idnits 2.17.1 draft-ietf-isis-te-app-00.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year == Line 513 has weird spacing: '...pecific y ...' == Line 520 has weird spacing: '...pecific n ...' -- The document date (August 18, 2017) is 2414 days in the past. Is this intentional? 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 5226 (Obsoleted by RFC 8126) ** Obsolete normative reference: RFC 7810 (Obsoleted by RFC 8570) Summary: 2 errors (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Networking Working Group L. Ginsberg 3 Internet-Draft P. Psenak 4 Intended status: Standards Track Cisco Systems 5 Expires: February 19, 2018 S. Previdi 6 Individual 7 W. Henderickx 8 Nokia 9 J. Drake 10 Juniper Networks 11 August 18, 2017 13 IS-IS TE Attributes per application 14 draft-ietf-isis-te-app-00.txt 16 Abstract 18 Existing traffic engineering related link attribute advertisements 19 have been defined and are used in RSVP-TE deployments. In cases 20 where multiple applications wish to make use of these link attributes 21 the current advertisements do not support application specific values 22 for a given attribute nor do they support indication of which 23 applications are using the advertised value for a given link. 25 This draft introduces new link attribute advertisements which address 26 both of these shortcomings. It also discusses backwards 27 compatibility issues and how to minimize duplicate advertisements in 28 the presence of routers which do not support the extensions defined 29 in this document. 31 Requirements Language 33 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 34 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 35 document are to be interpreted as described in RFC 2119 [RFC2119]. 37 Status of This Memo 39 This Internet-Draft is submitted in full conformance with the 40 provisions of BCP 78 and BCP 79. 42 Internet-Drafts are working documents of the Internet Engineering 43 Task Force (IETF). Note that other groups may also distribute 44 working documents as Internet-Drafts. The list of current Internet- 45 Drafts is at http://datatracker.ietf.org/drafts/current/. 47 Internet-Drafts are draft documents valid for a maximum of six months 48 and may be updated, replaced, or obsoleted by other documents at any 49 time. It is inappropriate to use Internet-Drafts as reference 50 material or to cite them other than as "work in progress." 52 This Internet-Draft will expire on February 19, 2018. 54 Copyright Notice 56 Copyright (c) 2017 IETF Trust and the persons identified as the 57 document authors. All rights reserved. 59 This document is subject to BCP 78 and the IETF Trust's Legal 60 Provisions Relating to IETF Documents 61 (http://trustee.ietf.org/license-info) in effect on the date of 62 publication of this document. Please review these documents 63 carefully, as they describe your rights and restrictions with respect 64 to this document. Code Components extracted from this document must 65 include Simplified BSD License text as described in Section 4.e of 66 the Trust Legal Provisions and are provided without warranty as 67 described in the Simplified BSD License. 69 Table of Contents 71 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 72 2. Requirements Discussion . . . . . . . . . . . . . . . . . . . 3 73 3. Legacy Advertisements . . . . . . . . . . . . . . . . . . . . 4 74 3.1. Legacy sub-TLVs . . . . . . . . . . . . . . . . . . . . . 4 75 3.2. Legacy SRLG Advertisements . . . . . . . . . . . . . . . 5 76 4. Advertising Application Specific Link Attributes . . . . . . 5 77 4.1. Application Identifier Bit Mask . . . . . . . . . . . . . 5 78 4.2. Application Specific Link Attributes sub-TLV . . . . . . 7 79 4.3. Application Specific SRLG TLV . . . . . . . . . . . . . . 8 80 5. Deployment Considerations . . . . . . . . . . . . . . . . . . 9 81 6. Attribute Advertisements and Enablement . . . . . . . . . . . 10 82 7. Interoperability, Backwards Compatibility and Migration 83 Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . 10 84 7.1. RSVP-TE only deployments . . . . . . . . . . . . . . . . 11 85 7.2. Multiple Applications: Common Attributes with RSVP-TE . 11 86 7.3. Multiple Applications: All Attributes Not Shared w RSVP- 87 TE . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 88 7.4. Deprecating legacy advertisements . . . . . . . . . . . . 11 89 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 90 9. Security Considerations . . . . . . . . . . . . . . . . . . . 13 91 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 13 92 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 93 11.1. Normative References . . . . . . . . . . . . . . . . . . 13 94 11.2. Informative References . . . . . . . . . . . . . . . . . 14 95 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 97 1. Introduction 99 Advertisement of link attributes by the Intermediate-System-to- 100 Intermediate-System (IS-IS) protocol in support of traffic 101 engineering (TE) was introduced by [RFC5305] and extended by 102 [RFC5307], [RFC6119], and [RFC7810]. Use of these extensions has 103 been associated with deployments supporting Traffic Engineering over 104 Multiprotocol Label Switching (MPLS) in the presence of Resource 105 Reservation Protocol (RSVP) - more succinctly referred to as RSVP-TE. 107 In recent years new applications have been introduced which have use 108 cases for many of the link attributes historically used by RSVP-TE. 109 Such applications include Segment Routing Traffic Engineering (SRTE) 110 and Loop Free Alternates (LFA). This has introduced ambiguity in 111 that if a deployment includes a mix of RSVP-TE support and SRTE 112 support (for example) it is not possible to unambiguously indicate 113 which advertisements are to be used by RSVP-TE and which 114 advertisements are to be used by SRTE. If the topologies are fully 115 congruent this may not be an issue, but any incongruence leads to 116 ambiguity. 118 An additional issue arises in cases where both applications are 119 supported on a link but the link attribute values associated with 120 each application differ. Current advertisements do not support 121 advertising application specific values for the same attribute on a 122 specific link. 124 This document defines extensions which address these issues. Also, 125 as evolution of use cases for link attributes can be expected to 126 continue in the years to come, this document defines a solution which 127 is easily extensible to the introduction of new applications and new 128 use cases. 130 2. Requirements Discussion 132 As stated previously, evolution of use cases for link attributes can 133 be expected to continue - so any discussion of existing use cases is 134 limited to requirements which are known at the time of this writing. 135 However, in order to determine the functionality required beyond what 136 already exists in IS-IS, it is only necessary to discuss use cases 137 which justify the key points identified in the introduction - which 138 are: 140 1. Support for indicating which applications are using the link 141 attribute advertisements on a link 143 2. Support for advertising application specific values for the same 144 attribute on a link 146 [RFC7855] discusses use cases/requirements for SR. Included among 147 these use cases is SRTE. If both RSVP-TE and SRTE are deployed in a 148 network, link attribute advertisements can be used by one or both of 149 these applications. As there is no requirement for the link 150 attributes advertised on a given link used by SRTE to be identical to 151 the link attributes advertised on that same link used by RSVP-TE, 152 there is a clear requirement to indicate independently which link 153 attribute advertisements are to be used by each application. 155 As the number of applications which may wish to utilize link 156 attributes may grow in the future, an additional requirement is that 157 the extensions defined allow the association of additional 158 applications to link attributes without altering the format of the 159 advertisements or introducing new backwards compatibility issues. 161 Finally, there may still be many cases where a single attribute value 162 can be shared among multiple applications, so the solution must 163 minimize advertising duplicate link/attribute pairs whenever 164 possible. 166 3. Legacy Advertisements 168 There are existing advertisements used in support of RSVP-TE. These 169 advertisements include sub-TLVs for TLVs 22, 23, 141, 222, and 223 170 and TLVs for SRLG advertisement. 172 3.1. Legacy sub-TLVs 174 Sub-TLVs for TLVs 22, 23, 141, 222, and 223 176 Code Point/Attribute Name 177 -------------------------- 178 3 Administrative group (color) 179 9 Maximum link bandwidth 180 10 Maximum reservable link bandwidth 181 11 Unreserved bandwidth 182 14 Extended Administrative Group 183 33 Unidirectional Link Delay 184 34 Min/Max Unidirectional Link Delay 185 35 Unidirectional Delay Variation 186 36 Unidirectional Link Loss 187 37 Unidirectional Residual Bandwidth 188 38 Unidirectional Available Bandwidth 189 39 Unidirectional Utilized Bandwidth 191 3.2. Legacy SRLG Advertisements 193 TLV 138 GMPLS-SRLG 194 Supports links identified by IPv4 addresses and 195 unnumbered links 197 TLV 139 IPv6 SRLG 198 Supports links identified by IPv6 addresses 200 Note that [RFC6119] prohibits the use of TLV 139 when it is possible 201 to use TLV 138. 203 4. Advertising Application Specific Link Attributes 205 Two new code points are defined in support of Application Specific 206 Link Attribute Advertisements: 208 1) Application Specific Link Attributes sub-TLV for TLVs 22, 23, 141, 209 222, and 223 211 2)Application Specific Shared Risk Link Group (SRLG) TLV 213 In support of these new advertisements, an application bit mask is 214 defined which identifies the application(s) associated with a given 215 advertisement. 217 The following sections define the format of these new advertisements. 219 4.1. Application Identifier Bit Mask 221 Identification of the set of applications associated with link 222 attribute advertisements utilizes two bit masks. One bit mask is for 223 standard applications where the definition of each bit is defined in 224 a new IANA controlled registry. A second bit mask is for non- 225 standard User Defined Applications(UDAs). 227 The encoding defined below is used by both the Application Specific 228 Link Attributes sub-TLV and the Application Specific SRLG TLV. 230 0 1 2 3 4 5 6 7 231 +-+-+-+-+-+-+-+-+ 232 | SABML+F | 1 octet 233 +-+-+-+-+-+-+-+-+ 234 | UDABML+F | 1 octet 235 +-+-+-+-+-+-+-+-+ 236 | SABM ... 0 - 127 octets 237 +-+-+-+-+-+-+-+-+ 238 | UDABM ... 0 - 127 octets 239 +-+-+-+-+-+-+-+-+ 241 SABML+F (1 octet) 242 Standard Application Bit Mask Length/Flags 244 0 1 2 3 4 5 6 7 245 +-+-+-+-+-+-+-+-+ 246 |L| SA-Length | 247 +-+-+-+-+-+-+-+-+ 249 L-flag: Applications listed (both Standard and 250 User Defined) MUST use the legacy advertisements 251 for the corresponding link found in TLVs 22, 23, 252 141, 222, and 223 or TLV 138 or TLV 139 as appropriate. 254 SA-Length: Indicates the length in octets (0-127) of the Bit Mask 255 for Standard Applications. 257 UDABML+F (1 octet) 258 User Defined Application Bit Mask Length/Flags 260 0 1 2 3 4 5 6 7 261 +-+-+-+-+-+-+-+-+ 262 |R| UDA-Length | 263 +-+-+-+-+-+-+-+-+ 265 R: Reserved. Transmitted as 0 and ignored on receipt 267 UDA-Length: Indicates the length in octets (0-127) of the Bit Mask 268 for User Defined Applications. 270 SABM (variable length) 271 Standard Application Bit Mask 273 (SA-Length * 8) bits 275 This is omitted if SA-Length is 0. 277 0 1 2 3 4 5 6 7 ... 278 +-+-+-+-+-+-+-+-+... 279 |R|S|F| ... 280 +-+-+-+-+-+-+-+-+... 282 R-bit: RSVP-TE 283 S-bit: Segment Routing Traffic Engineering 285 F-bit: Loop Free Alternate 287 UDABM (variable length) 288 User Defined Application Bit Mask 290 (UDA Length * 8) bits 292 0 1 2 3 4 5 6 7 ... 293 +-+-+-+-+-+-+-+-+... 294 | ... 295 +-+-+-+-+-+-+-+-+... 297 This is omitted if UDA-Length is 0. 299 NOTE: If both SA-length and UDA-Length are zero, then the 300 attributes associated with this attribute identifier bit mask 301 MAY be used by any Standard Application and any User Defined 302 Application. 304 Standard Application Bits are defined/sent starting with Bit 0. 305 Additional bit definitions that may be defined in the future SHOULD 306 be assigned in ascending bit order so as to minimize the number of 307 octets that will need to be transmitted. Undefined bits MUST be 308 transmitted as 0 and MUST be ignored on receipt. Bits that are NOT 309 transmitted MUST be treated as if they are set to 0 on receipt. 311 User Defined Application bits have no relationship to Standard 312 Application bits and are NOT managed by IANA or any other standards 313 body. It is recommended that bits are used starting with Bit 0 so as 314 to minimize the number of octets required to advertise all UDAs. 316 4.2. Application Specific Link Attributes sub-TLV 318 A new sub-TLV for TLVs 22, 23, 141, 222, and 223 is defined which 319 supports specification of the applications and application specific 320 attribute values. 322 Type: 15 (suggested value - to be assigned by IANA) 323 Length: Variable (1 octet) 324 Value: 326 Application Bit Mask (as defined in Section 3.1) 328 Link Attribute sub-sub-TLVs - format matches the 329 existing formats defined in [RFC5305] and [RFC7810] 331 When the L-flag is set in the Application Identifiers, all of the 332 applications specified in the bit mask MUST use the link attribute 333 sub-TLV advertisements listed in Section 3.1 for the corresponding 334 link. Application specific link attribute sub-sub-TLVs for the 335 corresponding link attributes MUST NOT be advertised for the set of 336 applications specified in the Standard/User Application Bit Masks and 337 all such advertisements MUST be ignored on receipt. 339 Multiple sub-TLVs for the same link MAY be advertised. When multiple 340 sub-TLVs for the same link are advertised, they SHOULD advertise non- 341 conflicting application/attribute pairs. A conflict exists when the 342 same application is associated with two different values of the same 343 link attribute for a given link. In cases where conflicting values 344 for the same application/attribute/link are advertised all the 345 conflicting values MUST be ignored. 347 For a given application, the setting of the L-flag MUST be the same 348 in all sub-TLVs for a given link. In cases where this constraint is 349 violated, the L-flag MUST be considered set for this application. 351 A new registry of sub-sub-TLVs is to be created by IANA which defines 352 the link attribute sub-sub-TLV code points. A sub-sub-TLV is defined 353 for each of the existing sub-TLVs listed in Section 3.1. Format of 354 the sub-sub-TLVs matches the format of the corresponding legacy sub- 355 TLV and IANA is requested to assign the legacy sub-TLV identifer to 356 the corresponding sub-sub-TLV. 358 4.3. Application Specific SRLG TLV 360 A new TLV is defined to advertise application specific SRLGs for a 361 given link. Although similar in functionality to TLV 138 (defined by 362 [RFC5307]) and TLV 139 (defined by [RFC6119], a single TLV provides 363 support for IPv4, IPv6, and unnumbered identifiers for a link. 364 Unlike TLVs 138/139, it utilizes sub-TLVs to encode the link 365 identifiers in order to provide the flexible formatting required to 366 support multiple link identifier types. 368 Type: 238 (Suggested value - to be assigned by IANA) 369 Length: Number of octets in the value field (1 octet) 370 Value: 371 Neighbor System-ID + pseudo-node ID (7 octets) 372 Application Bit Mask (as defined in Section 3.1) 373 Length of sub-TLVs (1 octet) 374 Link Identifier sub-TLVs (variable) 375 0 or more SRLG Values (Each value is 4 octets) 377 The following Link Identifier sub-TLVs are defined. The type 378 values are suggested and will be assigned by IANA - but as 379 the formats are identical to existing sub-TLVs defined for 380 TLVs 22, 23, 141, 222, and 223 the use of the suggested sub-TLV 381 types is strongly encouraged. 383 Type Description 384 4 Link Local/Remote Identifiers (see [RFC5307]) 385 6 IPv4 interface address (see [RFC5305]) 386 8 IPv4 neighbor address (see [RFC5305]) 387 12 IPv6 Interface Address (see [RFC6119]) 388 13 IPv6 Neighbor Address (see [RFC6119]) 390 At least one set of link identifiers (IPv4, IPv6, or unnumbered) MUST 391 be present. TLVs which do not meet this requirement MUST be ignored. 393 Multiple TLVs for the same link MAY be advertised. 395 When the L-flag is set in the Application Identifiers, SRLG values 396 MUST NOT be included in the TLV. Any SRLG values which are 397 advertised MUST be ignored. Based on the link identifiers advertised 398 the corresponding legacy TLV (see Section 3.2) can be identified and 399 the SRLG values advertised in the legacy TLV MUST be used by the set 400 of applications specified in the Application Bit Mask. 402 For a given application, the setting of the L-flag MUST be the same 403 in all TLVs for a given link. In cases where this constraint is 404 violated, the L-flag MUST be considered set for this application. 406 5. Deployment Considerations 408 If link attributes are advertised associated with zero length 409 application bit masks for both standard applications and user defined 410 applications, then that set of link attributes MAY be used by any 411 application. If support for a new application is introduced on any 412 node in a network in the presence of such advertisements, these 413 advertisements MAY be used by the new application. If this is not 414 what is intended, then existing advertisements MUST be readvertised 415 with an explicit set of applications specified before a new 416 application is introduced. 418 6. Attribute Advertisements and Enablement 420 This document defines extensions to support the advertisement of 421 application specific link attributes. The presence or absence of 422 link attribute advertisements for a given application on a link does 423 NOT indicate the state of enablement of that application on that 424 link. Enablement of an application on a link is controlled by other 425 means. 427 For some applications, the concept of enablement is implicit. For 428 example, SRTE implicitly is enabled on all links which are part of 429 the Segment Routing enabled topology. Advertisement of link 430 attributes supports constraints which may be applied when specifying 431 an explicit path through that topology. 433 For other applications enablement is controlled by local 434 configuration. For example, use of a link as an LFA can be 435 controlled by local enablement/disablement and/or the use of 436 administrative tags. 438 It is an application specific policy as to whether a given link can 439 be used by that application even in the abscence of any application 440 specififc link attributes. 442 7. Interoperability, Backwards Compatibility and Migration Concerns 444 Existing deployments of RSVP-TE utilize the legacy advertisements 445 listed in Section 3. Routers which do not support the extensions 446 defined in this document will only process legacy advertisements and 447 are likely to infer that RSVP-TE is enabled on the links for which 448 legacy advertisements exist. It is expected that deployments using 449 the legacy advertisements will persist for a significant period of 450 time - therefore deployments using the extensions defined in this 451 document must be able to co-exist with use of the legacy 452 advertisements by routers which do not support the extensions defined 453 in this document. The following sub-sections discuss 454 interoperability and backwards compatibility concerns for a number of 455 deployment scenarios. 457 Note that in all cases the defined strategy can be employed on a per 458 link basis. 460 7.1. RSVP-TE only deployments 462 In deployments where RSVP-TE is the only application utilizing link 463 attribute advertisements, use of the the legacy advertisements can 464 continue without change. 466 7.2. Multiple Applications: Common Attributes with RSVP-TE 468 In cases where multiple applications are utilizing a given link, one 469 of the applications is RSVP-TE, and all link attributes for a given 470 link are common to the set of applications utilizing that link, 471 interoperability is achieved by using legacy advertisements and 472 sending application specific advertisements with L-bit set and no 473 link attribute values. This avoids duplication of link attribute 474 advertisements. 476 7.3. Multiple Applications: All Attributes Not Shared w RSVP-TE 478 In cases where one or more applications other than RSVP-TE are 479 utilizing a given link and one or more link attribute values are NOT 480 shared with RSVP-TE, it is necessary to use application specific 481 advertisements as defined in this document. Attributes for 482 applications other than RSVP-TE MUST be advertised using application 483 specific advertisements which have the L-bit clear. In cases where 484 some link attributes are shared with RSVP-TE, this requires duplicate 485 advertisements for those attributes. 487 The discussion in this section applies to cases where RSVP-TE is NOT 488 using any advertised attributes on a link and to cases where RSVP-TE 489 is using some link attribute advertisements on the link but some link 490 attributes cannot be shared with RSVP-TE. 492 7.4. Deprecating legacy advertisements 494 The extensions defined in this document support RSVP-TE as one of the 495 supported applications - so a long term goal for deployments would be 496 to deprecate use of the legacy advertisements in support of RSVP-TE. 497 This can be done in the following step-wise manner: 499 1)Upgrade all routers to support extensions in this document 501 2)Readvertise all legacy link attributes using application specific 502 advertisements with L-bit clear and R-bit set. 504 3)Remove legacy advertisements 506 8. IANA Considerations 508 This document defines a new sub-TLV for TLVs 22, 23, 141, 222, and 509 223. 511 Type Description 22 23 141 222 223 512 ---- --------------------- --- --- --- --- --- 513 15 Application Specific y y y y y 514 Link Attributes 516 This document defines one new TLV: 518 Type Description IIH SNP LSP Purge 519 ---- --------------------- --- --- --- ----- 520 238 Application Specific n n y n 521 SRLG 523 This document requests a new IANA registry be created to control the 524 assignment of sub-sub-TLV codepoints for the Application Specific 525 Link Attributes sub-TLV. The suggested name of the new registry is 526 "sub-sub-TLV code points for application link attributes". The 527 registration procedure is "Expert Review" as defined in [RFC5226]. 528 The following assignments are made by this document: 530 Type Description 531 --------------------------------------------------------- 532 3 Administrative group (color) 533 9 Maximum link bandwidth 534 10 Maximum reservable link bandwidth 535 11 Unreserved bandwidth 536 14 Extended Administrative Group 537 33 Unidirectional Link Delay 538 34 Min/Max Unidirectional Link Delay 539 35 Unidirectional Delay Variation 540 36 Unidirectional Link Loss 541 37 Unidirectional Residual Bandwidth 542 38 Unidirectional Available Bandwidth 543 39 Unidirectional Utilized Bandwidth 545 This document requests a new IANA registry be created to control the 546 assignment of application bit identifiers. The suggested name of the 547 new registry is "Link Attribute Applications". The registration 548 procedure is "Expert Review" as defined in [RFC5226]. The following 549 assignments are made by this document: 551 Bit # Name 552 --------------------------------------------------------- 553 0 RSVP-TE (R-bit) 554 1 Segment Routing Traffic Engineering (S-bit) 555 2 Loop Free Alternate (F-bit) 557 This document requests a new IANA registry be created to control the 558 assignment of sub-TLV types for the application specific SRLG TLV. 559 The suggested name of the new registry is "Sub-TLVs for TLV 238". 560 The registration procedure is "Expert Review" as defined in 561 [RFC5226]. The following assignments are made by this document: 563 Value Description 564 --------------------------------------------------------- 565 4 Link Local/Remote Identifiers (see [RFC5307]) 566 6 IPv4 interface address (see [RFC5305]) 567 8 IPv4 neighbor address (see [RFC5305]) 568 12 IPv6 Interface Address (see [RFC6119]) 569 13 IPv6 Neighbor Address (see [RFC6119]) 571 9. Security Considerations 573 Security concerns for IS-IS are addressed in [ISO10589, [RFC5304], 574 and [RFC5310]. 576 10. Acknowledgements 578 The authors would like to thank John Drake and Acee Lindem for their 579 careful review and content suggestions. 581 11. References 583 11.1. Normative References 585 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 586 Requirement Levels", BCP 14, RFC 2119, 587 DOI 10.17487/RFC2119, March 1997, . 590 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 591 IANA Considerations Section in RFCs", RFC 5226, 592 DOI 10.17487/RFC5226, May 2008, . 595 [RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic 596 Authentication", RFC 5304, DOI 10.17487/RFC5304, October 597 2008, . 599 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 600 Engineering", RFC 5305, DOI 10.17487/RFC5305, October 601 2008, . 603 [RFC5307] Kompella, K., Ed. and Y. Rekhter, Ed., "IS-IS Extensions 604 in Support of Generalized Multi-Protocol Label Switching 605 (GMPLS)", RFC 5307, DOI 10.17487/RFC5307, October 2008, 606 . 608 [RFC5310] Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R., 609 and M. Fanto, "IS-IS Generic Cryptographic 610 Authentication", RFC 5310, DOI 10.17487/RFC5310, February 611 2009, . 613 [RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic 614 Engineering in IS-IS", RFC 6119, DOI 10.17487/RFC6119, 615 February 2011, . 617 [RFC7810] Previdi, S., Ed., Giacalone, S., Ward, D., Drake, J., and 618 Q. Wu, "IS-IS Traffic Engineering (TE) Metric Extensions", 619 RFC 7810, DOI 10.17487/RFC7810, May 2016, 620 . 622 11.2. Informative References 624 [RFC7855] Previdi, S., Ed., Filsfils, C., Ed., Decraene, B., 625 Litkowski, S., Horneffer, M., and R. Shakir, "Source 626 Packet Routing in Networking (SPRING) Problem Statement 627 and Requirements", RFC 7855, DOI 10.17487/RFC7855, May 628 2016, . 630 Authors' Addresses 632 Les Ginsberg 633 Cisco Systems 634 821 Alder Drive 635 Milpitas, CA 95035 636 USA 638 Email: ginsberg@cisco.com 639 Peter Psenak 640 Cisco Systems 641 Apollo Business Center Mlynske nivy 43 642 Bratislava 821 09 643 Slovakia 645 Email: ppsenak@cisco.com 647 Stefano Previdi 648 Individual 650 Email: stefano@previdi.net 652 Wim Henderickx 653 Nokia 654 Copernicuslaan 50 655 Antwerp 2018 94089 656 Belgium 658 Email: wim.henderickx@nokia.com 660 John Drake 661 Juniper Networks 663 Email: jdrake@juniper.net