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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 7810 (Obsoleted by RFC 8570) Summary: 1 error (**), 0 flaws (~~), 2 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: April 20, 2019 S. Previdi 6 Huawei 7 W. Henderickx 8 Nokia 9 J. Drake 10 Juniper Networks 11 October 17, 2018 13 IS-IS TE Attributes per application 14 draft-ietf-isis-te-app-05.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", "NOT RECOMMENDED", "MAY", and 35 "OPTIONAL" in this document are to be interpreted as described in BCP 36 14 [RFC2119] [RFC8174] when, and only when, they appear in all 37 capitals, as shown here. 39 Status of This Memo 41 This Internet-Draft is submitted in full conformance with the 42 provisions of BCP 78 and BCP 79. 44 Internet-Drafts are working documents of the Internet Engineering 45 Task Force (IETF). Note that other groups may also distribute 46 working documents as Internet-Drafts. The list of current Internet- 47 Drafts is at https://datatracker.ietf.org/drafts/current/. 49 Internet-Drafts are draft documents valid for a maximum of six months 50 and may be updated, replaced, or obsoleted by other documents at any 51 time. It is inappropriate to use Internet-Drafts as reference 52 material or to cite them other than as "work in progress." 54 This Internet-Draft will expire on April 20, 2019. 56 Copyright Notice 58 Copyright (c) 2018 IETF Trust and the persons identified as the 59 document authors. All rights reserved. 61 This document is subject to BCP 78 and the IETF Trust's Legal 62 Provisions Relating to IETF Documents 63 (https://trustee.ietf.org/license-info) in effect on the date of 64 publication of this document. Please review these documents 65 carefully, as they describe your rights and restrictions with respect 66 to this document. Code Components extracted from this document must 67 include Simplified BSD License text as described in Section 4.e of 68 the Trust Legal Provisions and are provided without warranty as 69 described in the Simplified BSD License. 71 Table of Contents 73 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 74 2. Requirements Discussion . . . . . . . . . . . . . . . . . . . 3 75 3. Legacy Advertisements . . . . . . . . . . . . . . . . . . . . 4 76 3.1. Legacy sub-TLVs . . . . . . . . . . . . . . . . . . . . . 4 77 3.2. Legacy SRLG Advertisements . . . . . . . . . . . . . . . 5 78 4. Advertising Application Specific Link Attributes . . . . . . 5 79 4.1. Application Identifier Bit Mask . . . . . . . . . . . . . 6 80 4.2. Application Specific Link Attributes sub-TLV . . . . . . 8 81 4.2.1. Special Considerations for Maximum Link Bandwidth . . 9 82 4.2.2. Special Considerations for Unreserved Bandwidth . . . 9 83 4.3. Application Specific SRLG TLV . . . . . . . . . . . . . . 9 84 5. Deployment Considerations . . . . . . . . . . . . . . . . . . 10 85 6. Attribute Advertisements and Enablement . . . . . . . . . . . 11 86 7. Interoperability, Backwards Compatibility and Migration 87 Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . 12 88 7.1. RSVP-TE only deployments . . . . . . . . . . . . . . . . 12 89 7.2. Multiple Applications: Common Attributes with RSVP-TE . 12 90 7.3. Multiple Applications: All Attributes Not Shared w RSVP- 91 TE . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 92 7.4. Deprecating legacy advertisements . . . . . . . . . . . . 13 93 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 94 9. Security Considerations . . . . . . . . . . . . . . . . . . . 15 95 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15 96 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 97 11.1. Normative References . . . . . . . . . . . . . . . . . . 15 98 11.2. Informative References . . . . . . . . . . . . . . . . . 16 99 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17 101 1. Introduction 103 Advertisement of link attributes by the Intermediate-System-to- 104 Intermediate-System (IS-IS) protocol in support of traffic 105 engineering (TE) was introduced by [RFC5305] and extended by 106 [RFC5307], [RFC6119], and [RFC7810]. Use of these extensions has 107 been associated with deployments supporting Traffic Engineering over 108 Multiprotocol Label Switching (MPLS) in the presence of Resource 109 Reservation Protocol (RSVP) - more succinctly referred to as RSVP-TE. 111 In recent years new applications have been introduced which have use 112 cases for many of the link attributes historically used by RSVP-TE. 113 Such applications include Segment Routing Traffic Engineering (SRTE) 114 and Loop Free Alternates (LFA). This has introduced ambiguity in 115 that if a deployment includes a mix of RSVP-TE support and SRTE 116 support (for example) it is not possible to unambiguously indicate 117 which advertisements are to be used by RSVP-TE and which 118 advertisements are to be used by SRTE. If the topologies are fully 119 congruent this may not be an issue, but any incongruence leads to 120 ambiguity. 122 An additional issue arises in cases where both applications are 123 supported on a link but the link attribute values associated with 124 each application differ. Current advertisements do not support 125 advertising application specific values for the same attribute on a 126 specific link. 128 This document defines extensions which address these issues. Also, 129 as evolution of use cases for link attributes can be expected to 130 continue in the years to come, this document defines a solution which 131 is easily extensible to the introduction of new applications and new 132 use cases. 134 2. Requirements Discussion 136 As stated previously, evolution of use cases for link attributes can 137 be expected to continue - so any discussion of existing use cases is 138 limited to requirements which are known at the time of this writing. 139 However, in order to determine the functionality required beyond what 140 already exists in IS-IS, it is only necessary to discuss use cases 141 which justify the key points identified in the introduction - which 142 are: 144 1. Support for indicating which applications are using the link 145 attribute advertisements on a link 147 2. Support for advertising application specific values for the same 148 attribute on a link 150 [RFC7855] discusses use cases/requirements for SR. Included among 151 these use cases is SRTE which is defined in 152 [I-D.filsfils-spring-segment-routing-policy]. If both RSVP-TE and 153 SRTE are deployed in a network, link attribute advertisements can be 154 used by one or both of these applications. As there is no 155 requirement for the link attributes advertised on a given link used 156 by SRTE to be identical to the link attributes advertised on that 157 same link used by RSVP-TE, there is a clear requirement to indicate 158 independently which link attribute advertisements are to be used by 159 each application. 161 As the number of applications which may wish to utilize link 162 attributes may grow in the future, an additional requirement is that 163 the extensions defined allow the association of additional 164 applications to link attributes without altering the format of the 165 advertisements or introducing new backwards compatibility issues. 167 Finally, there may still be many cases where a single attribute value 168 can be shared among multiple applications, so the solution must 169 minimize advertising duplicate link/attribute pairs whenever 170 possible. 172 3. Legacy Advertisements 174 There are existing advertisements used in support of RSVP-TE. These 175 advertisements include sub-TLVs for TLVs 22, 23, 141, 222, and 223 176 and TLVs for SRLG advertisement. 178 3.1. Legacy sub-TLVs 179 Sub-TLVs for TLVs 22, 23, 141, 222, and 223 181 Code Point/Attribute Name 182 -------------------------- 183 3 Administrative group (color) 184 9 Maximum link bandwidth 185 10 Maximum reservable link bandwidth 186 11 Unreserved bandwidth 187 14 Extended Administrative Group 188 18 TE Default Metric 189 33 Unidirectional Link Delay 190 34 Min/Max Unidirectional Link Delay 191 35 Unidirectional Delay Variation 192 36 Unidirectional Link Loss 193 37 Unidirectional Residual Bandwidth 194 38 Unidirectional Available Bandwidth 195 39 Unidirectional Utilized Bandwidth 197 3.2. Legacy SRLG Advertisements 199 TLV 138 GMPLS-SRLG 200 Supports links identified by IPv4 addresses and 201 unnumbered links 203 TLV 139 IPv6 SRLG 204 Supports links identified by IPv6 addresses 206 Note that [RFC6119] prohibits the use of TLV 139 when it is possible 207 to use TLV 138. 209 4. Advertising Application Specific Link Attributes 211 Two new code points are defined in support of Application Specific 212 Link Attribute Advertisements: 214 1) Application Specific Link Attributes sub-TLV for TLVs 22, 23, 141, 215 222, and 223 217 2)Application Specific Shared Risk Link Group (SRLG) TLV 219 In support of these new advertisements, an application bit mask is 220 defined which identifies the application(s) associated with a given 221 advertisement. 223 The following sections define the format of these new advertisements. 225 4.1. Application Identifier Bit Mask 227 Identification of the set of applications associated with link 228 attribute advertisements utilizes two bit masks. One bit mask is for 229 standard applications where the definition of each bit is defined in 230 a new IANA controlled registry. A second bit mask is for non- 231 standard User Defined Applications(UDAs). 233 The encoding defined below is used by both the Application Specific 234 Link Attributes sub-TLV and the Application Specific SRLG TLV. 236 0 1 2 3 4 5 6 7 237 +-+-+-+-+-+-+-+-+ 238 | SABML+F | 1 octet 239 +-+-+-+-+-+-+-+-+ 240 | UDABML+F | 1 octet 241 +-+-+-+-+-+-+-+-+ 242 | SABM ... 0 - 127 octets 243 +-+-+-+-+-+-+-+-+ 244 | UDABM ... 0 - 127 octets 245 +-+-+-+-+-+-+-+-+ 247 SABML+F (1 octet) 248 Standard Application Bit Mask Length/Flags 250 0 1 2 3 4 5 6 7 251 +-+-+-+-+-+-+-+-+ 252 |L| SA-Length | 253 +-+-+-+-+-+-+-+-+ 255 L-flag: Applications listed (both Standard and 256 User Defined) MUST use the legacy advertisements 257 for the corresponding link found in TLVs 22, 23, 258 141, 222, and 223 or TLV 138 or TLV 139 as appropriate. 260 SA-Length: Indicates the length in octets (0-127) of the Bit Mask 261 for Standard Applications. 263 UDABML+F (1 octet) 264 User Defined Application Bit Mask Length/Flags 266 0 1 2 3 4 5 6 7 267 +-+-+-+-+-+-+-+-+ 268 |R| UDA-Length | 269 +-+-+-+-+-+-+-+-+ 271 R: Reserved. Transmitted as 0 and ignored on receipt 272 UDA-Length: Indicates the length in octets (0-127) of the Bit Mask 273 for User Defined Applications. 275 SABM (variable length) 276 Standard Application Bit Mask 278 (SA-Length * 8) bits 280 This is omitted if SA-Length is 0. 282 0 1 2 3 4 5 6 7 ... 283 +-+-+-+-+-+-+-+-+... 284 |R|S|F|X| ... 285 +-+-+-+-+-+-+-+-+... 287 R-bit: RSVP-TE 289 S-bit: Segment Routing Traffic Engineering 291 F-bit: Loop Free Alternate 293 X-bit: Flex-Algo 295 UDABM (variable length) 296 User Defined Application Bit Mask 298 (UDA Length * 8) bits 300 0 1 2 3 4 5 6 7 ... 301 +-+-+-+-+-+-+-+-+... 302 | ... 303 +-+-+-+-+-+-+-+-+... 305 This is omitted if UDA-Length is 0. 307 NOTE: If both SA-length and UDA-Length are zero, then the 308 attributes associated with this attribute identifier bit mask 309 MAY be used by any Standard Application and any User Defined 310 Application. 312 Standard Application Bits are defined/sent starting with Bit 0. 313 Additional bit definitions that may be defined in the future SHOULD 314 be assigned in ascending bit order so as to minimize the number of 315 octets that will need to be transmitted. Undefined bits MUST be 316 transmitted as 0 and MUST be ignored on receipt. Bits that are NOT 317 transmitted MUST be treated as if they are set to 0 on receipt. 319 User Defined Application bits have no relationship to Standard 320 Application bits and are NOT managed by IANA or any other standards 321 body. It is recommended that bits are used starting with Bit 0 so as 322 to minimize the number of octets required to advertise all UDAs. 324 4.2. Application Specific Link Attributes sub-TLV 326 A new sub-TLV for TLVs 22, 23, 141, 222, and 223 is defined which 327 supports specification of the applications and application specific 328 attribute values. 330 Type: 16 (suggested value - to be assigned by IANA) 331 Length: Variable (1 octet) 332 Value: 334 Application Bit Mask (as defined in Section 3.1) 336 Link Attribute sub-sub-TLVs - format matches the 337 existing formats defined in [RFC5305] and [RFC7810] 339 When the L-flag is set in the Application Identifiers, all of the 340 applications specified in the bit mask MUST use the link attribute 341 sub-TLV advertisements listed in Section 3.1 for the corresponding 342 link. Application specific link attribute sub-sub-TLVs for the 343 corresponding link attributes MUST NOT be advertised for the set of 344 applications specified in the Standard/User Application Bit Masks and 345 all such advertisements MUST be ignored on receipt. 347 Multiple sub-TLVs for the same link MAY be advertised. When multiple 348 sub-TLVs for the same link are advertised, they SHOULD advertise non- 349 conflicting application/attribute pairs. A conflict exists when the 350 same application is associated with two different values of the same 351 link attribute for a given link. In cases where conflicting values 352 for the same application/attribute/link are advertised all the 353 conflicting values MUST be ignored. 355 For a given application, the setting of the L-flag MUST be the same 356 in all sub-TLVs for a given link. In cases where this constraint is 357 violated, the L-flag MUST be considered set for this application. 359 A new registry of sub-sub-TLVs is to be created by IANA which defines 360 the link attribute sub-sub-TLV code points. A sub-sub-TLV is defined 361 for each of the existing sub-TLVs listed in Section 3.1 except as 362 noted below. The format of the sub-sub-TLVs matches the format of 363 the corresponding legacy sub-TLV and IANA is requested to assign the 364 legacy sub-TLV identifer to the corresponding sub-sub-TLV. 366 4.2.1. Special Considerations for Maximum Link Bandwidth 368 Maximum link bandwidth is an application independent attribute of the 369 link. When advertised using the Application Specific Link Attributes 370 sub-TLV, multiple values for the same link MUST NOT be advertised. 371 This can be accomplished most efficiently by having a single 372 advertisement for a given link where the Application Bit Mask 373 identifies all the applications which are making use of the value for 374 that link. 376 It is also possible to advertise the same value for a given link 377 multiple times with disjoint sets of applications specified in the 378 Application Bit Mask. This is less efficient but still valid. 380 If different values for Maximum Link Bandwidth for a given link are 381 advertised, all values MUST be ignored. 383 4.2.2. Special Considerations for Unreserved Bandwidth 385 Unreserved bandwidth is an attribute specific to RSVP. When 386 advertised using the Application Specific Link Attributes sub-TLV, 387 bits other than the RSVP-TE(R-bit) MUST NOT be set in the Application 388 Bit Mask. If an advertisement of Unreserved Bandwidth is received 389 with bits other than the RSVP-TE bit set, the advertisement MUST be 390 ignored. 392 4.3. Application Specific SRLG TLV 394 A new TLV is defined to advertise application specific SRLGs for a 395 given link. Although similar in functionality to TLV 138 (defined by 396 [RFC5307]) and TLV 139 (defined by [RFC6119], a single TLV provides 397 support for IPv4, IPv6, and unnumbered identifiers for a link. 398 Unlike TLVs 138/139, it utilizes sub-TLVs to encode the link 399 identifiers in order to provide the flexible formatting required to 400 support multiple link identifier types. 402 Type: 238 (Suggested value - to be assigned by IANA) 403 Length: Number of octets in the value field (1 octet) 404 Value: 405 Neighbor System-ID + pseudo-node ID (7 octets) 406 Application Bit Mask (as defined in Section 3.1) 407 Length of sub-TLVs (1 octet) 408 Link Identifier sub-TLVs (variable) 409 0 or more SRLG Values (Each value is 4 octets) 411 The following Link Identifier sub-TLVs are defined. The type 412 values are suggested and will be assigned by IANA - but as 413 the formats are identical to existing sub-TLVs defined for 414 TLVs 22, 23, 141, 222, and 223 the use of the suggested sub-TLV 415 types is strongly encouraged. 417 Type Description 418 4 Link Local/Remote Identifiers (see [RFC5307]) 419 6 IPv4 interface address (see [RFC5305]) 420 8 IPv4 neighbor address (see [RFC5305]) 421 12 IPv6 Interface Address (see [RFC6119]) 422 13 IPv6 Neighbor Address (see [RFC6119]) 424 At least one set of link identifiers (IPv4, IPv6, or unnumbered) MUST 425 be present. TLVs which do not meet this requirement MUST be ignored. 427 Multiple TLVs for the same link MAY be advertised. 429 When the L-flag is set in the Application Identifiers, SRLG values 430 MUST NOT be included in the TLV. Any SRLG values which are 431 advertised MUST be ignored. Based on the link identifiers advertised 432 the corresponding legacy TLV (see Section 3.2) can be identified and 433 the SRLG values advertised in the legacy TLV MUST be used by the set 434 of applications specified in the Application Bit Mask. 436 For a given application, the setting of the L-flag MUST be the same 437 in all TLVs for a given link. In cases where this constraint is 438 violated, the L-flag MUST be considered set for this application. 440 5. Deployment Considerations 442 If link attributes are advertised associated with zero length 443 application bit masks for both standard applications and user defined 444 applications, then that set of link attributes MAY be used by any 445 application. If support for a new application is introduced on any 446 node in a network in the presence of such advertisements, these 447 advertisements MAY be used by the new application. If this is not 448 what is intended, then existing advertisements MUST be readvertised 449 with an explicit set of applications specified before a new 450 application is introduced. 452 6. Attribute Advertisements and Enablement 454 This document defines extensions to support the advertisement of 455 application specific link attributes. 457 Whether the presence of link attribute advertisements for a given 458 application indicates that the application is enabled on that link 459 depends upon the application. Similarly, whether the absence of link 460 attribute advertisements indicates that the application is not 461 enabled depends upon the application. 463 In the case of RSVP-TE, the advertisement of application specific 464 link attributes implies that RSVP is enabled on that link. 466 In the case of SRTE, advertisement of application specific link 467 attributes does NOT indicate enablement of SRTE. The advertisements 468 are only used to support constraints which may be applied when 469 specifying an explicit path. SRTE is implicitly enabled on all links 470 which are part of the Segment Routing enabled topology independent of 471 the existence of link attribute advertisements 473 In the case of LFA, advertisement of application specific link 474 attributes does NOT indicate enablement of LFA on that link. 475 Enablement is controlled by local configuration. 477 In the case of Flex-Algo, advertisement of application specific link 478 attributes does NOT indicate enablement of Flex-Algo. Rather the 479 attributes are used to determine what links are included/excluded in 480 the algorithm specific constrained SPF. This is fully specified in 481 [I-D.hegdeppsenak-isis-sr-flex-algo]. 483 If, in the future, additional standard applications are defined to 484 use this mechanism, the specification defining this use MUST define 485 the relationship between application specific link attribute 486 advertisements and enablement for that application. 488 This document allows the advertisement of application specific link 489 attributes with no application identifiers i.e., both the Standard 490 Application Bit Mask and the User Defined Application Bit Mask are 491 not present (See Section 4.1). This supports the use of the link 492 attribute by any application. In the presence of an application 493 where the advertisement of link attribute advertisements is used to 494 infer the enablement of an application on that link (e.g., RSVP-TE), 495 the absence of the application identifier leaves ambiguous whether 496 that application is enabled on such a link. This needs to be 497 considered when making use of the "any application" encoding. 499 7. Interoperability, Backwards Compatibility and Migration Concerns 501 Existing deployments of RSVP-TE utilize the legacy advertisements 502 listed in Section 3. Routers which do not support the extensions 503 defined in this document will only process legacy advertisements and 504 are likely to infer that RSVP-TE is enabled on the links for which 505 legacy advertisements exist. It is expected that deployments using 506 the legacy advertisements will persist for a significant period of 507 time - therefore deployments using the extensions defined in this 508 document must be able to co-exist with use of the legacy 509 advertisements by routers which do not support the extensions defined 510 in this document. The following sub-sections discuss 511 interoperability and backwards compatibility concerns for a number of 512 deployment scenarios. 514 Note that in all cases the defined strategy can be employed on a per 515 link basis. 517 7.1. RSVP-TE only deployments 519 In deployments where RSVP-TE is the only application utilizing link 520 attribute advertisements, use of the the legacy advertisements can 521 continue without change. 523 7.2. Multiple Applications: Common Attributes with RSVP-TE 525 In cases where multiple applications are utilizing a given link, one 526 of the applications is RSVP-TE, and all link attributes for a given 527 link are common to the set of applications utilizing that link, 528 interoperability is achieved by using legacy advertisements and 529 sending application specific advertisements with L-bit set and no 530 link attribute values. This avoids duplication of link attribute 531 advertisements. 533 7.3. Multiple Applications: All Attributes Not Shared w RSVP-TE 535 In cases where one or more applications other than RSVP-TE are 536 utilizing a given link and one or more link attribute values are NOT 537 shared with RSVP-TE, it is necessary to use application specific 538 advertisements as defined in this document. Attributes for 539 applications other than RSVP-TE MUST be advertised using application 540 specific advertisements which have the L-bit clear. In cases where 541 some link attributes are shared with RSVP-TE, this requires duplicate 542 advertisements for those attributes. 544 The discussion in this section applies to cases where RSVP-TE is NOT 545 using any advertised attributes on a link and to cases where RSVP-TE 546 is using some link attribute advertisements on the link but some link 547 attributes cannot be shared with RSVP-TE. 549 7.4. Deprecating legacy advertisements 551 The extensions defined in this document support RSVP-TE as one of the 552 supported applications - so a long term goal for deployments would be 553 to deprecate use of the legacy advertisements in support of RSVP-TE. 554 This can be done in the following step-wise manner: 556 1)Upgrade all routers to support extensions in this document 558 2)Readvertise all legacy link attributes using application specific 559 advertisements with L-bit clear and R-bit set. 561 3)Remove legacy advertisements 563 8. IANA Considerations 565 This document defines a new sub-TLV for TLVs 22, 23, 141, 222, and 566 223. 568 Type Description 22 23 25 141 222 223 569 ---- --------------------- ---- ---- ---- ---- ---- ---- 570 16 Application Specific y y y(s) y y y 571 Link Attributes 573 This document defines one new TLV: 575 Type Description IIH LSP SNP Purge 576 ---- --------------------- --- --- --- ----- 577 238 Application Specific n y n n 578 SRLG 580 This document requests a new IANA registry be created to control the 581 assignment of sub-sub-TLV codepoints for the Application Specific 582 Link Attributes sub-TLV. The suggested name of the new registry is 583 "sub-sub-TLV code points for application specific link attributes". 584 The registration procedure is "Expert Review" as defined in 585 [RFC8126]. The following assignments are made by this document: 587 Type Description 588 --------------------------------------------------------- 589 0-2 Unassigned 590 3 Administrative group (color) 591 4-8 Unassigned 592 9 Maximum link bandwidth 593 10 Maximum reservable link bandwidth 594 11 Unreserved bandwidth 595 12-13 Unassigned 596 14 Extended Administrative Group 597 15-17 Unassigned 598 18 TE Default Metric 599 19-32 Unassigned 600 33 Unidirectional Link Delay 601 34 Min/Max Unidirectional Link Delay 602 35 Unidirectional Delay Variation 603 36 Unidirectional Link Loss 604 37 Unidirectional Residual Bandwidth 605 38 Unidirectional Available Bandwidth 606 39 Unidirectional Utilized Bandwidth 607 40-255 Unassigned 609 This document requests a new IANA registry be created, under the 610 category of "Interior Gateway Protocol (IGP) Parameters", to control 611 the assignment of application bit identifiers. The suggested name of 612 the new registry is "Link Attribute Applications". The registration 613 policy for this registry is "Standards Action" ([RFC8126] and 614 [RFC7120]). The following assignments are made by this document: 616 Bit # Name 617 --------------------------------------------------------- 618 0 RSVP-TE (R-bit) 619 1 Segment Routing Traffic Engineering (S-bit) 620 2 Loop Free Alternate (F-bit) 621 3 Flex Algorithm (X-bit) 623 This document requests a new IANA registry be created to control the 624 assignment of sub-TLV types for the application specific SRLG TLV. 625 The suggested name of the new registry is "Sub-TLVs for TLV 238". 626 The registration procedure is "Expert Review" as defined in 627 [RFC8126]. The following assignments are made by this document: 629 Value Description 630 --------------------------------------------------------- 631 0-3 Unassigned 632 4 Link Local/Remote Identifiers (see [RFC5307]) 633 5 Unassigned 634 6 IPv4 interface address (see [RFC5305]) 635 7 Unassigned 636 8 IPv4 neighbor address (see [RFC5305]) 637 9-11 Unassigned 638 12 IPv6 Interface Address (see [RFC6119]) 639 13 IPv6 Neighbor Address (see [RFC6119]) 640 14-255 Unassigned 642 9. Security Considerations 644 Security concerns for IS-IS are addressed in [ISO10589, [RFC5304], 645 and [RFC5310]. 647 10. Acknowledgements 649 The authors would like to thank Eric Rosen and Acee Lindem for their 650 careful review and content suggestions. 652 11. References 654 11.1. Normative References 656 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 657 Requirement Levels", BCP 14, RFC 2119, 658 DOI 10.17487/RFC2119, March 1997, 659 . 661 [RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic 662 Authentication", RFC 5304, DOI 10.17487/RFC5304, October 663 2008, . 665 [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic 666 Engineering", RFC 5305, DOI 10.17487/RFC5305, October 667 2008, . 669 [RFC5307] Kompella, K., Ed. and Y. Rekhter, Ed., "IS-IS Extensions 670 in Support of Generalized Multi-Protocol Label Switching 671 (GMPLS)", RFC 5307, DOI 10.17487/RFC5307, October 2008, 672 . 674 [RFC5310] Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R., 675 and M. Fanto, "IS-IS Generic Cryptographic 676 Authentication", RFC 5310, DOI 10.17487/RFC5310, February 677 2009, . 679 [RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic 680 Engineering in IS-IS", RFC 6119, DOI 10.17487/RFC6119, 681 February 2011, . 683 [RFC7120] Cotton, M., "Early IANA Allocation of Standards Track Code 684 Points", BCP 100, RFC 7120, DOI 10.17487/RFC7120, January 685 2014, . 687 [RFC7810] Previdi, S., Ed., Giacalone, S., Ward, D., Drake, J., and 688 Q. Wu, "IS-IS Traffic Engineering (TE) Metric Extensions", 689 RFC 7810, DOI 10.17487/RFC7810, May 2016, 690 . 692 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 693 Writing an IANA Considerations Section in RFCs", BCP 26, 694 RFC 8126, DOI 10.17487/RFC8126, June 2017, 695 . 697 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 698 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 699 May 2017, . 701 11.2. Informative References 703 [I-D.filsfils-spring-segment-routing-policy] 704 Filsfils, C., Sivabalan, S., Hegde, S., 705 daniel.voyer@bell.ca, d., Lin, S., bogdanov@google.com, 706 b., Krol, P., Horneffer, M., Steinberg, D., Decraene, B., 707 Litkowski, S., Mattes, P., Ali, Z., Talaulikar, K., Liste, 708 J., Clad, F., and K. Raza, "Segment Routing Policy 709 Architecture", draft-filsfils-spring-segment-routing- 710 policy-06 (work in progress), May 2018. 712 [I-D.hegdeppsenak-isis-sr-flex-algo] 713 Psenak, P., Hegde, S., Filsfils, C., and A. Gulko, "ISIS 714 Segment Routing Flexible Algorithm", draft-hegdeppsenak- 715 isis-sr-flex-algo-02 (work in progress), February 2018. 717 [RFC7855] Previdi, S., Ed., Filsfils, C., Ed., Decraene, B., 718 Litkowski, S., Horneffer, M., and R. Shakir, "Source 719 Packet Routing in Networking (SPRING) Problem Statement 720 and Requirements", RFC 7855, DOI 10.17487/RFC7855, May 721 2016, . 723 Authors' Addresses 725 Les Ginsberg 726 Cisco Systems 727 821 Alder Drive 728 Milpitas, CA 95035 729 USA 731 Email: ginsberg@cisco.com 733 Peter Psenak 734 Cisco Systems 735 Apollo Business Center Mlynske nivy 43 736 Bratislava 821 09 737 Slovakia 739 Email: ppsenak@cisco.com 741 Stefano Previdi 742 Huawei 744 Email: stefano@previdi.net 746 Wim Henderickx 747 Nokia 748 Copernicuslaan 50 749 Antwerp 2018 94089 750 Belgium 752 Email: wim.henderickx@nokia.com 754 John Drake 755 Juniper Networks 757 Email: jdrake@juniper.net