idnits 2.17.00 (12 Aug 2021) /tmp/idnits64426/draft-ietf-ospf-rfc4970bis-00.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (January 23, 2015) is 2675 days in the past. Is this intentional? 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 4970 (Obsoleted by RFC 7770) Summary: 1 error (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group A. Lindem, Ed. 3 Internet-Draft N. Shen 4 Obsoletes: 4970 (if approved) J. Vasseur 5 Intended status: Standards Track Cisco Systems 6 Expires: July 27, 2015 R. Aggarwal 7 Arktan 8 S. Shaffer 9 Akamai 10 January 23, 2015 12 Extensions to OSPF for Advertising Optional Router Capabilities 13 draft-ietf-ospf-rfc4970bis-00.txt 15 Abstract 17 It is useful for routers in an OSPFv2 or OSPFv3 routing domain to 18 know the capabilities of their neighbors and other routers in the 19 routing domain. This document proposes extensions to OSPFv2 and 20 OSPFv3 for advertising optional router capabilities. A new Router 21 Information (RI) Link State Advertisement (LSA) is proposed for this 22 purpose. In OSPFv2, the RI LSA will be implemented with a new opaque 23 LSA type ID. In OSPFv3, the RI LSA will be implemented with a new 24 LSA type function code. In both protocols, the RI LSA can be 25 advertised at any of the defined flooding scopes (link, area, or 26 autonomous system (AS)). This document obsoletes RFC 4970 by 27 providing a revised specification including support for advertisement 28 of multiple instances of the RI LSA and a TLV for functional 29 capabilities. 31 Status of This Memo 33 This Internet-Draft is submitted in full conformance with the 34 provisions of BCP 78 and BCP 79. 36 Internet-Drafts are working documents of the Internet Engineering 37 Task Force (IETF). Note that other groups may also distribute 38 working documents as Internet-Drafts. The list of current Internet- 39 Drafts is at http://datatracker.ietf.org/drafts/current/. 41 Internet-Drafts are draft documents valid for a maximum of six months 42 and may be updated, replaced, or obsoleted by other documents at any 43 time. It is inappropriate to use Internet-Drafts as reference 44 material or to cite them other than as "work in progress." 46 This Internet-Draft will expire on July 27, 2015. 48 Copyright Notice 50 Copyright (c) 2015 IETF Trust and the persons identified as the 51 document authors. All rights reserved. 53 This document is subject to BCP 78 and the IETF Trust's Legal 54 Provisions Relating to IETF Documents 55 (http://trustee.ietf.org/license-info) in effect on the date of 56 publication of this document. Please review these documents 57 carefully, as they describe your rights and restrictions with respect 58 to this document. Code Components extracted from this document must 59 include Simplified BSD License text as described in Section 4.e of 60 the Trust Legal Provisions and are provided without warranty as 61 described in the Simplified BSD License. 63 Table of Contents 65 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 66 1.1. Requirements Notation . . . . . . . . . . . . . . . . . . 3 67 1.2. Summary of Changes from RFC 4970 . . . . . . . . . . . . 3 68 2. OSPF Router Information (RI) LSA . . . . . . . . . . . . . . 3 69 2.1. OSPFv2 Router Information (RI) Opaque LSA . . . . . . . . 4 70 2.2. OSPFv3 Router Information (RI) Opaque LSA . . . . . . . . 6 71 2.3. OSPF Router Informational Capabilities TLV . . . . . . . 6 72 2.4. Assigned OSPF Router Informational Capability Bits . . . 7 73 2.5. OSPF Router Functional Capabilities TLV . . . . . . . . . 8 74 2.6. Flooding Scope of the Router Information LSA . . . . . . 9 75 3. Security Considerations . . . . . . . . . . . . . . . . . . . 10 76 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 77 5. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 78 5.1. Normative References . . . . . . . . . . . . . . . . . . 12 79 5.2. Informative References . . . . . . . . . . . . . . . . . 13 80 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 13 81 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 83 1. Introduction 85 It is useful for routers in an OSPFv2 [OSPF] or OSPFv3 [OSPFV3] 86 routing domain to know the capabilities of their neighbors and other 87 routers in the routing domain. This can be useful for both the 88 advertisement and discovery of OSPFv2 and OSPFv3 capabilities. 89 Throughout this document, OSPF will be used when the specification is 90 applicable to both OSPFv2 and OSPFv3. Similarly, OSPFv2 or OSPFv3 91 will be used when the text is protocol specific. 93 OSPF uses the options field in LSAs and hello packets to advertise 94 optional router capabilities. In the case of OSPFv2, all the bits in 95 this field have been allocated so new optional capabilities cannot be 96 advertised. This document proposes extensions to OSPF to advertise 97 these optional capabilities via opaque LSAs in OSPFv2 and new LSAs in 98 OSPFv3. For existing OSPF capabilities, backward-compatibility 99 issues dictate that this advertisement is used primarily for 100 informational purposes. For future OSPF extensions, this 101 advertisement MAY be used as the sole mechanism for advertisement and 102 discovery. 104 This document obsoletes RFC 4970 by providing a revised specification 105 including support for advertisement of multiple instances of the RI 106 LSA and a TLV for functional capabilities. 108 1.1. Requirements Notation 110 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 111 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 112 document are to be interpreted as described in [RFC-KEYWORDS]. 114 1.2. Summary of Changes from RFC 4970 116 This document includes the following changes from RFC 4970 [RFC4970]: 118 1. The main change is that an OSPF router will be able to advertise 119 multiple instances of the OSPF Router Information LSA. This 120 change permeates through much of the document 122 2. Additionally, Section 2.5 includes a new TLV for functional 123 capabilities. This is constast to the existing TLV which is used 124 to advertise capabilities for informational purposes only. 126 3. Finally, references have been updated for drafts that have become 127 RFCs and RFCs that have been obseleted since the publication of 128 RFC 4970. 130 2. OSPF Router Information (RI) LSA 132 OSPFv2 routers will advertise a link scoped, area-scoped, or AS- 133 scoped Opaque-LSA [OPAQUE]. The OSPFv2 Router Information LSA has an 134 Opaque type of 4 and Opaque ID is the instance ID. The first 135 instance ID, i.e., 0, should always contain the Router Informational 136 Capabilities TLV and, if advertised, the Router Functional 137 Capabilities TLV. RI Information LSAs subsequence to the first can 138 be used for information which doesn't fit in the first instance. 140 2.1. OSPFv2 Router Information (RI) Opaque LSA 142 OSPFv2 routers will advertise a link scoped, area-scoped, or AS- 143 scoped Opaque-LSA [OPAQUE]. The OSPFv2 Router Information LSA has an 144 Opaque type of 4 and Opaque ID specifies the LSA instance ID with the 145 first instance always having an Instance ID of 0. 147 0 1 2 3 148 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 1 149 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 150 | LS age | Options | 9, 10, or 11 | 151 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 152 | 4 | Opaque ID (Instance ID) | 153 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 154 | Advertising Router | 155 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 156 | LS sequence number | 157 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 158 | LS checksum | length | 159 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 160 | | 161 +- TLVs -+ 162 | ... | 164 OSPFv2 Router Information Opaque LSA 166 The format of the TLVs within the body of an RI LSA is the same as 167 the format used by the Traffic Engineering Extensions to OSPF [TE]. 168 The LSA payload consists of one or more nested Type/Length/Value 169 (TLV) triplets. The format of each TLV is: 171 0 1 2 3 172 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 1 173 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 174 | Type | Length | 175 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 176 | Value... | 177 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 179 TLV Format 181 The Length field defines the length of the value portion in octets 182 (thus a TLV with no value portion would have a length of 0). The TLV 183 is padded to 4-octet alignment; padding is not included in the length 184 field (so a 3-octet value would have a length of 3, but the total 185 size of the TLV would be 8 octets). Nested TLVs are also 32-bit 186 aligned. For example, a 1-byte value would have the length field set 187 to 1, and 3 octets of padding would be added to the end of the value 188 portion of the TLV. Unrecognized types are ignored. 190 2.2. OSPFv3 Router Information (RI) Opaque LSA 192 The OSPFv3 Router Information LSA has a function code of 12 while the 193 S1/S2 bits are dependent on the desired flooding scope for the LSA. 194 The U bit will be set indicating that the OSPFv3 RI LSA should be 195 flooded even if it is not understood. The Link State ID (LSID) value 196 for this LSA is the instance ID. The first instance ID, i.e., 0, 197 should always contain the Router Informational Capabilities TLV and, 198 if advertised, the Router Functional Capabilities TLV. OSPFv3 Router 199 Information LSAs subsequence to the first can be used for information 200 which doesn't fit in the first instance. OSPFv3 routers MAY 201 advertise multiple RIs LSA per flooding scope. 203 0 1 2 3 204 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 1 205 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 206 | LS age |1|S12| 12 | 207 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 208 | Link State ID (Instance ID) | 209 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 210 | Advertising Router | 211 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 212 | LS sequence number | 213 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 214 | LS checksum | Length | 215 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 216 | | 217 +- TLVs -+ 218 | ... | 220 OSPFv3 Router Information LSA 222 The format of the TLVs within the body of an RI LSA is as defined in 223 Section 2.1 225 When a new Router Information LSA TLV is defined, the specification 226 MUST explicitly state whether the TLV is applicable to OSPFv2 only, 227 OSPFv3 only, or both OSPFv2 and OSPFv3. 229 2.3. OSPF Router Informational Capabilities TLV 231 The first defined TLV in the body of an RI LSA is the Router 232 Informational Capabilities TLV. An OSPF router advertising an OSPF 233 RI LSA MAY include the Router Informational Capabilities TLV. If 234 included, it MUST be the first TLV in the first instance of the OSPF 235 RI LSA. Additionally, the TLV MUST accurately reflect the OSPF 236 router's capabilities in the scope advertised. However, the 237 informational capabilities advertised have no impact on the OSPF's 238 operation -- they are advertised purely for informational purposes. 240 The format of the Router Informational Capabilities TLV is as 241 follows: 243 0 1 2 3 244 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 1 245 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 246 | Type | Length | 247 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 248 | Informational Capabilities | 249 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 251 Type A 16-bit field set to 1. 253 Length A 16-bit field that indicates the length of the value 254 portion in octets and will be a multiple of 4 octets 255 dependent on the number of capabilities advertised. 256 Initially, the length will be 4, denoting 4 octets of 257 informational capability bits. 259 Value A variable length sequence of capability bits rounded 260 to a multiple of 4 octets padded with undefined bits. 261 Initially, there are 4 octets of capability bits. Bits 262 are numbered left-to-right starting with the most 263 significant bit being bit 0. 265 OSPF Router Informational Capabilities TLV 267 The Router Informational Capabilities TLV MAY be followed by optional 268 TLVs that further specify a capability. 270 2.4. Assigned OSPF Router Informational Capability Bits 272 The following informational capability bits are assigned: 274 Bit Capabilities 276 0 OSPF graceful restart capable [GRACE] 277 1 OSPF graceful restart helper [GRACE] 278 2 OSPF Stub Router support [STUB] 279 3 OSPF Traffic Engineering support [TE] 280 4 OSPF point-to-point over LAN [P2PLAN] 281 5 OSPF Experimental TE [EXP-TE] 282 6-31 Unassigned (Standards Action) 284 OSPF Router Informational Capabilities Bits 286 References for [GRACE], [STUB], [TE], [P2PLAN], and [EXP-TE] are 287 included herein. 289 2.5. OSPF Router Functional Capabilities TLV 291 This specification also defines the Router Functional Capabilities 292 TLV for advertisement within the OSPF Router Information LSA. An 293 OSPF router advertising an OSPF RI LSA MAY include the Router 294 Functional Capabilities TLV. If included, it MUST be the included in 295 the first instance of the LSA. Additionally, the TLV MUST be used to 296 reflect OSPF router functional capabilities. If the TLV is not 297 included or the length doesn't include the assigned OSPF functional 298 capability bit, the corresponding OSPF functional capabilty is 299 implicitly advertised as not being support by the advertising OSPF 300 router. 302 The format of the Router Functional Capabilities TLV is as follows: 304 0 1 2 3 305 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 1 306 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 307 | Type | Length | 308 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 309 | Functional Capabilities | 310 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 312 Type A 16-bit field set to 1. 314 Length A 16-bit field that indicates the length of the value 315 portion in octets and will be a multiple of 4 octets 316 dependent on the number of capabilities advertised. 317 Initially, the length will be 4, denoting 4 octets of 318 informational capability bits. 320 Value A variable length sequence of capability bits rounded 321 to a multiple of 4 octets padded with undefined bits. 322 Initially, there are 4 octets of capability bits. Bits 323 are numbered left-to-right starting with the most 324 significant bit being bit 0. 326 OSPF Router Functional Capabilities TLV 328 The Router Functional Capabilities TLV MAY be followed by optional 329 TLVs that further specify a capability. In contrast to the Router 330 Informatioal Capabilities TLV, the OSPF extensions advertised in this 331 TLV MAY be used to by other OSPF routers to dicate protocol 332 operation. The specifications for functional capabilities 333 adveritised in this TLV MUST describe protocol behavior and address 334 backward compatibility. 336 2.6. Flooding Scope of the Router Information LSA 338 The flooding scope for a Router Information LSA is determined by the 339 LSA type. For OSPFv2, type 9 (link-scoped), type 10 (area-scoped), 340 or a type 11 (AS-scoped) opaque LSA may be flooded. For OSPFv3, the 341 S1 and S2 bits in the LSA type determine the flooding scope. If AS- 342 wide flooding scope is chosen, the originating router should also 343 advertise area-scoped LSA(s) into any attached Not-So-Stubby Area 344 (NSSA) area(s). An OSPF router MAY advertise different capabilities 345 when both NSSA area scoped LSA(s) and an AS-scoped LSA are 346 advertised. This allows functional capabilities to be limited in 347 scope. For example, a router may be an area border router but only 348 support traffic engineering (TE) in a subset of its attached areas. 350 The choice of flooding scope is made by the advertising router and is 351 a matter of local policy. The originating router MAY advertise 352 multiple RI LSAs as long as the flooding scopes differ. TLV flooding 353 scope rules will be specified on a per-TLV basis and MUST be 354 specified in the accompanying specifications for new Router 355 Information LSA TLVs. 357 3. Security Considerations 359 This document describes both a generic mechanism for advertising 360 router capabilities and a TLV for advertising informational and 361 functional capability bits. The capability TLVs are less critical 362 than the topology information currently advertised by the base OSPF 363 protocol. The security considerations for the generic mechanism are 364 dependent on the future application and, as such, should be described 365 as additional capabilities are proposed for advertisement. Security 366 considerations for the base OSPF protocol are covered in [OSPF] and 367 [OSPFV3]. 369 4. IANA Considerations 371 The following IANA assignment was made from an existing registry: 373 The OSPFv2 opaque LSA type 4 has been reserved for the OSPFv2 RI 374 opaque LSA. 376 The following registries have been defined for the following 377 purposes: 379 1. Registry for OSPFv3 LSA Function Codes - This new top-level 380 registry will be comprised of the fields Value, LSA function code 381 name, and Document Reference. The OSPFv3 LSA function code is 382 defined in section A.4.2.1 of [OSPFV3]. The OSPFv3 LSA function 383 code 12 has been reserved for the OSPFv3 Router Information (RI) 384 LSA. 386 +-----------+-------------------------------------+ 387 | Range | Assignment Policy | 388 +-----------+-------------------------------------+ 389 | 0 | Reserved (not to be assigned) | 390 | | | 391 | 1-9 | Already assigned | 392 | | | 393 | 10-11 | Unassigned (Standards Action) | 394 | | | 395 | 12 | OSPFv3 RI LSA (Assigned herein) | 396 | | | 397 | 13-255 | Unassigned (Standards Action) | 398 | | | 399 | 256-8175 | Reserved (No assignments) | 400 | | | 401 | 8176-8183 | Experimentation (No assignments) | 402 | | | 403 | 8184-8191 | Vendor Private Use (No assignments) | 404 +-----------+-------------------------------------+ 406 OSPFv3 LSA Function Codes 408 * OSPFv3 LSA function codes in the range 256-8175 are not to be 409 assigned at this time. Before any assignments can be made in 410 this range, there MUST be a Standards Track RFC that specifies 411 IANA Considerations that cover the range being assigned. 413 * OSPFv3 LSA function codes in the range 8176-8181 are for 414 experimental use; these will not be registered with IANA and 415 MUST NOT be mentioned by RFCs. 417 * OSPFv3 LSAs with an LSA Function Code in the Vendor Private 418 Use range 8184-8191 MUST include the Vendor Enterprise Code as 419 the first 4 octets following the 20 octets of LSA header. 421 * If a new LSA Function Code is documented, the documentation 422 MUST include the valid combinations of the U, S2, and S1 bits 423 for the LSA. It SHOULD also describe how the Link State ID is 424 to be assigned. 426 2. Registry for OSPF RI TLVs - This top-level registry will be 427 comprised of the fields Value, TLV Name, and Document Reference. 428 The value of 1 for the capabilities TLV is defined herein. 430 +-------------+-----------------------------------+ 431 | Range | Assignment Policy | 432 +-------------+-----------------------------------+ 433 | 0 | Reserved (not to be assigned) | 434 | | | 435 | 1 | Already assigned | 436 | | | 437 | 2-32767 | Unassigned (Standards Action) | 438 | | | 439 | 32768-32777 | Experimentation (No assignements) | 440 | | | 441 | 32778-65535 | Reserved (Not to be assigned) | 442 +-----------+-------------------------------------+ 444 OSPF RI TLVs 446 * Types in the range 32768-32777 are for experimental use; these 447 will not be registered with IANA and MUST NOT be mentioned by 448 RFCs. 450 * Types in the range 32778-65535 are reserved and are not to be 451 assigned at this time. Before any assignments can be made in 452 this range, there MUST be a Standards Track RFC that specifies 453 IANA Considerations that covers the range being assigned. 455 3. Registry for OSPF Router Informational Capability Bits - This 456 sub-registry of the OSPF RI TLV registry will be comprised of the 457 fields Bit Number, Capability Name, and Document Reference. The 458 values are defined in Section 2.4. All Router Informational 459 Capability TLV additions are to be assigned through standards 460 action. 462 4. Registry for OSPF Router Functional Capability Bits - This sub- 463 registry of the OSPF RI TLV registry will be comprised of the 464 fields Bit Number, Capability Name, and Document Reference. 465 Initially, the sub-registry will be empty but will be available 466 for future capabilities. All Router Functional Capability TLV 467 additions are to be assigned through standards action. 469 5. References 471 5.1. Normative References 473 [OPAQUE] Berger, L., Bryskin, I., Zinin, A., and R. Coltun, "The 474 OSPF Opaque LSA Option", RFC 5250, July 2008. 476 [OSPF] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998. 478 [OSPFV3] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF 479 for IPv6", RFC 5340, July 2008. 481 [RFC-KEYWORDS] 482 Bradner, S., "Key words for use in RFC's to Indicate 483 Requirement Levels", BCP 14, RFC 2119, March 1997. 485 [RFC4970] Lindem, A., Shen, N., Vasseur, J., Aggarwal, R., and S. 486 Shaffer, "Extensions to OSPF for Advertising Optional 487 Router Capabilities", RFC 4970, July 2007. 489 [TE] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 490 Extensions to OSPF", RFC 3630, September 2003. 492 5.2. Informative References 494 [EXP-TE] Srisuresh, P. and P. Joseph, "OSPF-xTE: Experimental 495 Extension to OSPF for Traffic Engineering", RFC 4973, July 496 2007. 498 [GRACE] Moy, J., Pillay-Esnault, P., and A. Lindem, "Graceful OSPF 499 Restart", RFC 3623, November 2003. 501 [P2PLAN] Shen, N. and A. Zinin, "Point-to-point operation over LAN 502 in link-state routing protocols", RFC 5309, October 2008. 504 [STUB] Retana, A., Nguyen, L., White, R., Zinin, A., and D. 505 McPherson, "OSPF Stub Router Advertisement", RFC 6987, 506 September 2013. 508 Appendix A. Acknowledgments 510 The idea for this work grew out of a conversation with Andrew Partan 511 and we would like to thank him for his contribution. The authors 512 would like to thanks Peter Psenak for his review and helpful comments 513 on early versions of the document. 515 Comments from Abhay Roy, Vishwas Manral, Vivek Dubey, and Adrian 516 Farrel have been incorporated into later versions. 518 The RFC text was produced using Marshall Rose's xml2rfc tool. 520 Authors' Addresses 521 Acee Lindem (editor) 522 Cisco Systems 523 301 Midenhall Way 524 Cary, NC 27513 525 USA 527 Email: acee@cisco.com 529 Naiming Shen 530 Cisco Systems 531 225 West Tasman Drive 532 San Jose, CA 95134 533 USA 535 Email: naiming@cisco.com 537 Jean-Philippe Vasseur 538 Cisco Systems 539 1414 Massachusetts Avenue 540 Boxborough, MA 01719 541 USA 543 Email: jpv@cisco.com 545 Rahul Aggarwal 546 Arktan 548 Email: raggarwa_1@yahoo.com 550 Scott Shaffer 551 Akamai 552 8 Cambridge Center 553 Cambridge, MA 02142 554 USA 556 Email: sshaffer@akamai.com