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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references to lower-maturity documents in RFCs) ** Downref: Normative reference to an Informational RFC: RFC 5714 == Outdated reference: A later version (-27) exists of draft-ietf-ospf-segment-routing-extensions-18 Summary: 1 error (**), 0 flaws (~~), 3 warnings (==), 1 comment (--).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 23, 2018 Cisco Systems 6 W. Henderickx 7 Nokia 8 J. Tantsura 9 Individual 10 H. Gredler 11 RtBrick Inc. 12 J. Drake 13 Juniper Networks 14 August 22, 2017 16 OSPFv2 Link Traffic Engineering (TE) Attribute Reuse 17 draft-ietf-ospf-te-link-attr-reuse-01.txt 19 Abstract 21 Various link attributes have been defined in OSPFv2 in the context of 22 the MPLS Traffic Engineering (TE) and GMPLS. Many of these link 23 attributes can be used for purposes other than MPLS Traffic 24 Engineering or GMPLS. This documents defines how to distribute such 25 attributes in OSPFv2 for applications other than MPLS Traffic 26 Engineering or GMPLS purposes. 28 Status of This Memo 30 This Internet-Draft is submitted in full conformance with the 31 provisions of BCP 78 and BCP 79. 33 Internet-Drafts are working documents of the Internet Engineering 34 Task Force (IETF). Note that other groups may also distribute 35 working documents as Internet-Drafts. The list of current Internet- 36 Drafts is at http://datatracker.ietf.org/drafts/current/. 38 Internet-Drafts are draft documents valid for a maximum of six months 39 and may be updated, replaced, or obsoleted by other documents at any 40 time. It is inappropriate to use Internet-Drafts as reference 41 material or to cite them other than as "work in progress." 43 This Internet-Draft will expire on February 23, 2018. 45 Copyright Notice 47 Copyright (c) 2017 IETF Trust and the persons identified as the 48 document authors. All rights reserved. 50 This document is subject to BCP 78 and the IETF Trust's Legal 51 Provisions Relating to IETF Documents 52 (http://trustee.ietf.org/license-info) in effect on the date of 53 publication of this document. Please review these documents 54 carefully, as they describe your rights and restrictions with respect 55 to this document. Code Components extracted from this document must 56 include Simplified BSD License text as described in Section 4.e of 57 the Trust Legal Provisions and are provided without warranty as 58 described in the Simplified BSD License. 60 This document may contain material from IETF Documents or IETF 61 Contributions published or made publicly available before November 62 10, 2008. The person(s) controlling the copyright in some of this 63 material may not have granted the IETF Trust the right to allow 64 modifications of such material outside the IETF Standards Process. 65 Without obtaining an adequate license from the person(s) controlling 66 the copyright in such materials, this document may not be modified 67 outside the IETF Standards Process, and derivative works of it may 68 not be created outside the IETF Standards Process, except to format 69 it for publication as an RFC or to translate it into languages other 70 than English. 72 Table of Contents 74 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 75 1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3 76 2. Link attributes examples . . . . . . . . . . . . . . . . . . 3 77 3. Advertising Link Attributes . . . . . . . . . . . . . . . . . 4 78 3.1. TE Opaque LSA . . . . . . . . . . . . . . . . . . . . . . 4 79 3.2. Extended Link Opaque LSA . . . . . . . . . . . . . . . . 5 80 3.3. Selected Approach . . . . . . . . . . . . . . . . . . . . 5 81 4. Reused TE link attributes . . . . . . . . . . . . . . . . . . 6 82 4.1. Remote interface IP address . . . . . . . . . . . . . . . 6 83 4.2. Link Local/Remote Identifiers . . . . . . . . . . . . . . 6 84 4.3. Shared Risk Link Group (SRLG) . . . . . . . . . . . . . . 7 85 4.4. Extended Metrics . . . . . . . . . . . . . . . . . . . . 7 86 5. Advertisement of Application Specific Values . . . . . . . . 7 87 6. Deployment Considerations . . . . . . . . . . . . . . . . . . 10 88 7. Attribute Advertisements and Enablement . . . . . . . . . . . 11 89 8. Backward Compatibility . . . . . . . . . . . . . . . . . . . 11 90 9. Security Considerations . . . . . . . . . . . . . . . . . . . 12 91 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 92 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 93 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 94 12.1. Normative References . . . . . . . . . . . . . . . . . . 13 95 12.2. Informative References . . . . . . . . . . . . . . . . . 13 96 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 98 1. Introduction 100 Various link attributes have been defined in OSPFv2 [RFC2328] in the 101 context of the MPLS traffic engineering and GMPLS. All these 102 attributes are distributed by OSPFv2 as sub-TLVs of the Link-TLV 103 advertised in the OSPFv2 TE Opaque LSA [RFC3630]. 105 Many of these link attributes are useful outside of the traditional 106 MPLS Traffic Engineering or GMPLS. This brings its own set of 107 problems, in particular how to distribute these link attributes in 108 OSPFv2 when MPLS TE or GMPLS are not deployed or are deployed in 109 parallel with other applications that use these link attributes. 111 [RFC7855] discusses use cases/requirements for SR. Included among 112 these use cases is SRTE. If both RSVP-TE and SRTE are deployed in a 113 network, link attribute advertisements can be used by one or both of 114 these applications. As there is no requirement for the link 115 attributes advertised on a given link used by SRTE to be identical to 116 the link attributes advertised on that same link used by RSVP-TE, 117 there is a clear requirement to indicate independently which link 118 attribute advertisements are to be used by each application. 120 As the number of applications which may wish to utilize link 121 attributes may grow in the future, an additional requirement is that 122 the extensions defined allow the association of additional 123 applications to link attributes without altering the format of the 124 advertisements or introducing new backwards compatibility issues. 126 Finally, there may still be many cases where a single attribute value 127 can be shared among multiple applications, so the solution should 128 minimize advertising duplicate link/attribute when possible. 130 1.1. Requirements notation 132 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 133 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 134 document are to be interpreted as described in [RFC2119]. 136 2. Link attributes examples 138 This section lists some of the link attributes originally defined for 139 MPLS Traffic Engineering that can be used for other purposes in 140 OSPFv2. The list doesn't necessarily contain all the required 141 attributes. 143 1. Remote Interface IP address [RFC3630] - OSPFv2 currently cannot 144 distinguish between parallel links between two OSPFv2 routers. 145 As a result, the two-way connectivity check performed during SPF 146 may succeed when the two routers disagree on which of the links 147 to use for data traffic. 149 2. Link Local/Remote Identifiers - [RFC4203] - Used for the two-way 150 connectivity check for parallel unnumbered links. Also used for 151 identifying adjacencies for unnumbered links in Segment Routing 152 traffic engineering. 154 3. Shared Risk Link Group (SRLG) [RFC4203] - In IPFRR, the SRLG is 155 used to compute diverse backup paths [RFC5714]. 157 4. Unidirectional Link Delay/Loss Metrics [RFC7471] - Could be used 158 for the shortest path first (SPF) computation using alternate 159 metrics within an OSPF area. 161 3. Advertising Link Attributes 163 This section outlines possible approaches for advertising link 164 attributes originally defined for MPLS Traffic Engineering purposes 165 or GMPLS when they are used for other applications. 167 3.1. TE Opaque LSA 169 One approach for advertising link attributes is to continue to use TE 170 Opaque LSA ([RFC3630]). There are several problems with this 171 approach: 173 1. Whenever the link is advertised in a TE Opaque LSA, the link 174 becomes a part of the TE topology, which may not match IP routed 175 topology. By making the link part of the TE topology, remote 176 nodes may mistakenly believe that the link is available for MPLS 177 TE or GMPLS, when, in fact, MPLS is not enabled on the link. 179 2. The TE Opaque LSA carries link attributes that are not used or 180 required by MPLS TE or GMPLS. There is no mechanism in a TE 181 Opaque LSA to indicate which of the link attributes are passed to 182 MPLS TE application and which are used by other applications 183 including OSPFv2 itself. 185 3. Link attributes used for non-TE purposes are partitioned across 186 multiple LSAs - the TE Opaque LSA and the Extended Link Opaque 187 LSA. This partitioning will require implementations to lookup 188 multiple LSAs to extract link attributes for a single link, 189 bringing needless complexity to OSPFv2 implementations. 191 The advantage of this approach is that there is no additional 192 standardization requirement to advertise the TE/GMPL attributes for 193 other applications. Additionally, link attributes are only 194 advertised once when both OSPF TE and other applications are deployed 195 on the same link. This is not expected to be a common deployment 196 scenario. 198 3.2. Extended Link Opaque LSA 200 An alternative approach for advertising link attributes is to use 201 Extended Link Opaque LSAs as defined in [RFC7684]. This LSA was 202 defined as a generic container for distribution of the extended link 203 attributes. There are several advantages in using Extended Link LSA: 205 1. Advertisement of the link attributes does not make the link part 206 of the TE topology. It avoids any conflicts and is fully 207 compatible with the [RFC3630]. 209 2. The TE Opaque LSA remains truly opaque to OSPFv2 as originally 210 defined in [RFC3630]. Its content is not inspected by OSPFv2 and 211 OSPFv2 acts as a pure transport. 213 3. There is clear distinction between link attributes used by TE and 214 link attributes used by other OSPFv2 applications. 216 4. All link attributes that are used by OSPFv2 applications are 217 advertised in a single LSA, the Extended Link Opaque LSA. 219 The disadvantage of this approach is that in rare cases, the same 220 link attribute is advertised in both the TE Opaque and Extended Link 221 Attribute LSAs. Additionally, there will be additional 222 standardization effort. However, this could also be viewed as an 223 advantage as the non-TE use cases for the TE link attributes are 224 documented and validated by the OSPF working group. 226 3.3. Selected Approach 228 It is RECOMMENDED to use the Extended Link Opaque LSA ([RFC7684] to 229 advertise any link attributes used for non-TE purposes in OSPFv2, 230 including those that have been originally defined for TE purposes. 231 TE link attributes used for TE purposes continue to use TE Opaque LSA 232 ([RFC3630]). 234 It is also RECOMMENDED to keep the format of the link attribute TLVs 235 that have been defined for TE purposes unchanged even when they are 236 used for non-TE purposes. 238 Finally, it is RECOMMENDED to allocate unique code points for link 239 attribute TLVs that have been defined for TE purposes for the OSPFv2 240 Extended Link TLV Sub-TLV Registry as defined in [RFC7684]. For each 241 reused TLV, the code point will be defined in an IETF document along 242 with the expected usecase(s). 244 4. Reused TE link attributes 246 This section defines the use case and code points for the OSPFv2 247 Extended Link TLV Sub-TLV Registry for some of the link attributes 248 that have been originally defined for TE or GMPLS purposes. 250 4.1. Remote interface IP address 252 The OSPFv2 description of an IP numbered point-to-point adjacency 253 does not include the remote IP address. As described in Section 2, 254 this makes the two-way connectivity check ambiguous in the presence 255 of the parallel point-to-point links between two OSPFv2 routers. 257 The Remote IP address of the link can also be used for Segment 258 Routing traffic engineering to identify the link in a set of parallel 259 links between two OSPFv2 routers 260 [I-D.ietf-ospf-segment-routing-extensions]. Similarly, the remote IP 261 address is useful in identifying individual parallel OSPF links 262 advertised in BGP Link-State as described in 263 [I-D.ietf-idr-ls-distribution]. 265 To advertise the Remote interface IP address in the OSPFv2 Extended 266 Link TLV, the same format of the sub-TLV as defined in section 2.5.4. 267 of [RFC3630] is used and TLV type TBD1 is used. 269 4.2. Link Local/Remote Identifiers 271 The OSPFv2 description of an IP unnumbered point-to-point adjacency 272 does not include the remote link identifier. As described in 273 Section 2, this makes the two-way connectivity check ambiguous in the 274 presence of the parallel point-to-point IP unnumbered links between 275 two OSPFv2 routers. 277 The local and remote link identifiers can also be used for Segment 278 Routing traffic engineering to identify the link in a set of parallel 279 IP unnumbered links between two OSPFv2 routers 280 [I-D.ietf-ospf-segment-routing-extensions]. Similarly, these 281 identifiers are useful in identifying individual parallel OSPF links 282 advertised in BGP Link-State as described in 283 [I-D.ietf-idr-ls-distribution]. 285 To advertise the link Local/Remote identifiers in the OSPFv2 Extended 286 Link TLV, the same format of the sub-TLV as defined in section 1.1. 287 of [RFC4203] is used and TLV type TBD2 is used. 289 4.3. Shared Risk Link Group (SRLG) 291 The SRLG of a link can be used in IPFRR to compute a backup path that 292 does not share any SRLG group with the protected link. 294 To advertise the SRLG of the link in the OSPFv2 Extended Link TLV, 295 the same format of the sub-TLV as defined in section 1.3. of 296 [RFC4203] is used and TLV type TBD3 is used. 298 4.4. Extended Metrics 300 [RFC3630] defines several link bandwidth types. [RFC7471] defines 301 extended link metrics that are based on link bandwidth, delay and 302 loss characteristics. All these can be used to compute best paths 303 within an OSPF area to satisfy requirements for bandwidth, delay 304 (nominal or worst case) or loss. 306 To advertise extended link metrics in the OSPFv2 Extended Link TLV, 307 the same format of the sub-TLVs as defined in [RFC7471] is used with 308 following TLV types: 310 TBD4 - Unidirectional Link Delay 312 TBD5 - Min/Max Unidirectional Link Delay 314 TBD6 - Unidirectional Delay Variation 316 TBD7 - Unidirectional Link Loss 318 TBD8 - Unidirectional Residual Bandwidth 320 TBD9 - Unidirectional Available Bandwidth 322 TBD10 - Unidirectional Utilized Bandwidth 324 5. Advertisement of Application Specific Values 326 Multiple applications can utilize link attributes that are flooded by 327 OSPFv2. Some examples of applications using the link attributes are 328 Segment Routing Traffic Engineering and LFA [RFC5286]. 330 In some cases the link attribute only has a single value that is 331 applicable to all applications. An example is a Remote interface IP 332 address [Section 4.1] or Link Local/Remote Identifiers [Section 4.2]. 334 In some cases the link attribute MAY have different values for 335 different applications. An example could be SRLG [Section 4.3], 336 where values used by LFA could be different then the values used by 337 Segment Routing Traffic Engineering. 339 To allow advertisement of the application specific values of the link 340 attribute, a new Extended Link Attribute sub-TLV of the Extended Link 341 TLV [RFC7471] is defined. The Extended Link Attribute sub-TLV is an 342 optional sub-TLV and can appear multiple times in the Extended Link 343 TLV. It has following format: 345 0 1 2 3 346 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 1 347 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 348 | Type | Length | 349 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 350 | SABML | UDABML | Reserved | 351 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 352 | Standard Application Bit-Mask | 353 +- -+ 354 | ... | 355 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 356 | User Defined Application Bit-Mask | 357 +- -+ 358 | ... | 359 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 360 | Link Attribute sub-sub-TLVs | 361 +- -+ 362 | ... | 364 where: 366 Type: TBD11, suggested value 14 368 Length: variable 370 SABML: Standard Application Bit-Mask Length. If the Standard 371 Application Bit-Mask is not present, the Standard Application Bit- 372 Mask Length MUST be set to 0. 374 UDABML: User Defined Application Bit-Mask Length. If the User 375 Defined Application Bit-Mask is not present, the User Defined 376 Application Bit-Mask Length MUST be set to 0. 378 Standard Application Bit-Mask: Optional set of bits, where each 379 bit represents a single standard application. The following bits 380 are defined by this document: 382 Bit-0: RSVP Traffic Engineering 384 Bit-1: Segment Routing Traffic Engineering 386 Bit-2: Loop Free Alternate (LFA). Includes all LFA types. 388 User Defined Application Bit-Mask: Optional set of bits, where 389 each bit represents a single user defined application. 391 Standard Application Bits are defined/sent starting with Bit 0. 392 Additional bit definitions that may be defined in the future SHOULD 393 be assigned in ascending bit order so as to minimize the number of 394 octets that will need to be transmitted. 396 User Defined Application bits have no relationship to Standard 397 Application bits and are NOT managed by IANA or any other standards 398 body. It is recommended that bits are used starting with Bit 0 so as 399 to minimize the number of octets required to advertise all of them. 401 Undefined bits in both Bit-Masks MUST be transmitted as 0 and MUST be 402 ignored on receipt. Bits that are NOT transmitted MUST be treated as 403 if they are set to 0 on receipt. 405 If the link attribute advertisement is limited to be used by a 406 specific set of applications, corresponding Bit-Masks MUST be present 407 and application specific bit(s) MUST be set for all applications that 408 use the link attributes advertised in the Extended Link Attribute 409 sub-TLV. 411 Application Bit-Masks apply to all link attributes that support 412 application specific values and are advertised in the Extended Link 413 Attribute sub-TLV. 415 The advantage of not making the Application Bit-Masks part of the 416 attribute advertisement itself is that we can keep the format of the 417 link attributes that have been defined previously and reuse the same 418 format when advertising them in the Extended Link Attribute sub-TLV. 420 If the link attribute is advertised and there is no Application Bit- 421 Mask present in the Extended Link Attribute Sub-TLV, the link 422 attribute advertisement MAY be used by any application. If, however, 423 another advertisement of the same link attribute includes any 424 Application Bit-Mask in the Extended Link Attribute sub-TLV, 425 applications that are listed in the Application Bit-Masks of such 426 Extended Link Attribute sub-TLV SHOULD use the attribute 427 advertisement which has the application specific bit set in the 428 Application Bit-Masks. 430 If the same application is listed in the Application Bit-Masks of 431 more then one Extended Link Attribute sub-TLV, the application SHOULD 432 use the first advertisement and ignore any subsequent advertisements 433 of the same attribute. This situation SHOULD be logged as an error. 435 This document defines the set of link attributes for which the 436 Application Bit-Masks may be advertised. If any of the Application 437 Bit-Masks is included in the Extended Link Attribute sub-TLV that 438 advertises any link attribute(s) NOT listed below, the Application 439 Bit-Masks MUST NOT be used for such link attribute(s). It MUST be 440 used for those attribute(s) that support application specific values. 441 Documents which define new link attributes MUST state whether the new 442 attributes support application specific values. The link attributes 443 to which the Application Bit-Masks may apply are: 445 - Shared Risk Link Group 447 - Unidirectional Link Delay 449 - Min/Max Unidirectional Link Delay 451 - Unidirectional Delay Variation 453 - Unidirectional Link Loss 455 - Unidirectional Residual Bandwidth 457 - Unidirectional Available Bandwidth 459 - Unidirectional Utilized Bandwidth 461 6. Deployment Considerations 463 If link attributes are advertised associated with zero length 464 application bit masks for both standard applications and user defined 465 applications, then that set of link attributes MAY be used by any 466 application. If support for a new application is introduced on any 467 node in a network in the presence of such advertisements, these 468 advertisements MAY be used by the new application. If this is not 469 what is intended, then existing advertisements MUST be readvertised 470 with an explicit set of applications specified before a new 471 application is introduced. 473 7. Attribute Advertisements and Enablement 475 This document defines extensions to support the advertisement of 476 application specific link attributes. The presence or absence of 477 link attribute advertisements for a given application on a link does 478 NOT indicate the state of enablement of that application on that 479 link. Enablement of an application on a link is controlled by other 480 means. 482 For some applications, the concept of enablement is implicit. For 483 example, SRTE implicitly is enabled on all links which are part of 484 the Segment Routing enabled topology. Advertisement of link 485 attributes supports constraints which may be applied when specifying 486 an explicit path through that topology. 488 For other applications enablement is controlled by local 489 configuration. For example, use of a link as an LFA can be 490 controlled by local enablement/disablement and/or the use of 491 administrative tags. 493 It is an application specific policy as to whether a given link can 494 be used by that application even in the absence of any application 495 specific link attributes. 497 8. Backward Compatibility 499 Link attributes may be concurrently advertised in both the TE Opaque 500 LSA [RFC3630] and the Extended Link Opaque LSA [RFC7684]. 502 In fact, there is at least one OSPF implementation that utilizes the 503 link attributes advertised in TE Opaque LSAs [RFC3630] for Non-RSVP 504 TE applications. For example, this implementation of LFA and remote 505 LFA utilizes links attributes such as Shared Risk Link Groups (SRLG) 506 [RFC4203] and Admin Group [[RFC3630]advertised in TE Opaque LSAs. 507 These applications are described in [RFC5286], [RFC7490], 508 [I-D.ietf-rtgwg-lfa-manageability] and 509 [I-D.psarkar-rtgwg-rlfa-node-protection]. 511 When an OSPF routing domain includes routers using link attributes 512 from TE Opaque LSAs for Non-RSVP TE applications such as LFA, OSPF 513 routers in that domain should continue to advertise such TE Opaque 514 LSAs. If there are also OSPF routers using the link attributes 515 described herein for any application, OSPF routers in the routing 516 domain will also need to advertise these attributes in OSPF Extended 517 Link Attributes LSAs [RFC7684]. In such a deployment, the advertised 518 attributes SHOULD be the same and Non-RSVP application access to link 519 attributes is a matter of local policy. 521 9. Security Considerations 523 Implementations must assure that malformed TLV and Sub-TLV 524 permutations do not result in errors that cause hard OSPFv2 failures. 526 10. IANA Considerations 528 OSPFv2 Extended Link TLV Sub-TLVs registry [RFC7684] defines sub-TLVs 529 at any level of nesting for OSPFv2 Extended Link TLVs. This 530 specification updates OSPFv2 Extended Link TLV sub-TLVs registry with 531 the following TLV types: 533 TBD1 (4 Recommended) - Remote interface IP address 535 TBD2 (5 Recommended) - Link Local/Remote Identifiers 537 TBD3 (6 Recommended) - Shared Risk Link Group 539 TBD4 (7 Recommended) - Unidirectional Link Delay 541 TBD5 (8 Recommended) - Min/Max Unidirectional Link Delay 543 TBD6 (9 Recommended) - Unidirectional Delay Variation 545 TBD7 (10 Recommended) - Unidirectional Link Loss 547 TBD8 (11 Recommended) - Unidirectional Residual Bandwidth 549 TBD9 (12 Recommended) - Unidirectional Available Bandwidth 551 TBD10 (13 Recommended) - Unidirectional Utilized Bandwidth 553 TBD11 (14 Recommended) - Extended Link Attribute 555 This specification defines a new Link-Attribute-Applicability 556 Application Bits registry and defines following bits: 558 Bit-0 - Segment Routing Traffic Engineering 560 Bit-1 - LFA 562 11. Acknowledgments 564 Thanks to Chris Bowers for his review and comments. 566 12. References 568 12.1. Normative References 570 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 571 Requirement Levels", BCP 14, RFC 2119, 572 DOI 10.17487/RFC2119, March 1997, . 575 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 576 (TE) Extensions to OSPF Version 2", RFC 3630, 577 DOI 10.17487/RFC3630, September 2003, . 580 [RFC5714] Shand, M. and S. Bryant, "IP Fast Reroute Framework", 581 RFC 5714, DOI 10.17487/RFC5714, January 2010, 582 . 584 [RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W., 585 Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute 586 Advertisement", RFC 7684, DOI 10.17487/RFC7684, November 587 2015, . 589 12.2. Informative References 591 [I-D.ietf-idr-ls-distribution] 592 Gredler, H., Medved, J., Previdi, S., Farrel, A., and S. 593 Ray, "North-Bound Distribution of Link-State and TE 594 Information using BGP", draft-ietf-idr-ls-distribution-13 595 (work in progress), October 2015. 597 [I-D.ietf-ospf-segment-routing-extensions] 598 Psenak, P., Previdi, S., Filsfils, C., Gredler, H., 599 Shakir, R., Henderickx, W., and J. Tantsura, "OSPF 600 Extensions for Segment Routing", draft-ietf-ospf-segment- 601 routing-extensions-18 (work in progress), July 2017. 603 [I-D.ietf-rtgwg-lfa-manageability] 604 Litkowski, S., Decraene, B., Filsfils, C., Raza, K., and 605 M. Horneffer, "Operational management of Loop Free 606 Alternates", draft-ietf-rtgwg-lfa-manageability-11 (work 607 in progress), June 2015. 609 [I-D.psarkar-rtgwg-rlfa-node-protection] 610 psarkar@juniper.net, p., Gredler, H., Hegde, S., Bowers, 611 C., Litkowski, S., and H. Raghuveer, "Remote-LFA Node 612 Protection and Manageability", draft-psarkar-rtgwg-rlfa- 613 node-protection-05 (work in progress), June 2014. 615 [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, 616 DOI 10.17487/RFC2328, April 1998, . 619 [RFC4203] Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in 620 Support of Generalized Multi-Protocol Label Switching 621 (GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005, 622 . 624 [RFC5286] Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for 625 IP Fast Reroute: Loop-Free Alternates", RFC 5286, 626 DOI 10.17487/RFC5286, September 2008, . 629 [RFC7471] Giacalone, S., Ward, D., Drake, J., Atlas, A., and S. 630 Previdi, "OSPF Traffic Engineering (TE) Metric 631 Extensions", RFC 7471, DOI 10.17487/RFC7471, March 2015, 632 . 634 [RFC7490] Bryant, S., Filsfils, C., Previdi, S., Shand, M., and N. 635 So, "Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)", 636 RFC 7490, DOI 10.17487/RFC7490, April 2015, 637 . 639 [RFC7855] Previdi, S., Ed., Filsfils, C., Ed., Decraene, B., 640 Litkowski, S., Horneffer, M., and R. Shakir, "Source 641 Packet Routing in Networking (SPRING) Problem Statement 642 and Requirements", RFC 7855, DOI 10.17487/RFC7855, May 643 2016, . 645 Authors' Addresses 647 Peter Psenak 648 Cisco Systems 649 Apollo Business Center 650 Mlynske nivy 43 651 Bratislava, 821 09 652 Slovakia 654 Email: ppsenak@cisco.com 655 Acee Lindem 656 Cisco Systems 657 301 Midenhall Way 658 Cary, NC 27513 659 USA 661 Email: acee@cisco.com 663 Les Ginsberg 664 Cisco Systems 665 821 Alder Drive 666 MILPITAS, CA 95035 667 USA 669 Email: ginsberg@cisco.com 671 Wim Henderickx 672 Nokia 673 Copernicuslaan 50 674 Antwerp, 2018 94089 675 Belgium 677 Email: wim.henderickx@nokia.com 679 Jeff Tantsura 680 Individual 681 USA 683 Email: jefftant.ietf@gmail.com 685 Hannes Gredler 686 RtBrick Inc. 688 Email: hannes@rtbrick.com 690 John Drake 691 Juniper Networks 693 Email: jdrake@juniper.net