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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 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: February 1, 2015 R. Aggarwal 7 Arktan 8 S. Shaffer 9 Akamai 10 July 31, 2014 12 Extensions to OSPF for Advertising Optional Router Capabilities 13 draft-acee-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 February 1, 2015. 48 Copyright Notice 49 Copyright (c) 2014 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents 54 (http://trustee.ietf.org/license-info) in effect on the date of 55 publication of this document. Please review these documents 56 carefully, as they describe your rights and restrictions with respect 57 to this document. Code Components extracted from this document must 58 include Simplified BSD License text as described in Section 4.e of 59 the Trust Legal Provisions and are provided without warranty as 60 described in the Simplified BSD License. 62 Table of Contents 64 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 65 1.1. Requirements Notation . . . . . . . . . . . . . . . . . . 3 66 1.2. Summary of Changes from RFC 4970 . . . . . . . . . . . . . 3 67 2. OSPF Router Information (RI) LSA . . . . . . . . . . . . . . . 4 68 2.1. OSPFv2 Router Information (RI) Opaque LSA . . . . . . . . 4 69 2.2. OSPFv3 Router Information (RI) Opaque LSA . . . . . . . . 6 70 2.3. OSPF Router Informational Capabilities TLV . . . . . . . . 6 71 2.4. Assigned OSPF Router Informational Capability Bits . . . . 8 72 2.5. OSPF Router Functional Capabilities TLV . . . . . . . . . 8 73 2.6. Flooding Scope of the Router Information LSA . . . . . . . 9 74 3. Security Considerations . . . . . . . . . . . . . . . . . . . 11 75 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 76 5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 15 77 5.1. Normative References . . . . . . . . . . . . . . . . . . . 15 78 5.2. Informative References . . . . . . . . . . . . . . . . . . 15 79 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 16 80 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 17 82 1. Introduction 84 It is useful for routers in an OSPFv2 [OSPF] or OSPFv3 [OSPFV3] 85 routing domain to know the capabilities of their neighbors and other 86 routers in the routing domain. This can be useful for both the 87 advertisement and discovery of OSPFv2 and OSPFv3 capabilities. 88 Throughout this document, OSPF will be used when the specification is 89 applicable to both OSPFv2 and OSPFv3. Similarly, OSPFv2 or OSPFv3 90 will be used when the text is protocol specific. 92 OSPF uses the options field in LSAs and hello packets to advertise 93 optional router capabilities. In the case of OSPFv2, all the bits in 94 this field have been allocated so new optional capabilities cannot be 95 advertised. This document proposes extensions to OSPF to advertise 96 these optional capabilities via opaque LSAs in OSPFv2 and new LSAs in 97 OSPFv3. For existing OSPF capabilities, backward-compatibility 98 issues dictate that this advertisement is used primarily for 99 informational purposes. For future OSPF extensions, this 100 advertisement MAY be used as the sole mechanism for advertisement and 101 discovery. 103 This document obsoletes RFC 4970 by providing a revised specification 104 including support for advertisement of multiple instances of the RI 105 LSA and a TLV for functional capabilities. 107 1.1. Requirements Notation 109 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 110 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 111 document are to be interpreted as described in [RFC-KEYWORDS]. 113 1.2. Summary of Changes from RFC 4970 115 This document includes the following changes from RFC 4970 [RFC4970]: 117 1. The main change is that an OSPF router will be able to advertise 118 multiple instances of the OSPF Router Information LSA. This 119 change permeates through much of the document 121 2. Additionally, Section 2.5 includes a new TLV for functional 122 capabilities. This is constast to the existing TLV which is used 123 to advertise capabilities for informational purposes only. 125 3. Finally, references have been updated for drafts that have become 126 RFCs and RFCs that have been obseleted since the publication of 127 RFC 4970. 129 2. OSPF Router Information (RI) LSA 131 OSPFv2 routers will advertise a link scoped, area-scoped, or AS- 132 scoped Opaque-LSA [OPAQUE]. The OSPFv2 Router Information LSA has an 133 Opaque type of 4 and Opaque ID is the instance ID. The first 134 instance ID, i.e., 0, should always contain the Router Informational 135 Capabilities TLV and, if advertised, the Router Functional 136 Capabilities TLV. RI Information LSAs subsequence to the first can 137 be used for information which doesn't fit in the first instance. 139 2.1. OSPFv2 Router Information (RI) Opaque LSA 141 OSPFv2 routers will advertise a link scoped, area-scoped, or AS- 142 scoped Opaque-LSA [OPAQUE]. The OSPFv2 Router Information LSA has an 143 Opaque type of 4 and Opaque ID specifies the LSA instance ID with the 144 first instance always having an Instance ID of 0. 146 0 1 2 3 147 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 1 148 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 149 | LS age | Options | 9, 10, or 11 | 150 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 151 | 4 | Opaque ID (Instance ID) | 152 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 153 | Advertising Router | 154 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 155 | LS sequence number | 156 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 157 | LS checksum | length | 158 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 159 | | 160 +- TLVs -+ 161 | ... | 163 OSPFv2 Router Information Opaque LSA 165 The format of the TLVs within the body of an RI LSA is the same as 166 the format used by the Traffic Engineering Extensions to OSPF [TE]. 167 The LSA payload consists of one or more nested Type/Length/Value 168 (TLV) triplets. The format of each TLV is: 170 0 1 2 3 171 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 1 172 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 173 | Type | Length | 174 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 175 | Value... | 176 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 178 TLV Format 180 The Length field defines the length of the value portion in octets 181 (thus a TLV with no value portion would have a length of 0). The TLV 182 is padded to 4-octet alignment; padding is not included in the length 183 field (so a 3-octet value would have a length of 3, but the total 184 size of the TLV would be 8 octets). Nested TLVs are also 32-bit 185 aligned. For example, a 1-byte value would have the length field set 186 to 1, and 3 octets of padding would be added to the end of the value 187 portion of the TLV. Unrecognized types are ignored. 189 2.2. OSPFv3 Router Information (RI) Opaque LSA 191 The OSPFv3 Router Information LSA has a function code of 12 while the 192 S1/S2 bits are dependent on the desired flooding scope for the LSA. 193 The U bit will be set indicating that the OSPFv3 RI LSA should be 194 flooded even if it is not understood. The Link State ID (LSID) value 195 for this LSA is the instance ID. The first instance ID, i.e., 0, 196 should always contain the Router Informational Capabilities TLV and, 197 if advertised, the Router Functional Capabilities TLV. OSPFv3 Router 198 Information LSAs subsequence to the first can be used for information 199 which doesn't fit in the first instance. OSPFv3 routers MAY 200 advertise multiple RIs LSA per flooding scope. 202 0 1 2 3 203 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 1 204 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 205 | LS age |1|S12| 12 | 206 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 207 | Link State ID (Instance ID) | 208 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 209 | Advertising Router | 210 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 211 | LS sequence number | 212 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 213 | LS checksum | Length | 214 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 215 | | 216 +- TLVs -+ 217 | ... | 219 OSPFv3 Router Information LSA 221 The format of the TLVs within the body of an RI LSA is as defined in 222 Section 2.1 224 When a new Router Information LSA TLV is defined, the specification 225 MUST explicitly state whether the TLV is applicable to OSPFv2 only, 226 OSPFv3 only, or both OSPFv2 and OSPFv3. 228 2.3. OSPF Router Informational Capabilities TLV 230 The first defined TLV in the body of an RI LSA is the Router 231 Informational Capabilities TLV. An OSPF router advertising an OSPF 232 RI LSA MAY include the Router Informational Capabilities TLV. If 233 included, it MUST be the first TLV in the first instance of the OSPF 234 RI LSA. Additionally, the TLV MUST accurately reflect the OSPF 235 router's capabilities in the scope advertised. However, the 236 informational capabilities advertised have no impact on the OSPF's 237 operation -- they are advertised purely for informational purposes. 239 The format of the Router Informational Capabilities TLV is as 240 follows: 242 0 1 2 3 243 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 1 244 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 245 | Type | Length | 246 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 247 | Informational Capabilities | 248 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 250 Type A 16-bit field set to 1. 252 Length A 16-bit field that indicates the length of the value 253 portion in octets and will be a multiple of 4 octets 254 dependent on the number of capabilities advertised. 255 Initially, the length will be 4, denoting 4 octets of 256 informational capability bits. 258 Value A variable length sequence of capability bits rounded 259 to a multiple of 4 octets padded with undefined bits. 260 Initially, there are 4 octets of capability bits. Bits 261 are numbered left-to-right starting with the most 262 significant bit being bit 0. 264 OSPF Router Informational Capabilities TLV 266 The Router Informational Capabilities TLV MAY be followed by optional 267 TLVs that further specify a capability. 269 2.4. Assigned OSPF Router Informational Capability Bits 271 The following informational capability bits are assigned: 273 Bit Capabilities 275 0 OSPF graceful restart capable [GRACE] 276 1 OSPF graceful restart helper [GRACE] 277 2 OSPF Stub Router support [STUB] 278 3 OSPF Traffic Engineering support [TE] 279 4 OSPF point-to-point over LAN [P2PLAN] 280 5 OSPF Experimental TE [EXP-TE] 281 6-31 Unassigned (Standards Action) 283 OSPF Router Informational Capabilities Bits 285 References for [GRACE], [STUB], [TE], [P2PLAN], and [EXP-TE] are 286 included herein. 288 2.5. OSPF Router Functional Capabilities TLV 290 This specification also defines the Router Functional Capabilities 291 TLV for advertisement within the OSPF Router Information LSA. An 292 OSPF router advertising an OSPF RI LSA MAY include the Router 293 Functional Capabilities TLV. If included, it MUST be the included in 294 the first instance of the LSA. Additionally, the TLV MUST be used to 295 reflect OSPF router functional capabilities. If the TLV is not 296 included or the length doesn't include the assigned OSPF functional 297 capability bit, the corresponding OSPF functional capabilty is 298 implicitly advertised as not being support by the advertising OSPF 299 router. 301 The format of the Router Functional Capabilities TLV is as follows: 303 0 1 2 3 304 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 1 305 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 306 | Type | Length | 307 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 308 | Functional Capabilities | 309 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 311 Type A 16-bit field set to 1. 313 Length A 16-bit field that indicates the length of the value 314 portion in octets and will be a multiple of 4 octets 315 dependent on the number of capabilities advertised. 316 Initially, the length will be 4, denoting 4 octets of 317 informational capability bits. 319 Value A variable length sequence of capability bits rounded 320 to a multiple of 4 octets padded with undefined bits. 321 Initially, there are 4 octets of capability bits. Bits 322 are numbered left-to-right starting with the most 323 significant bit being bit 0. 325 OSPF Router Functional Capabilities TLV 327 The Router Functional Capabilities TLV MAY be followed by optional 328 TLVs that further specify a capability. In contrast to the Router 329 Informatioal Capabilities TLV, the OSPF extensions advertised in this 330 TLV MAY be used to by other OSPF routers to dicate protocol 331 operation. The specifications for functional capabilities 332 adveritised in this TLV MUST describe protocol behavior and address 333 backward compatibility. 335 2.6. Flooding Scope of the Router Information LSA 337 The flooding scope for a Router Information LSA is determined by the 338 LSA type. For OSPFv2, type 9 (link-scoped), type 10 (area-scoped), 339 or a type 11 (AS-scoped) opaque LSA may be flooded. For OSPFv3, the 340 S1 and S2 bits in the LSA type determine the flooding scope. If AS- 341 wide flooding scope is chosen, the originating router should also 342 advertise area-scoped LSA(s) into any attached Not-So-Stubby Area 343 (NSSA) area(s). An OSPF router MAY advertise different capabilities 344 when both NSSA area scoped LSA(s) and an AS-scoped LSA are 345 advertised. This allows functional capabilities to be limited in 346 scope. For example, a router may be an area border router but only 347 support traffic engineering (TE) in a subset of its attached areas. 349 The choice of flooding scope is made by the advertising router and is 350 a matter of local policy. The originating router MAY advertise 351 multiple RI LSAs as long as the flooding scopes differ. TLV flooding 352 scope rules will be specified on a per-TLV basis and MUST be 353 specified in the accompanying specifications for new Router 354 Information LSA TLVs. 356 3. Security Considerations 358 This document describes both a generic mechanism for advertising 359 router capabilities and a TLV for advertising informational and 360 functional capability bits. The capability TLVs are less critical 361 than the topology information currently advertised by the base OSPF 362 protocol. The security considerations for the generic mechanism are 363 dependent on the future application and, as such, should be described 364 as additional capabilities are proposed for advertisement. Security 365 considerations for the base OSPF protocol are covered in [OSPF] and 366 [OSPFV3]. 368 4. IANA Considerations 370 The following IANA assignment was made from an existing registry: 372 The OSPFv2 opaque LSA type 4 has been reserved for the OSPFv2 RI 373 opaque LSA. 375 The following registries have been defined for the following 376 purposes: 378 1. Registry for OSPFv3 LSA Function Codes - This new top-level 379 registry will be comprised of the fields Value, LSA function code 380 name, and Document Reference. The OSPFv3 LSA function code is 381 defined in section A.4.2.1 of [OSPFV3]. The OSPFv3 LSA function 382 code 12 has been reserved for the OSPFv3 Router Information (RI) 383 LSA. 385 +-----------+-------------------------------------+ 386 | Range | Assignment Policy | 387 +-----------+-------------------------------------+ 388 | 0 | Reserved (not to be assigned) | 389 | | | 390 | 1-9 | Already assigned | 391 | | | 392 | 10-11 | Unassigned (Standards Action) | 393 | | | 394 | 12 | OSPFv3 RI LSA (Assigned herein) | 395 | | | 396 | 13-255 | Unassigned (Standards Action) | 397 | | | 398 | 256-8175 | Reserved (No assignments) | 399 | | | 400 | 8176-8183 | Experimentation (No assignments) | 401 | | | 402 | 8184-8191 | Vendor Private Use (No assignments) | 403 +-----------+-------------------------------------+ 405 OSPFv3 LSA Function Codes 407 * OSPFv3 LSA function codes in the range 256-8175 are not to be 408 assigned at this time. Before any assignments can be made in 409 this range, there MUST be a Standards Track RFC that specifies 410 IANA Considerations that cover the range being assigned. 412 * OSPFv3 LSA function codes in the range 8176-8181 are for 413 experimental use; these will not be registered with IANA and 414 MUST NOT be mentioned by RFCs. 416 * OSPFv3 LSAs with an LSA Function Code in the Vendor Private 417 Use range 8184-8191 MUST include the Vendor Enterprise Code as 418 the first 4 octets following the 20 octets of LSA header. 420 * If a new LSA Function Code is documented, the documentation 421 MUST include the valid combinations of the U, S2, and S1 bits 422 for the LSA. It SHOULD also describe how the Link State ID is 423 to be assigned. 425 2. Registry for OSPF RI TLVs - This top-level registry will be 426 comprised of the fields Value, TLV Name, and Document Reference. 427 The value of 1 for the capabilities TLV is defined herein. 429 +-------------+-----------------------------------+ 430 | Range | Assignment Policy | 431 +-------------+-----------------------------------+ 432 | 0 | Reserved (not to be assigned) | 433 | | | 434 | 1 | Already assigned | 435 | | | 436 | 2-32767 | Unassigned (Standards Action) | 437 | | | 438 | 32768-32777 | Experimentation (No assignements) | 439 | | | 440 | 32778-65535 | Reserved (Not to be assigned) | 441 +-----------+-------------------------------------+ 443 OSPF RI TLVs 445 * Types in the range 32768-32777 are for experimental use; these 446 will not be registered with IANA and MUST NOT be mentioned by 447 RFCs. 449 * Types in the range 32778-65535 are reserved and are not to be 450 assigned at this time. Before any assignments can be made in 451 this range, there MUST be a Standards Track RFC that specifies 452 IANA Considerations that covers the range being assigned. 454 3. Registry for OSPF Router Informational Capability Bits - This 455 sub-registry of the OSPF RI TLV registry will be comprised of the 456 fields Bit Number, Capability Name, and Document Reference. The 457 values are defined in Section 2.4. All Router Informational 458 Capability TLV additions are to be assigned through standards 459 action. 461 4. Registry for OSPF Router Functional Capability Bits - This sub- 462 registry of the OSPF RI TLV registry will be comprised of the 463 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, 496 July 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 522 Acee Lindem (editor) 523 Cisco Systems 524 301 Midenhall Way 525 Cary, NC 27513 526 USA 528 Email: acee@cisco.com 530 Naiming Shen 531 Cisco Systems 532 225 West Tasman Drive 533 San Jose, CA 95134 534 USA 536 Email: naiming@cisco.com 538 Jean-Philippe Vasseur 539 Cisco Systems 540 1414 Massachusetts Avenue 541 Boxborough, MA 01719 542 USA 544 Email: jpv@cisco.com 546 Rahul Aggarwal 547 Arktan 549 Email: raggarwa_1@yahoo.com 551 Scott Shaffer 552 Akamai 553 8 Cambridge Center 554 Cambridge, MA 02142 555 USA 557 Email: sshaffer@akamai.com