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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 'OSPFV3') (Obsoleted by RFC 5340) == Outdated reference: A later version (-06) exists of draft-ietf-isis-igp-p2p-over-lan-05 -- Obsolete informational reference (is this intentional?): RFC 3137 (ref.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: 5 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 N. Shen 4 Intended status: Standards Track J. Vasseur 5 Expires: April 23, 2007 Cisco Systems 6 R. Aggarwal 7 Juniper Networks 8 S. Shaffer 9 BridgePort Networks 10 October 20, 2006 12 Extensions to OSPF for Advertising Optional Router Capabilities 13 draft-ietf-ospf-cap-09.txt 15 Status of this Memo 17 By submitting this Internet-Draft, each author represents that any 18 applicable patent or other IPR claims of which he or she is aware 19 have been or will be disclosed, and any of which he or she becomes 20 aware will be disclosed, in accordance with Section 6 of BCP 79. 22 Internet-Drafts are working documents of the Internet Engineering 23 Task Force (IETF), its areas, and its working groups. Note that 24 other groups may also distribute working documents as Internet- 25 Drafts. 27 Internet-Drafts are draft documents valid for a maximum of six months 28 and may be updated, replaced, or obsoleted by other documents at any 29 time. It is inappropriate to use Internet-Drafts as reference 30 material or to cite them other than as "work in progress." 32 The list of current Internet-Drafts can be accessed at 33 http://www.ietf.org/ietf/1id-abstracts.txt. 35 The list of Internet-Draft Shadow Directories can be accessed at 36 http://www.ietf.org/shadow.html. 38 This Internet-Draft will expire on April 23, 2007. 40 Copyright Notice 42 Copyright (C) The Internet Society (2006). 44 Abstract 46 It is useful for routers in an OSPFv2 or OSPFv3 routing domain to 47 know the capabilities of their neighbors and other routers in the 48 routing domain. This draft proposes extensions to OSPFv2 and OSPFv3 49 for advertising optional router capabilities. A new Router 50 Information (RI) LSA is proposed for this purpose. In OSPFv2, the RI 51 LSA will be implemented with a new opaque LSA type ID. In OSPFv3, 52 the RI LSA will be implemented with a new LSA type function code. In 53 both protocols, the RI LSA can be advertised at any of the defined 54 flooding scopes (link, area, or AS). 56 Table of Contents 58 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 59 1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3 60 2. OSPF Router Information (RI) LSA . . . . . . . . . . . . . . . 4 61 2.1. OSPFv2 Router Information (RI) Opaque LSA . . . . . . . . 4 62 2.2. OSPFv3 Router Information (RI) Opaque LSA . . . . . . . . 5 63 2.3. OSPF Router Informational Capabilities TLV . . . . . . . . 6 64 2.4. Assigned OSPF Router Informational Capability Bits . . . . 7 65 2.5. Flooding Scope of the Router Information LSA . . . . . . . 7 66 3. Router Information LSA Opaque Usage and Applicability . . . . 8 67 4. Security Considerations . . . . . . . . . . . . . . . . . . . 9 68 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 69 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 70 6.1. Normative References . . . . . . . . . . . . . . . . . . . 11 71 6.2. Informative References . . . . . . . . . . . . . . . . . . 11 72 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 12 73 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13 74 Intellectual Property and Copyright Statements . . . . . . . . . . 14 76 1. Introduction 78 It is useful for routers in an OSPFv2 [OSPF] or OSPFv3 [OSPFV3] 79 routing domain to know the capabilities of their neighbors and other 80 routers in the routing domain. This can be useful for both the 81 advertisement and discovery of OSPFv2 and OSPFv3 capabilities. 82 Throughout this document, OSPF will be used when the specification is 83 applicable to both OSPFv2 and OSPFv3. Similarly, OSPFv2 or OSPFv3 84 will be used when the text is protocol specific. 86 OSPF uses the options field in LSAs and hello packets to advertise 87 optional router capabilities. In the case of OSPFv2, all the bits in 88 this field have been allocated and there is no way to advertise new 89 optional capabilities. This document proposes extensions to OSPF to 90 advertise these optional capabilities via opaque LSAs in OSPFv2 and 91 new LSAs in OSPFv3. For existing OSPF capabilities, backward 92 compatibility issues dictate that this advertisement is used 93 primarily for informational purposes. For future OSPF features, this 94 advertisement MAY be used as the sole mechanism for advertisement and 95 discovery. 97 1.1. Requirements notation 99 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 100 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 101 document are to be interpreted as described in RFC2119 [RFC2119]. 103 2. OSPF Router Information (RI) LSA 105 OSPF routers MAY optionally advertise their optional capabilities in 106 a link-scoped, area-scoped, or AS-scoped LSA. For existing OSPF 107 capabilities, this advertisement will be used primarily for 108 informational purposes. Future OSPF features could use the RI LSA as 109 the sole mechanism for advertisement and discovery. The RI LSA will 110 be originated initially when an OSPF router instance is created and 111 whenever one of the advertised capabilities is configured or changed. 113 2.1. OSPFv2 Router Information (RI) Opaque LSA 115 OSPFv2 routers will advertise a link scoped, area-scoped, or AS- 116 scoped Opaque-LSA [OPAQUE]. The OSPFv2 Router Information LSA has an 117 Opaque type of 4 and Opaque ID of 0. 119 0 1 2 3 120 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 1 121 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 122 | LS age | Options | 9, 10 or 11 | 123 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 124 | 4 | 0 | 125 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 126 | Advertising Router | 127 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 128 | LS sequence number | 129 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 130 | LS checksum | length | 131 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 132 | | 133 +- TLVs -+ 134 | ... | 136 OSPFv2 Router Information Opaque LSA 138 The format of the TLVs within the body of an RI LSA is the same as 139 the format used by the Traffic Engineering Extensions to OSPF [TE]. 140 The LSA payload consists of one or more nested Type/Length/Value 141 (TLV) triplets. The format of each TLV is: 143 0 1 2 3 144 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 1 145 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 146 | Type | Length | 147 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 148 | Value... | 149 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 151 TLV Format 153 The Length field defines the length of the value portion in octets 154 (thus a TLV with no value portion would have a length of zero). The 155 TLV is padded to four-octet alignment; padding is not included in the 156 length field (so a three octet value would have a length of three, 157 but the total size of the TLV would be eight octets). Nested TLVs 158 are also 32-bit aligned. For example, a one-byte value would have 159 the length field set to 1, and three octets of padding would be added 160 to the end of the value portion of the TLV. Unrecognized types are 161 ignored. 163 2.2. OSPFv3 Router Information (RI) Opaque LSA 165 The OSPFv3 Router Information LSA has a function code of 12 while the 166 S1/S2 bit are dependent on the desired flooding scope for the LSA. 167 The U bit will be set indicating the OSPFv3 RI LSA should be flooded 168 even if it is not understood. The Link State ID (LSID) value for 169 this LSA is 0. This is unambiguous since an OSPFv3 router will only 170 advertise a single RI LSA per flooding scope. 172 0 1 2 3 173 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 1 174 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 175 | LS age |1|S12| 12 | 176 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 177 | 0 (Link State ID) | 178 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 179 | Advertising Router | 180 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 181 | LS sequence number | 182 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 183 | LS checksum | Length | 184 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 185 | | 186 +- TLVs -+ 187 | ... | 188 OSPFv3 Router Information LSA 190 The format of the TLVs within the body of an RI LSA as defined in 191 Section 2.1 193 When a new Router Information LSA TLV is defined, the specification 194 MUST explicitly state whether the TLV is applicable to OSPFv2 only, 195 OSPFv3 only, or both OSPFv2 and OSPFv3. 197 2.3. OSPF Router Informational Capabilities TLV 199 The first defined TLV in the body of an RI LSA is the Router 200 Informational Capabilities TLV. A router advertising an RI LSA MAY 201 include the Router Informational Capabilities TLV. If included, it 202 MUST be the first TLV in the LSA. Additionally, the TLV MUST 203 accurately reflect the OSPF router's capabilities in the scope 204 advertised. However, the informational capabilities advertised have 205 no impact on the OSPFs operation - they are advertised purely for 206 informational purposes 208 The format of the Router Informational Capabilities TLV is as 209 follows: 211 0 1 2 3 212 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 1 213 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 214 | Type | Length | 215 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 216 | Informational Capabilities | 217 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 219 Type A 16-bit field set to 1. 220 Length A 16-bit field that indicates the length of the value 221 portion in octets and will be a multiple of 4 octets 222 dependent on the number of capabilities advertised. 223 Initially, the length will be 4 denoting 4 octets of 224 informational capability bits. 225 Value A variable length sequence of capability bits rounded 226 to a multiple of 4 octets padded with undefined bits. 227 Initially, there are 4 octets of capability bits. Bits 228 are numbered left-to-right starting with the most 229 significant bit being bit zero. 231 OSPF Router Informational Capabilities TLV 233 The Router Informational Capabilities TLV MAY be followed by optional 234 TLVs that further specify a capability. 236 2.4. Assigned OSPF Router Informational Capability Bits 238 The following informational capability bits assigned: 240 Bit Capabilities 242 0 OSPF graceful restart capable [GRACE] 243 1 OSPF graceful restart helper [GRACE] 244 2 OSPF Stub Router support [STUB] 245 3 OSPF Traffic Engineering support [TE] 246 4 OSPF point-to-point over LAN [P2PLAN] 247 5 OSPF Experimental TE [EXPTE] 248 6-31 Future assignments 250 OSPF Router Informational Capabilities Bits 252 2.5. Flooding Scope of the Router Information LSA 254 The flooding scope for a Router Information LSA is determined by the 255 LSA type. For OSPFv2, type 9 (link-scoped), type 10 (area-scoped), 256 or a type 11 (AS-scoped) opaque LSA may be flooded. For OSPFv3, the 257 S1 and S2 bits in the LSA type determine flooding scope. If AS wide 258 flooding scope is chosen, the originating router should also 259 advertise area scoped LSA(s) into any attached NSSA area(s). An OSPF 260 router MAY advertise different capabilities when both NSSA area 261 scoped LSA(s) and an AS scoped LSA are advertised. This allows 262 functional capabilities to be limited in scope. For example, a 263 router may be an area border router but only support traffic 264 engineering (TE) in a subset of its attached areas. 266 The choice of flooding scope is made by the advertising router and is 267 a matter of local policy. The originating router MAY advertise 268 multiple RI LSAs as long as the flooding scopes differ. TLV flooding 269 scope rules will be specified on a per-TLV basis and MUST be 270 specified in the accompanying specifications for new Router 271 Information LSA TLVs. 273 3. Router Information LSA Opaque Usage and Applicability 275 The purpose of the Router Information (RI) LSA is to advertise 276 information relating to the aggregate OSPF router. Normally, this 277 should be confined to TLVs with a single value or very few values. 278 It is not meant to be a generic container to carry any and all 279 information. The intent is to both limit the size of the RI LSA to 280 the point where an OSPF router will always be able to contain the 281 TLVs in a single LSA and to keep the task of determining what has 282 changed between LSA instances reasonably simple. Hence, discretion 283 and sound engineering judgment MUST be adhered to when deciding 284 whether newly proposed TLV(s) in support of a new application are 285 advertised in the RI LSA or warrant the creation of an application 286 specific LSA. 288 4. Security Considerations 290 The function described in this document does not create any new 291 security issues for the OSPF protocol. Security considerations for 292 the base OSPF protocol are covered in [OSPF] and [OSPFV3]. 294 5. IANA Considerations 296 The following IANA assignments are to be made from existing 297 registries: 299 1. The OSPFv2 opaque LSA type 4 will need to be reserved for the 300 OSPFv2 RI opaque LSA. 302 2. The OSPFv3 LSA type function code 18 will need to be reserved for 303 the OSPFv3 RI LSA. 305 New registries are defined for the following purposes: 307 1. Registry for OSPF RI TLVs - The value of 1 for the capabilities 308 TLV is defined herein. All TLV additions are subject to review 309 by an expert designated by the IESG. 311 2. Registry for OSPF Router Informational Capability Bits - The 312 values defined in Section 2.3. All Router Informational 313 Capability TLV additions are subject to review by an expert 314 designated by the IESG. 316 6. References 318 6.1. Normative References 320 [OPAQUE] Coltun, R., "The OSPF Opaque LSA Option", RFC 2370, 321 July 1998. 323 [OSPF] Moy, J., "OSPF Version 2", RFC 2328, April 1998. 325 [OSPFV3] Coltun, R., Ferguson, D., and J. Moy, "OSPF for IPv6", 326 RFC 2740, December 1999. 328 [RFC2119] Bradner, S., "Key words for use in RFC's to Indicate 329 Requirement Levels", RFC 2119, March 1997. 331 [TE] Katz, D., Yeung, D., and K. Kompella, "Traffic Engineering 332 Extensions to OSPF", RFC 3630, September 2003. 334 6.2. Informative References 336 [EXPTE] Srisuresh, P. and P. Joseph, "OSPF OSPF-TE: An 337 experimental extension to OSPF for Traffic Engineering", 338 draft-srisuresh-ospf-te-07.txt (work in progress). 340 [GRACE] Moy, J., Pillay-Esnault, P., and A. Lindem, "Graceful OSPF 341 Restart", RFC 3623, November 2003. 343 [P2PLAN] Shen, N. and A. Zinin, "Point-to-point operation over LAN 344 in link-state routing protocols", 345 draft-ietf-isis-igp-p2p-over-lan-05.txt (work in progress). 347 [STUB] Retana, A., Nguyen, L., White, R., Zinin, A., and D. 348 McPherson, "OSPF Stub Router Advertisement", RFC 3137, 349 June 2001. 351 Appendix A. Acknowledgments 353 The idea for this work grew out of a conversation with Andrew Partan 354 and we would like to thank him for his contribution. The authors 355 would like to thanks Peter Psenak for his review and helpful comments 356 on early versions of the draft. 358 Comments from Abhay Roy, Vishwas Manral, Vivek Dubey, and Adrian 359 Farrel have been incorporated into later draft versions. 361 The RFC text was produced using Marshall Rose's xml2rfc tool. 363 Authors' Addresses 365 Acee Lindem 366 Cisco Systems 367 7025 Kit Creek Road 368 Research Triangle Park, NC 27709 369 USA 371 Email: acee@cisco.com 373 Naiming Shen 374 Cisco Systems 375 225 West Tasman Drive 376 San Jose, CA 95134 377 USA 379 Email: naiming@cisco.com 381 Jean-Philippe Vasseur 382 Cisco Systems 383 300 Beaver Brook Road 384 Boxborough, MA 01719 385 USA 387 Email: jpv@cisco.com 389 Rahul Aggarwal 390 Juniper Networks 391 1194 N. Mathilda Ave. 392 Sunnyvale, CA 94089 393 USA 395 Email: rahul@juniper.net 397 Scott Shaffer 398 BridgePort Networks 399 One Main Street, 7th Floor 400 Cambridge, MA 02142 401 USA 403 Email: sshafferl@bridgeport-networks.com 405 Full Copyright Statement 407 Copyright (C) The Internet Society (2006). 409 This document is subject to the rights, licenses and restrictions 410 contained in BCP 78, and except as set forth therein, the authors 411 retain all their rights. 413 This document and the information contained herein are provided on an 414 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 415 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET 416 ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, 417 INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE 418 INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 419 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 421 Intellectual Property 423 The IETF takes no position regarding the validity or scope of any 424 Intellectual Property Rights or other rights that might be claimed to 425 pertain to the implementation or use of the technology described in 426 this document or the extent to which any license under such rights 427 might or might not be available; nor does it represent that it has 428 made any independent effort to identify any such rights. 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