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Checking references for intended status: Best Current Practice ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) -- No information found for draft-ietf-softwire-iftunnel - is the name correct? -- Obsolete informational reference (is this intentional?): RFC 1573 (Obsoleted by RFC 2233) -- Obsolete informational reference (is this intentional?): RFC 2667 (Obsoleted by RFC 4087) Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 5 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group D. Thaler 3 Internet-Draft Microsoft 4 Updates: 2863 (if approved) D. Romascanu 5 Intended status: Best Current Practice Independent 6 Expires: May 5, 2020 November 02, 2019 8 Guidelines and Registration Procedures for Interface Types and Tunnel 9 Types 10 draft-thaler-iftype-reg-06 12 Abstract 14 This document provides guidelines and procedures for those who are 15 defining, registering, or evaluating definitions of new interface 16 types ("ifType" values) and tunnel types. The original definition of 17 the IANA interface type registry predated the use of IANA 18 Considerations sections and YANG modules, and so some confusion arose 19 over time. Tunnel types were added later, with the same requirements 20 and allocation policy as interface types. This document updates RFC 21 2863, and provides updated guidance for these registries. 23 Status of This Memo 25 This Internet-Draft is submitted in full conformance with the 26 provisions of BCP 78 and BCP 79. 28 Internet-Drafts are working documents of the Internet Engineering 29 Task Force (IETF). Note that other groups may also distribute 30 working documents as Internet-Drafts. The list of current Internet- 31 Drafts is at http://datatracker.ietf.org/drafts/current/. 33 Internet-Drafts are draft documents valid for a maximum of six months 34 and may be updated, replaced, or obsoleted by other documents at any 35 time. It is inappropriate to use Internet-Drafts as reference 36 material or to cite them other than as "work in progress." 38 This Internet-Draft will expire on May 5, 2020. 40 Copyright Notice 42 Copyright (c) 2019 IETF Trust and the persons identified as the 43 document authors. All rights reserved. 45 This document is subject to BCP 78 and the IETF Trust's Legal 46 Provisions Relating to IETF Documents 47 (http://trustee.ietf.org/license-info) in effect on the date of 48 publication of this document. Please review these documents 49 carefully, as they describe your rights and restrictions with respect 50 to this document. Code Components extracted from this document must 51 include Simplified BSD License text as described in Section 4.e of 52 the Trust Legal Provisions and are provided without warranty as 53 described in the Simplified BSD License. 55 Table of Contents 57 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 58 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 59 3. Problems . . . . . . . . . . . . . . . . . . . . . . . . . . 3 60 4. Interface Sub-Layers and Sub-Types . . . . . . . . . . . . . 4 61 4.1. Alternate Values . . . . . . . . . . . . . . . . . . . . 5 62 5. Available Formats . . . . . . . . . . . . . . . . . . . . . . 6 63 6. Registration . . . . . . . . . . . . . . . . . . . . . . . . 6 64 6.1. Procedures . . . . . . . . . . . . . . . . . . . . . . . 7 65 6.2. Media-specific OID-subtree assignments . . . . . . . . . 8 66 6.3. Registration Template . . . . . . . . . . . . . . . . . . 8 67 6.3.1. ifType . . . . . . . . . . . . . . . . . . . . . . . 8 68 6.3.2. tunnelType . . . . . . . . . . . . . . . . . . . . . 9 69 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 70 7.1. MIB and YANG Modules . . . . . . . . . . . . . . . . . . 11 71 7.2. Transmission Number Assignments . . . . . . . . . . . . . 12 72 8. Security Considerations . . . . . . . . . . . . . . . . . . . 12 73 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 74 9.1. Normative References . . . . . . . . . . . . . . . . . . 12 75 9.2. Informative References . . . . . . . . . . . . . . . . . 13 76 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15 78 1. Introduction 80 The IANA IfType-MIB, which contains the list of interface type 81 (ifType) values, was originally defined in [RFC1573] as a separate 82 MIB module together with the Interfaces Group MIB (IF-MIB) module. 83 The IF-MIB module was subsequently updated and is currently specified 84 in [RFC2863], but this latest IF-MIB RFC no longer contains the IANA 85 IfType-MIB. Instead, the IANA IfType-MIB is maintained by IANA as a 86 separate module. Similarly, [RFC7224] created an initial IANA 87 Interface Type YANG Module, and the current version is maintained by 88 IANA. 90 The current IANA IfType registry is at [ifType-registry], with the 91 same values also appearing in both [yang-if-type] and the IANAifType 92 textual convention at [IANAifType-MIB]. 94 Although the ifType registry was originally defined in a MIB module, 95 the assignment and use of interface type values are not tied to MIB 96 modules or any other management mechanism. An interface type value 97 can be used as the value of a data model object (MIB object, YANG 98 object, etc.), or as part of a unique identifier of a data model for 99 a given interface type (e.g., in an OID), or simply as a value 100 exposed by local APIs or UI on a device. 102 The TUNNEL-MIB was defined in [RFC2667] (now obsoleted by [RFC4087]) 103 which created a tunnelType registry ([tunnelType-registry] and the 104 IANAtunnelType textual convention at [IANAifType-MIB]) and defined 105 the assignment policy for tunnelType values to always be identical to 106 the policy for assigning ifType values. 108 2. Terminology 110 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 111 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 112 "OPTIONAL" in this document are to be interpreted as described in BCP 113 14 [RFC2119] [RFC8174] when, and only when, they appear in all 114 capitals, as shown here. 116 3. Problems 118 This document addresses the following issues: 120 1. As noted in Section 1, the original guidance was written with 121 wording specific to MIB modules, and accordingly some confusion 122 has resulted when using YANG modules. This document clarifies 123 that ifTypes and tunnelTypes are independent from the type of, or 124 even existence of, a data model. 126 2. The use of, and requirements around, sub-layers and sub-types 127 were not well understood, but good examples of both now exist. 128 This is discussed in Section 4. 130 3. Since the ifType and tunnelType registries were originally 131 defined, and are still retrievable, in the format of MIB modules 132 (in addition to other formats), confusion arose when adding YANG 133 modules as another format, as to whether each is a separate 134 registry. This is discussed in Section 5. 136 4. The registries are retrievable in the format of MIB and YANG 137 modules, but there was previously no process guidance written to 138 check that those formats were syntactically correct as updates 139 were made, which led to the registry having syntax errors that 140 broke tools. Section 6.1 adds a validation step to the 141 documented assignment procedure. 143 5. Various documents and registries previously said to submit 144 requests via email, but a web form exists for submitting 145 requests, which caused some confusion around which was to be 146 used. This is addressed in Section 6.1. 148 6. Transmission values [transmission-registry] have generally been 149 allocated as part of ifType allocation, but no guidance existed 150 as to whether a requester must ask for it or not, and the request 151 form had no such required field. As a result, IANA has asked the 152 Designated Expert to decide for each allocation, but no relevant 153 guidance for the Designated Expert has been documented. This is 154 remedied in Section 6.2. 156 4. Interface Sub-Layers and Sub-Types 158 When multiple sub-layers exist below the network layer, each sub- 159 layer can be represented by its own row in the ifTable with its own 160 ifType, with the ifStackTable being used to identify the upward and 161 downward multiplexing relationships between rows. Section 3.1.1 of 162 [RFC2863] provided more discussion, and Section 3.1.2 of that RFC 163 provided guidance for defining interface sub-layers. More recent 164 experience shows that those guidelines were phrased in a way that is 165 now too restrictive, since at the time [RFC2863] was written, MIB 166 modules were the dominant data model. 168 This document clarifies that the same guidance also applies to YANG 169 modules. 171 Some ifTypes may define sub-types. For example, the tunnel(131) 172 ifType defines sub-types, where each tunnelType can have its own MIB 173 and/or YANG module with protocol-specific information, but there is 174 enough in common that some information is exposed in a generic IP 175 Tunnel MIB corresponding to the tunnel(131) ifType. 177 For requests that involve multiple sub-layers below the network 178 layer, requests MUST include (or reference) a discussion of the 179 multiplexing relationships between sub-layers, ideally with a 180 diagram. Various well-written examples exist of such definitions, 181 including [RFC3637] section 3.4.1, [RFC4087] section 3.1.1, and 182 [RFC5066] section 3.1.1. 184 Definers of sub-layers and sub-types should consider which model is 185 more appropriate for their needs. A sub-layer is generally used 186 whenever either a dynamic relationship exists (i.e., which instances 187 layer over which other instances can change over time) or a 188 multiplexing relationship exists with another sub-layer. A sub-type 189 can be used when neither of these are true, but where one interface 190 type is conceptually a subclass of another interface type, as far as 191 a management data model is concerned. 193 In general, the intent of an interface type or sub-type is that its 194 definition should be sufficient to identify an interoperable 195 protocol. In some cases, however, a protocol might be defined in a 196 way that is not sufficient to provide interoperability with other 197 compliant implementations of that protocol. In such a case, an 198 ifType definition should discuss whether specific instantiations (or 199 profiles) of behavior should use a sub-layer model (e.g., each vendor 200 might layer the protocol over its own sub-layer that provides the 201 missing details), or a sub-type model (i.e., each vendor might 202 subclass the protocol without any layering relationship). If a sub- 203 type model is more appropriate, then the data model for the protocol 204 might include a sub-type identifier so that management software can 205 discover objects specific to the subtype. In either case, such 206 discussion is important to guide definers of a data model for the 207 more specific information (i.e., a lower sub-layer or a subtype), as 208 well as the Designated Expert that must review requests for any such 209 ifTypes or sub-types. 211 4.1. Alternate Values 213 Another design decision is whether to reuse an existing ifType or 214 tunnelType value, possibly using a sub-type or sub-layer model for 215 refinements, or to use a different value for a new mechanism. 217 If there is already an entry that could easily satisfy the modeling 218 and functional requirements for the requested entry, it should be 219 reused so that applications and tools that use the existing value can 220 be used without changes. If however, the modeling and functional 221 requirements are significantly different enough such that having 222 existing applications and tools use the existing value would be seen 223 as a problem, a new value should be used. 225 For example, originally different ifType values were used for 226 different flavors of Ethernet (ethernetCsmacd(6), iso88023Csmacd(7), 227 fastEther(62), etc.), typically because they were registered by 228 different vendors. Using different values was, however, seen as 229 problematic because all were functionally similar, and so [RFC3635] 230 then deprecated all but ethernetCsmacd(6). 232 As another example, a udp(8) tunnelType value was defined in 233 [RFC2667] with the description "The value UDP indicates that the 234 payload packet is encapsulated within a normal UDP packet (e.g., RFC 235 1234)." The Teredo tunnel protocol [RFC4380] was later defined and 236 encapsulates packets over UDP, but the protocol model is quite 237 different between [RFC1234] and Teredo. For example, [RFC1234] 238 supports encapsulation of multicast/broadcast traffic whereas Teredo 239 does not. As such, it would be more confusing to applications and 240 tools to represent them using the same tunnel type, and so [RFC4087] 241 defined a new value for Teredo. 243 In summary, definers of new interface or tunnel mechanisms should use 244 a new ifType or tunnelType value rather than reusing an existing 245 value when key aspects such as the header format or the link model 246 (point-to-point, non-broadcast multi-access, broadcast capable multi- 247 access, unidirectional broadcast, etc.) are significantly different 248 from existing values, but reuse the same value when the differences 249 can be expressed in terms of differing values of existing objects 250 other than ifType/tunnelType, in the standard YANG or MIB module. 252 5. Available Formats 254 Many registries are available in multiple formats. For example, XML, 255 HTML, CSV, and plain text are common formats in which many registries 256 are available. This document clarifies that the [IANAifType-MIB], 257 [yang-if-type], and [yang-tunnel-type] MIB and YANG modules are 258 merely additional formats in which the ifType and tunnelType 259 registries are available. The MIB and YANG modules are not separate 260 registries, and the same values are always present in all formats of 261 the same registry. 263 The confusion stemmed in part from the fact that the IANA "Protocol 264 Registries" [protocol-registries] listed the YANG and MIB module 265 formats separately, as if they were separate registries. However, 266 the entries for the yang-if-type and iana-tunnel-type YANG modules 267 said "See ifType definitions registry." and "See tunnelType registry 268 (mib-2.interface.ifTable.ifEntry.ifType.tunnelType)." respectively, 269 although the entry for the IANAifType-MIB had no such note. 270 Section 7.1 addresses this. 272 6. Registration 274 The IANA policy (using terms defined in [RFC8126]) for registration 275 is Expert Review, for both interface types and tunnel types. The 276 role of the Designated Expert in the procedure is to raise possible 277 concerns about wider implications of proposals for use and deployment 278 of interface types. While it is recommended that the responsible 279 Area Director and the IESG take into consideration the Designated 280 Expert opinions, nothing in the procedure empowers the Designated 281 Expert to override properly arrived-at IETF or working group 282 consensus. 284 6.1. Procedures 286 Someone wishing to register a new ifType or tunnelType value MUST: 288 1. Check the IANA registry to see whether there is already an entry 289 that could easily satisfy the modeling and functional 290 requirements for the requested entry. If there is already such 291 an entry, use it or update the existing specification. Text in 292 an Internet-Draft, or part of some other permanently available, 293 stable specification may be written to clarify the usage of an 294 existing entry or entries for the desired purpose. 296 2. Check the IANA registry to see whether there is already some 297 other entry with the desired name. If there is already an 298 unrelated entry under the name, choose a different name. 300 3. Prepare a registration request using the template specified in 301 Section 6.3. The registration request can be contained in an 302 Internet-Draft, submitted alone, or as part of some other 303 permanently available, stable, specification. The registration 304 request can also be submitted in some other form (as part of 305 another document or as a stand-alone document), but the 306 registration request will be treated as an "IETF Contribution" 307 under the guidelines of [RFC5378]. 309 4. Submit the registration request (or pointer to a document 310 containing it) to IANA at iana@iana.org or (if requesting an 311 ifType) via the web form at https://www.iana.org/form/iftype . 313 Upon receipt of a registration request, the following steps MUST be 314 followed: 316 1. IANA checks the submission for completeness; if required 317 information is missing or any citations are not correct, IANA 318 will reject the registration request. A registrant can resubmit 319 a corrected request if desired. 321 2. IANA requests Expert Review of the registration request against 322 the corresponding guidelines from this document. 324 3. The Designated Expert will evaluate the request against the 325 criteria. 327 4. Once the Designated Expert approves registration, IANA updates 328 [ifType-registry], [IANAifType-MIB], and [yang-if-type] to show 329 the registration for an interface type, or [tunnelType-registry], 330 [IANAifType-MIB], and [yang-tunnel-type] to show the registration 331 for a tunnel type. When adding values, IANA should verify that 332 the updated MIB module and YANG module formats are syntactically 333 correct before publishing the update. There are various existing 334 tools or web sites that can be used to do this verification. 336 5. If instead the Designated Expert does not approve registration 337 (e.g., for any of the reasons in [RFC8126] section 3), a 338 registrant can resubmit a corrected request if desired, or the 339 IESG can override the Designated Expert and approve it per the 340 process in Section 5.3 of [RFC8126]. 342 6.2. Media-specific OID-subtree assignments 344 [IANAifType-MIB] notes: 346 The relationship between the assignment of ifType values and of 347 OIDs to particular media-specific MIBs is solely the purview of 348 IANA and is subject to change without notice. Quite often, a 349 media-specific MIB's OID-subtree assignment within MIB-II's 350 'transmission' subtree will be the same as its ifType value. 351 However, in some circumstances this will not be the case, and 352 implementors must not pre-assume any specific relationship between 353 ifType values and transmission subtree OIDs. 355 The advice above remains unchanged, but this document changes the 356 allocation procedure to streamline the process, so that an ifType 357 value and a transmission number value with the same value will be 358 assigned at the same time. 360 Rationale: (1) This saves effort in the future since if a 361 transmission number is later needed, no IANA request is needed that 362 would then require another Expert Review. (2) The transmision 363 numbering space is not scarce, so there seems little need to reserve 364 the number for a different purpose than what the ifType is for. (3) 365 The Designated Expert need not review whether a transmission number 366 value should be registered when processing each ifType request, thus 367 reducing the possibility of delaying assignment of ifType values. (4) 368 There is no case on record where allocating the same value could have 369 caused any problem. 371 6.3. Registration Template 373 6.3.1. ifType 375 The following template describes the fields that MUST be supplied in 376 a registration request suitable for adding to the ifType registry: 378 Label for IANA ifType requested: As explained in Section 7.1.1 of 379 [RFC2578], a label for a named-number enumeration must consist of 380 one or more letters or digits, up to a maximum of 64 characters, 381 and the initial character must be a lower-case letter. (However, 382 labels longer than 32 characters are not recommended.) Note that 383 hyphens are not allowed. 385 Name of IANA ifType requested: A short description (e.g., a protocol 386 name), suitable to appear in a comment in the registry. 388 Description of the proposed use of the IANA ifType: Requesters MUST 389 include answers, either directly or via a link to some document 390 with the answers, to the following questions in the explanation of 391 the proposed use of the IANA IfType: 393 o How would IP run over your ifType? 395 o Would there be another interface sublayer between your ifType 396 and IP? 398 o Would your ifType be vendor-specific or proprietary? (If so, 399 the label MUST start with a string that shows that. For 400 example, if your company's name or acronym is xxx, then the 401 ifType label would be something like xxxSomeIfTypeLabel.) 403 o Would your ifType require or allow vendor-specific extensions? 404 If so, would the vendor use their own ifType in a sub-layer 405 below the requested ifType, or a sub-type of the ifType, or 406 some other mechanism? 408 Reference, Internet-Draft, or Specification: A link to some document 409 is required. 411 Additional information or comments: Optionally any additional 412 comments for IANA or the Designated Expert. 414 6.3.2. tunnelType 416 Prior to this document, no form existed for tunnelType (and new 417 tunnelType requests did not need to use the ifType form that did 418 exist). This document therefore specifies a tunnelType form. 420 The following template describes the fields that MUST be supplied in 421 a registration request suitable for adding to the tunnelType 422 registry: 424 Label for IANA tunnelType requested: As explained in Section 7.1.1 425 of [RFC2578], a label for a named-number enumeration must consist 426 of one or more letters or digits, up to a maximum of 64 427 characters, and the initial character must be a lower-case letter. 429 (However, labels longer than 32 characters are not recommended.) 430 Note that hyphens are not allowed. 432 Name of IANA tunnelType requested: A short description (e.g., a 433 protocol name), suitable to appear in a comment in the registry. 435 Description of the proposed use of the IANA tunnelType: Requesters 436 MUST include answers, either directly or via a link to some 437 document with the answers, to the following questions in the 438 explanation of the proposed use of the IANA tunnelType: 440 o How would IP run over your tunnelType? 442 o Would there be another interface sublayer between your 443 tunnelType and IP? 445 o Would your tunnelType be vendor-specific or proprietary? (If 446 so, the label MUST start with a string that shows that. For 447 example, if your company's name or acronym is xxx, then the 448 tunnelType label would be something like xxxSomeIfTypeLabel.) 450 o Would your tunnelType require or allow vendor-specific 451 extensions? If so, would the vendor use their own tunnelType 452 in a sub-layer below the requested tunnelType, or some sort of 453 sub-type of the tunnelType, or some other mechanism? 455 Reference, Internet-Draft, or Specification: A link to some document 456 is required. 458 Additional information or comments: Optionally any additional 459 comments for IANA or the Designated Expert. 461 7. IANA Considerations 463 This entire document is about IANA considerations, but this section 464 discusses actions to be taken by IANA. There are three registries 465 affected: 467 1. ifType definitions [ifType-registry]: The registration process is 468 updated in Section 6.1, and the template is updated in 469 Section 6.3.1. 471 2. tunnelType definitions [tunnelType-registry]: The registration 472 process is updated in Section 6.1, and the template is updated in 473 Section 6.3.2. 475 3. transmission numbers [transmission-registry]: The assignment 476 process is updated in Section 6.2. 478 7.1. MIB and YANG Modules 480 The following actions are to be taken to clarify the relationship 481 between MIB modules, YANG modules, and the relevant registries: 483 1. Add the following note to the entry for the IANAifType-MIB at 484 [protocol-registries]: "This is one of the available formats of 485 the ifType and tunnelType registries." 487 2. Change the note on the entry for the iana-if-type YANG module at 488 [protocol-registries] to read: "This is one of the available 489 formats of the ifType registry." 491 3. Change the note on the entry for the iana-tunnel-type YANG module 492 at [protocol-registries] to read: "This is one of the available 493 formats of the tunnelType registry." 495 4. Create a section for "Interface Parameters" at 496 [protocol-registries], with entries for "Interface Types 497 (ifType)" [ifType-registry], "Tunnel Types (tunnelType)" 498 [tunnelType-registry], and "Transmission Values" 499 [transmission-registry]. 501 5. Update the ifType definitions registry [ifType-registry] to list 502 MIB [IANAifType-MIB] and YANG [yang-if-type] as Available 503 Formats. 505 6. Update the tunnelType definitions registry [tunnelType-registry] 506 to list MIB [IANAifType-MIB] and YANG [yang-tunnel-type] as 507 Available Formats, and change the title to "tunnelType 508 Definitions" for consistency with the [ifType-registry] title. 510 7. Replace the [yang-if-type] page with the YANG module content, 511 rather than having a page that itself claims to have multiple 512 Available Formats. 514 8. Replace the [yang-tunnel-type] page with the YANG module content, 515 rather than having a page that itself claims to have multiple 516 Available Formats. 518 In addition [IANAifType-MIB] is to be updated as follows: 520 OLD: Requests for new values should be made to IANA via email 521 (iana@iana.org). 523 NEW: Interface types must not be directly added to the IANAifType-MIB 524 MIB module. They must instead be added to the "ifType definitions" 525 registry at [ifType-registry]. 527 (Note that [yang-if-type] was previously updated with this language.) 529 7.2. Transmission Number Assignments 531 Per the discussion in Section 6.2, [ifType-registry] is to be updated 532 as follows: 534 OLD: For every ifType registration, the corresponding transmission 535 number value should be registered or marked "Reserved." 537 NEW: For future ifType assignments, an OID-subtree assignment MIB- 538 II's 'transmission' subtree will be made with the same value. 540 Similarly, the following change is to be made to 541 [transmission-registry]: 543 OLD: For every transmission number registration, the corresponding 544 ifType value should be registered or marked "Reserved." 546 NEW: For future transmission number assignments, an 'ifType' will be 547 made with the same value. 549 8. Security Considerations 551 Since this document does not introduce any technology or protocol, 552 there are no security issues to be considered for this document 553 itself. 555 For security considerations related to MIB and YANG modules that 556 expose these values, see Section 9 of [RFC2863], Section 6 of 557 [RFC4087], and Section 3 of [I-D.ietf-softwire-iftunnel]. 559 9. References 561 9.1. Normative References 563 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 564 Requirement Levels", BCP 14, RFC 2119, 565 DOI 10.17487/RFC2119, March 1997, . 568 [RFC2578] McCloghrie, K., Ed., Perkins, D., Ed., and J. 569 Schoenwaelder, Ed., "Structure of Management Information 570 Version 2 (SMIv2)", STD 58, RFC 2578, 571 DOI 10.17487/RFC2578, April 1999, . 574 [RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group 575 MIB", RFC 2863, DOI 10.17487/RFC2863, June 2000, 576 . 578 [RFC5378] Bradner, S., Ed. and J. Contreras, Ed., "Rights 579 Contributors Provide to the IETF Trust", BCP 78, RFC 5378, 580 DOI 10.17487/RFC5378, November 2008, . 583 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 584 Writing an IANA Considerations Section in RFCs", BCP 26, 585 RFC 8126, DOI 10.17487/RFC8126, June 2017, 586 . 588 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 589 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 590 May 2017, . 592 9.2. Informative References 594 [I-D.ietf-softwire-iftunnel] 595 Boucadair, M., Farrer, I., and R. Asati, "Tunnel Interface 596 Types YANG Module", draft-ietf-softwire-iftunnel-07 (work 597 in progress), June 2019. 599 [IANAifType-MIB] 600 IANA, "IANAifType-MIB", February 2019, 601 . 603 [ifType-registry] 604 IANA, "ifType definitions", June 2019, 605 . 608 [protocol-registries] 609 IANA, "Protocol Registries", June 2019, 610 . 612 [RFC1234] Provan, D., "Tunneling IPX traffic through IP networks", 613 RFC 1234, DOI 10.17487/RFC1234, June 1991, 614 . 616 [RFC1573] McCloghrie, K. and F. Kastenholz, "Evolution of the 617 Interfaces Group of MIB-II", RFC 1573, 618 DOI 10.17487/RFC1573, January 1994, . 621 [RFC2667] Thaler, D., "IP Tunnel MIB", RFC 2667, 622 DOI 10.17487/RFC2667, August 1999, . 625 [RFC3635] Flick, J., "Definitions of Managed Objects for the 626 Ethernet-like Interface Types", RFC 3635, 627 DOI 10.17487/RFC3635, September 2003, . 630 [RFC3637] Heard, C., Ed., "Definitions of Managed Objects for the 631 Ethernet WAN Interface Sublayer", RFC 3637, 632 DOI 10.17487/RFC3637, September 2003, . 635 [RFC4087] Thaler, D., "IP Tunnel MIB", RFC 4087, 636 DOI 10.17487/RFC4087, June 2005, . 639 [RFC4380] Huitema, C., "Teredo: Tunneling IPv6 over UDP through 640 Network Address Translations (NATs)", RFC 4380, 641 DOI 10.17487/RFC4380, February 2006, . 644 [RFC5066] Beili, E., "Ethernet in the First Mile Copper (EFMCu) 645 Interfaces MIB", RFC 5066, DOI 10.17487/RFC5066, November 646 2007, . 648 [RFC7224] Bjorklund, M., "IANA Interface Type YANG Module", 649 RFC 7224, DOI 10.17487/RFC7224, May 2014, 650 . 652 [transmission-registry] 653 IANA, "transmission definitions", June 2019, 654 . 657 [tunnelType-registry] 658 IANA, "Internet-standard MIB - mib- 659 2.interface.ifTable.ifEntry.ifType.tunnelType", June 2019, 660 . 663 [yang-if-type] 664 IANA, "iana-if-type YANG Module", February 2019, 665 . 667 [yang-tunnel-type] 668 IANA, "iana-tunnel-type YANG Module", June 2019, 669 . 671 Authors' Addresses 673 Dave Thaler 674 Microsoft 676 EMail: dthaler@microsoft.com 678 Dan Romascanu 679 Independent 681 EMail: dromasca@gmail.com