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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references to lower-maturity documents in RFCs) ** Downref: Normative reference to an Informational RFC: RFC 5714 == Outdated reference: A later version (-27) exists of draft-ietf-ospf-segment-routing-extensions-18 Summary: 1 error (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group P. Psenak 3 Internet-Draft A. Lindem 4 Intended status: Standards Track L. Ginsberg 5 Expires: February 22, 2018 Cisco Systems 6 W. Henderickx 7 Nokia 8 J. Tantsura 9 Individual 10 H. Gredler 11 RtBrick Inc. 12 August 21, 2017 14 OSPFv2 Link Traffic Engineering (TE) Attribute Reuse 15 draft-ietf-ospf-te-link-attr-reuse-00.txt 17 Abstract 19 Various link attributes have been defined in OSPFv2 in the context of 20 the MPLS Traffic Engineering (TE) and GMPLS. Many of these link 21 attributes can be used for purposes other than MPLS Traffic 22 Engineering or GMPLS. This documents defines how to distribute such 23 attributes in OSPFv2 for applications other than MPLS Traffic 24 Engineering or GMPLS purposes. 26 Status of This Memo 28 This Internet-Draft is submitted in full conformance with the 29 provisions of BCP 78 and BCP 79. 31 Internet-Drafts are working documents of the Internet Engineering 32 Task Force (IETF). Note that other groups may also distribute 33 working documents as Internet-Drafts. The list of current Internet- 34 Drafts is at http://datatracker.ietf.org/drafts/current/. 36 Internet-Drafts are draft documents valid for a maximum of six months 37 and may be updated, replaced, or obsoleted by other documents at any 38 time. It is inappropriate to use Internet-Drafts as reference 39 material or to cite them other than as "work in progress." 41 This Internet-Draft will expire on February 22, 2018. 43 Copyright Notice 45 Copyright (c) 2017 IETF Trust and the persons identified as the 46 document authors. All rights reserved. 48 This document is subject to BCP 78 and the IETF Trust's Legal 49 Provisions Relating to IETF Documents 50 (http://trustee.ietf.org/license-info) in effect on the date of 51 publication of this document. Please review these documents 52 carefully, as they describe your rights and restrictions with respect 53 to this document. Code Components extracted from this document must 54 include Simplified BSD License text as described in Section 4.e of 55 the Trust Legal Provisions and are provided without warranty as 56 described in the Simplified BSD License. 58 This document may contain material from IETF Documents or IETF 59 Contributions published or made publicly available before November 60 10, 2008. The person(s) controlling the copyright in some of this 61 material may not have granted the IETF Trust the right to allow 62 modifications of such material outside the IETF Standards Process. 63 Without obtaining an adequate license from the person(s) controlling 64 the copyright in such materials, this document may not be modified 65 outside the IETF Standards Process, and derivative works of it may 66 not be created outside the IETF Standards Process, except to format 67 it for publication as an RFC or to translate it into languages other 68 than English. 70 Table of Contents 72 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 73 1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3 74 2. Link attributes examples . . . . . . . . . . . . . . . . . . 3 75 3. Advertising Link Attributes . . . . . . . . . . . . . . . . . 4 76 3.1. TE Opaque LSA . . . . . . . . . . . . . . . . . . . . . . 4 77 3.2. Extended Link Opaque LSA . . . . . . . . . . . . . . . . 5 78 3.3. Selected Approach . . . . . . . . . . . . . . . . . . . . 5 79 4. Reused TE link attributes . . . . . . . . . . . . . . . . . . 6 80 4.1. Remote interface IP address . . . . . . . . . . . . . . . 6 81 4.2. Link Local/Remote Identifiers . . . . . . . . . . . . . . 6 82 4.3. Shared Risk Link Group (SRLG) . . . . . . . . . . . . . . 7 83 4.4. Extended Metrics . . . . . . . . . . . . . . . . . . . . 7 84 5. Advertisement of Application Specific Values . . . . . . . . 7 85 6. Deployment Considerations . . . . . . . . . . . . . . . . . . 10 86 7. Attribute Advertisements and Enablement . . . . . . . . . . . 10 87 8. Backward Compatibility . . . . . . . . . . . . . . . . . . . 11 88 9. Security Considerations . . . . . . . . . . . . . . . . . . . 11 89 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 90 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 91 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 92 12.1. Normative References . . . . . . . . . . . . . . . . . . 12 93 12.2. Informative References . . . . . . . . . . . . . . . . . 13 94 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 96 1. Introduction 98 Various link attributes have been defined in OSPFv2 [RFC2328] in the 99 context of the MPLS traffic engineering and GMPLS. All these 100 attributes are distributed by OSPFv2 as sub-TLVs of the Link-TLV 101 advertised in the OSPFv2 TE Opaque LSA [RFC3630]. 103 Many of these link attributes are useful outside of the traditional 104 MPLS Traffic Engineering or GMPLS. This brings its own set of 105 problems, in particular how to distribute these link attributes in 106 OSPFv2 when MPLS TE or GMPLS are not deployed or are deployed in 107 parallel with other applications that use these link attributes. 109 [RFC7855] discusses use cases/requirements for SR. Included among 110 these use cases is SRTE. If both RSVP-TE and SRTE are deployed in a 111 network, link attribute advertisements can be used by one or both of 112 these applications. As there is no requirement for the link 113 attributes advertised on a given link used by SRTE to be identical to 114 the link attributes advertised on that same link used by RSVP-TE, 115 there is a clear requirement to indicate independently which link 116 attribute advertisements are to be used by each application. 118 As the number of applications which may wish to utilize link 119 attributes may grow in the future, an additional requirement is that 120 the extensions defined allow the association of additional 121 applications to link attributes without altering the format of the 122 advertisements or introducing new backwards compatibility issues. 124 Finally, there may still be many cases where a single attribute value 125 can be shared among multiple applications, so the solution should 126 minimize advertising duplicate link/attribute when possible. 128 1.1. Requirements notation 130 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 131 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 132 document are to be interpreted as described in [RFC2119]. 134 2. Link attributes examples 136 This section lists some of the link attributes originally defined for 137 MPLS Traffic Engineering that can be used for other purposes in 138 OSPFv2. The list doesn't necessarily contain all the required 139 attributes. 141 1. Remote Interface IP address [RFC3630] - OSPFv2 currently cannot 142 distinguish between parallel links between two OSPFv2 routers. 143 As a result, the two-way connectivity check performed during SPF 144 may succeed when the two routers disagree on which of the links 145 to use for data traffic. 147 2. Link Local/Remote Identifiers - [RFC4203] - Used for the two-way 148 connectivity check for parallel unnumbered links. Also used for 149 identifying adjacencies for unnumbered links in Segment Routing 150 traffic engineering. 152 3. Shared Risk Link Group (SRLG) [RFC4203] - In IPFRR, the SRLG is 153 used to compute diverse backup paths [RFC5714]. 155 4. Unidirectional Link Delay/Loss Metrics [RFC7471] - Could be used 156 for the shortest path first (SPF) computation using alternate 157 metrics within an OSPF area. 159 3. Advertising Link Attributes 161 This section outlines possible approaches for advertising link 162 attributes originally defined for MPLS Traffic Engineering purposes 163 or GMPLS when they are used for other applications. 165 3.1. TE Opaque LSA 167 One approach for advertising link attributes is to continue to use TE 168 Opaque LSA ([RFC3630]). There are several problems with this 169 approach: 171 1. Whenever the link is advertised in a TE Opaque LSA, the link 172 becomes a part of the TE topology, which may not match IP routed 173 topology. By making the link part of the TE topology, remote 174 nodes may mistakenly believe that the link is available for MPLS 175 TE or GMPLS, when, in fact, MPLS is not enabled on the link. 177 2. The TE Opaque LSA carries link attributes that are not used or 178 required by MPLS TE or GMPLS. There is no mechanism in a TE 179 Opaque LSA to indicate which of the link attributes are passed to 180 MPLS TE application and which are used by other applications 181 including OSPFv2 itself. 183 3. Link attributes used for non-TE purposes are partitioned across 184 multiple LSAs - the TE Opaque LSA and the Extended Link Opaque 185 LSA. This partitioning will require implementations to lookup 186 multiple LSAs to extract link attributes for a single link, 187 bringing needless complexity to OSPFv2 implementations. 189 The advantage of this approach is that there is no additional 190 standardization requirement to advertise the TE/GMPL attributes for 191 other applications. Additionally, link attributes are only 192 advertised once when both OSPF TE and other applications are deployed 193 on the same link. This is not expected to be a common deployment 194 scenario. 196 3.2. Extended Link Opaque LSA 198 An alternative approach for advertising link attributes is to use 199 Extended Link Opaque LSAs as defined in [RFC7684]. This LSA was 200 defined as a generic container for distribution of the extended link 201 attributes. There are several advantages in using Extended Link LSA: 203 1. Advertisement of the link attributes does not make the link part 204 of the TE topology. It avoids any conflicts and is fully 205 compatible with the [RFC3630]. 207 2. The TE Opaque LSA remains truly opaque to OSPFv2 as originally 208 defined in [RFC3630]. Its content is not inspected by OSPFv2 and 209 OSPFv2 acts as a pure transport. 211 3. There is clear distinction between link attributes used by TE and 212 link attributes used by other OSPFv2 applications. 214 4. All link attributes that are used by OSPFv2 applications are 215 advertised in a single LSA, the Extended Link Opaque LSA. 217 The disadvantage of this approach is that in rare cases, the same 218 link attribute is advertised in both the TE Opaque and Extended Link 219 Attribute LSAs. Additionally, there will be additional 220 standardization effort. However, this could also be viewed as an 221 advantage as the non-TE use cases for the TE link attributes are 222 documented and validated by the OSPF working group. 224 3.3. Selected Approach 226 It is RECOMMENDED to use the Extended Link Opaque LSA ([RFC7684] to 227 advertise any link attributes used for non-TE purposes in OSPFv2, 228 including those that have been originally defined for TE purposes. 229 TE link attributes used for TE purposes continue to use TE Opaque LSA 230 ([RFC3630]). 232 It is also RECOMMENDED to keep the format of the link attribute TLVs 233 that have been defined for TE purposes unchanged even when they are 234 used for non-TE purposes. 236 Finally, it is RECOMMENDED to allocate unique code points for link 237 attribute TLVs that have been defined for TE purposes for the OSPFv2 238 Extended Link TLV Sub-TLV Registry as defined in [RFC7684]. For each 239 reused TLV, the code point will be defined in an IETF document along 240 with the expected usecase(s). 242 4. Reused TE link attributes 244 This section defines the use case and code points for the OSPFv2 245 Extended Link TLV Sub-TLV Registry for some of the link attributes 246 that have been originally defined for TE or GMPLS purposes. 248 4.1. Remote interface IP address 250 The OSPFv2 description of an IP numbered point-to-point adjacency 251 does not include the remote IP address. As described in Section 2, 252 this makes the two-way connectivity check ambiguous in the presence 253 of the parallel point-to-point links between two OSPFv2 routers. 255 The Remote IP address of the link can also be used for Segment 256 Routing traffic engineering to identify the link in a set of parallel 257 links between two OSPFv2 routers 258 [I-D.ietf-ospf-segment-routing-extensions]. Similarly, the remote IP 259 address is useful in identifying individual parallel OSPF links 260 advertised in BGP Link-State as described in 261 [I-D.ietf-idr-ls-distribution]. 263 To advertise the Remote interface IP address in the OSPFv2 Extended 264 Link TLV, the same format of the sub-TLV as defined in section 2.5.4. 265 of [RFC3630] is used and TLV type TBD1 is used. 267 4.2. Link Local/Remote Identifiers 269 The OSPFv2 description of an IP unnumbered point-to-point adjacency 270 does not include the remote link identifier. As described in 271 Section 2, this makes the two-way connectivity check ambiguous in the 272 presence of the parallel point-to-point IP unnumbered links between 273 two OSPFv2 routers. 275 The local and remote link identifiers can also be used for Segment 276 Routing traffic engineering to identify the link in a set of parallel 277 IP unnumbered links between two OSPFv2 routers 278 [I-D.ietf-ospf-segment-routing-extensions]. Similarly, these 279 identifiers are useful in identifying individual parallel OSPF links 280 advertised in BGP Link-State as described in 281 [I-D.ietf-idr-ls-distribution]. 283 To advertise the link Local/Remote identifiers in the OSPFv2 Extended 284 Link TLV, the same format of the sub-TLV as defined in section 1.1. 285 of [RFC4203] is used and TLV type TBD2 is used. 287 4.3. Shared Risk Link Group (SRLG) 289 The SRLG of a link can be used in IPFRR to compute a backup path that 290 does not share any SRLG group with the protected link. 292 To advertise the SRLG of the link in the OSPFv2 Extended Link TLV, 293 the same format of the sub-TLV as defined in section 1.3. of 294 [RFC4203] is used and TLV type TBD3 is used. 296 4.4. Extended Metrics 298 [RFC3630] defines several link bandwidth types. [RFC7471] defines 299 extended link metrics that are based on link bandwidth, delay and 300 loss characteristics. All these can be used to compute best paths 301 within an OSPF area to satisfy requirements for bandwidth, delay 302 (nominal or worst case) or loss. 304 To advertise extended link metrics in the OSPFv2 Extended Link TLV, 305 the same format of the sub-TLVs as defined in [RFC7471] is used with 306 following TLV types: 308 TBD4 - Unidirectional Link Delay 310 TBD5 - Min/Max Unidirectional Link Delay 312 TBD6 - Unidirectional Delay Variation 314 TBD7 - Unidirectional Link Loss 316 TBD8 - Unidirectional Residual Bandwidth 318 TBD9 - Unidirectional Available Bandwidth 320 TBD10 - Unidirectional Utilized Bandwidth 322 5. Advertisement of Application Specific Values 324 Multiple applications can utilize link attributes that are flooded by 325 OSPFv2. Some examples of applications using the link attributes are 326 Segment Routing Traffic Engineering and LFA [RFC5286]. 328 In some cases the link attribute only has a single value that is 329 applicable to all applications. An example is a Remote interface IP 330 address [Section 4.1] or Link Local/Remote Identifiers [Section 4.2]. 332 In some cases the link attribute MAY have different values for 333 different applications. An example could be SRLG [Section 4.3], 334 where values used by LFA could be different then the values used by 335 Segment Routing Traffic Engineering. 337 To allow advertisement of the application specific values of the link 338 attribute, a new Extended Link Attribute sub-TLV of the Extended Link 339 TLV [RFC7471] is defined. The Extended Link Attribute sub-TLV is an 340 optional sub-TLV and can appear multiple times in the Extended Link 341 TLV. It has following format: 343 0 1 2 3 344 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 1 345 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 346 | Type | Length | 347 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 348 | SABML | UDABML | Reserved | 349 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 350 | Standard Application Bit-Mask | 351 +- -+ 352 | ... | 353 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 354 | User Defined Application Bit-Mask | 355 +- -+ 356 | ... | 357 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 358 | Link Attribute sub-sub-TLVs | 359 +- -+ 360 | ... | 362 where: 364 Type: TBD11, suggested value 14 366 Length: variable 368 SABML: Standard Application Bit-Mask Length. If the Standard 369 Application Bit-Mask is not present, the Standard Application Bit- 370 Mask Length MUST be set to 0. 372 UDABML: User Defined Application Bit-Mask Length. If the User 373 Defined Application Bit-Mask is not present, the User Defined 374 Application Bit-Mask Length MUST be set to 0. 376 Standard Application Bit-Mask: Optional set of bits, where each 377 bit represents a single standard application. The following bits 378 are defined by this document: 380 Bit-0: RSVP Traffic Engineering 381 Bit-1: Segment Routing Traffic Engineering 383 Bit-2: Loop Free Alternate (LFA). Includes all LFA types. 385 User Defined Application Bit-Mask: Optional set of bits, where 386 each bit represents a single user defined application. 388 Standard Application Bits are defined/sent starting with Bit 0. 389 Additional bit definitions that may be defined in the future SHOULD 390 be assigned in ascending bit order so as to minimize the number of 391 octets that will need to be transmitted. 393 User Defined Application bits have no relationship to Standard 394 Application bits and are NOT managed by IANA or any other standards 395 body. It is recommended that bits are used starting with Bit 0 so as 396 to minimize the number of octets required to advertise all of them. 398 Undefined bits in both Bit-Masks MUST be transmitted as 0 and MUST be 399 ignored on receipt. Bits that are NOT transmitted MUST be treated as 400 if they are set to 0 on receipt. 402 If the link attribute advertisement is limited to be used by a 403 specific set of applications, corresponding Bit-Masks MUST be present 404 and application specific bit(s) MUST be set for all applications that 405 use the link attributes advertised in the Extended Link Attribute 406 sub-TLV. 408 Application Bit-Masks apply to all link attributes that support 409 application specific values and are advertised in the Extended Link 410 Attribute sub-TLV. 412 The advantage of not making the Application Bit-Masks part of the 413 attribute advertisement itself is that we can keep the format of the 414 link attributes that have been defined previously and reuse the same 415 format when advertising them in the Extended Link Attribute sub-TLV. 417 If the link attribute is advertised and there is no Application Bit- 418 Mask present in the Extended Link Attribute Sub-TLV, the link 419 attribute advertisement MAY be used by any application. If, however, 420 another advertisement of the same link attribute includes any 421 Application Bit-Mask in the Extended Link Attribute sub-TLV, 422 applications that are listed in the Application Bit-Masks of such 423 Extended Link Attribute sub-TLV SHOULD use the attribute 424 advertisement which has the application specific bit set in the 425 Application Bit-Masks. 427 If the same application is listed in the Application Bit-Masks of 428 more then one Extended Link Attribute sub-TLV, the application SHOULD 429 use the first advertisement and ignore any subsequent advertisements 430 of the same attribute. This situation SHOULD be logged as an error. 432 This document defines the set of link attributes for which the 433 Application Bit-Masks may be advertised. If any of the Application 434 Bit-Masks is included in the Extended Link Attribute sub-TLV that 435 advertises any link attribute(s) NOT listed below, the Application 436 Bit-Masks MUST NOT be used for such link attribute(s). It MUST be 437 used for those attribute(s) that support application specific values. 438 Documents which define new link attributes MUST state whether the new 439 attributes support application specific values. The link attributes 440 to which the Application Bit-Masks may apply are: 442 - Shared Risk Link Group 444 - Unidirectional Link Delay 446 - Min/Max Unidirectional Link Delay 448 - Unidirectional Delay Variation 450 - Unidirectional Link Loss 452 - Unidirectional Residual Bandwidth 454 - Unidirectional Available Bandwidth 456 - Unidirectional Utilized Bandwidth 458 6. Deployment Considerations 460 If link attributes are advertised associated with zero length 461 application bit masks for both standard applications and user defined 462 applications, then that set of link attributes MAY be used by any 463 application. If support for a new application is introduced on any 464 node in a network in the presence of such advertisements, these 465 advertisements MAY be used by the new application. If this is not 466 what is intended, then existing advertisements MUST be readvertised 467 with an explicit set of applications specified before a new 468 application is introduced. 470 7. Attribute Advertisements and Enablement 472 This document defines extensions to support the advertisement of 473 application specific link attributes. The presence or absence of 474 link attribute advertisements for a given application on a link does 475 NOT indicate the state of enablement of that application on that 476 link. Enablement of an application on a link is controlled by other 477 means. 479 For some applications, the concept of enablement is implicit. For 480 example, SRTE implicitly is enabled on all links which are part of 481 the Segment Routing enabled topology. Advertisement of link 482 attributes supports constraints which may be applied when specifying 483 an explicit path through that topology. 485 For other applications enablement is controlled by local 486 configuration. For example, use of a link as an LFA can be 487 controlled by local enablement/disablement and/or the use of 488 administrative tags. 490 It is an application specific policy as to whether a given link can 491 be used by that application even in the absence of any application 492 specific link attributes. 494 8. Backward Compatibility 496 Link attributes may be concurrently advertised in both the TE Opaque 497 LSA [RFC3630] and the Extended Link Opaque LSA [RFC7684]. 499 In fact, there is at least one OSPF implementation that utilizes the 500 link attributes advertised in TE Opaque LSAs [RFC3630] for Non-RSVP 501 TE applications. For example, this implementation of LFA and remote 502 LFA utilizes links attributes such as Shared Risk Link Groups (SRLG) 503 [RFC4203] and Admin Group [[RFC3630]advertised in TE Opaque LSAs. 504 These applications are described in [RFC5286], [RFC7490], 505 [I-D.ietf-rtgwg-lfa-manageability] and 506 [I-D.psarkar-rtgwg-rlfa-node-protection]. 508 When an OSPF routing domain includes routers using link attributes 509 from TE Opaque LSAs for Non-RSVP TE applications such as LFA, OSPF 510 routers in that domain should continue to advertise such TE Opaque 511 LSAs. If there are also OSPF routers using the link attributes 512 described herein for any application, OSPF routers in the routing 513 domain will also need to advertise these attributes in OSPF Extended 514 Link Attributes LSAs [RFC7684]. In such a deployment, the advertised 515 attributes SHOULD be the same and Non-RSVP application access to link 516 attributes is a matter of local policy. 518 9. Security Considerations 520 Implementations must assure that malformed TLV and Sub-TLV 521 permutations do not result in errors that cause hard OSPFv2 failures. 523 10. IANA Considerations 525 OSPFv2 Extended Link TLV Sub-TLVs registry [RFC7684] defines sub-TLVs 526 at any level of nesting for OSPFv2 Extended Link TLVs. This 527 specification updates OSPFv2 Extended Link TLV sub-TLVs registry with 528 the following TLV types: 530 TBD1 (4 Recommended) - Remote interface IP address 532 TBD2 (5 Recommended) - Link Local/Remote Identifiers 534 TBD3 (6 Recommended) - Shared Risk Link Group 536 TBD4 (7 Recommended) - Unidirectional Link Delay 538 TBD5 (8 Recommended) - Min/Max Unidirectional Link Delay 540 TBD6 (9 Recommended) - Unidirectional Delay Variation 542 TBD7 (10 Recommended) - Unidirectional Link Loss 544 TBD8 (11 Recommended) - Unidirectional Residual Bandwidth 546 TBD9 (12 Recommended) - Unidirectional Available Bandwidth 548 TBD10 (13 Recommended) - Unidirectional Utilized Bandwidth 550 TBD11 (14 Recommended) - Extended Link Attribute 552 This specification defines a new Link-Attribute-Applicability 553 Application Bits registry and defines following bits: 555 Bit-0 - Segment Routing Traffic Engineering 557 Bit-1 - LFA 559 11. Acknowledgments 561 Thanks to Chris Bowers for his review and comments. 563 12. References 565 12.1. Normative References 567 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 568 Requirement Levels", BCP 14, RFC 2119, 569 DOI 10.17487/RFC2119, March 1997, . 572 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 573 (TE) Extensions to OSPF Version 2", RFC 3630, 574 DOI 10.17487/RFC3630, September 2003, . 577 [RFC5714] Shand, M. and S. Bryant, "IP Fast Reroute Framework", 578 RFC 5714, DOI 10.17487/RFC5714, January 2010, 579 . 581 [RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W., 582 Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute 583 Advertisement", RFC 7684, DOI 10.17487/RFC7684, November 584 2015, . 586 12.2. Informative References 588 [I-D.ietf-idr-ls-distribution] 589 Gredler, H., Medved, J., Previdi, S., Farrel, A., and S. 590 Ray, "North-Bound Distribution of Link-State and TE 591 Information using BGP", draft-ietf-idr-ls-distribution-13 592 (work in progress), October 2015. 594 [I-D.ietf-ospf-segment-routing-extensions] 595 Psenak, P., Previdi, S., Filsfils, C., Gredler, H., 596 Shakir, R., Henderickx, W., and J. Tantsura, "OSPF 597 Extensions for Segment Routing", draft-ietf-ospf-segment- 598 routing-extensions-18 (work in progress), July 2017. 600 [I-D.ietf-rtgwg-lfa-manageability] 601 Litkowski, S., Decraene, B., Filsfils, C., Raza, K., and 602 M. Horneffer, "Operational management of Loop Free 603 Alternates", draft-ietf-rtgwg-lfa-manageability-11 (work 604 in progress), June 2015. 606 [I-D.psarkar-rtgwg-rlfa-node-protection] 607 psarkar@juniper.net, p., Gredler, H., Hegde, S., Bowers, 608 C., Litkowski, S., and H. Raghuveer, "Remote-LFA Node 609 Protection and Manageability", draft-psarkar-rtgwg-rlfa- 610 node-protection-05 (work in progress), June 2014. 612 [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, 613 DOI 10.17487/RFC2328, April 1998, . 616 [RFC4203] Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in 617 Support of Generalized Multi-Protocol Label Switching 618 (GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005, 619 . 621 [RFC5286] Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for 622 IP Fast Reroute: Loop-Free Alternates", RFC 5286, 623 DOI 10.17487/RFC5286, September 2008, . 626 [RFC7471] Giacalone, S., Ward, D., Drake, J., Atlas, A., and S. 627 Previdi, "OSPF Traffic Engineering (TE) Metric 628 Extensions", RFC 7471, DOI 10.17487/RFC7471, March 2015, 629 . 631 [RFC7490] Bryant, S., Filsfils, C., Previdi, S., Shand, M., and N. 632 So, "Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)", 633 RFC 7490, DOI 10.17487/RFC7490, April 2015, 634 . 636 [RFC7855] Previdi, S., Ed., Filsfils, C., Ed., Decraene, B., 637 Litkowski, S., Horneffer, M., and R. Shakir, "Source 638 Packet Routing in Networking (SPRING) Problem Statement 639 and Requirements", RFC 7855, DOI 10.17487/RFC7855, May 640 2016, . 642 Authors' Addresses 644 Peter Psenak 645 Cisco Systems 646 Apollo Business Center 647 Mlynske nivy 43 648 Bratislava, 821 09 649 Slovakia 651 Email: ppsenak@cisco.com 653 Acee Lindem 654 Cisco Systems 655 301 Midenhall Way 656 Cary, NC 27513 657 USA 659 Email: acee@cisco.com 660 Les Ginsberg 661 Cisco Systems 662 821 Alder Drive 663 MILPITAS, CA 95035 664 USA 666 Email: ginsberg@cisco.com 668 Wim Henderickx 669 Nokia 670 Copernicuslaan 50 671 Antwerp, 2018 94089 672 Belgium 674 Email: wim.henderickx@nokia.com 676 Jeff Tantsura 677 Individual 678 USA 680 Email: jefftant.ietf@gmail.com 682 Hannes Gredler 683 RtBrick Inc. 685 Email: hannes@rtbrick.com