following informational capability bits assigned: 241 Bit Capabilities 243 0 OSPF graceful restart capable [GRACE] 244 1 OSPF graceful restart helper [GRACE] 245 2 OSPF Stub Router support [STUB] 246 3 OSPF Traffic Engineering support [TE] 247 4 OSPF point-to-point over LAN [P2PLAN] 248 5 OSPF Experimental TE [EXP-TE] 249 6-31 Future assignments 251 OSPF Router Informational Capabilities Bits 253 2.5. Flooding Scope of the Router Information LSA 255 The flooding scope for a Router Information LSA is determined by the 256 LSA type. For OSPFv2, type 9 (link-scoped), type 10 (area-scoped), 257 or a type 11 (AS-scoped) opaque LSA may be flooded. For OSPFv3, the 258 S1 and S2 bits in the LSA type determine flooding scope. If AS wide 259 flooding scope is chosen, the originating router should also 260 advertise area scoped LSA(s) into any attached NSSA area(s). An OSPF 261 router MAY advertise different capabilities when both NSSA area 262 scoped LSA(s) and an AS scoped LSA are advertised. This allows 263 functional capabilities to be limited in scope. For example, a 264 router may be an area border router but only support traffic 265 engineering (TE) in a subset of its attached areas. 267 The choice of flooding scope is made by the advertising router and is 268 a matter of local policy. The originating router MAY advertise 269 multiple RI LSAs as long as the flooding scopes differ. TLV flooding 270 scope rules will be specified on a per-TLV basis and MUST be 271 specified in the accompanying specifications for new Router 272 Information LSA TLVs. 274 3. Router Information LSA Opaque Usage and Applicability 276 The purpose of the Router Information (RI) LSA is to advertise 277 information relating to the aggregate OSPF router. Normally, this 278 should be confined to TLVs with a single value or very few values. 279 It is not meant to be a generic container to carry any and all 280 information. The intent is to both limit the size of the RI LSA to 281 the point where an OSPF router will always be able to contain the 282 TLVs in a single LSA and to keep the task of determining what has 283 changed between LSA instances reasonably simple. Hence, discretion 284 and sound engineering judgment will need to be applied when deciding 285 whether newly proposed TLV(s) in support of a new application are 286 advertised in the RI LSA or warrant the creation of an application 287 specific LSA. 289 4. Security Considerations 291 This document describes both a generic mechanism for advertising 292 router capabilities and a TLV for advertising informational 293 capability bits. The latter TLV is less critical than the topology 294 information currently advertised by the base OSPF protocol. The 295 security considerations for the generic mechanism are dependent on 296 the future application and, as such, should be described as 297 additional capabilities are proposed for advertisement. Security 298 considerations for the base OSPF protocol are covered in [OSPF] and 299 [OSPFV3]. 301 5. IANA Considerations 303 The following IANA assignments are to be made from existing 304 registries: 306 1. The OSPFv2 opaque LSA type 4 will need to be reserved for the 307 OSPFv2 RI opaque LSA. 309 New registries will need to be defined for the following purposes: 311 1. Registry for OSPFv3 LSA Function Codes - This new top-level 312 registry will be comprised of the fields Value, LSA function code 313 name, and Document Reference. The OSPFv3 LSA function code is 314 defined in section A.4.2.1 of [OSPFV3]. The OSPFv3 LSA function 315 code 12 will need to be reserved for the OSPFv3 Router 316 Information (RI) LSA. 318 +-----------+--------------------+ 319 | Range | Assignment Policy | 320 +-----------+--------------------+ 321 | 0 | Not to be assigned | 322 | | | 323 | 1-9 | Already assigned | 324 | | | 325 | 10-255 | Standards Action | 326 | | | 327 | 256-8175 | Reserved | 328 | | | 329 | 8176-8183 | Experimentation | 330 | | | 331 | 8184-8191 | Vendor Private Use | 332 +-----------+--------------------+ 334 OSPFv3 LSA Function Codes 336 * OSPFv3 LSA function codes in the range 256-8175 are for 337 experimental use; these will not be registered with IANA and 338 MUST NOT be mentioned by RFCs. 340 * OSPFv3 LSA function codes in the range 8176-8183 are not to be 341 assigned at this time. Before any assignments can be made in 342 this range, there MUST be a Standards Track RFC that specifies 343 IANA Considerations that covers the range being assigned. 345 * OSPFv3 LSAs with an LSA Function Code in the Vendor Private 346 Use range 8184-8191 MUST include the Vendor Enterprise Code as 347 the first four octets following the 20 octets of LSA header. 349 * If a new LSA Function Code is documented, the documentation 350 MUST include the valid combinations of the U, S2 and S1 bits 351 for the LSA. It SHOULD also describe how the Link State ID is 352 to be assigned. 354 2. Registry for OSPF RI TLVs - This top-level registry will be 355 comprised of the fields Value, TLV Name, and Document Reference. 356 The value of 1 for the capabilities TLV is defined herein. 358 +-------------+--------------------+ 359 | Range | Assignment Policy | 360 +-------------+--------------------+ 361 | 0 | Not to be assigned | 362 | | | 363 | 1 | Already assigned | 364 | | | 365 | 2-32767 | Standards Action | 366 | | | 367 | 32768-32777 | Experimentation | 368 | | | 369 | 32778-65535 | Reserved | 370 +-----------+----------------------+ 372 OSPF RI TLVs 374 * Types in the range 32768-32777 are for experimental use; these 375 will not be registered with IANA and MUST NOT be mentioned by 376 RFCs. 378 * Types in the range 32778-65535 are not to be assigned at this 379 time. Before any assignments can be made in this range, there 380 MUST be a Standards Track RFC that specifies IANA 381 Considerations that covers the range being assigned. 383 3. Registry for OSPF Router Informational Capability Bits - This 384 sub-registry of the OSPF RI TLV registry will be comprised of the 385 fields Bit Number, Capability Name, and Document Reference. The 386 values are defined in Section 2.3. All Router Informational 387 Capability TLV additions are to be assigned through standards 388 action. 390 6. References 392 6.1. Normative References 394 [OPAQUE] Coltun, R., "The OSPF Opaque LSA Option", RFC 2370, 395 July 1998. 397 [OSPF] Moy, J., "OSPF Version 2", RFC 2328, April 1998. 399 [OSPFV3] Coltun, R., Ferguson, D., and J. Moy, "OSPF for IPv6", 400 RFC 2740, December 1999. 402 [RFC-KEYWORDS] 403 Bradner, S., "Key words for use in RFC's to Indicate 404 Requirement Levels", RFC 2119, March 1997. 406 [TE] Katz, D., Yeung, D., and K. Kompella, "Traffic Engineering 407 Extensions to OSPF", RFC 3630, September 2003. 409 6.2. Informative References 411 [EXP-TE] Srisuresh, P. and P. Joseph, "OSPF OSPF-TE: An 412 experimental extension to OSPF for Traffic Engineering", 413 draft-srisuresh-ospf-te-07.txt (work in progress). 415 [GRACE] Moy, J., Pillay-Esnault, P., and A. Lindem, "Graceful OSPF 416 Restart", RFC 3623, November 2003. 418 [P2PLAN] Shen, N. and A. Zinin, "Point-to-point operation over LAN 419 in link-state routing protocols", 420 draft-ietf-isis-igp-p2p-over-lan-05.txt (work in 421 progress). 423 [STUB] Retana, A., Nguyen, L., White, R., Zinin, A., and D. 424 McPherson, "OSPF Stub Router Advertisement", RFC 3137, 425 June 2001. 427 Appendix A. Acknowledgments 429 The idea for this work grew out of a conversation with Andrew Partan 430 and we would like to thank him for his contribution. The authors 431 would like to thanks Peter Psenak for his review and helpful comments 432 on early versions of the draft. 434 Comments from Abhay Roy, Vishwas Manral, Vivek Dubey, and Adrian 435 Farrel have been incorporated into later draft versions. 437 The RFC text was produced using Marshall Rose's xml2rfc tool. 439 Authors' Addresses 441 Acee Lindem 442 Redback Networks 443 102 Carric Bend Court 444 Cary, NC 27519 445 USA 447 Email: acee@redback.com 449 Naiming Shen 450 Cisco Systems 451 225 West Tasman Drive 452 San Jose, CA 95134 453 USA 455 Email: naiming@cisco.com 457 Jean-Philippe Vasseur 458 Cisco Systems 459 300 Beaver Brook Road 460 Boxborough, MA 01719 461 USA 463 Email: jpv@cisco.com 465 Rahul Aggarwal 466 Juniper Networks 467 1194 N. Mathilda Ave. 468 Sunnyvale, CA 94089 469 USA 471 Email: rahul@juniper.net 473 Scott Shaffer 474 BridgePort Networks 475 One Main Street, 7th Floor 476 Cambridge, MA 02142 477 USA 479 Email: sshafferl@bridgeport-networks.com 481 Full Copyright Statement 483 Copyright (C) The IETF Trust (2007). 485 This document is subject to the rights, licenses and restrictions 486 contained in BCP 78, and except as set forth therein, the authors 487 retain all their rights. 489 This document and the information contained herein are provided on an 490 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 491 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND 492 THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS 493 OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF 494 THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 495 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 497 Intellectual Property 499 The IETF takes no position regarding the validity or scope of any 500 Intellectual Property Rights or other rights that might be claimed to 501 pertain to the implementation or use of the technology described in 502 this document or the extent to which any license under such rights 503 might or might not be available; nor does it represent that it has 504 made any independent effort to identify any such rights. 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