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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(See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-19) exists of draft-ietf-isis-te-app-08 Summary: 0 errors (**), 0 flaws (~~), 2 warnings (==), 1 comment (--).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: May 2, 2020 W. Henderickx 6 Nokia 7 J. Tantsura 8 Apstra 9 J. Drake 10 Juniper Networks 11 October 30, 2019 13 OSPF Link Traffic Engineering Attribute Reuse 14 draft-ietf-ospf-te-link-attr-reuse-10.txt 16 Abstract 18 Various link attributes have been defined in OSPF in the context of 19 the MPLS Traffic Engineering (TE) and GMPLS. Since the original 20 RSVP-TE use case was defined, additional applications (e.g., SRTE, 21 LFA) have been defined which also make use of the link attribute 22 advertisements. This document defines how to distribute link 23 attributes in OSPFv2 and OSPFv3 for applications other than MPLS TE 24 or GMPLS. 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 https://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 May 2, 2020. 43 Copyright Notice 45 Copyright (c) 2019 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 (https://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 Table of Contents 60 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 61 1.1. Requirements notation . . . . . . . . . . . . . . . . . . 3 62 2. Advertisement of Link Attributes . . . . . . . . . . . . . . 3 63 2.1. OSPFv2 Extended Link Opaque LSA and OSPFv3 E-Router-LSA . 3 64 3. Advertisement of Application Specific Values . . . . . . . . 4 65 4. Reused TE link attributes . . . . . . . . . . . . . . . . . . 7 66 4.1. Shared Risk Link Group (SRLG) . . . . . . . . . . . . . . 7 67 4.2. Extended Metrics . . . . . . . . . . . . . . . . . . . . 8 68 4.3. Administrative Group . . . . . . . . . . . . . . . . . . 9 69 4.4. TE Metric . . . . . . . . . . . . . . . . . . . . . . . . 9 70 5. Maximum Link Bandwidth . . . . . . . . . . . . . . . . . . . 9 71 6. Local Interface IPv6 Address Sub-TLV . . . . . . . . . . . . 10 72 7. Remote Interface IPv6 Address Sub-TLV . . . . . . . . . . . . 10 73 8. Deployment Considerations . . . . . . . . . . . . . . . . . . 10 74 8.1. Use of TE LSA Advertisements . . . . . . . . . . . . . . 10 75 8.2. Use of Zero Length Application Identifier Bit Masks . . . 11 76 9. Attribute Advertisements and Enablement . . . . . . . . . . . 11 77 10. Backward Compatibility . . . . . . . . . . . . . . . . . . . 12 78 11. Security Considerations . . . . . . . . . . . . . . . . . . . 13 79 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 80 12.1. OSPFv2 . . . . . . . . . . . . . . . . . . . . . . . . . 13 81 12.2. OSPFv3 . . . . . . . . . . . . . . . . . . . . . . . . . 14 82 13. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 15 83 14. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 15 84 15. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 85 15.1. Normative References . . . . . . . . . . . . . . . . . . 15 86 15.2. Informative References . . . . . . . . . . . . . . . . . 16 87 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 18 89 1. Introduction 91 Various link attributes have been defined in OSPFv2 [RFC2328] and 92 OSPFv3 [RFC5340] in the context of the MPLS TE and GMPLS. All these 93 attributes are distributed by OSPFv2 as sub-TLVs of the Link-TLV 94 advertised in the OSPFv2 TE Opaque LSA [RFC3630]. In OSPFv3, they 95 are distributed as sub-TLVs of the Link-TLV advertised in the OSPFv3 96 Intra-Area-TE-LSA as defined in [RFC5329]. 98 Many of these link attributes are useful outside of traditional MPLS 99 Traffic Engineering or GMPLS. This brings its own set of problems, 100 in particular how to distribute these link attributes in OSPFv2 and 101 OSPFv3 when MPLS TE and GMPLS are not deployed or are deployed in 102 parallel with other applications that use these link attributes. 104 [RFC7855] discusses use cases/requirements for Segment Routing (SR). 105 Included among these use cases is Segment Routing Traffic Engineering 106 (SRTE). If both RSVP-TE and SRTE are deployed in a network, link 107 attribute advertisements can be used by one or both of these 108 applications. As there is no requirement for the link attributes 109 advertised on a given link used by SRTE to be identical to the link 110 attributes advertised on that same link used by RSVP-TE, there is a 111 clear requirement to indicate independently which link attribute 112 advertisements are to be used by each application. 114 As the number of applications which may wish to utilize link 115 attributes may grow in the future, an additional requirement is that 116 the extensions defined allow the association of additional 117 applications to link attributes without altering the format of the 118 advertisements or introducing new backwards compatibility issues. 120 Finally, there may still be many cases where a single attribute value 121 can be shared among multiple applications, so the solution should 122 minimize advertising duplicate link/attribute when possible. 124 1.1. Requirements notation 126 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 127 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 128 document are to be interpreted as described in [RFC2119]. 130 2. Advertisement of Link Attributes 132 This section outlines the solution for advertising link attributes 133 originally defined for MPLS TE or GMPLS when they are used for other 134 applications. 136 2.1. OSPFv2 Extended Link Opaque LSA and OSPFv3 E-Router-LSA 138 Extended Link Opaque LSAs as defined in [RFC7684] for OSPFv2 and 139 Extended Router-LSAs [RFC8362] for OSPFv3 are used to advertise link 140 attributes that are used by applications other then MPLS TE or GMPLS. 141 These LSAs were defined as a generic containers for distribution of 142 the extended link attributes. There are several advantages in using 143 them: 145 1. Advertisement of the link attributes does not make the link part 146 of the TE topology. It avoids any conflicts and is fully 147 compatible with [RFC3630] and [RFC5329]. 149 2. The OSPFv2 TE Opaque LSA and OSPFv3 Intra-Area-TE-LSA remains 150 truly opaque to OSPFv2 and OSPFv3 as originally defined in 151 [RFC3630] and [RFC5329] respectively. Their contents are not 152 inspected by OSPF, that acts as a pure transport. 154 3. There is clear distinction between link attributes used by TE and 155 link attributes used by other OSPFv2 or OSPFv3 applications. 157 4. All link attributes that are used by other applications are 158 advertised in a single LSA, the Extended Link Opaque LSA in 159 OSPFv2 or the OSPFv3 E-Router-LSA [RFC8362] in OSPFv3. 161 The disadvantage of this approach is that in rare cases, the same 162 link attribute is advertised in both the TE Opaque and Extended Link 163 Attribute LSAs in OSPFv2 or the Intra-Area-TE-LSA and E-Router-LSA in 164 OSPFv3. Additionally, there will be additional standardization 165 effort. However, this could also be viewed as an advantage as the 166 non-TE use cases for the TE link attributes are documented and 167 validated by the LSR working group. 169 Extended Link Opaque LSA [RFC7684] and E-Router-LSA [RFC8362] are 170 used to advertise any link attributes used for non-TE applications in 171 OSPFv2 or OSPFv3 respectively, including those that have been 172 originally defined for TE applications. 174 TE link attributes used for RSVP-TE/GMPLS continue to use OSPFv2 TE 175 Opaque LSA [RFC3630] and OSPFv3 Intra-Area-TE-LSA [RFC5329]. 177 The format of the link attribute TLVs that have been defined for TE 178 applications will be kept unchanged even when they are used for non- 179 TE applications. Unique code points will be allocated for these TE 180 link attribute TLVs from the OSPFv2 Extended Link TLV Sub-TLV 181 Registry [RFC7684] and from the OSPFv3 Extended LSA Sub-TLV Registry 182 [RFC8362]. For each reused TLV, the code point will be defined in an 183 IETF document along with the expected use-case(s). 185 3. Advertisement of Application Specific Values 187 To allow advertisement of the application specific values of the link 188 attribute, a new Application Specific Link Attributes (ASLA) sub-TLV 189 is defined. The ASLA sub-TLV is a sub-TLV of the OSPFv2 Extended 190 Link TLV [RFC7471] and OSPFv3 Router-Link TLV [RFC8362]. 192 The ASLA sub-TLV is an optional sub-TLV and can appear multiple times 193 in the OSPFv2 Extended Link TLV and OSPFv3 Router-Link TLV. It has 194 the following format: 196 0 1 2 3 197 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 1 198 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 199 | Type | Length | 200 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 201 | SABM Length | UDABM Length | Reserved | 202 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 203 | Standard Application Identifier Bit-Mask | 204 +- -+ 205 | ... | 206 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 207 | User Defined Application Identifier Bit-Mask | 208 +- -+ 209 | ... | 210 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 211 | Link Attribute sub-sub-TLVs | 212 +- -+ 213 | ... | 215 where: 217 Type: 10 (OSPFv2), 11 (OSPFv3) 219 Length: variable 221 SABM Length: Standard Application Identifier Bit-Mask Length. It 222 MUST be a multiple of 4 bytes. If the Standard Application Bit- 223 Mask is not present, the Standard Application Bit-Mask Length MUST 224 be set to 0. 226 UDABM Length: User Defined Application Identifier Bit-Mask Length. 227 It MUST be a multiple of 4 bytes. If the User Defined Application 228 Bit-Mask is not present, the User Defined Application Bit-Mask 229 Length MUST be set to 0. 231 Standard Application Identifier Bit-Mask: Optional set of bits, 232 where each bit represents a single standard application. Bits are 233 defined in [I-D.ietf-isis-te-app], which also request a new IANA 234 "Link Attribute Applications" registry under "Interior Gateway 235 Protocol (IGP) Parameters" for them. The bits are repeated here 236 for informational purpose: 238 Bit-0 (R-bit): RSVP TE 240 Bit-1 (S-bit): Segment Routing TE 242 Bit-2 (F-bit): Loop Free Alternate (LFA). Includes all LFA 243 types 245 User Defined Application Identifier Bit-Mask: Optional set of 246 bits, where each bit represents a single user defined application. 248 Standard Application Identifier Bits are defined/sent starting with 249 Bit 0. Additional bit definitions that are defined in the future 250 SHOULD be assigned in ascending bit order so as to minimize the 251 number of octets that will need to be transmitted. 253 User Defined Application Identifier Bits have no relationship to 254 Standard Application bits and are NOT managed by IANA or any other 255 standards body. It is recommended that bits are used starting with 256 Bit 0 so as to minimize the number of octets required to advertise 257 all of them. 259 Undefined bits in both Bit-Masks MUST be transmitted as 0 and MUST be 260 ignored on receipt. Bits that are NOT transmitted MUST be treated as 261 if they are set to 0 on receipt. 263 If the link attribute advertisement is limited to be used by a 264 specific set of applications, corresponding Bit-Masks MUST be present 265 and application specific bit(s) MUST be set for all applications that 266 use the link attributes advertised in the ASLA sub-TLV. 268 Application Bit-Masks apply to all link attributes that support 269 application specific values and are advertised in the ASLA sub-TLV. 271 The advantage of not making the Application Bit-Masks part of the 272 attribute advertisement itself is that we can keep the format of the 273 link attributes that have been defined previously and reuse the same 274 format when advertising them in the ASLA sub-TLV. 276 When neither the Standard Application Bits nor the User Defined 277 Application bits are set (i.e., both SABM Length and UDABM Length are 278 0) in the ASLA sub-TLV, then the link attributes included in it MUST 279 be considered as being applicable to all applications. 281 If, however, another advertisement of the same link attribute 282 includes any Application Bit-Mask in the ASLA sub-TLV, applications 283 that are listed in the Application Bit-Masks of such ASLA sub-TLV 284 SHOULD use the attribute advertisement which has the application 285 specific bit set in the Application Bit-Masks. 287 If the same application is listed in the Application Bit-Masks of 288 more then one ASLA sub-TLV, the application SHOULD use the first 289 advertisement and ignore any subsequent advertisements of the same 290 attribute. This situation SHOULD be logged as an error. 292 This document defines the initial set of link attributes that MUST 293 use ASLA sub-TLV if advertised in the OSPFv2 Extended Link TLV or in 294 the OSPFv3 Router-Link TLV. If the ASLA sub-TLV includes any link 295 attribute(s) NOT listed below, they MUST be ignored. Documents which 296 define new link attributes MUST state whether the new attributes 297 support application specific values and as such MUST be advertised in 298 an ASLA sub-TLV. The link attributes that MUST be advertised in ASLA 299 sub-TLVs are: 301 - Shared Risk Link Group 303 - Unidirectional Link Delay 305 - Min/Max Unidirectional Link Delay 307 - Unidirectional Delay Variation 309 - Unidirectional Link Loss 311 - Unidirectional Residual Bandwidth 313 - Unidirectional Available Bandwidth 315 - Unidirectional Utilized Bandwidth 317 - Administrative Group 319 - Extended Administrative Group 321 - TE Metric 323 4. Reused TE link attributes 325 This section defines the use case and code points from the OSPFv2 326 Extended Link TLV Sub-TLV Registry and OSPFv3 Extended LSA Sub-TLV 327 Registry for some of the link attributes that have been originally 328 defined for TE or GMPLS. 330 4.1. Shared Risk Link Group (SRLG) 332 The SRLG of a link can be used in OSPF calculated IPFRR [RFC5714] to 333 compute a backup path that does not share any SRLG group with the 334 protected link. 336 To advertise the SRLG of the link in the OSPFv2 Extended Link TLV, 337 the same format for the sub-TLV defined in section 1.3 of [RFC4203] 338 is used and TLV type 11 is used. Similarly, for OSPFv3 to advertise 339 the SRLG in the OSPFv3 Router-Link TLV, TLV type 12 is used. 341 4.2. Extended Metrics 343 [RFC3630] defines several link bandwidth types. [RFC7471] defines 344 extended link metrics that are based on link bandwidth, delay and 345 loss characteristics. All these can be used to compute primary and 346 backup paths within an OSPF area to satisfy requirements for 347 bandwidth, delay (nominal or worst case) or loss. 349 To advertise extended link metrics in the OSPFv2 Extended Link TLV, 350 the same format for the sub-TLVs defined in [RFC7471] is used with 351 the following TLV types: 353 12 - Unidirectional Link Delay 355 13 - Min/Max Unidirectional Link Delay 357 14 - Unidirectional Delay Variation 359 15 - Unidirectional Link Loss 361 16 - Unidirectional Residual Bandwidth 363 17 - Unidirectional Available Bandwidth 365 18 - Unidirectional Utilized Bandwidth 367 To advertise extended link metrics in the OSPFv3 Extended LSA Router- 368 Link TLV, the same format for the sub-TLVs defined in [RFC7471] is 369 used with the following TLV types: 371 13 - Unidirectional Link Delay 373 14 - Min/Max Unidirectional Link Delay 375 15 - Unidirectional Delay Variation 377 16 - Unidirectional Link Loss 379 17 - Unidirectional Residual Bandwidth 381 18 - Unidirectional Available Bandwidth 383 19 - Unidirectional Utilized Bandwidth 385 4.3. Administrative Group 387 [RFC3630] and [RFC7308] define the Administrative Group and Extended 388 Administrative Group sub-TLVs respectively. 390 To advertise the Administrative Group and Extended Administrative 391 Group in the OSPFv2 Extended Link TLV, the same format for the sub- 392 TLVs defined in [RFC3630] and [RFC7308] is used with the following 393 TLV types: 395 19 - Administrative Group 397 20 - Extended Administrative Group 399 To advertise Administrative Group and Extended Administrative Group 400 in the OSPFv3 Router-Link TLV, the same format for the sub-TLVs 401 defined in [RFC3630] and [RFC7308] is used with the following TLV 402 types: 404 20 - Administrative Group 406 21 - Extended Administrative Group 408 4.4. TE Metric 410 [RFC3630] defines TE Metric. 412 To advertise the TE Metric in the OSPFv2 Extended Link TLV, the same 413 format for the sub-TLV defined in section 2.5.5 of [RFC3630] is used 414 and TLV type 22 is used. Similarly, for OSPFv3 to advertise the TE 415 Metric in the OSPFv3 Router-Link TLV, TLV type 22 is used. 417 5. Maximum Link Bandwidth 419 Maximum link bandwidth is an application independent attribute of the 420 link that is defined in [RFC3630]. Because it is an application 421 independent attribute, it MUST NOT be advertised in ASLA sub-TLV. 422 Instead, it MAY be advertised as a sub-TLV of the Extended Link 423 Opaque LSA Extended Link TLV in OSPFv2 [RFC7684] or sub-TLV of OSPFv3 424 E-Router-LSA Router-Link TLV in OSPFv3 [RFC8362]. 426 To advertise the Maximum link bandwidth in the OSPFv2 Extended Link 427 TLV, the same format for sub-TLV defined in [RFC3630] is used with 428 TLV type 23. 430 To advertise the Maximum link bandwidth in the OSPFv3 Router-Link 431 TLV, the same format for sub-TLV defined in [RFC3630] is used with 432 TLV type 23. 434 6. Local Interface IPv6 Address Sub-TLV 436 The Local Interface IPv6 Address Sub-TLV is an application 437 independent attribute of the link that is defined in [RFC5329]. 438 Because it is an application independent attribute, it MUST NOT be 439 advertised in the ASLA sub-TLV. Instead, it MAY be advertised as a 440 sub-TLV of the OSPFv3 E-Router-LSA Router-Link TLV [RFC8362]. 442 To advertise the Local Interface IPv6 Address Sub-TLV in the OSPFv3 443 Router-Link TLV, the same format for sub-TLV defined in [RFC5329] is 444 used with TLV type 24. 446 7. Remote Interface IPv6 Address Sub-TLV 448 The Remote Interface IPv6 Address Sub-TLV is an application 449 independent attribute of the link that is defined in [RFC5329]. 450 Because it is an application independent attribute, it MUST NOT be 451 advertised in the ASLA sub-TLV. Instead, it MAY be advertised as a 452 sub-TLV of the OSPFv3 E-Router-LSA Router-Link TLV [RFC8362]. 454 To advertise the Remote Interface IPv6 Address Sub-TLV in the OSPFv3 455 Router-Link TLV, the same format for sub-TLV defined in [RFC5329] is 456 used with TLV type 25. 458 8. Deployment Considerations 460 8.1. Use of TE LSA Advertisements 462 Bit Identifers for Standard Applications are defined in Section 3. 463 All of the identifiers defined in this document are associated with 464 applications which were already deployed in some networks prior to 465 the writing of this document. Therefore, such applications have been 466 deployed using the TE LSA advertisements. The Standard Applications 467 defined in this document MAY continue to use TE LSA advertisements 468 for a given link so long as at least one of the following conditions 469 is true: 471 The application is RSVP-TE 473 The application is SRTE or LFA and RSVP-TE is not deployed 474 anywhere in the network 476 The application is SRTE or LFA, RSVP-TE is deployed in the 477 network, and both the set of links on which SRTE and/or LFA 478 advertisements are required and the attribute values used by SRTE 479 and/or LFA on all such links is fully congruent with the links and 480 attribute values used by RSVP-TE 482 Under the conditions defined above, implementations which support the 483 extensions defined in this document have the choice of using TE LSA 484 advertisements or application specific advertisements in support of 485 SRTE and/or LFA. This will require implementations to provide 486 controls specifying which type of advertisements are to be sent/ 487 processed on receive for these applications. Further discussion of 488 the associated issues can be found in Section 10. 490 New applications which future documents define to make use of the 491 advertisements defined in this document MUST NOT make use of TE LSA 492 advertisements. 494 8.2. Use of Zero Length Application Identifier Bit Masks 496 If link attributes are advertised associated with zero length 497 Application Identifier Bit-Masks for both standard applications and 498 user defined applications, then that set of link attributes MAY be 499 used by any application. If support for a new application is 500 introduced on any node in a network in the presence of such 501 advertisements, these advertisements MAY be used by the new 502 application. If this is not what is intended, then existing 503 advertisements MUST be readvertised with an explicit set of 504 applications specified before a new application is introduced. 506 9. Attribute Advertisements and Enablement 508 This document defines extensions to support the advertisement of 509 application specific link attributes. 511 Whether the presence of link attribute advertisements for a given 512 application indicates that the application is enabled on that link 513 depends upon the application. Similarly, whether the absence of link 514 attribute advertisements indicates that the application is not 515 enabled depends upon the application. 517 In the case of RSVP-TE, the advertisement of application specific 518 link attributes implies that RSVP is enabled on that link. The 519 absence of RSVP-TE application specific link attributes in 520 combination with the absence of legacy advertisements implies that 521 RSVP is NOT enabled on that link. 523 In the case of SRTE, advertisement of application specific link 524 attributes does NOT indicate enablement of SRTE. The advertisements 525 are only used to support constraints which may be applied when 526 specifying an explicit path. SRTE is implicitly enabled on all links 527 which are part of the Segment Routing enabled topology independent of 528 the existence of link attribute advertisements. 530 In the case of LFA, advertisement of application specific link 531 attributes does NOT indicate enablement of LFA on that link. 532 Enablement is controlled by local configuration. 534 If, in the future, additional standard applications are defined to 535 use this mechanism, the specification defining this use MUST define 536 the relationship between application specific link attribute 537 advertisements and enablement for that application. 539 This document allows the advertisement of application specific link 540 attributes with no application identifiers i.e., both the Standard 541 Application Identifier Bit-Mask and the User Defined Application Bit 542 Mask are not present (See Section 3). This supports the use of the 543 link attribute by any application. In the presence of an application 544 where the advertisement of link attribute advertisements is used to 545 infer the enablement of an application on that link (e.g., RSVP-TE), 546 the absence of the Application Identifier leaves ambiguous whether 547 that application is enabled on such a link. This needs to be 548 considered when making use of the "any application" encoding. 550 10. Backward Compatibility 552 Link attributes may be concurrently advertised in both the TE Opaque 553 LSA and the Extended Link Opaque LSA in OSPFv2 and the OSPFv3 Intra- 554 Area-TE-LSA and OSPFv3 Extended LSA Router-Link TLV in OSPFv3. 556 In fact, there is at least one OSPF implementation that utilizes the 557 link attributes advertised in TE Opaque LSAs [RFC3630] for Non-RSVP 558 TE applications. For example, this implementation of LFA and remote 559 LFA utilizes links attributes such as Shared Risk Link Groups (SRLG) 560 [RFC4203] and Admin Group [[RFC3630] advertised in TE Opaque LSAs. 561 These applications are described in [RFC5286], [RFC7490], [RFC7916] 562 and [RFC8102]. 564 When an OSPF routing domain includes routers using link attributes 565 from the OSPFv2 TE Opaque LSAs or the OSPFv3 Intra-Area-TE-LSA for 566 Non-RSVP TE applications defined in this document (i.e. SRTE and 567 LFA), OSPF routers in that domain SHOULD continue to advertise such 568 OSPFv2 TE Opaque LSAs or the OSPFv3 Intra-Area-TE-LSA. In such a 569 deployment, the advertised attributes SHOULD be the same and Non- 570 RSVP application access to link attributes is a matter of local 571 policy. 573 When advertising link-attributes for any new applications other then 574 RSVP-TE, SRTE or LFA, OSPF routers MUST NOT use TE Opaque LSA or 575 OSPFv3 Intra-Area-TE-LSA. Instead, advertisement in the OSPFv2 576 Extended Link Attributes LSAs or OSPFv3 E-Router-LSA MUST be used. 578 It is RECOMMENDED to advertise link-attributes for RSVP-TE in the 579 existing TE LSAs. 581 11. Security Considerations 583 Existing security extensions as described in [RFC2328], [RFC5340] and 584 [RFC8362] apply to extensions defined in this document. While OSPF 585 is under a single administrative domain, there can be deployments 586 where potential attackers have access to one or more networks in the 587 OSPF routing domain. In these deployments, stronger authentication 588 mechanisms such as those specified in [RFC5709], [RFC7474], [RFC4552] 589 or [RFC7166] SHOULD be used. 591 Implementations MUST assure that malformed TLV and Sub-TLV defined in 592 this document are detected and do not provide a vulnerability for 593 attackers to crash the OSPF router or routing process. Reception of 594 a malformed TLV or Sub-TLV SHOULD be counted and/or logged for 595 further analysis. Logging of malformed TLVs and Sub-TLVs SHOULD be 596 rate-limited to prevent a Denial of Service (DoS) attack (distributed 597 or otherwise) from overloading the OSPF control plane. 599 12. IANA Considerations 601 12.1. OSPFv2 603 OSPFv2 Extended Link TLV Sub-TLVs registry [RFC7684] defines sub-TLVs 604 at any level of nesting for OSPFv2 Extended Link TLVs. This 605 specification updates OSPFv2 Extended Link TLV sub-TLVs registry with 606 the following TLV types: 608 10 - Application Specific Link Attributes 610 11 - Shared Risk Link Group 612 12 - Unidirectional Link Delay 614 13 - Min/Max Unidirectional Link Delay 616 14 - Unidirectional Delay Variation 618 15 - Unidirectional Link Loss 620 16 - Unidirectional Residual Bandwidth 622 17 - Unidirectional Available Bandwidth 624 18 - Unidirectional Utilized Bandwidth 625 19 - Administrative Group 627 20 - Extended Administrative Group 629 22 - TE Metric 631 23 - Maximum Link Bandwidth 633 12.2. OSPFv3 635 OSPFv3 Extended LSA Sub-TLV Registry [RFC8362] defines sub-TLVs at 636 any level of nesting for OSPFv3 Extended LSAs. This specification 637 updates OSPFv3 Extended LSA Sub-TLV Registry with the following TLV 638 types: 640 11 - Application Specific Link Attributes 642 12 - Shared Risk Link Group 644 13 - Unidirectional Link Delay 646 14 - Min/Max Unidirectional Link Delay 648 15 - Unidirectional Delay Variation 650 16 - Unidirectional Link Loss 652 16 - Unidirectional Residual Bandwidth 654 18 - Unidirectional Available Bandwidth 656 19 - Unidirectional Utilized Bandwidth 658 20 - Administrative Group 660 21 - Extended Administrative Group 662 22 - TE Metric 664 23 - Maximum Link Bandwidth 666 24 - Local Interface IPv6 Address Sub-TLV 668 25 - Remote Interface IPv6 Address Sub-TLV 670 13. Contributors 672 The following people contributed to the content of this document and 673 should be considered as co-authors: 675 Acee Lindem 676 Cisco Systems 677 301 Midenhall Way 678 Cary, NC 27513 679 USA 681 Email: acee@cisco.com 683 Ketan Talaulikar 684 Cisco Systems, Inc. 685 India 687 Email: ketant@cisco.com 689 Hannes Gredler 690 RtBrick Inc. 691 Austria 693 Email: hannes@rtbrick.com 695 14. Acknowledgments 697 Thanks to Chris Bowers for his review and comments. 699 15. References 701 15.1. Normative References 703 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 704 Requirement Levels", BCP 14, RFC 2119, 705 DOI 10.17487/RFC2119, March 1997, 706 . 708 [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering 709 (TE) Extensions to OSPF Version 2", RFC 3630, 710 DOI 10.17487/RFC3630, September 2003, 711 . 713 [RFC5329] Ishiguro, K., Manral, V., Davey, A., and A. Lindem, Ed., 714 "Traffic Engineering Extensions to OSPF Version 3", 715 RFC 5329, DOI 10.17487/RFC5329, September 2008, 716 . 718 [RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF 719 for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008, 720 . 722 [RFC7308] Osborne, E., "Extended Administrative Groups in MPLS 723 Traffic Engineering (MPLS-TE)", RFC 7308, 724 DOI 10.17487/RFC7308, July 2014, 725 . 727 [RFC7684] Psenak, P., Gredler, H., Shakir, R., Henderickx, W., 728 Tantsura, J., and A. Lindem, "OSPFv2 Prefix/Link Attribute 729 Advertisement", RFC 7684, DOI 10.17487/RFC7684, November 730 2015, . 732 [RFC8362] Lindem, A., Roy, A., Goethals, D., Reddy Vallem, V., and 733 F. Baker, "OSPFv3 Link State Advertisement (LSA) 734 Extensibility", RFC 8362, DOI 10.17487/RFC8362, April 735 2018, . 737 15.2. Informative References 739 [I-D.ietf-isis-te-app] 740 Ginsberg, L., Psenak, P., Previdi, S., Henderickx, W., and 741 J. Drake, "IS-IS TE Attributes per application", draft- 742 ietf-isis-te-app-08 (work in progress), October 2019. 744 [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, 745 DOI 10.17487/RFC2328, April 1998, 746 . 748 [RFC4203] Kompella, K., Ed. and Y. Rekhter, Ed., "OSPF Extensions in 749 Support of Generalized Multi-Protocol Label Switching 750 (GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October 2005, 751 . 753 [RFC4552] Gupta, M. and N. Melam, "Authentication/Confidentiality 754 for OSPFv3", RFC 4552, DOI 10.17487/RFC4552, June 2006, 755 . 757 [RFC5286] Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for 758 IP Fast Reroute: Loop-Free Alternates", RFC 5286, 759 DOI 10.17487/RFC5286, September 2008, 760 . 762 [RFC5709] Bhatia, M., Manral, V., Fanto, M., White, R., Barnes, M., 763 Li, T., and R. Atkinson, "OSPFv2 HMAC-SHA Cryptographic 764 Authentication", RFC 5709, DOI 10.17487/RFC5709, October 765 2009, . 767 [RFC5714] Shand, M. and S. Bryant, "IP Fast Reroute Framework", 768 RFC 5714, DOI 10.17487/RFC5714, January 2010, 769 . 771 [RFC7166] Bhatia, M., Manral, V., and A. Lindem, "Supporting 772 Authentication Trailer for OSPFv3", RFC 7166, 773 DOI 10.17487/RFC7166, March 2014, 774 . 776 [RFC7471] Giacalone, S., Ward, D., Drake, J., Atlas, A., and S. 777 Previdi, "OSPF Traffic Engineering (TE) Metric 778 Extensions", RFC 7471, DOI 10.17487/RFC7471, March 2015, 779 . 781 [RFC7474] Bhatia, M., Hartman, S., Zhang, D., and A. Lindem, Ed., 782 "Security Extension for OSPFv2 When Using Manual Key 783 Management", RFC 7474, DOI 10.17487/RFC7474, April 2015, 784 . 786 [RFC7490] Bryant, S., Filsfils, C., Previdi, S., Shand, M., and N. 787 So, "Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)", 788 RFC 7490, DOI 10.17487/RFC7490, April 2015, 789 . 791 [RFC7855] Previdi, S., Ed., Filsfils, C., Ed., Decraene, B., 792 Litkowski, S., Horneffer, M., and R. Shakir, "Source 793 Packet Routing in Networking (SPRING) Problem Statement 794 and Requirements", RFC 7855, DOI 10.17487/RFC7855, May 795 2016, . 797 [RFC7916] Litkowski, S., Ed., Decraene, B., Filsfils, C., Raza, K., 798 Horneffer, M., and P. Sarkar, "Operational Management of 799 Loop-Free Alternates", RFC 7916, DOI 10.17487/RFC7916, 800 July 2016, . 802 [RFC8102] Sarkar, P., Ed., Hegde, S., Bowers, C., Gredler, H., and 803 S. Litkowski, "Remote-LFA Node Protection and 804 Manageability", RFC 8102, DOI 10.17487/RFC8102, March 805 2017, . 807 Authors' Addresses 809 Peter Psenak (editor) 810 Cisco Systems 811 Eurovea Centre, Central 3 812 Pribinova Street 10 813 Bratislava 81109 814 Slovakia 816 Email: ppsenak@cisco.com 818 Les Ginsberg 819 Cisco Systems 820 821 Alder Drive 821 MILPITAS, CA 95035 822 USA 824 Email: ginsberg@cisco.com 826 Wim Henderickx 827 Nokia 828 Copernicuslaan 50 829 Antwerp, 2018 94089 830 Belgium 832 Email: wim.henderickx@nokia.com 834 Jeff Tantsura 835 Apstra 836 US 838 Email: jefftant.ietf@gmail.com 840 John Drake 841 Juniper Networks 842 1194 N. Mathilda Ave 843 Sunnyvale, California 94089 844 USA 846 Email: jdrake@juniper.net