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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(See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-19) exists of draft-ietf-isis-te-app-06 == Outdated reference: A later version (-26) exists of draft-ietf-lsr-flex-algo-01 Summary: 0 errors (**), 0 flaws (~~), 4 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 LSR Working Group P. Psenak, Ed. 3 Internet-Draft L. Ginsberg 4 Intended status: Standards Track Cisco Systems 5 Expires: October 13, 2019 W. Henderickx 6 Nokia 7 J. Tantsura 8 Apstra 9 J. Drake 10 Juniper Networks 11 April 11, 2019 13 OSPF Link Traffic Engineering (TE) Attribute Reuse 14 draft-ietf-ospf-te-link-attr-reuse-07.txt 16 Abstract 18 Various link attributes have been defined in OSPF in the context of 19 the MPLS Traffic Engineering (TE) and GMPLS. Many of these link 20 attributes can be used for applications other than MPLS Traffic 21 Engineering or GMPLS. This document defines how to distribute such 22 attributes in OSPFv2 and OSPFv3 for applications other than MPLS 23 Traffic Engineering or GMPLS. 25 Status of This Memo 27 This Internet-Draft is submitted in full conformance with the 28 provisions of BCP 78 and BCP 79. 30 Internet-Drafts are working documents of the Internet Engineering 31 Task Force (IETF). Note that other groups may also distribute 32 working documents as Internet-Drafts. The list of current Internet- 33 Drafts is at https://datatracker.ietf.org/drafts/current/. 35 Internet-Drafts are draft documents valid for a maximum of six months 36 and may be updated, replaced, or obsoleted by other documents at any 37 time. It is inappropriate to use Internet-Drafts as reference 38 material or to cite them other than as "work in progress." 40 This Internet-Draft will expire on October 13, 2019. 42 Copyright Notice 44 Copyright (c) 2019 IETF Trust and the persons identified as the 45 document authors. All rights reserved. 47 This document is subject to BCP 78 and the IETF Trust's Legal 48 Provisions Relating to IETF Documents 49 (https://trustee.ietf.org/license-info) in effect on the date of 50 publication of this document. Please review these documents 51 carefully, as they describe your rights and restrictions with respect 52 to this document. Code Components extracted from this document must 53 include Simplified BSD License text as described in Section 4.e of 54 the Trust Legal Provisions and are provided without warranty as 55 described in the Simplified BSD License. 57 This document may contain material from IETF Documents or IETF 58 Contributions published or made publicly available before November 59 10, 2008. The person(s) controlling the copyright in some of this 60 material may not have granted the IETF Trust the right to allow 61 modifications of such material outside the IETF Standards Process. 62 Without obtaining an adequate license from the person(s) controlling 63 the copyright in such materials, this document may not be modified 64 outside the IETF Standards Process, and derivative works of it may 65 not be created outside the IETF Standards Process, except to format 66 it for publication as an RFC or to translate it into languages other 67 than English. 69 Table of Contents 71 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 72 1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3 73 2. Advertisement of Link Attributes . . . . . . . . . . . . . . 3 74 2.1. OSPFv2 Extended Link Opaque LSA and OSPFv3 E-Router-LSA . 4 75 3. Advertisement of Application Specific Values . . . . . . . . 5 76 4. Reused TE link attributes . . . . . . . . . . . . . . . . . . 8 77 4.1. Shared Risk Link Group (SRLG) . . . . . . . . . . . . . . 8 78 4.2. Extended Metrics . . . . . . . . . . . . . . . . . . . . 8 79 4.3. Administrative Group . . . . . . . . . . . . . . . . . . 9 80 4.4. Traffic Engineering Metric . . . . . . . . . . . . . . . 9 81 5. Maximum Link Bandwidth . . . . . . . . . . . . . . . . . . . 10 82 6. Local Interface IPv6 Address Sub-TLV . . . . . . . . . . . . 10 83 7. Remote Interface IPv6 Address Sub-TLV . . . . . . . . . . . . 10 84 8. Deployment Considerations . . . . . . . . . . . . . . . . . . 11 85 9. Attribute Advertisements and Enablement . . . . . . . . . . . 11 86 10. Backward Compatibility . . . . . . . . . . . . . . . . . . . 12 87 11. Security Considerations . . . . . . . . . . . . . . . . . . . 12 88 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 89 12.1. OSPFv2 . . . . . . . . . . . . . . . . . . . . . . . . . 13 90 12.2. OSPFv3 . . . . . . . . . . . . . . . . . . . . . . . . . 13 91 13. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 14 92 14. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 15 93 15. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 94 15.1. Normative References . . . . . . . . . . . . . . . . . . 15 95 15.2. Informative References . . . . . . . . . . . . . . . . . 16 96 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18 98 1. Introduction 100 Various link attributes have been defined in OSPFv2 [RFC2328] and 101 OSPFv3 [RFC5340] in the context of the MPLS traffic engineering and 102 GMPLS. All these attributes are distributed by OSPFv2 as sub-TLVs of 103 the Link-TLV advertised in the OSPFv2 TE Opaque LSA [RFC3630]. In 104 OSPFv3, they are distributed as sub-TLVs of the Link-TLV advertised 105 in the OSPFv3 Intra-Area-TE-LSA as defined in [RFC5329]. 107 Many of these link attributes are useful outside of traditional MPLS 108 Traffic Engineering or GMPLS. This brings its own set of problems, 109 in particular how to distribute these link attributes in OSPFv2 and 110 OSPFv3 when MPLS TE and GMPLS are not deployed or are deployed in 111 parallel with other applications that use these link attributes. 113 [RFC7855] discusses use cases/requirements for Segment Routing. 114 Included among these use cases is SRTE. If both RSVP-TE and SRTE are 115 deployed in a network, link attribute advertisements can be used by 116 one or both of these applications. As there is no requirement for 117 the link attributes advertised on a given link used by SRTE to be 118 identical to the link attributes advertised on that same link used by 119 RSVP-TE, there is a clear requirement to indicate independently which 120 link attribute advertisements are to be used by each application. 122 As the number of applications which may wish to utilize link 123 attributes may grow in the future, an additional requirement is that 124 the extensions defined allow the association of additional 125 applications to link attributes without altering the format of the 126 advertisements or introducing new backwards compatibility issues. 128 Finally, there may still be many cases where a single attribute value 129 can be shared among multiple applications, so the solution should 130 minimize advertising duplicate link/attribute when possible. 132 1.1. Requirements notation 134 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 135 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 136 document are to be interpreted as described in [RFC2119]. 138 2. Advertisement of Link Attributes 140 This section outlines the solution for advertising link attributes 141 originally defined for MPLS Traffic Engineering or GMPLS when they 142 are used for other applications. 144 2.1. OSPFv2 Extended Link Opaque LSA and OSPFv3 E-Router-LSA 146 Extended Link Opaque LSAs as defined in [RFC7684] for OSPFv2 and 147 Extended Router-LSAs [RFC8362] for OSPFv3 are used to advertise link 148 attributes that are used by applications other then MPLS traffic 149 engineering or GMPLS. These LSAs were defined as a generic 150 containers for distribution of the extended link attributes. There 151 are several advantages in using them: 153 1. Advertisement of the link attributes does not make the link part 154 of the TE topology. It avoids any conflicts and is fully 155 compatible with [RFC3630] and [RFC5329]. 157 2. The OSPFv2 TE Opaque LSA and OSPFv3 Intra-Area-TE-LSA remains 158 truly opaque to OSPFv2 and OSPFv3 as originally defined in 159 [RFC3630] and [RFC5329] respectively. Their contents are not 160 inspected by OSPF, that acts as a pure transport. 162 3. There is clear distinction between link attributes used by TE and 163 link attributes used by other OSPFv2 or OSPFv3 applications. 165 4. All link attributes that are used by other applications are 166 advertised in a single LSA, the Extended Link Opaque LSA in 167 OSPFv2 or the OSPFv3 E-Router-LSA [RFC8362] in OSPFv3. 169 The disadvantage of this approach is that in rare cases, the same 170 link attribute is advertised in both the TE Opaque and Extended Link 171 Attribute LSAs in OSPFv2 or the Intra-Area-TE-LSA and E-Router-LSA in 172 OSPFv3. Additionally, there will be additional standardization 173 effort. However, this could also be viewed as an advantage as the 174 non-TE use cases for the TE link attributes are documented and 175 validated by the LSR working group. 177 It is RECOMMENDED to use the Extended Link Opaque LSA [RFC7684] and 178 E-Router-LSA [RFC8362] to advertise any link attributes used for non- 179 TE applications in OSPFv2 or OSPFv3 respectively, including those 180 that have been originally defined for TE applications. 182 It is also RECOMMENDED that TE link attributes used for RSVP-TE/GMPLS 183 continue to use OSPFv2 TE Opaque LSA [RFC3630] and OSPFv3 Intra-Area- 184 TE-LSA [RFC5329]. 186 The format of the link attribute TLVs that have been defined for TE 187 applications will be kept unchanged even when they are used for non- 188 TE applications. Unique code points will be allocated for these TE 189 link attribute TLVs from the OSPFv2 Extended Link TLV Sub-TLV 190 Registry [RFC7684] and from the OSPFv3 Extended LSA Sub-TLV Registry 192 [RFC8362]. For each reused TLV, the code point will be defined in an 193 IETF document along with the expected use-case(s). 195 3. Advertisement of Application Specific Values 197 To allow advertisement of the application specific values of the link 198 attribute, a new Application Specific Link Attributes (ASLA) sub-TLV 199 is defined. The ASLA sub-TLV is a sub-TLV of the OSPFv2 Extended 200 Link TLV [RFC7471] and OSPFv3 Router-Link TLV [RFC8362]. 202 The ASLA sub-TLV is an optional sub-TLV and can appear multiple times 203 in the OSPFv2 Extended Link TLV and OSPFv3 Router-Link TLV. It has 204 the following format: 206 0 1 2 3 207 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 1 208 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 209 | Type | Length | 210 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 211 | SABML | UDABML | Reserved | 212 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 213 | Standard Application Bit-Mask | 214 +- -+ 215 | ... | 216 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 217 | User Defined Application Bit-Mask | 218 +- -+ 219 | ... | 220 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 221 | Link Attribute sub-sub-TLVs | 222 +- -+ 223 | ... | 225 where: 227 Type: 10 (OSPFv2), TBD1 (OSPFv3) 229 Length: variable 231 SABML: Standard Application Bit-Mask Length. It MUST be a 232 multiple of 4 bytes. If the Standard Application Bit-Mask is not 233 present, the Standard Application Bit-Mask Length MUST be set to 234 0. 236 UDABML: User Defined Application Bit-Mask Length. It MUST be a 237 multiple of 4 bytes. If the User Defined Application Bit-Mask is 238 not present, the User Defined Application Bit-Mask Length MUST be 239 set to 0. 241 Standard Application Bit-Mask: Optional set of bits, where each 242 bit represents a single standard application. Bits are defined in 243 [I-D.ietf-isis-te-app], which also request a new IANA "Link 244 Attribute Applications" registry under "Interior Gateway Protocol 245 (IGP) Parameters" for them. The bits are repeated here for 246 informational purpose: 248 Bit-0: RSVP Traffic Engineering 250 Bit-1: Segment Routing Traffic Engineering 252 Bit-2: Loop Free Alternate (LFA). Includes all LFA types 254 Bit-3: Flexible Algorithm 256 User Defined Application Bit-Mask: Optional set of bits, where 257 each bit represents a single user defined application. 259 Standard Application Bits are defined/sent starting with Bit 0. 260 Additional bit definitions that are defined in the future SHOULD be 261 assigned in ascending bit order so as to minimize the number of 262 octets that will need to be transmitted. 264 User Defined Application bits have no relationship to Standard 265 Application bits and are NOT managed by IANA or any other standards 266 body. It is recommended that bits are used starting with Bit 0 so as 267 to minimize the number of octets required to advertise all of them. 269 Undefined bits in both Bit-Masks MUST be transmitted as 0 and MUST be 270 ignored on receipt. Bits that are NOT transmitted MUST be treated as 271 if they are set to 0 on receipt. 273 If the link attribute advertisement is limited to be used by a 274 specific set of applications, corresponding Bit-Masks MUST be present 275 and application specific bit(s) MUST be set for all applications that 276 use the link attributes advertised in the ASLA sub-TLV. 278 Application Bit-Masks apply to all link attributes that support 279 application specific values and are advertised in the ASLA sub-TLV. 281 The advantage of not making the Application Bit-Masks part of the 282 attribute advertisement itself is that we can keep the format of the 283 link attributes that have been defined previously and reuse the same 284 format when advertising them in the ASLA sub-TLV. 286 When neither the Standard Application Bits nor the User Defined 287 Application bits are set (i.e., both SABML and UDABML are 0) in the 288 ASLA sub-TLV, then the link attributes included in it MUST be 289 considered as being applicable to all applications. 291 If, however, another advertisement of the same link attribute 292 includes any Application Bit-Mask in the ASLA sub-TLV, applications 293 that are listed in the Application Bit-Masks of such ASLA sub-TLV 294 SHOULD use the attribute advertisement which has the application 295 specific bit set in the Application Bit-Masks. 297 If the same application is listed in the Application Bit-Masks of 298 more then one ASLA sub-TLV, the application SHOULD use the first 299 advertisement and ignore any subsequent advertisements of the same 300 attribute. This situation SHOULD be logged as an error. 302 This document defines the initial set of link attributes that MUST 303 use ASLA sub-TLV if advertised in the OSPFv2 Extended Link TLV or in 304 the OSPFv3 Router-Link TLV. If the ASLA sub-TLV includes any link 305 attribute(s) NOT listed below, they MUST be ignored. Documents which 306 define new link attributes MUST state whether the new attributes 307 support application specific values and as such MUST be advertised in 308 an ASLA sub-TLV. The link attributes that MUST be advertised in ASLA 309 sub-TLVs are: 311 - Shared Risk Link Group 313 - Unidirectional Link Delay 315 - Min/Max Unidirectional Link Delay 317 - Unidirectional Delay Variation 319 - Unidirectional Link Loss 321 - Unidirectional Residual Bandwidth 323 - Unidirectional Available Bandwidth 325 - Unidirectional Utilized Bandwidth 327 - Administrative Group 329 - Extended Administrative Group 331 - Traffic Engineering Metric 333 4. Reused TE link attributes 335 This section defines the use case and code points from the OSPFv2 336 Extended Link TLV Sub-TLV Registry and OSPFv3 Extended LSA Sub-TLV 337 Registry for some of the link attributes that have been originally 338 defined for TE or GMPLS. 340 4.1. Shared Risk Link Group (SRLG) 342 The SRLG of a link can be used in OSPF calculated IPFRR [RFC5714] to 343 compute a backup path that does not share any SRLG group with the 344 protected link. 346 To advertise the SRLG of the link in the OSPFv2 Extended Link TLV, 347 the same format for the sub-TLV defined in section 1.3 of [RFC4203] 348 is used and TLV type 11 is used. Similarly, for OSPFv3 to advertise 349 the SRLG in the OSPFv3 Router-Link TLV, TLV type TBD2 is used. 351 4.2. Extended Metrics 353 [RFC3630] defines several link bandwidth types. [RFC7471] defines 354 extended link metrics that are based on link bandwidth, delay and 355 loss characteristics. All these can be used to compute primary and 356 backup paths within an OSPF area to satisfy requirements for 357 bandwidth, delay (nominal or worst case) or loss. 359 To advertise extended link metrics in the OSPFv2 Extended Link TLV, 360 the same format for the sub-TLVs defined in [RFC7471] is used with 361 the following TLV types: 363 12 - Unidirectional Link Delay 365 13 - Min/Max Unidirectional Link Delay 367 14 - Unidirectional Delay Variation 369 15 - Unidirectional Link Loss 371 16 - Unidirectional Residual Bandwidth 373 17 - Unidirectional Available Bandwidth 375 18 - Unidirectional Utilized Bandwidth 377 To advertise extended link metrics in the OSPFv3 Extended LSA Router- 378 Link TLV, the same format for the sub-TLVs defined in [RFC7471] is 379 used with the following TLV types: 381 TBD3 - Unidirectional Link Delay 383 TBD4 - Min/Max Unidirectional Link Delay 385 TBD5 - Unidirectional Delay Variation 387 TBD6 - Unidirectional Link Loss 389 TBD7 - Unidirectional Residual Bandwidth 391 TBD8 - Unidirectional Available Bandwidth 393 TBD9 - Unidirectional Utilized Bandwidth 395 4.3. Administrative Group 397 [RFC3630] and [RFC7308] define the Administrative Group and Extended 398 Administrative Group sub-TLVs respectively. 400 One use case where advertisement of the Extended Administrative 401 Group(s) for a link is required is described in 402 [I-D.ietf-lsr-flex-algo]. 404 To advertise the Administrative Group and Extended Administrative 405 Group in the OSPFv2 Extended Link TLV, the same format for the sub- 406 TLVs defined in [RFC3630] and [RFC7308] is used with the following 407 TLV types: 409 19 - Administrative Group 411 20 - Extended Administrative Group 413 To advertise Administrative Group and Extended Administrative Group 414 in the OSPFv3 Router-Link TLV, the same format for the sub-TLVs 415 defined in [RFC3630] and [RFC7308] is used with the following TLV 416 types: 418 TBD10 - Administrative Group 420 TBD11 - Extended Administrative Group 422 4.4. Traffic Engineering Metric 424 [RFC3630] defines Traffic Engineering Metric. 426 To advertise the Traffic Engineering Metric in the OSPFv2 Extended 427 Link TLV, the same format for the sub-TLV defined in section 2.5.5 of 428 [RFC3630] is used and TLV type TBD12 is used. Similarly, for OSPFv3 429 to advertise the Traffic Engineering Metric in the OSPFv3 Router-Link 430 TLV, TLV type TBD13 is used. 432 5. Maximum Link Bandwidth 434 Maximum link bandwidth is an application independent attribute of the 435 link that is defined in [RFC3630]. Because it is an application 436 independent attribute, it MUST NOT be advertised in ASLA sub-TLV. 437 Instead, it MAY be advertised as a sub-TLV of the Extended Link 438 Opaque LSA Extended Link TLV in OSPFv2 [RFC7684] or sub-TLV of OSPFv3 439 E-Router-LSA Router-Link TLV in OSPFv3 [RFC8362]. 441 To advertise the Maximum link bandwidth in the OSPFv2 Extended Link 442 TLV, the same format for sub-TLV defined in [RFC3630] is used with 443 TLV type TBD14. 445 To advertise the Maximum link bandwidth in the OSPFv3 Router-Link 446 TLV, the same format for sub-TLV defined in [RFC3630] is used with 447 TLV type TBD15. 449 6. Local Interface IPv6 Address Sub-TLV 451 The Local Interface IPv6 Address Sub-TLV is an application 452 independent attribute of the link that is defined in [RFC5329]. 453 Because it is an application independent attribute, it MUST NOT be 454 advertised in the ASLA sub-TLV. Instead, it MAY be advertised as a 455 sub-TLV of the OSPFv3 E-Router-LSA Router-Link TLV [RFC8362]. 457 To advertise the Local Interface IPv6 Address Sub-TLV in the OSPFv3 458 Router-Link TLV, the same format for sub-TLV defined in [RFC5329] is 459 used with TLV type TBD16. 461 7. Remote Interface IPv6 Address Sub-TLV 463 The Remote Interface IPv6 Address Sub-TLV is an application 464 independent attribute of the link that is defined in [RFC5329]. 465 Because it is an application independent attribute, it MUST NOT be 466 advertised in the ASLA sub-TLV. Instead, it MAY be advertised as a 467 sub-TLV of the OSPFv3 E-Router-LSA Router-Link TLV [RFC8362]. 469 To advertise the Remote Interface IPv6 Address Sub-TLV in the OSPFv3 470 Router-Link TLV, the same format for sub-TLV defined in [RFC5329] is 471 used with TLV type TBD17. 473 8. Deployment Considerations 475 If link attributes are advertised associated with zero length 476 application bit masks for both standard applications and user defined 477 applications, then that set of link attributes MAY be used by any 478 application. If support for a new application is introduced on any 479 node in a network in the presence of such advertisements, these 480 advertisements MAY be used by the new application. If this is not 481 what is intended, then existing advertisements MUST be readvertised 482 with an explicit set of applications specified before a new 483 application is introduced. 485 9. Attribute Advertisements and Enablement 487 This document defines extensions to support the advertisement of 488 application specific link attributes. 490 Whether the presence of link attribute advertisements for a given 491 application indicates that the application is enabled on that link 492 depends upon the application. Similarly, whether the absence of link 493 attribute advertisements indicates that the application is not 494 enabled depends upon the application. 496 In the case of RSVP-TE, the advertisement of application specific 497 link attributes implies that RSVP is enabled on that link. 499 In the case of SRTE, advertisement of application specific link 500 attributes does NOT indicate enablement of SRTE. The advertisements 501 are only used to support constraints which may be applied when 502 specifying an explicit path. SRTE is implicitly enabled on all links 503 which are part of the Segment Routing enabled topology independent of 504 the existence of link attribute advertisements. 506 In the case of LFA, advertisement of application specific link 507 attributes does NOT indicate enablement of LFA on that link. 508 Enablement is controlled by local configuration. 510 In the case of Flexible Algorithm, advertisement of application 511 specific link attributes does NOT indicate enablement of Flexible 512 Algorithm on that link. Rather the attributes are used to determine 513 what links are included/excluded in the algorithm specific 514 constrained SPF. This is fully specified in 515 [I-D.ietf-lsr-flex-algo]. 517 If, in the future, additional standard applications are defined to 518 use this mechanism, the specification defining this use MUST define 519 the relationship between application specific link attribute 520 advertisements and enablement for that application. 522 This document allows the advertisement of application specific link 523 attributes with no application identifiers i.e., both the Standard 524 Application Bit Mask and the User Defined Application Bit Mask are 525 not present (See Section 3). This supports the use of the link 526 attribute by any application. In the presence of an application 527 where the advertisement of link attribute advertisements is used to 528 infer the enablement of an application on that link (e.g., RSVP-TE), 529 the absence of the application identifier leaves ambiguous whether 530 that application is enabled on such a link. This needs to be 531 considered when making use of the "any application" encoding. 533 10. Backward Compatibility 535 Link attributes may be concurrently advertised in both the TE Opaque 536 LSA and the Extended Link Opaque LSA in OSPFv2 and the OSPFv3 Intra- 537 Area-TE-LSA and OSPFv3 Extended LSA Router-Link TLV in OSPFv3. 539 In fact, there is at least one OSPF implementation that utilizes the 540 link attributes advertised in TE Opaque LSAs [RFC3630] for Non-RSVP 541 TE applications. For example, this implementation of LFA and remote 542 LFA utilizes links attributes such as Shared Risk Link Groups (SRLG) 543 [RFC4203] and Admin Group [[RFC3630] advertised in TE Opaque LSAs. 544 These applications are described in [RFC5286], [RFC7490], [RFC7916] 545 and [RFC8102]. 547 When an OSPF routing domain includes routers using link attributes 548 from the OSPFv2 TE Opaque LSAs or the OSPFv3 Intra-Area-TE-LSA for 549 Non-RSVP TE applications such as LFA, OSPF routers in that domain 550 SHOULD continue to advertise such OSPFv2 TE Opaque LSAs or the OSPFv3 551 Intra-Area-TE-LSA. If there are also OSPF routers using the link 552 attributes described herein for any other application, OSPF routers 553 in the routing domain will also need to advertise these attributes in 554 OSPFv2 Extended Link Attributes LSAs or OSPFv3 E-Router-LSA. In such 555 a deployment, the advertised attributes SHOULD be the same and Non- 556 RSVP application access to link attributes is a matter of local 557 policy. 559 11. Security Considerations 561 Existing security extensions as described in [RFC2328], [RFC5340] and 562 [RFC8362] apply to extensions defined in this document. While OSPF 563 is under a single administrative domain, there can be deployments 564 where potential attackers have access to one or more networks in the 565 OSPF routing domain. In these deployments, stronger authentication 566 mechanisms such as those specified in [RFC5709], [RFC7474], [RFC4552] 567 or [RFC7166] SHOULD be used. 569 Implementations MUST assure that malformed TLV and Sub-TLV defined in 570 this document are detected and do not provide a vulnerability for 571 attackers to crash the OSPF router or routing process. Reception of 572 a malformed TLV or Sub-TLV SHOULD be counted and/or logged for 573 further analysis. Logging of malformed TLVs and Sub-TLVs SHOULD be 574 rate-limited to prevent a Denial of Service (DoS) attack (distributed 575 or otherwise) from overloading the OSPF control plane. 577 12. IANA Considerations 579 12.1. OSPFv2 581 OSPFv2 Extended Link TLV Sub-TLVs registry [RFC7684] defines sub-TLVs 582 at any level of nesting for OSPFv2 Extended Link TLVs. This 583 specification updates OSPFv2 Extended Link TLV sub-TLVs registry with 584 the following TLV types: 586 10 - Application Specific Link Attributes 588 11 - Shared Risk Link Group 590 12 - Unidirectional Link Delay 592 13 - Min/Max Unidirectional Link Delay 594 14 - Unidirectional Delay Variation 596 15 - Unidirectional Link Loss 598 16 - Unidirectional Residual Bandwidth 600 17 - Unidirectional Available Bandwidth 602 18 - Unidirectional Utilized Bandwidth 604 19 - Administrative Group 606 20 - Extended Administrative Group 608 TBD12 (22 Recommended) - Traffic Engineering Metric 610 TBD14 (21 Recommended) - Maximum Link Bandwidth 612 12.2. OSPFv3 614 OSPFv3 Extended LSA Sub-TLV Registry [RFC8362] defines sub-TLVs at 615 any level of nesting for OSPFv3 Extended LSAs. This specification 616 updates OSPFv3 Extended LSA Sub-TLV Registry with the following TLV 617 types: 619 TBD1 (10 Recommended) - Application Specific Link Attributes 621 TBD2 (11 Recommended) - Shared Risk Link Group 623 TBD3 (12 Recommended) - Unidirectional Link Delay 625 TBD4 (13 Recommended) - Min/Max Unidirectional Link Delay 627 TBD5 (14 Recommended) - Unidirectional Delay Variation 629 TBD6 (15 Recommended) - Unidirectional Link Loss 631 TBD7 (16 Recommended) - Unidirectional Residual Bandwidth 633 TBD8 (17 Recommended) - Unidirectional Available Bandwidth 635 TBD9 (18 Recommended) - Unidirectional Utilized Bandwidth 637 TBD10 (19 Recommended) - Administrative Group 639 TBD11 (20 Recommended) - Extended Administrative Group 641 TBD13 (21 Recommended) - Traffic Engineering Metric 643 TBD15 (22 Recommended) - Maximum Link Bandwidth 645 TBD16 (23 Recommended) - Local Interface IPv6 Address Sub-TLV 647 TBD17 (24 Recommended) - Local Interface IPv6 Address Sub-TLV 649 13. Contributors 651 The following people contributed to the content of this document and 652 should be considered as co-authors: 654 Acee Lindem 655 Cisco Systems 656 301 Midenhall Way 657 Cary, NC 27513 658 USA 660 Email: acee@cisco.com 662 Ketan Talaulikar 663 Cisco Systems, Inc. 664 India 666 Email: ketant@cisco.com 668 Hannes Gredler 669 RtBrick Inc. 670 Austria 672 Email: hannes@rtbrick.com 674 14. Acknowledgments 676 Thanks to Chris Bowers for his review and comments. 678 15. References 680 15.1. Normative References 682 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 683 Requirement Levels", BCP 14, RFC 2119, 684 DOI 10.17487/RFC2119, March 1997, 685 . 687 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 688 (TE) Extensions to OSPF Version 2", RFC 3630, 689 DOI 10.17487/RFC3630, September 2003, 690 . 692 [RFC5329] Ishiguro, K., Manral, V., Davey, A., and A. Lindem, Ed., 693 "Traffic Engineering Extensions to OSPF Version 3", 694 RFC 5329, DOI 10.17487/RFC5329, September 2008, 695 . 697 [RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF 698 for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008, 699 . 701 [RFC7308] Osborne, E., "Extended Administrative Groups in MPLS 702 Traffic Engineering (MPLS-TE)", RFC 7308, 703 DOI 10.17487/RFC7308, July 2014, 704 . 706 [RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W., 707 Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute 708 Advertisement", RFC 7684, DOI 10.17487/RFC7684, November 709 2015, . 711 [RFC8362] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and 712 F. Baker, "OSPFv3 Link State Advertisement (LSA) 713 Extensibility", RFC 8362, DOI 10.17487/RFC8362, April 714 2018, . 716 15.2. Informative References 718 [I-D.ietf-isis-te-app] 719 Ginsberg, L., Psenak, P., Previdi, S., Henderickx, W., and 720 J. Drake, "IS-IS TE Attributes per application", draft- 721 ietf-isis-te-app-06 (work in progress), April 2019. 723 [I-D.ietf-lsr-flex-algo] 724 Psenak, P., Hegde, S., Filsfils, C., Talaulikar, K., and 725 A. Gulko, "IGP Flexible Algorithm", draft-ietf-lsr-flex- 726 algo-01 (work in progress), November 2018. 728 [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, 729 DOI 10.17487/RFC2328, April 1998, 730 . 732 [RFC4203] Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in 733 Support of Generalized Multi-Protocol Label Switching 734 (GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005, 735 . 737 [RFC4552] Gupta, M. and N. Melam, "Authentication/Confidentiality 738 for OSPFv3", RFC 4552, DOI 10.17487/RFC4552, June 2006, 739 . 741 [RFC5286] Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for 742 IP Fast Reroute: Loop-Free Alternates", RFC 5286, 743 DOI 10.17487/RFC5286, September 2008, 744 . 746 [RFC5709] Bhatia, M., Manral, V., Fanto, M., White, R., Barnes, M., 747 Li, T., and R. Atkinson, "OSPFv2 HMAC-SHA Cryptographic 748 Authentication", RFC 5709, DOI 10.17487/RFC5709, October 749 2009, . 751 [RFC5714] Shand, M. and S. Bryant, "IP Fast Reroute Framework", 752 RFC 5714, DOI 10.17487/RFC5714, January 2010, 753 . 755 [RFC7166] Bhatia, M., Manral, V., and A. Lindem, "Supporting 756 Authentication Trailer for OSPFv3", RFC 7166, 757 DOI 10.17487/RFC7166, March 2014, 758 . 760 [RFC7471] Giacalone, S., Ward, D., Drake, J., Atlas, A., and S. 761 Previdi, "OSPF Traffic Engineering (TE) Metric 762 Extensions", RFC 7471, DOI 10.17487/RFC7471, March 2015, 763 . 765 [RFC7474] Bhatia, M., Hartman, S., Zhang, D., and A. Lindem, Ed., 766 "Security Extension for OSPFv2 When Using Manual Key 767 Management", RFC 7474, DOI 10.17487/RFC7474, April 2015, 768 . 770 [RFC7490] Bryant, S., Filsfils, C., Previdi, S., Shand, M., and N. 771 So, "Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)", 772 RFC 7490, DOI 10.17487/RFC7490, April 2015, 773 . 775 [RFC7855] Previdi, S., Ed., Filsfils, C., Ed., Decraene, B., 776 Litkowski, S., Horneffer, M., and R. Shakir, "Source 777 Packet Routing in Networking (SPRING) Problem Statement 778 and Requirements", RFC 7855, DOI 10.17487/RFC7855, May 779 2016, . 781 [RFC7916] Litkowski, S., Ed., Decraene, B., Filsfils, C., Raza, K., 782 Horneffer, M., and P. Sarkar, "Operational Management of 783 Loop-Free Alternates", RFC 7916, DOI 10.17487/RFC7916, 784 July 2016, . 786 [RFC8102] Sarkar, P., Ed., Hegde, S., Bowers, C., Gredler, H., and 787 S. Litkowski, "Remote-LFA Node Protection and 788 Manageability", RFC 8102, DOI 10.17487/RFC8102, March 789 2017, . 791 Authors' Addresses 793 Peter Psenak (editor) 794 Cisco Systems 795 Eurovea Centre, Central 3 796 Pribinova Street 10 797 Bratislava 81109 798 Slovakia 800 Email: ppsenak@cisco.com 802 Les Ginsberg 803 Cisco Systems 804 821 Alder Drive 805 MILPITAS, CA 95035 806 USA 808 Email: ginsberg@cisco.com 810 Wim Henderickx 811 Nokia 812 Copernicuslaan 50 813 Antwerp, 2018 94089 814 Belgium 816 Email: wim.henderickx@nokia.com 818 Jeff Tantsura 819 Apstra 820 US 822 Email: jefftant.ietf@gmail.com 824 John Drake 825 Juniper Networks 826 1194 N. Mathilda Ave 827 Sunnyvale, California 94089 828 USA 830 Email: jdrake@juniper.net