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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 7752 (Obsoleted by RFC 9552) ** Obsolete normative reference: RFC 8919 (Obsoleted by RFC 9479) ** Obsolete normative reference: RFC 8920 (Obsoleted by RFC 9492) == Outdated reference: A later version (-17) exists of draft-ietf-idr-bgp-model-10 == Outdated reference: A later version (-19) exists of draft-ietf-idr-eag-distribution-16 Summary: 3 errors (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Inter-Domain Routing K. Talaulikar, Ed. 3 Internet-Draft P. Psenak 4 Intended status: Standards Track Cisco Systems 5 Expires: November 22, 2021 J. Tantsura 6 Apstra 7 May 21, 2021 9 Application-Specific Attributes Advertisement with BGP Link-State 10 draft-ietf-idr-bgp-ls-app-specific-attr-06 12 Abstract 14 Various link attributes have been defined in link-state routing 15 protocols like OSPF and IS-IS in the context of the MPLS Traffic 16 Engineering (TE) and GMPLS. BGP Link-State (BGP-LS) extensions have 17 been defined to distribute these attributes along with other topology 18 information from these link-state routing protocols. Many of these 19 link attributes can be used for applications other than MPLS-TE or 20 GMPLS. 22 Extensions to link-state routing protocols have been defined for such 23 link attributes that enable distribution of their application- 24 specific values. This document defines extensions to BGP-LS address- 25 family to enable advertisement of these application-specific 26 attributes as a part of the topology information from the network. 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 https://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 November 22, 2021. 45 Copyright Notice 47 Copyright (c) 2021 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 (https://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 Table of Contents 62 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 63 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 64 2. Application Specific Link Attributes TLV . . . . . . . . . . 3 65 3. Application-Specific Link Attributes . . . . . . . . . . . . 5 66 4. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 7 67 5. Deployment Considerations . . . . . . . . . . . . . . . . . . 9 68 6. Backward Compatibility . . . . . . . . . . . . . . . . . . . 9 69 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 70 8. Manageability Considerations . . . . . . . . . . . . . . . . 10 71 9. Security Considerations . . . . . . . . . . . . . . . . . . . 10 72 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11 73 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 74 11.1. Normative References . . . . . . . . . . . . . . . . . . 11 75 11.2. Informative References . . . . . . . . . . . . . . . . . 11 76 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 78 1. Introduction 80 Various link attributes have been defined in link-state routing 81 protocols (viz., IS-IS [RFC1195], OSPFv2 [RFC2328] and OSPFv3 82 [RFC5340] ) in the context of the MPLS traffic engineering and GMPLS. 83 All these attributes are distributed by these protocols using TLVs 84 that were originally defined for traditional MPLS Traffic Engineering 85 (i.e., using RSVP-TE [RFC3209]) or GMPLS [RFC4202] applications. 87 In recent years new applications have been introduced that have use 88 cases for many of the link attributes historically used by RSVP-TE 89 and GMPLS. Such applications include Segment Routing (SR) Policy 90 [RFC8402] and Loop Free Alternates (LFA) [RFC5286]. This has 91 introduced ambiguity in that if a deployment includes a mix of RSVP- 92 TE support and SR Policy support (for example) it is not possible to 93 unambiguously indicate which advertisements are to be used by RSVP-TE 94 and which advertisements are to be used by SR Policy. If the 95 topologies are fully congruent this may not be an issue, but any 96 incongruence leads to ambiguity. An additional issue arises in cases 97 where both applications are supported on a link but the link 98 attribute values associated with each application differ. Current 99 advertisements do not support advertising application-specific values 100 for the same attribute on a specific link. 102 [RFC8920] and [RFC8919] define extensions for OSPF and IS-IS 103 respectively that address these issues. Also, as the evolution of 104 use cases for link attributes can be expected to continue in the 105 years to come, these documents define an easily extensible solution 106 for the introduction of new applications and new use cases. 108 BGP Link-State extensions [RFC7752] have been specified to enable 109 distribution of the link-state topology information from the IGPs to 110 an application like a controller or Path Computation Engine (PCE) via 111 BGP. The controller/PCE gets the end-to-end topology information 112 across IGP domains so it can perform path computations for use cases 113 like end-to-end traffic engineering (TE) using RSVP-TE or SR Policy 114 mechanisms. A similar challenge to what was described above is hence 115 also faced by such centralized computation entities. 117 There is thus a need for BGP-LS extensions to also report link 118 attributes on a per-application basis on the same lines as introduced 119 in the link-state routing protocols. This document defines these 120 BGP-LS extensions and also covers the backward compatibility issues 121 related to existing BGP-LS deployments. 123 1.1. Requirements Language 125 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 126 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 127 "OPTIONAL" in this document are to be interpreted as described in BCP 128 14 [RFC2119] [RFC8174] when, and only when, they appear in all 129 capitals, as shown here. 131 2. Application Specific Link Attributes TLV 133 The BGP-LS [RFC7752] specifies the Link NLRI for the advertisement of 134 links and their attributes using the BGP-LS Attribute. The 135 Application-Specific Link Attributes (ASLA) TLV is a new optional 136 top-level BGP-LS Attribute TLV that is introduced for Link NLRIs. It 137 is defined such that it may act as a container for certain existing 138 and future link attributes that require application-specific 139 definition. 141 The format of this TLV is as follows and is similar to the 142 corresponding ASLA sub-TLVs defined for OSPF and IS-IS in [RFC8920] 143 and [RFC8919] respectively. 145 0 1 2 3 146 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 1 147 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 148 | Type | Length | 149 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 150 | SABM Length | UDABM Length | Reserved | 151 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 152 | Standard Application Identifier Bit Mask (variable) // 153 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 154 | User-Defined Application Identifier Bit Mask (variable) // 155 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 156 | Link Attribute sub-TLVs // 157 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 159 Figure 1: Application-Specific Link Attributes TLV 161 where: 163 o Type: 1122 165 o Length: variable. 167 o SABM Length : Standard Application Identifier Bit Mask Length in 168 octets. The values MUST be 0, 4, or 8. If the Standard 169 Application Identifier Bit Mask is not present, the value MUST be 170 set to 0. 172 o UDABM Length : User-Defined Application Identifier Bit Mask Length 173 in octets. The values MUST be 0, 4, or 8. If the User-Defined 174 Application Identifier Bit Mask is not present, the value MUST be 175 set to 0. 177 o Standard Application Identifier Bit Mask : of size 0, 4, or 8 178 octets as indicated by the SABML. Optional set of bits, where 179 each bit represents a single standard application. The bits are 180 defined in the IANA "IGP Parameters" registries under the "Link 181 Attribute Applications" registry [RFC8919]. 183 o User-Defined Application Identifier Bit Mask : of size 0, 4, or 8 184 octets as indicated by the UDABML. Optional set of bits, where 185 each bit represents a single user-defined application. The bits 186 are not managed or assigned by IANA or any other standards body 187 and definition is left to the implementation. 189 o sub-TLVs : BGP-LS Attribute TLVs corresponding to the Link NLRI 190 that are application-specific (as specified in Section 3) are 191 included as sub-TLVs of the ASLA TLV. 193 An ASLA TLV with both the SABML and UDABML set to 0 (i.e. without any 194 application identifier bit masks) indicates that the link attribute 195 sub-TLVs that it encloses are applicable for all applications. 197 The ASLA TLV and its sub-TLVs can only be added to the BGP-LS 198 Attribute associated with the Link NLRI of the node that originates 199 the underlying IGP link attribute TLVs/sub-TLVs. The procedures for 200 originating link attributes in the ASLA TLV from underlying IGPs are 201 specified in Section 4. 203 When the node is not running any of the IGPs but running a protocol 204 like BGP, then the link attributes for the node's local links MAY be 205 originated as part of the BGP-LS Attribute using the ASLA TLV and its 206 sub-TLVs within the Link NLRI corresponding to the local node. 208 3. Application-Specific Link Attributes 210 Several BGP-LS Attribute TLVs corresponding to the Link NLRI are 211 defined in BGP-LS and more may be added in the future. The following 212 types of link attributes are required to be considered application- 213 specific. 215 o those that have different values for different applications (e.g., 216 a different TE metric value used for RSVP-TE than for SR Policy) 218 o those that apply to multiple applications but need to be used only 219 by a specific application (e.g., certain SRLG values are 220 configured on a node for LFA but the same do not need to be used 221 for RSVP-TE) 223 The following table lists the currently defined BGP-LS Attributes 224 TLVs corresponding to Link NLRI that have application-specific 225 semantics. These were originally defined with semantics for RSVP-TE 226 and GMPLS applications. 228 +-----------+---------------------+---------------------------------+ 229 | TLV Code | Description | Reference Document | 230 | Point | | | 231 +-----------+---------------------+---------------------------------+ 232 | 1088 | Administrative | [RFC7752] | 233 | | group (color) | | 234 | 1092 | TE Default Metric | [RFC7752] | 235 | 1096 | Shared Risk Link | [RFC7752] | 236 | | Group | | 237 | 1114 | Unidirectional Link | [RFC8571] | 238 | | Delay | | 239 | 1115 | Min/Max | [RFC8571] | 240 | | Unidirectional Link | | 241 | | Delay | | 242 | 1116 | Unidirectional | [RFC8571] | 243 | | Delay Variation | | 244 | 1117 | Unidirectional Link | [RFC8571] | 245 | | Loss | | 246 | 1118 | Unidirectional | [RFC8571] | 247 | | Residual Bandwidth | | 248 | 1119 | Unidirectional | [RFC8571] | 249 | | Available Bandwidth | | 250 | 1120 | Unidirectional | [RFC8571] | 251 | | Utilized Bandwidth | | 252 | 1173 | Extended | [I-D.ietf-idr-eag-distribution] | 253 | | Administrative | | 254 | | Group | | 255 +-----------+---------------------+---------------------------------+ 257 Table 1: BGP-LS Attribute TLVs also used as sub-TLVs of ASLA TLV 259 All the BGP-LS Attribute TLVs defined in the table above are 260 RECOMMENDED to continue to be advertised at the top-level in the BGP- 261 LS Attribute for carrying attributes specific to RSVP-TE without the 262 use of the ASLA TLV. 264 When a new link attribute is introduced, it may be thought of as 265 being specific to only a single application. However, subsequently, 266 it may be also shared by other applications and/or require 267 application-specific values. In such cases, it is RECOMMENDED to err 268 on the side of caution and define such attributes as application- 269 specific to ensure flexibility in the future. 271 BGP-LS Attribute TLVs corresponding to Link NLRI that are defined in 272 the future MUST specify if they are application-specific and hence 273 are REQUIRED to be encoded within an ASLA TLV. 275 Only application-specific link attributes need to be advertised 276 within the ASLA TLV. Link attributes that do not have application- 277 specific semantics MUST NOT be advertised within the ASLA TLV. 278 Receivers MUST ignore any non-application-specific attribute sub-TLVs 279 within the ASLA TLV. 281 When the same application-specific link attributes are advertised 282 both within the ASLA TLV and as top-level TLVs in the BGP-LS 283 Attribute, the attributes advertised within the ASLA TLV take 284 precedence for the applications indicated in the ASLA TLV encoding. 286 4. Procedures 288 The procedures described in this section apply to networks where all 289 BGP-LS originators and consumers support this specification. The 290 backward compatibility aspects and operations in deployments where 291 there are some BGP-LS originators or consumers that do not support 292 this specification are described further in Section 6. 294 The BGP-LS originator learns of the association of an application- 295 specific attribute to one or more applications from either the 296 underlying IGP protocol LSA/LSPs from which it is advertising the 297 topology information or from the local node configuration when 298 advertising attributes for the local node only. 300 The association of an application-specific link attribute with a 301 specific application context when advertising attributes for the 302 local node only (e.g., when running BGP as the only routing protocol) 303 is an implementation-specific matter and outside the scope of this 304 document. 306 [RFC8920] and [RFC8919] specify the mechanisms for advertising 307 application-specific link attributes in OSPFv2/v3 and IS-IS 308 respectively. These IGP specifications also describe the backward 309 compatibility aspects and the existing RSVP-TE/GMPLS specific TLV 310 encoding mechanisms in the respective protocols. 312 A BGP-LS originator node that is advertising link-state information 313 from the underlying IGP determines the protocol encoding of 314 application-specific link attributes based on the following rules: 316 1. Application-specific link attributes received from an IGP node 317 using existing RSVP-TE/GMPLS encodings MUST be encoded using the 318 respective BGP-LS top-level TLVs listed in Table 1. 320 2. Application-specific link attributes received from an IGP node 321 using ASLA sub-TLV MUST be encoded in the BGP-LS ASLA TLV as sub- 322 TLVs. 324 3. In the case of IS-IS, the following specific procedures are to be 325 followed: 327 * When application-specific link attributes are received from a 328 node with the L bit set in the ASLA sub-TLV AND application 329 bits other than RSVP-TE are set in the application bit masks 330 then the application-specific link attributes advertised in 331 the corresponding legacy IS-IS TLVs/sub-TLVs MUST be encoded 332 within the BGP-LS ASLA TLV as sub-TLVs with the application 333 bits, other than the RSVP-TE bit, copied from the IS-IS ASLA 334 sub-TLV. The link attributes advertised in the legacy IS-IS 335 TLVs/sub-TLVs are also advertised in BGP-LS top-level TLVs 336 listed in Table 1. Note that this is true regardless of 337 whether the RSVP-TE bit was set in the IS-IS ASLA TLV/sub-TLV. 339 * When the ASLA sub-TLV has the RSVP-TE application bit set, 340 then the link attributes for the corresponding ASLA sub-TLV 341 MUST be encoded using the respective BGP-LS top-level TLVs 342 listed in Table 1. 344 * [RFC8919] allows the advertisement of the Maximum Link 345 Bandwidth within an ASLA sub-TLV even though it is not an 346 application-specific attribute. However, when originating the 347 Maximum Link Bandwidth into BGP-LS, the attribute MUST be 348 encoded only in the top-level BGP-LS Maximum Link Bandwidth 349 TLV (1089) and the receiver MUST ignore them when advertised 350 within the BGP-LS ASLA TLV. 352 * [RFC8919] also allows the advertisement of the Maximum 353 Reservable Link Bandwidth and the Unreserved Bandwidth within 354 an ASLA sub-TLV even though these attributes are specific to 355 RSVP-TE application. However, when originating the Maximum 356 Reservable Link Bandwidth and Unreserved Bandwidth into BGP- 357 LS, these attributes MUST be encoded only in the BGP-LS top- 358 level Maximum Reservable Link Bandwidth TLV (1090) and 359 Unreserved Bandwidth TLV (1091) respectively and not within 360 the BGP-LS ASLA TLV. 362 These rules ensure that a BGP-LS originator performs the 363 advertisement for all application-specific link attributes from the 364 IGP nodes that support or do not support the ASLA extension. 365 Furthermore, it also ensures that the top-level BGP-LS TLVs defined 366 for RSVP-TE and GMPLS applications continue to be used for 367 advertisement of their application-specific attributes. 369 A BGP-LS consumer node would normally receive all the application- 370 specific link attributes corresponding to RSVP-TE and GMPLS 371 applications as existing top-level BGP-LS TLVs while for other 372 applications they are encoded in ASLA TLV(s) with appropriate 373 applicable bit mask setting. A BGP-LS consumer that implements this 374 specification SHOULD prefer the application-specific attribute value 375 received via sub-TLVs within the ASLA TLV over the value received via 376 the top-level TLVs. 378 5. Deployment Considerations 380 SR Policy and LFA applications have been deployed in some networks 381 using the IGP link attributes defined originally for RSVP-TE as 382 discussed in [RFC8920] and [RFC8919]. The corresponding BGP-LS top- 383 level link attribute TLVs originally defined for RSVP-TE have also 384 been similarly used for SR Policy and LFA applications by BGP-LS 385 consumers. Such usage MAY continue without requiring the support of 386 the application-specific link attribute encodings described in this 387 document as long as the following conditions are met: 389 o The application is SR Policy or LFA and RSVP-TE is not deployed 390 anywhere in the network 392 o The application is SR Policy or LFA, RSVP-TE is deployed in the 393 network, and both the set of links on which SR Policy and/or LFA 394 advertisements are required and the attribute values used by SR 395 Policy and/or LFA on all such links is fully congruent with the 396 links and attribute values used by RSVP-TE 398 6. Backward Compatibility 400 The backward compatibility aspects for BGP-LS are associated with the 401 originators (i.e., nodes) and consumers (e.g., PCE, controllers, 402 applications, etc.) of the topology information. BGP-LS 403 implementations have been originating link attributes and consuming 404 them without any application-specific scoping prior to the extensions 405 specified in this document. 407 IGP backward compatibility aspects associated with application- 408 specific link attributes for RSVP-TE, SR Policy, and LFA applications 409 are discussed in the Backward Compatibility sections of [RFC8920] and 410 [RFC8919]. While the backward compatibility aspects ensure 411 compatibility of IGP advertisements, they also serve to ensure the 412 backward compatibility of the BGP-LS advertisements used by BGP-LS 413 consumers. In deployments where the BGP-LS originators or consumers 414 do not support the extensions specified in this document, the IGPs 415 need to continue to advertise link attributes intended for use by SR 416 Policy and LFA applications using the RSVP-TE/GMPLS encodings. This 417 allows BGP-LS advertisements to be consistent with the behavior prior 418 to the extensions defined in this document 419 It is RECOMMENDED that nodes that support this specification are 420 selected as originators of BGP-LS information when advertising the 421 link-state information from the IGPs. 423 7. IANA Considerations 425 This document requests assignment of code-points from the registry 426 "BGP-LS Node Descriptor, Link Descriptor, Prefix Descriptor, and 427 Attribute TLVs" based on the table below which reflects the values 428 assigned via the early allocation process. The column "IS-IS TLV/ 429 Sub-TLV" defined in the registry does not require any value and 430 should be left empty. 432 +------------+------------------------------------------+----------+ 433 | Code Point | Description | Length | 434 +------------+------------------------------------------+----------+ 435 | 1122 | Application-Specific Link Attributes TLV | variable | 436 +------------+------------------------------------------+----------+ 438 8. Manageability Considerations 440 The new protocol extensions introduced in this document augment the 441 existing IGP topology information defined in [RFC7752]. Procedures 442 and protocol extensions defined in this document do not affect the 443 BGP protocol operations and management other than as discussed in the 444 Manageability Considerations section of [RFC7752]. Specifically, the 445 malformed NLRIs attribute tests in the Fault Management section of 446 [RFC7752] now encompasses the BGP-LS TLVs defined in this document. 448 The extensions specified in this document do not specify any new 449 configuration or monitoring aspects in BGP or BGP-LS. The 450 specification of BGP models is an ongoing work based on 451 [I-D.ietf-idr-bgp-model]. 453 9. Security Considerations 455 The procedures and protocol extensions defined in this document do 456 not affect the BGP security model. See the "Security Considerations" 457 section of [RFC4271] for a discussion of BGP security. Also, refer 458 to [RFC4272] and [RFC6952] for analyses of security issues for BGP. 459 Security considerations for acquiring and distributing BGP-LS 460 information are discussed in [RFC7752]. The TLVs introduced in this 461 document are used to propagate the application-specific link 462 attributes IGP extensions defined in [RFC8919] and [RFC8920]. It is 463 assumed that the IGP instances originating these TLVs will support 464 all the required security (as described in [RFC8919] and [RFC8920]) 465 in order to prevent any security issues when propagating the TLVs 466 into BGP-LS. The advertisement of the link attribute information 467 defined in this document presents no significant additional risk 468 beyond that associated with the existing link attribute information 469 already supported in [RFC7752]. 471 10. Acknowledgements 473 The authors would like to thank Les Ginsberg, Baalajee S, Amalesh 474 Maity, Acee Lindem, Keyur Patel and Paul Wouters for their review and 475 feedback on this document. 477 11. References 479 11.1. Normative References 481 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 482 Requirement Levels", BCP 14, RFC 2119, 483 DOI 10.17487/RFC2119, March 1997, 484 . 486 [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and 487 S. Ray, "North-Bound Distribution of Link-State and 488 Traffic Engineering (TE) Information Using BGP", RFC 7752, 489 DOI 10.17487/RFC7752, March 2016, 490 . 492 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 493 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 494 May 2017, . 496 [RFC8919] Ginsberg, L., Psenak, P., Previdi, S., Henderickx, W., and 497 J. Drake, "IS-IS Application-Specific Link Attributes", 498 RFC 8919, DOI 10.17487/RFC8919, October 2020, 499 . 501 [RFC8920] Psenak, P., Ed., Ginsberg, L., Henderickx, W., Tantsura, 502 J., and J. Drake, "OSPF Application-Specific Link 503 Attributes", RFC 8920, DOI 10.17487/RFC8920, October 2020, 504 . 506 11.2. Informative References 508 [I-D.ietf-idr-bgp-model] 509 Jethanandani, M., Patel, K., Hares, S., and J. Haas, "BGP 510 YANG Model for Service Provider Networks", draft-ietf-idr- 511 bgp-model-10 (work in progress), November 2020. 513 [I-D.ietf-idr-eag-distribution] 514 Tantsura, J., Wang, Z., Wu, Q., and K. Talaulikar, 515 "Distribution of Traffic Engineering Extended 516 Administrative Groups using BGP-LS", draft-ietf-idr-eag- 517 distribution-16 (work in progress), April 2021. 519 [RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and 520 dual environments", RFC 1195, DOI 10.17487/RFC1195, 521 December 1990, . 523 [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, 524 DOI 10.17487/RFC2328, April 1998, 525 . 527 [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., 528 and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP 529 Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, 530 . 532 [RFC4202] Kompella, K., Ed. and Y. Rekhter, Ed., "Routing Extensions 533 in Support of Generalized Multi-Protocol Label Switching 534 (GMPLS)", RFC 4202, DOI 10.17487/RFC4202, October 2005, 535 . 537 [RFC4271] Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A 538 Border Gateway Protocol 4 (BGP-4)", RFC 4271, 539 DOI 10.17487/RFC4271, January 2006, 540 . 542 [RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis", 543 RFC 4272, DOI 10.17487/RFC4272, January 2006, 544 . 546 [RFC5286] Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for 547 IP Fast Reroute: Loop-Free Alternates", RFC 5286, 548 DOI 10.17487/RFC5286, September 2008, 549 . 551 [RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF 552 for IPv6", RFC 5340, DOI 10.17487/RFC5340, July 2008, 553 . 555 [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of 556 BGP, LDP, PCEP, and MSDP Issues According to the Keying 557 and Authentication for Routing Protocols (KARP) Design 558 Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, 559 . 561 [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., 562 Decraene, B., Litkowski, S., and R. Shakir, "Segment 563 Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, 564 July 2018, . 566 [RFC8571] Ginsberg, L., Ed., Previdi, S., Wu, Q., Tantsura, J., and 567 C. Filsfils, "BGP - Link State (BGP-LS) Advertisement of 568 IGP Traffic Engineering Performance Metric Extensions", 569 RFC 8571, DOI 10.17487/RFC8571, March 2019, 570 . 572 Authors' Addresses 574 Ketan Talaulikar (editor) 575 Cisco Systems 576 India 578 Email: ketant@cisco.com 580 Peter Psenak 581 Cisco Systems 582 Slovakia 584 Email: ppsenak@cisco.com 586 Jeff Tantsura 587 Apstra 589 Email: jefftant.ietf@gmail.com