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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group M. Cotton 3 Internet-Draft ICANN 4 BCP: 26 B. Leiba 5 Obsoletes: 5226 (if approved) Huawei Technologies 6 Intended status: Best Current Practice T. Narten 7 Expires: February 28, 2015 IBM Corporation 8 August 29, 2014 10 Guidelines for Writing an IANA Considerations Section in RFCs 11 draft-leiba-cotton-iana-5226bis-07 13 Abstract 15 Many protocols make use of points of extensibility that use constants 16 to identify various protocol parameters. To ensure that the values 17 used in these fields do not have conflicting uses, and to promote 18 interoperability, their allocation is often coordinated by a central 19 authority. For IETF protocols, that role is filled by the Internet 20 Assigned Numbers Authority (IANA). 22 To make assignments in a given namespace prudently, IANA needs 23 guidance describing the conditions under which new values should be 24 assigned, as well as when and how modifications to existing values 25 can be made. This document defines a framework for the documentation 26 of these guidelines by specification authors, in order to assure that 27 the guidance given to IANA is clear and addresses the various issues 28 that are likely in the operation of a registry. 30 This is the third edition, and obsoletes RFC 5226. 32 Status of this Memo 34 This Internet-Draft is submitted in full conformance with the 35 provisions of BCP 78 and BCP 79. 37 Internet-Drafts are working documents of the Internet Engineering 38 Task Force (IETF). Note that other groups may also distribute 39 working documents as Internet-Drafts. The list of current Internet- 40 Drafts is at http://datatracker.ietf.org/drafts/current/. 42 Internet-Drafts are draft documents valid for a maximum of six months 43 and may be updated, replaced, or obsoleted by other documents at any 44 time. It is inappropriate to use Internet-Drafts as reference 45 material or to cite them other than as "work in progress." 47 This Internet-Draft will expire on February 28, 2015. 49 Copyright Notice 51 Copyright (c) 2014 IETF Trust and the persons identified as the 52 document authors. All rights reserved. 54 This document is subject to BCP 78 and the IETF Trust's Legal 55 Provisions Relating to IETF Documents (http://trustee.ietf.org/ 56 license-info) in effect on the date of publication of this document. 57 Please review these documents carefully, as they describe your rights 58 and restrictions with respect to this document. Code Components 59 extracted from this document must include Simplified BSD License text 60 as described in Section 4.e of the Trust Legal Provisions and are 61 provided without warranty as described in the Simplified BSD License. 63 Table of Contents 65 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 66 1.1. Keep IANA Considerations for IANA . . . . . . . . . . . . 3 67 1.2. For More Information . . . . . . . . . . . . . . . . . . . 4 68 1.3. Terminology Used In This Document . . . . . . . . . . . . 4 69 2. Creating and Revising Registries . . . . . . . . . . . . . . . 4 70 2.1. Hierarchical Registry Structure . . . . . . . . . . . . . 5 71 2.2. Documentation Requirements for Registries . . . . . . . . 6 72 2.3. Defining an Appropriate Registry Policy . . . . . . . . . 8 73 2.3.1. Using the Well-Known Registration Policies . . . . . . 10 74 2.3.2. Using Multiple Policies in Combination . . . . . . . . 11 75 2.3.3. Specifying Change Control for a Registry . . . . . . . 12 76 2.4. Revising Existing Registries . . . . . . . . . . . . . . . 12 77 3. Registering New Values in an Existing Registry . . . . . . . . 13 78 3.1. Documentation Requirements for Registrations . . . . . . . 13 79 3.2. Updating Existing Registrations . . . . . . . . . . . . . 14 80 3.3. Overriding Registration Procedures . . . . . . . . . . . . 15 81 3.4. Early Allocations . . . . . . . . . . . . . . . . . . . . 15 82 4. Well-Known Registration Policies . . . . . . . . . . . . . . . 16 83 4.1. Private Use . . . . . . . . . . . . . . . . . . . . . . . 17 84 4.2. Experimental Use . . . . . . . . . . . . . . . . . . . . . 17 85 4.3. Hierarchical Allocation . . . . . . . . . . . . . . . . . 17 86 4.4. First Come First Served . . . . . . . . . . . . . . . . . 17 87 4.5. Expert Review . . . . . . . . . . . . . . . . . . . . . . 18 88 4.6. Specification Required . . . . . . . . . . . . . . . . . . 19 89 4.7. RFC Required . . . . . . . . . . . . . . . . . . . . . . . 19 90 4.8. IETF Review . . . . . . . . . . . . . . . . . . . . . . . 19 91 4.9. Standards Action . . . . . . . . . . . . . . . . . . . . . 20 92 4.10. IESG Approval . . . . . . . . . . . . . . . . . . . . . . 20 93 5. Designated Experts . . . . . . . . . . . . . . . . . . . . . . 21 94 5.1. The Motivation for Designated Experts . . . . . . . . . . 21 95 5.2. The Role of the Designated Expert . . . . . . . . . . . . 22 96 5.2.1. Managing Designated Experts in the IETF . . . . . . . 23 97 5.3. Designated Expert Reviews . . . . . . . . . . . . . . . . 23 98 5.4. Expert Reviews and the Document Lifecycle . . . . . . . . 25 99 6. Well-Known Registration Status Terminology . . . . . . . . . . 25 100 7. Documentation References in IANA Registries . . . . . . . . . 26 101 8. What to Do in "bis" Documents . . . . . . . . . . . . . . . . 26 102 9. Miscellaneous Issues . . . . . . . . . . . . . . . . . . . . . 27 103 9.1. When There Are No IANA Actions . . . . . . . . . . . . . . 27 104 9.2. Namespaces Lacking Documented Guidance . . . . . . . . . . 28 105 9.3. After-the-Fact Registrations . . . . . . . . . . . . . . . 28 106 9.4. Reclaiming Assigned Values . . . . . . . . . . . . . . . . 29 107 9.5. Contact Person vs Assignee or Owner . . . . . . . . . . . 29 108 9.6. Closing or Obsoleting a Registry . . . . . . . . . . . . . 30 109 10. Appeals . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 110 11. Mailing Lists . . . . . . . . . . . . . . . . . . . . . . . . 30 111 12. Security Considerations . . . . . . . . . . . . . . . . . . . 30 112 13. Changes Relative to Earlier Editions of BCP 26 . . . . . . . . 31 113 13.1. 2014: Changes in This Document Relative to RFC 5226 . . . 31 114 13.2. 2008: Changes in RFC 5226 Relative to RFC 2434 . . . . . 32 115 14. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 33 116 14.1. Acknowledgments for This Document (2014) . . . . . . . . 33 117 14.2. Acknowledgments from the second edition (2008) . . . . . 33 118 14.3. Acknowledgments from the first edition (1998) . . . . . . 33 119 15. References . . . . . . . . . . . . . . . . . . . . . . . . . . 33 120 15.1. Normative References . . . . . . . . . . . . . . . . . . 34 121 15.2. Informative References . . . . . . . . . . . . . . . . . 34 122 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 36 124 1. Introduction 126 Many protocols make use of points of extensibility that use constants 127 to identify various protocol parameters. To ensure that the values 128 used in these fields do not have conflicting uses, and to promote 129 interoperability, their allocation is often coordinated by a central 130 authority. For IETF protocols, that role is filled by the Internet 131 Assigned Numbers Authority (IANA) [RFC2860]. IANA services are 132 currently provided by the International Corporation for Assigned 133 Names and Numbers (ICANN). 135 The Protocol field in the IP header [RFC0791] and MIME media types 136 [RFC4288] are two examples of such coordinations. 138 In this document, we call the range of possible values for such a 139 field a "namespace". The binding or association of a specific value 140 with a particular purpose within a namespace is called an assignment 141 (or, variously: an assigned number, assigned value, code point, 142 protocol constant, or protocol parameter). The act of assignment is 143 called a registration, and it takes place in the context of a 144 registry. The terms "assignment" and "registration" are used 145 interchangably throughout this document. 147 To make assignments in a given namespace prudently, IANA needs 148 guidance describing the conditions under which new values should be 149 assigned, as well as when and how modifications to existing values 150 can be made. This document defines a framework for the documentation 151 of these guidelines by specification authors, in order to assure that 152 the guidance given to IANA is clear and addresses the various issues 153 that are likely in the operation of a registry. 155 Typically, this information is recorded in a dedicated section of the 156 specification with the title "IANA Considerations". 158 1.1. Keep IANA Considerations for IANA 159 The purpose of having a dedicated IANA Considerations section is to 160 provide a single place to collect clear and concise information and 161 instructions for IANA. Technical documentation should reside in 162 other parts of the document, and should be included by reference 163 only. Using the IANA Considerations section as primary technical 164 documentation both hides it from the target audience of the document 165 and interferes with IANA's review of the actions they need to take. 167 If, for example, the registration of an item in a registry includes a 168 short description of the item being registered, that should be placed 169 in the IANA Considerations directly. But if it's necessary to 170 include a longer technical explanation of the purpose and use of the 171 item, the IANA Considerations should refer to a technical section of 172 the document where that information resides. Similarly, if the 173 document is pointing out the use of an existing assignment in a 174 registry, but makes no modification to the registration, that should 175 be in a technical section of the document, reserving the IANA 176 Considerations section for instructions to IANA. 178 An ideal IANA Considerations section clearly enumerates and specifies 179 each requested IANA action; includes all information IANA needs, such 180 as the full names of all applicable registries; and includes clear 181 references to elsewhere in the document for other information. 183 1.2. For More Information 185 IANA maintains a web page that includes current important information 186 from IANA. Document authors should check that page for additional 187 information, beyond what is provided here. 189 . 191 [[***** The URI above is not yet ready. IANA is setting it up. 192 *****]] 194 1.3. Terminology Used In This Document 196 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 197 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 198 document are to be interpreted as described in RFC 2119 [RFC2119]. 199 For this document, "the specification" as used by RFC 2119 refers to 200 the processing of protocol documents within the IETF standards 201 process. 203 2. Creating and Revising Registries 205 Defining a registry involves describing the namespace(s) to be 206 created, listing an initial set of assignments (if appropriate), and 207 documenting guidelines on how future assignments are to be made. 209 Before defining a registry, however, consider delegating the 210 namespace in some manner. This route should be pursued when 211 appropriate, as it lessens the burden on IANA for dealing with 212 assignments. 214 In particular, not all namespaces require a registry; in some cases, 215 assignments can be made independently and with no further (central) 216 coordination. In the Domain Name System, for example, IANA only 217 deals with assignments at the higher levels, while subdomains are 218 administered by the organization to which the space has been 219 delegated. When a namespace is delegated in this manner, the scope 220 of IANA is limited to the parts of the namespace where IANA has 221 authority. 223 2.1. Hierarchical Registry Structure 225 It's important to start with a word on the IANA registry structure. 226 All registries are anchored from the IANA "Protocol Registries" page: 228 . 230 That page lists registries in protocol category groups, like this: 232 --------------------------------------------------------------- 233 Author Domain Signing Practices (ADSP) Parameters 235 ADSP Outbound Signing Practices RFC 5617 236 IETF Review 238 ADSP Specification Tags RFC 5617 239 IETF Review 241 Automatic Responses to Electronic Mail Parameters 243 Auto-Submitted Header Field RFC 5436 244 Keywords Specification Required 246 Auto-Submitted header field RFC 3834 247 optional parameters IETF Consensus 249 Autonomous System (AS) Numbers 251 16-bit Autonomous System Numbers RFC 1930, RFC 5398, RFC 6996 252 RIR request to the IANA 253 or IETF Review 255 32-bit Autonomous System Numbers RFC 1930, RFC 5398, RFC 6793, 256 RFC 6996 257 RIR request to the IANA 258 or IETF Review 259 --------------------------------------------------------------- 261 The grouping allows related registries to be placed together, making 262 it easier for users of the registries to find the necessary 263 information. In the example section above, there are two registries 264 related to the ADSP protocol, and they are both placed in the "ADSP 265 Parameters" group. 267 Within the "ADSP Parameters" group are two registries: "ADSP Outbound 268 Signing Practices" and "ADSP Specification Tags". Clicking on the 269 title of one of these registries on the IANA Protocol Registries page 270 will take the reader to the details page for that registry. Often, 271 multiple registries are shown on the same details page. 273 Unfortunately, we have been inconsistent in how we refer to these 274 entities. The group names, as they are referred to here, have been 275 variously called "protocol category groups", "groups", "top-level 276 registries", or just "registries". The registries under them have 277 been called "registries" or "sub-registries". And when new 278 registries are created, the documents that define them often don't 279 specify the grouping at all, but only name the new registry. This 280 results in questions from IANA and delays in processing, or, worse, 281 in related registries that should have been grouped together, but 282 that are instead scattered about and hard to find and correlate. 284 Regardless of the terminology used, document authors should pay 285 attention to the registry groupings, should request that related 286 registries be grouped together, and, when creating a new registry, 287 should check whether that registry might best be included in an 288 existing group. That grouping information should be clearly 289 communicated to IANA in the registry creation request. 291 2.2. Documentation Requirements for Registries 293 Documents that create a new namespace (or modify the definition of an 294 existing space) and that expect IANA to play a role in maintaining 295 that space (serving as a repository for registered values) MUST 296 provide clear instructions on details of the namespace, either in the 297 IANA Considerations section, or referenced from it. 299 In particular, such instructions MUST include: 301 The name of the registry (or sub-registry) 302 This name will appear on the IANA web page and will be referred to 303 in future documents that need to allocate a value from the new 304 space. The full name (and abbreviation, if appropriate) should be 305 provided. It is highly desirable that the chosen name not be 306 easily confused with the name of another registry. 308 When creating a sub-registry, the registry that it is a part of 309 must be identified using its full name, exactly as it appears in 310 the IANA registry list. 312 Providing a URL to precisely identify the registry helps IANA 313 understand the request. Such URLs can be removed from the RFC 314 prior to final publication. If they are to be left in, it is 315 important that they be permanent links -- IANA intends to include 316 the permalink for each registry in the registry header. [[***** 317 This is not yet done, but is planned. *****]] 319 For example, a document could contain something like this: 321 This registration should be made in the Foobar Operational 322 Parameters registry, located at . 325 It might be tempting to use the URL that appears in your web 326 browser's address bar, which might look something like this for 327 the example above: 329 http://www.iana.org/assignments/foobar-registry/foobar- 330 registry.xml 332 ...but that is not the permanent link to the registry. 334 Required information for registrations 336 This information may include the need to document relevant 337 Security Considerations, if any. 339 Applicable review process 341 The review process that will apply to all future requests for 342 registration. See Section 2.3. 344 Size, format and syntax of registry entries 346 What fields to record in the registry, any technical requirements 347 on registry entries (valid ranges for integers, length limitations 348 on strings, and such), and the exact format in which registry 349 values should be displayed. For numeric assignments, one should 350 specify whether values are to be recorded in decimal, in 351 hexadecimal, or in some other format. For strings, the encoding 352 format should be specified (ASCII, UTF8, etc.). 354 Initial assignments and reservations 356 Any initial assignments or registrations to be included. In 357 addition, any ranges that are to be reserved for "Private Use", 358 "Reserved", "Unassigned", etc. should be indicated. 360 For example, a document might specify a new registry by including: 362 --------------------------------------------------------------- 364 X. IANA Considerations 366 This document defines a new DHCP option, entitled "FooBar" (see 367 Section y), assigned a value of TBD1 from the DHCP Option space 368 [to be removed upon publication: 369 http://www.iana.org/assignments/bootp-dhcp-parameters] 370 [RFC2132] [RFC2939]: 371 Data 372 Tag Name Length Meaning 373 ---- ---- ------ ------- 374 TBD1 FooBar N FooBar server 376 The FooBar option also defines an 8-bit FooType field, for which 377 IANA is to create and maintain a new sub-registry entitled 378 "FooType values" under the FooBar option. Initial values for the 379 DHCP FooBar FooType registry are given below; future assignments 380 are to be made through Expert Review [BCP26]. 381 Assignments consist of a DHCP FooBar FooType name and its 382 associated value. 384 Value DHCP FooBar FooType Name Definition 385 ---- ------------------------ ---------- 386 0 Reserved 387 1 Frobnitz See Section y.1 388 2 NitzFrob See Section y.2 389 3-254 Unassigned 390 255 Reserved 391 --------------------------------------------------------------- 393 For examples of documents that establish registries, consult 394 [RFC3575], [RFC3968], and [RFC4520]. 396 2.3. Defining an Appropriate Registry Policy 398 There are several issues to consider when defining the policy for the 399 new assignments in a registry. 401 If the registry's namespace is limited, assignments will need to be 402 made carefully to prevent exhaustion. 404 Even when the space is essentially unlimited, however, it is usually 405 desirable to have at least a minimal review prior to assignment in 406 order to: 408 o prevent the hoarding of or unnecessary wasting of values. For 409 example, if the space consists of text strings, it may be 410 desirable to prevent entities from obtaining large sets of strings 411 that correspond to desirable names (existing company names, for 412 example). 414 o provide a sanity check that the request actually makes sense and 415 is necessary. Experience has shown that some level of minimal 416 review from a subject matter expert is useful to prevent 417 assignments in cases where the request is malformed or not 418 actually needed (for example, an existing assignment for an 419 essentially equivalent service already exists). 421 Perhaps most importantly, unreviewed extensions can impact 422 interoperability and security. See [RFC6709]. 424 When the namespace is essentially unlimited and there are no 425 potential interoperability or security issues, assigned numbers can 426 usually be given out to anyone without any subjective review. In 427 such cases, IANA can make assignments directly, provided that IANA is 428 given detailed instructions on what types of requests it should 429 grant, and it is able to do so without exercising subjective 430 judgement. 432 When this is not the case, some level of review is required. 433 However, it's important to balance adequate review and ease of 434 registration. In many cases, those making registrations will not be 435 IETF participants; requests often come from other standards 436 organizations, from organizations not directly involved in standards, 437 from ad-hoc community work (from an open-source project, for 438 example), and so on. Registration must not be unnecessarily 439 difficult, unnecessarily costly (in terms of time and other 440 resources), nor unnecessarily subject to denial. 442 While it is sometimes necessary to restrict what gets registered 443 (e.g., for limited resources such as bits in a byte, or for items for 444 which unsupported values can be damaging to protocol operation), in 445 many cases having what's in use represented in the registry is more 446 important. Overly strict review criteria and excessive cost (in time 447 and effort) discourage people from even attempting to make a 448 registration. If a registry fails to reflect the protocol elements 449 actually in use, it can adversely affect deployment of protocols on 450 the Internet, and the registry itself is devalued. 452 In particular, when a registry policy that requires involvement of 453 Working Groups, directorates, or other bodies to be actively involved 454 and to support the effort, requests frequently run into concerns that 455 "it's not worth doing a Standards-Track RFC for something this 456 trivial," when, in fact, that requirement was created by the Working 457 Group in the first place, by placing the bar that high. 459 Indeed, publishing any RFC is costly, and a Standards Track RFC is 460 especially so, requiring a great deal of community time for review 461 and discussion, IETF-wide last call, involvement of the entire IESG 462 as well as concentrated time and review from the sponsoring AD, 463 review and action by IANA, and RFC-Editor processing. 465 Therefore, Working Groups and other document developers should use 466 care in selecting appropriate registration policies when their 467 documents create registries. They should select the least strict 468 policy that suits a registry's needs, and look for specific 469 justification for policies that require significant community 470 involvement (Specification Required, in terms of the well-known 471 policies). 473 2.3.1. Using the Well-Known Registration Policies 475 This document defines a number of registration policies in Section 4. 476 Because they benefit from both community experience and wide 477 understanding, their use is encouraged when appropriate. 479 It is also acceptable to cite one of the well-known policies and 480 include additional guidelines for what kind of considerations should 481 be taken into account by the review process. 483 For example, RADIUS [RFC3575] specifies the use of a Designated 484 Expert, but includes specific additional criteria the Designated 485 Expert should follow. 487 The well-known policies from "First Come First Served" to "Standards 488 Action" specify a range of policies in increasing order of strictness 489 (using the numbering from the full list in Section 4): 491 4. First Come First Served 492 No review, minimal documentation. 494 5. Expert Review 495 Expert review, sufficient documentation for review. 497 6. Specification Required 498 Expert review, significant, stable public documentation. 500 7. RFC Required 501 Any RFC publication, IETF or a non-IETF Stream. 503 8. IETF Review 504 RFC publication, IETF Stream only, but need not be Standards 505 Track. 507 9. Standards Action 508 RFC publication, IETF Stream, Standards Track only. 510 Examples of situations that might merit RFC Required, IETF Review, or 511 Standards Action include the following: 513 o When a resource is limited, such as bits in a byte (or in two 514 bytes, or four), or numbers in a limited range. In these cases, 515 allowing registrations that haven't been carefully reviewed and 516 agreed by community consensus could too quickly deplete the 517 allowable values. 519 o When thorough community review is necessary to avoid extending or 520 modifying the protocol in ways that could be damaging. One 521 example is in defining new command codes, as opposed to options 522 that use existing command codes: the former might require a strict 523 policy, where a more relaxed policy could be adequate for the 524 latter. Another example is in defining protocol elements that 525 change the semantics of existing operations. 527 The description in Section 4.10 of "IESG Approval" suggests that the 528 IESG "can (and should) reject a request if another path for 529 registration is available that is more appropriate and there is no 530 compelling reason not to use that path." The IESG should give 531 similar consideration to any registration policy more stringent than 532 Specification Required, asking for justification and ensuring that 533 more relaxed policies have been considered, and the strict policy is 534 the right one. 536 Accordingly, document developers need to anticipate this and document 537 their considerations for selecting the specified policy (ideally, in 538 the document itself; failing that, in the shepherd writeup). 539 Likewise, the document shepherd should ensure that the selected 540 policies have been justified before sending the document to the IESG. 542 When specifications are revised, registration policies should be 543 reviewed in light of experience since the policies were set. 545 Note that the well-known policies are not exclusive; there are 546 situations where a different policy might be more appropriate. 548 2.3.2. Using Multiple Policies in Combination 550 In some situations, it is necessary to define multiple registration 551 policies. For example, registrations through the normal IETF process 552 might use one policy, while registrations from outside the process 553 would have a different policy applied. 555 Thus, a particular registry might want to use a policy such as "RFC 556 Required" or "IETF Review" sometimes, with a designated expert 557 checking a "Specification Required" policy at other times. 559 The alternative to using a combination requires either that all 560 requests come through RFCs or that requests in RFCs go through review 561 by the designated expert, even though they already have IETF review 562 and consensus. 564 This can be documented in the IANA Considerations section when the 565 registry is created: 567 IANA is asked to create the registry "Fruit Access Flags" as a 568 sub-registry of "Fruit Parameters". New registrations will be 569 permitted through either the IETF Review policy or the 570 Specification Required policy [BCP26]. 572 Such combinations will commonly use one of {Standards Action, IETF 573 Review, RFC Required} in combination with one of {Specification 574 Required, Expert Review}. 576 2.3.3. Specifying Change Control for a Registry 578 Registry definitions and registrations within registries often need 579 to be changed after they are created. The process of making such 580 changes is complicated when it is unclear who is authorized to make 581 the changes. For registries created by RFCs in the IETF stream, 582 change control for the registry lies by default with the IETF, via 583 the IESG. The same is true for value registrations made in IETF- 584 stream RFCs. 586 Because registries can be created and registrations can be made 587 outside the IETF stream, it can sometimes be desired to have change 588 control outside the IETF and IESG, and clear specification of change 589 control policies is always helpful. 591 It is advised, therefore, that all registries that are created 592 clearly specify a change control policy and a change controller. It 593 is also advised that registries that allow registrations from outside 594 the IETF stream include, for each value, the designation of a change 595 controller for that value. If the definition or reference for a 596 registered value ever needs to change, or if a registered value needs 597 to be deprecated, it is critical that IANA know who is authorized to 598 make the change. See also Section 9.5. 600 2.4. Revising Existing Registries 602 Updating the registration process or making changes to the format of 603 an already existing (previously created) registry (whether created 604 explicitly or implicitly) follows a process similar to that used when 605 creating a new registry. That is, a document is produced that makes 606 reference to the existing namespace and then provides detailed 607 guidance for handling assignments in the registry, or detailed 608 instructions about the changes required. 610 If a change requires a new column in the registry, the instructions 611 need to be clear about how to populate that column for the existing 612 entries. Other changes may require similar clarity. Remember to 613 check this, and give clear instructions to IANA. 615 Such documents are normally processed with the same document status 616 as the document that created the registry, or as Best Current 617 Practices (BCPs) [RFC2026]. 619 Example documents that updated the guidelines for assignments in pre- 620 existing registries include: [RFC6195], [RFC3228], and [RFC3575]. 622 3. Registering New Values in an Existing Registry 624 3.1. Documentation Requirements for Registrations 626 Often, documents request an assignment in an existing namespace (one 627 created by a previously published document). 629 Such documents should clearly identify the namespace into which each 630 value is to be registered. If the registration goes into a sub- 631 registry, the author should clearly explain that. Use the exact 632 namespace name as listed on the IANA web page, and cite the RFC where 633 the namespace is defined. 635 There is no need to mention what the assignment policy is when making 636 new assignments in existing registries, as that should be clear from 637 the references. 639 When referring to an existing registry, providing a URL to precisely 640 identify the registry is helpful. See Section 2.2 for details on 641 specifying the correct URL. 643 For example, a document could contain something like this: 645 This registration should be made in the Foobar Operational 646 Parameters registry, located at . 649 Normally, numeric values to be used are chosen by IANA when the 650 document is approved, and drafts should not specify final values. 651 Instead, placeholders such as "TBD1" and "TBD2" should be used 652 consistently throughout the document, giving each item to be 653 registered a different placeholder. The IANA Considerations should 654 ask the RFC Editor to replace the placeholder names with the IANA- 655 assigned values. When drafts need to specify numeric values for 656 testing or early implementations, they will either request early 657 allocation (see Section 3.4) or use values that have already been set 658 aside for testing or experimentation. It is important that drafts 659 not choose their own values, lest IANA assign one of those values to 660 another document in the meantime. A draft can request a specific 661 value in the IANA Considerations section, and IANA will accommodate 662 such requests when that's possible, but the proposed number might 663 have been assigned to some other use by the time the draft is 664 approved. 666 Normally, text-string values to be used are specified in the 667 document, as collisions are less likely with text strings. IANA will 668 consult with the authors if there is, in fact, a collision, and a 669 different value has to be used. When drafts need to specify string 670 values for testing or early implementations, they sometimes use the 671 expected final value. But it is often useful to use a draft value 672 instead, possibly including the draft version number. This allows 673 the early implementations to be distinguished from those implementing 674 the final version. A document that intends to use "foobar" in the 675 final version might use "foobar-testing-draft-05" for the -05 version 676 of the draft, for example. 678 For some registries, IANA has a long-standing policy prohibiting 679 assignment of names or codes on a vanity or organization-name basis. 680 For example, codes might always be assigned sequentially unless there 681 is a strong reason for making an exception. Nothing in this document 682 is intended to change those policies or prevent their future 683 application. 685 The IANA Considerations section should summarize all of the IANA 686 actions, with pointers to the relevant sections elsewhere in the 687 document as appropriate. When multiple values are requested, it is 688 generally helpful to include a summary table. It is also helpful for 689 this table to be in the same format as it appears or will appear on 690 the IANA web site. For example: 692 Value Description Reference 693 -------- ------------------- --------- 694 TBD1 Foobar [[this RFC]] 696 Note: In cases where authors feel that including the full table is 697 too verbose or repetitive, authors should still include the table in 698 the draft, but may include a note asking that the table be removed 699 prior to publication of the final RFC. 701 As an example, the following text could be used to request assignment 702 of a DHCPv6 option number: 704 IANA has assigned an option code value of TBD1 to the DNS 705 Recursive Name Server option and an option code value of TBD2 to 706 the Domain Search List option from the DHCP option code space 707 defined in Section 24.3 of RFC 3315. 709 3.2. Updating Existing Registrations 711 Even after a number has been assigned, some types of registrations 712 contain additional information that may need to be updated over time. 714 For example, MIME media types, character sets, and language tags 715 typically include more information than just the registered value 716 itself, and may need updates to items such as point-of-contact 717 information, security issues, pointers to updates, and literature 718 references. 720 In such cases, the document defining the namespace must clearly state 721 who is responsible for maintaining and updating a registration. 722 Depending on the registry, it may be appropriate to specify one or 723 more of: 725 o Letting registrants and/or nominated change controllers update 726 their own registrations, subject to the same constraints and 727 review as with new registrations. 729 o Allowing attachment of comments to the registration. This can be 730 useful in cases where others have significant objections to a 731 registration, but the author does not agree to change the 732 registration. 734 o Designating the IESG, a designated expert, or another entity as 735 having the right to change the registrant associated with a 736 registration and any requirements or conditions on doing so. This 737 is mainly to get around the problem when a registrant cannot be 738 reached in order to make necessary updates. 740 3.3. Overriding Registration Procedures 742 Experience has shown that the documented IANA considerations for 743 individual protocols do not always adequately cover the reality of 744 registry operation, or are not sufficiently clear. In addition, 745 documented IANA considerations are sometimes found to be too 746 stringent to allow even working group documents (for which there is 747 strong consensus) to perform a registration in advance of actual RFC 748 publication. 750 In order to allow assignments in such cases, the IESG is granted 751 authority to override registration procedures and approve assignments 752 on a case-by-case basis. 754 The intention here is not to overrule properly documented procedures, 755 or to obviate the need for protocols to properly document their IANA 756 considerations. Rather, it is to permit assignments in specific 757 cases where it is obvious that the assignment should just be made, 758 but updating the IANA process beforehand is too onerous. 760 When the IESG is required to take action as described in this 761 section, it is a strong indicator that the applicable registration 762 procedures should be updated, possibly in parallel with the work that 763 instigated it. 765 3.4. Early Allocations 766 IANA normally takes its actions when a document is approved for 767 publication. There are times, though, when early allocation of a 768 value is important for the development of a technology: for example, 769 when early implementations are created while the document is still 770 under development. 772 IANA has a mechanism for handling such early allocations in some 773 cases. See [RFC7120] for details. 775 4. Well-Known Registration Policies 777 The following are some defined policies, most of which are in use 778 today. These cover a range of typical policies that have been used 779 to describe the procedure for assigning new values in a namespace. 780 It is not strictly required that documents use these terms; the 781 actual requirement is that the instructions to IANA be clear and 782 unambiguous. However, use of these terms is strongly RECOMMENDED, 783 because their meanings are widely understood. The terms are fully 784 explained in the following subsections. 786 1. Private Use 787 2. Experimental Use 788 3. Hierarchical Allocation 789 4. First Come First Served 790 5. Expert Review 791 6. Specification Required 792 7. RFC Required 793 8. IETF Review 794 9. Standards Action 795 10. IESG Approval 797 It should be noted that it often makes sense to partition a namespace 798 into multiple categories, with assignments within each category 799 handled differently. Many protocols now partition namespaces into 800 two or more parts, with one range reserved for Private or 801 Experimental Use while other ranges are reserved for globally unique 802 assignments assigned following some review process. Dividing a 803 namespace into ranges makes it possible to have different policies in 804 place for different ranges and different use cases. 806 Similarly, it will often be useful to specify multiple policies in 807 parallel, with each policy being used under different circumstances. 809 For more discussion of that topic, see Section 2.3.2. 811 Examples of RFCs that specify multiple policies in parallel: 813 LDAP [RFC4520] 814 TLS ClientCertificateType Identifiers [RFC5246] (as detailed in 815 the subsections below) 816 Pseudowire Edge to Edge Emulation (PWE3) [RFC4446] 818 4.1. Private Use 820 For private or local use only, with the type and purpose defined by 821 the local site. No attempt is made to prevent multiple sites from 822 using the same value in different (and incompatible) ways. There is 823 no need for IANA to review such assignments (since IANA does not 824 record them) and assignments are not generally useful for broad 825 interoperability. It is the responsibility of the sites making use 826 of the Private Use range to ensure that no conflicts occur (within 827 the intended scope of use). 829 Examples: 831 Site-specific options in DHCP [RFC2939] 832 Fibre Channel Port Type Registry [RFC4044] 833 TLS ClientCertificateType Identifiers 224-255 [RFC5246] 835 4.2. Experimental Use 837 Experimental Use is similar to Private Use only, but with the purpose 838 being to facilitate experimentation. See [RFC3692] for details. 840 Example: 842 Experimental Values in IPv4, IPv6, ICMPv4, ICMPv6, UDP, and TCP 843 Headers [RFC4727] 845 4.3. Hierarchical Allocation 847 With Hierarchical Allocation, delegated administrators are given 848 control over part of the namespace, and can assign values in that 849 part of the namespace. IANA makes allocations in the higher levels 850 of the namespace according to one of the other policies. 852 Examples: 854 DNS names 855 Object Identifiers 856 IP addresses 858 4.4. First Come First Served 859 For the First Come First Served policy, assignments are made to 860 anyone on a first come, first served basis. There is no substantive 861 review of the request, other than to ensure that it is well-formed 862 and doesn't duplicate an existing assignment. However, requests must 863 include a minimal amount of clerical information, such as a point of 864 contact (including an email address, and sometimes a postal address) 865 and a brief description of how the value will be used. Additional 866 information specific to the type of value requested may also need to 867 be provided, as defined by the namespace. For numbers, the exact 868 value is generally assigned by IANA; with names, specific text 869 strings can usually be requested. 871 When creating a new registry with First Come First Served as the 872 registration policy, in addition to the contact person field or 873 reference, the registry should contain a field for change controller. 874 Having a change controller for each entry for these types of 875 registrations makes authorization of future modifications more clear. 876 See Section 2.3.3 878 Examples: 880 SASL mechanism names [RFC4422] 881 LDAP Protocol Mechanisms and LDAP Syntax [RFC4520] 883 4.5. Expert Review 885 (Also called "Designated Expert" in earlier editions of this 886 document.) For the Expert Review policy, review and approval by a 887 designated expert (see Section 5) is required. The required 888 documentation and review criteria for use by the designated expert 889 should be provided when defining the registry. For example, see 890 Sections 6 and 7.2 in [RFC3748]. 892 It is particularly important, when using a designated expert, to give 893 clear guidance to the expert, laying out criteria for performing an 894 evaluation and reasons for rejecting a request. When specifying a 895 policy that involves a designated expert, the IANA Considerations 896 SHOULD contain such guidance. It is also a good idea to include, 897 when possible, a sense of whether many registrations are expected 898 over time, or if the registry is expected to be updated infrequently 899 or in exceptional circumstances only. 901 When creating a new registry with Expert Review as the registration 902 policy, in addition to the contact person field or reference, the 903 registry should contain a field for change controller. Having a 904 change controller for each entry for these types of registrations 905 makes authorization of future modifications more clear. See Section 906 2.3.3 908 Examples: 910 EAP Method Types [RFC3748] 911 HTTP Digest AKA algorithm versions [RFC4169] 912 URI schemes [RFC4395] 913 GEOPRIV Location Types [RFC4589] 915 4.6. Specification Required 917 For the Specification Required policy, review and approval by a 918 designated expert (see Section 5) is required, and the values and 919 their meanings must be documented in a permanent and readily 920 available public specification, in sufficient detail so that 921 interoperability between independent implementations is possible. 922 The designated expert will review the public specification and 923 evaluate whether it is sufficiently clear to allow interoperable 924 implementations. The intention behind "permanent and readily 925 available" is that a document can reasonably be expected to be 926 findable and retrievable long after IANA assignment of the requested 927 value. Publication of an RFC is an ideal means of achieving this 928 requirement, but Specification Required is intended to also cover the 929 case of a document published outside of the RFC path. For RFC 930 publication, the normal RFC review process is expected to provide the 931 necessary review for interoperability, though the designated expert 932 may be a particularly well-qualified person to perform such a review. 934 When specifying this policy, just use the term "Specification 935 Required". Some specifications have chosen to refer to it as "Expert 936 Review with Specification Required", and that only causes confusion. 938 Examples: 940 Diffserv-aware TE Bandwidth Constraints Model Identifiers 941 [RFC4124] 942 TLS ClientCertificateType Identifiers 64-223 [RFC5246] 943 ROHC Profile Identifiers [RFC5795] 945 4.7. RFC Required 947 With the RFC Required policy, the registration request, along with 948 associated documentation, must be published in an RFC. The RFC need 949 not be in the IETF stream, but may be in any RFC stream (currently an 950 RFC may be in the IETF, IRTF, or IAB stream, or an RFC Editor 951 Independent Submission [RFC5742]). Unless otherwise specified, any 952 type of RFC is sufficient (currently Standards Track, BCP, 953 Informational, Experimental, or Historic). 955 4.8. IETF Review 957 (Formerly called "IETF Consensus" in the first edition of this 958 document.) With the IETF Review policy, new values are assigned only 959 through RFCs in the IETF Stream -- those that have been shepherded 960 through the IESG as AD-Sponsored or IETF working group Documents 962 [RFC2026] [RFC5378]. 964 The intent is that the document and proposed assignment will be 965 reviewed by the IETF community (including appropriate IETF working 966 groups, directorates, and other experts) and by the IESG, to ensure 967 that the proposed assignment will not negatively affect 968 interoperability or otherwise extend IETF protocols in an 969 inappropriate or damaging manner. To ensure adequate community 970 review, such documents will always undergo an IETF Last Call. 972 Examples: 974 IPSECKEY Algorithm Types [RFC4025] 975 Accounting-Auth-Method AVP values in DIAMETER [RFC4005] 976 TLS Extension Types [RFC5246] 978 4.9. Standards Action 980 For the Standards Action policy, values are assigned only through 981 Standards Track RFCs approved by the IESG. 983 Examples: 985 BGP message types [RFC4271] 986 Mobile Node Identifier option types [RFC4283] 987 TLS ClientCertificateType Identifiers 0-63 [RFC5246] 988 DCCP Packet Types [RFC4340] 990 4.10. IESG Approval 992 New assignments may be approved by the IESG. Although there is no 993 requirement that the request be documented in an RFC, the IESG has 994 discretion to request documents or other supporting materials on a 995 case-by-case basis. 997 IESG Approval is not intended to be used often or as a "common case"; 998 indeed, it has seldom been used in practice during the period RFC 999 2434 was in effect. Rather, it is intended to be available in 1000 conjunction with other policies as a fall-back mechanism in the case 1001 where one of the other allowable approval mechanisms cannot be 1002 employed in a timely fashion or for some other compelling reason. 1003 IESG Approval is not intended to circumvent the public review 1004 processes implied by other policies that could have been employed for 1005 a particular assignment. IESG Approval would be appropriate, 1006 however, in cases where expediency is desired and there is strong 1007 consensus (such as from a working group) for making the assignment. 1009 The following guidelines are suggested for any evaluation under IESG 1010 Approval: 1012 o The IESG can (and should) reject a request if another path for 1013 registration is available that is more appropriate and there is no 1014 compelling reason not to use that path. 1016 o Before approving a request, the community should be consulted, via 1017 a "call for comments" that provides as much information as is 1018 reasonably possible about the request. 1020 Examples: 1022 IPv4 Multicast address assignments [RFC5771] 1023 IPv4 IGMP Type and Code values [RFC3228] 1024 Mobile IPv6 Mobility Header Type and Option values [RFC6275] 1026 5. Designated Experts 1028 5.1. The Motivation for Designated Experts 1030 IANA does not define registry policy itself; rather, it carries out 1031 policies that have been defined by others and published in RFCs. As 1032 part of that process, review of proposed registrations is often 1033 appropriate. 1035 A common way to ensure such review is for a proposed registration to 1036 be published as an RFC, as this ensures that the specification is 1037 publicly and permanently available. It is particularly important if 1038 any potential interoperability issues might arise. For example, some 1039 assignments are not just assignments, but also involve an element of 1040 protocol specification. A new option may define fields that need to 1041 be parsed and acted on, which (if specified poorly) may not fit 1042 cleanly with the architecture of other options or the base protocols 1043 on which they are built. 1045 In some cases, however, the burden of publishing an RFC in order to 1046 register a protocol element is excessive. 1048 However, it is generally still useful (and sometimes necessary) to 1049 discuss proposed registrations within the community, on a mailing 1050 list. Such a mailing list provides opportunity for public review 1051 prior to assignment, and allows for a consultative process when 1052 registrants want help in understanding what a proper registration 1053 should contain. 1055 While discussion on a mailing list can provide valuable technical 1056 feedback, opinions may vary and discussions may continue for some 1057 time without clear resolution. In addition, IANA cannot participate 1058 in all of these mailing lists and cannot determine if or when such 1059 discussions reach consensus. Therefore, IANA relies on a "designated 1060 expert" for advice regarding the specific question of whether an 1061 assignment should be made. The designated expert is an individual 1062 who is responsible for carrying out an appropriate evaluation and 1063 returning a recommendation to IANA. 1065 It should be noted that a key motivation for having designated 1066 experts is for the IETF to provide IANA with a subject matter expert 1067 to whom the evaluation process can be delegated. IANA forwards 1068 requests for an assignment to the expert for evaluation, and the 1069 expert (after performing the evaluation) informs IANA as to whether 1070 or not to make the assignment or registration. 1072 It will often be useful to use a designated expert only some of the 1073 time, as a supplement to other processes. For more discussion of 1074 that topic, see Section 2.3.2. 1076 5.2. The Role of the Designated Expert 1078 The designated expert is responsible for coordinating the appropriate 1079 review of an assignment request. The review may be wide or narrow, 1080 depending on the situation and the judgment of the designated expert. 1081 This may involve consultation with a set of technology experts, 1082 discussion on a public mailing list, consultation with a working 1083 group (or its mailing list if the working group has disbanded), etc. 1084 Ideally, the designated expert follows specific review criteria as 1085 documented with the protocol that creates or uses the namespace. See 1086 the IANA Considerations sections of [RFC3748] and [RFC3575] for 1087 specific examples. 1089 Designated experts are expected to be able to defend their decisions 1090 to the IETF community, and the evaluation process is not intended to 1091 be secretive or bestow unquestioned power on the expert. Experts are 1092 expected to apply applicable documented review or vetting procedures, 1093 or in the absence of documented criteria, follow generally accepted 1094 norms such as those in Section 5.3. 1096 In registries where a pool of experts evaluates requests, the pool 1097 should have a single chair responsible for defining how requests are 1098 to be assigned to and reviewed by experts. In some cases, the expert 1099 pool may consist of a primary and backups, with the backups involved 1100 only when the primary expert is unavailable. In other cases, IANA 1101 might assign requests to individual members in sequential or 1102 approximate random order. In the event that IANA finds itself having 1103 received conflicting advice from its experts, it is the 1104 responsibility of the pool's chair to resolve the issue and provide 1105 IANA with clear instructions. 1107 If a designated expert is conflicted for a particular review (is, for 1108 example, an author or significant proponent of a specification 1109 related to the registration under review), that expert should recuse 1110 himself. In the event that all the designated experts are 1111 conflicted, they should ask that a temporary expert be designated for 1112 the conflicted review. 1114 It has proven useful to have multiple designated experts for some 1115 registries. Sometimes those experts work together in evaluating a 1116 request, while in other cases additional experts serve as backups. 1117 In cases of disagreement among those experts, it is the 1118 responsibility of those experts to make a single clear recommendation 1119 to IANA. It is not appropriate for IANA to resolve disputes among 1120 experts. In extreme situations, such as deadlock, the designating 1121 body may need to step in to resolve the problem. 1123 This document defines the designated expert mechanism with respect to 1124 documents in the IETF stream only. Documents in other streams may 1125 only use a registration policy that requires a designated expert if 1126 those streams (or those documents) specify how designated experts are 1127 appointed and managed. What is described below, with management by 1128 the IESG, is only appropriate for the IETF stream. 1130 5.2.1. Managing Designated Experts in the IETF 1132 Designated experts for registries created by the IETF are appointed 1133 by the IESG, normally upon recommendation by the relevant Area 1134 Director. They may be appointed at the time a document creating or 1135 updating a namespace is approved by the IESG, or subsequently, when 1136 the first registration request is received. Because experts 1137 originally appointed may later become unavailable, the IESG will 1138 appoint replacements as necessary. The IESG may remove any 1139 designated expert that it appointed, at its discretion. 1141 The normal appeals process, as described in [RFC2026], Section 6.5.1, 1142 applies to issues that arise with the designated expert team. For 1143 this purpose, the designated expert team takes the place of the 1144 working group in that description. 1146 5.3. Designated Expert Reviews 1148 In the years since RFC 2434 was published and has been put to use, 1149 experience has led to the following observations: 1151 o A designated expert must respond in a timely fashion, normally 1152 within a week for simple requests to a few weeks for more complex 1153 ones. Unreasonable delays can cause significant problems for 1154 those needing assignments, such as when products need code points 1155 to ship. This is not to say that all reviews can be completed 1156 under a firm deadline, but they must be started, and the requester 1157 and IANA should have some transparency into the process if an 1158 answer cannot be given quickly. 1160 o If a designated expert does not respond to IANA's requests within 1161 a reasonable period of time, either with a response or with a 1162 reasonable explanation for the delay (some requests may be 1163 particularly complex), and if this is a recurring event, IANA must 1164 raise the issue with the IESG. Because of the problems caused by 1165 delayed evaluations and assignments, the IESG should take 1166 appropriate actions to ensure that the expert understands and 1167 accepts his or her responsibilities, or appoint a new expert. 1169 o The designated expert is not required to personally bear the 1170 burden of evaluating and deciding all requests, but acts as a 1171 shepherd for the request, enlisting the help of others as 1172 appropriate. In the case that a request is denied, and rejecting 1173 the request is likely to be controversial, the expert should have 1174 the support of other subject matter experts. That is, the expert 1175 must be able to defend a decision to the community as a whole. 1177 When a designated expert is used, the documentation should give clear 1178 guidance to the designated expert, laying out criteria for performing 1179 an evaluation and reasons for rejecting a request. In the case where 1180 there are no specific documented criteria, the presumption should be 1181 that a code point should be granted unless there is a compelling 1182 reason to the contrary. Possible reasons to deny a request include 1183 these: 1185 o Scarcity of code points, where the finite remaining code points 1186 should be prudently managed, or where a request for a large number 1187 of code points is made and a single code point is the norm. 1189 o Documentation is not of sufficient clarity to evaluate or ensure 1190 interoperability. 1192 o The code point is needed for a protocol extension, but the 1193 extension is not consistent with the documented (or generally 1194 understood) architecture of the base protocol being extended, and 1195 would be harmful to the protocol if widely deployed. It is not 1196 the intent that "inconsistencies" refer to minor differences "of a 1197 personal preference nature". Instead, they refer to significant 1198 differences such as inconsistencies with the underlying security 1199 model, implying a change to the semantics of an existing message 1200 type or operation, requiring unwarranted changes in deployed 1201 systems (compared with alternate ways of achieving a similar 1202 result), etc. 1204 o The extension would cause problems with existing deployed systems. 1206 o The extension would conflict with one under active development by 1207 the IETF, and having both would harm rather than foster 1208 interoperability. 1210 When a designated expert is used, documents MUST NOT name the 1211 designated expert in the document itself; instead, any suggested 1212 names should be relayed to the appropriate Area Director at the time 1213 the document is sent to the IESG for approval. This is usually done 1214 in the document shepherd writeup. 1216 If the request should also be reviewed on a specific public mailing 1217 list, its address should be specified. 1219 5.4. Expert Reviews and the Document Lifecycle 1221 Review by the designated expert is necessarily done at a particular 1222 point in time, and represents review of a particular version of the 1223 document. Deciding when the review should take place is a question 1224 of good judgment. And while re-reviews might be done when it's 1225 acknowledged that the documentation of the registered item has 1226 changed substantially, making sure that re-review happens requires 1227 attention and care. 1229 It is possible, through carelessness, accident, inattentiveness, or 1230 even willful disregard, that changes might be made after the 1231 designated expert's review and approval that would, if the document 1232 were re-reviewed, cause the expert not to approve the registration. 1233 It is up to the IESG, with the token held by the responsible Area 1234 Director, to be alert to such situations and to recognize that such 1235 changes need to be checked. 1237 6. Well-Known Registration Status Terminology 1239 The following labels describe the status of an assignment or range of 1240 assignments: 1242 Private Use: Private use only (not assigned), as described in 1243 Section 4.1. 1245 Experimental: Available for general experimental use as described 1246 in [RFC3692]. IANA does not record specific assignments for 1247 any particular use. 1249 Unassigned: Not currently assigned, and available for assignment 1250 via documented procedures. While it's generally clear that 1251 any values that are not registered are unassigned and 1252 available for assignment, it is sometimes useful to 1253 explicitly specify that situation. Note that this is 1254 distinctly different from "Reserved". 1256 Reserved: Not assigned and not available for assignment. Reserved 1257 values are held for special uses, such as to extend the 1258 namespace when it becomes exhausted. Note that this is 1259 distinctly different from "Unassigned". 1261 Reserved values can be released for assignment by the change 1262 controller for the registry (this is often the IESG, for 1263 registries created by RFCs in the IETF stream). 1265 7. Documentation References in IANA Registries 1267 Usually, registries and registry entries include references to 1268 documentation (RFCs or other documents). The purpose of these 1269 references is to provide pointers for implementors to find details 1270 necessary for implementation, NOT to simply note what document 1271 created the registry or entry. Therefore: 1273 o If a document registers an item that is defined and explained 1274 elsewhere, the registered reference should be to that document, 1275 and not to the document that is merely performing the 1276 registration. 1278 o If the registered item is defined and explained in the current 1279 document, it is important to include sufficient information to 1280 enable implementors to understand the item and to create a proper 1281 implementation. 1283 o If the registered item is explained primarily in a specific 1284 section of the reference document, it is useful to include a 1285 section reference. For example, "[RFC9876], Section 3.2", rather 1286 than just "[RFC9876]". 1288 o For documentation of a new registry, the reference should provide 1289 information about the registry itself, not just a pointer to the 1290 creation of it. Useful information includes the purpose of the 1291 registry, a rationale for its creation, documentation of the 1292 process and policy for new registrations, guidelines for new 1293 registrants or designated experts, and other such related 1294 information. But note that, while it's important to include this 1295 information in the document, it needn't (and shouldn't) all be in 1296 the IANA Considerations section. See Section 1.1. 1298 8. What to Do in "bis" Documents 1300 On occasion, an RFC is issued that obsoletes a previous edition of 1301 the same document. We sometimes call these "bis" documents, such as 1302 when RFC 9876 is updated by draft-ietf-foo-rfc9876bis. When the 1303 original document created registries and/or registered entries, there 1304 is a question of how to handle the IANA Considerations section in the 1305 "bis" document. 1307 If the registrations specify the original document as a reference, 1308 those registrations should be updated to point to the current (not 1309 obsolete) documentation for those items. Usually, that will mean 1310 changing the reference to be the "bis" document. There will, though, 1311 be times when a document updates another, and changes the definitive 1312 reference for some items, but not for others. Be sure that the 1313 references are always set to point to the correct, current 1314 documentation for each item. 1316 For example, suppose RFC 9876 registered the "BANANA" flag in the 1317 "Fruit Access Flags" registry, and the documentation for that flag is 1318 in Section 3.2. 1320 The current registry might look, in part, like this: 1322 Name Description Reference 1323 -------- ------------------- --------- 1324 BANANA Flag for bananas [RFC9876], Section 3.2 1326 If draft-ietf-foo-rfc9876bis obsoletes RFC 9876 and, because of some 1327 rearrangement, now documents the flag in Section 4.1.2, the IANA 1328 Considerations of the bis document might contain text such as this: 1330 IANA is asked to change the registration information for the 1331 BANANA flag in the "Fruit Access Flags" registry to the following: 1333 Name Description Reference 1334 -------- ------------------- --------- 1335 BANANA Flag for bananas [[this RFC]], Section 4.2.1 1337 In many cases, if there are a number of registered references to the 1338 original RFC and the document organization has not changed the 1339 registered section numbering much, it may simply be reasonable to do 1340 this: 1342 Because this document obsoletes RFC 9876, IANA is asked to change 1343 all registration information that references [RFC9876] to instead 1344 reference [[this RFC]]. 1346 If information for registered items has been or is being moved to 1347 other documents, then, of course, the registration information should 1348 be changed to point to those other documents. In no case is it 1349 reasonable to leave documentation pointers to the obsoleted document 1350 for any registries or registered items that are still in current use. 1352 It is extremely important to be clear in your instructions regarding 1353 updating references, especially in cases where some references need 1354 to be updated and others do not. 1356 9. Miscellaneous Issues 1358 9.1. When There Are No IANA Actions 1359 Before an Internet-Draft can be published as an RFC, IANA needs to 1360 know what actions (if any) it needs to perform. Experience has shown 1361 that it is not always immediately obvious whether a document has no 1362 IANA actions, without reviewing the document in some detail. In 1363 order to make it clear to IANA that it has no actions to perform (and 1364 that the author has consciously made such a determination), such 1365 documents should include an IANA Considerations section that states: 1367 This document has no IANA actions. 1369 This statement, or an equivalent, must only be inserted after the 1370 working group or individual submitter has carefully verified it to be 1371 true. Using such wording as a matter of "boilerplate" or without 1372 careful consideration can lead to incomplete or incorrect IANA 1373 actions being performed. 1375 If a specification makes use of values from a namespace in which 1376 assignments are not made by IANA, it may be useful to note this fact, 1377 with wording such as this: 1379 The values of the Foobar parameter are assigned by the Barfoo 1380 registry on behalf of the Rabfoo Forum. Therefore, this document 1381 has no IANA actions. 1383 IANA prefers that these "empty" IANA Considerations sections be left 1384 in the document for the record. This is a change from the prior 1385 practice of requesting that such sections be removed by the RFC 1386 Editor, and authors are asked to accommodate this change. 1388 9.2. Namespaces Lacking Documented Guidance 1390 For all existing RFCs that either explicitly or implicitly rely on 1391 IANA to make assignments without specifying a precise assignment 1392 policy, IANA (in consultation with the IESG) will continue to decide 1393 what policy is appropriate. Changes to existing policies can always 1394 be initiated through the normal IETF consensus process, or through 1395 the IESG when appropriate. 1397 All future RFCs that either explicitly or implicitly rely on IANA to 1398 register or otherwise administer namespace assignments MUST provide 1399 guidelines for administration of the namespace. 1401 9.3. After-the-Fact Registrations 1402 Occasionally, the IETF becomes aware that an unassigned value from a 1403 namespace is in use on the Internet or that an assigned value is 1404 being used for a different purpose than it was registered for. The 1405 IETF does not condone such misuse; procedures of the type described 1406 in this document MUST be applied to such cases. In the absence of 1407 specifications to the contrary, values may only be reassigned for a 1408 different purpose with the consent of the original assignee (when 1409 possible) and with due consideration of the impact of such a 1410 reassignment. In cases of likely controversy, consultation with the 1411 IESG is advised. 1413 9.4. Reclaiming Assigned Values 1415 Reclaiming previously assigned values for reuse is tricky, because 1416 doing so can lead to interoperability problems with deployed systems 1417 still using the assigned values. Moreover, it can be extremely 1418 difficult to determine the extent of deployment of systems making use 1419 of a particular value. However, in cases where the namespace is 1420 running out of unassigned values and additional ones are needed, it 1421 may be desirable to attempt to reclaim unused values. When 1422 reclaiming unused values, the following (at a minimum) should be 1423 considered: 1425 o Attempts should be made to contact the original party to which a 1426 value is assigned, to determine if the value was ever used, and if 1427 so, the extent of deployment. (In some cases, products were never 1428 shipped or have long ceased being used. In other cases, it may be 1429 known that a value was never actually used at all.) 1431 o Reassignments should not normally be made without the concurrence 1432 of the original requester. Reclamation under such conditions 1433 should only take place where there is strong evidence that a value 1434 is not widely used, and the need to reclaim the value outweighs 1435 the cost of a hostile reclamation. In any case, IESG Approval is 1436 needed in this case. 1438 o It may be appropriate to write up the proposed action and solicit 1439 comments from relevant user communities. In some cases, it may be 1440 appropriate to write an RFC that goes through a formal IETF 1441 process (including IETF Last Call) as was done when DHCP reclaimed 1442 some of its "Private Use" options [RFC3942]. 1444 9.5. Contact Person vs Assignee or Owner 1446 Many registries include designation of a technical or administrative 1447 contact associated with each entry. Often, this is recorded as 1448 contact information for an individual. It is unclear, though, what 1449 role the individual has with respect to the registration: is this 1450 item registered on behalf of the individual, the company the 1451 individual worked for, or perhaps another organization the individual 1452 was acting for? 1453 This matters because some time later, when the individual has changed 1454 jobs or roles, and perhaps can no longer be contacted, someone might 1455 want to update the registration. IANA has no way to know what 1456 company, organization, or individual should be allowed to take the 1457 registration over. For registrations rooted in RFCs, the stream 1458 owner (such as the IESG or the IAB) can make an overriding decision. 1459 But in other cases, there is no recourse. 1461 Registries can include, in addition to a "Contact" field, an 1462 "Assignee" or "Owner" field that can be used to address this 1463 situation, giving IANA clear guidance as to the actual owner of the 1464 registration. This is strongly advised especially for registries 1465 that do not require RFCs to manage their information (registries with 1466 policies such as First Come First Served Section 4.4, Expert Review 1467 Section 4.5, and Specification Required Section 4.6). Alternatively, 1468 organizations can put an organizational role into the "Contact" field 1469 in order to make their ownership clear. 1471 9.6. Closing or Obsoleting a Registry 1473 Sometimes there is a request to "close" a registry to further 1474 registrations. When a registry is closed, no further registrations 1475 will be accepted. The information in the registry will still be 1476 valid and registrations already in the registry can still be updated. 1478 A closed registry can also be marked as "obsolete", as an indication 1479 that the information in the registry is no longer in current use. 1481 Specific entries in a registry can be marked as "obsolete" (no longer 1482 in use) or "deprecated" (use is not recommended). 1484 Such changes to registries and registered values are subject to 1485 normal change controls (see Section 2.3.3). Any closure, 1486 obsolescence, or deprecation serves to annotate the registry 1487 involved; the information in the registry remains there for 1488 informational and historic purposes. 1490 10. Appeals 1492 Appeals of protocol parameter registration decisions can be made 1493 using the normal IETF appeals process as described in [RFC2026], 1494 Section 6.5. That is, an initial appeal should be directed to the 1495 IESG, followed (if necessary) by an appeal to the IAB. 1497 11. Mailing Lists 1499 All IETF mailing lists associated with evaluating or discussing 1500 assignment requests as described in this document are subject to 1501 whatever rules of conduct and methods of list management are 1502 currently defined by Best Current Practices or by IESG decision. 1504 12. Security Considerations 1505 Information that creates or updates a registration needs to be 1506 authenticated and authorized. IANA updates registries according to 1507 instructions in published RFCs and from the IESG. It also may accept 1508 clarifications from document authors, relevant working group chairs, 1509 Designated Experts, and mail list participants, too. 1511 Information concerning possible security vulnerabilities of a 1512 protocol may change over time. Likewise, security vulnerabilities 1513 related to how an assigned number is used may change as well. As new 1514 vulnerabilities are discovered, information about such 1515 vulnerabilities may need to be attached to existing registrations, so 1516 that users are not misled as to the true security issues surrounding 1517 the use of a registered number. 1519 An analysis of security issues is generally required for all 1520 protocols that make use of parameters (data types, operation codes, 1521 keywords, etc.) used in IETF protocols or registered by IANA. Such 1522 security considerations are usually included in the protocol document 1523 [RFC3552]. It is the responsibility of the IANA considerations 1524 associated with a particular registry to specify what (if any) 1525 security considerations must be provided when assigning new values, 1526 and the process for reviewing such claims. 1528 13. Changes Relative to Earlier Editions of BCP 26 1530 13.1. 2014: Changes in This Document Relative to RFC 5226 1532 Significant additions: 1534 o Added Section 1.1, Keep IANA Considerations for IANA 1536 o Added Section 1.2, For More Information 1538 o Added Section 2.1, Hierarchical Registry Structure 1540 o Added Section 2.3, Best Practice for Selecting an Appropriate 1541 Policy. 1543 o Added Section 2.3.2, Using Multiple Policies in Combination. 1545 o Added Section 2.3.3, Specifying Change Control for a Registry 1547 o Added Section 3.4, Early Allocations 1549 o Moved well-known policies into a separate section for each, 1550 subsections of Section 4. 1552 o Added Section 5.4, Expert Reviews and the Document Lifecycle 1554 o Added Section 7, Documentation References in IANA Registries 1556 o Added Section 8, What to Do in "bis" Documents 1557 o Added Section 9.5, Contact Person vs Assignee or Owner 1559 o Added Section 9.6, Closing or Obsoleting a Registry 1561 Clarifications and such: 1563 o Some reorganization -- moved text around for clarity and easier 1564 reading. 1566 o Made clarifications about identification of IANA registries and 1567 use of URLs for them. 1569 o Clarified the distinction between "Unassigned" and "Reserved". 1571 o Made some clarifications in "Expert Review" about instructions to 1572 the designated expert. 1574 o Made some clarifications in "Specification Required" about how to 1575 declare this policy. 1577 o Assorted minor clarifications and editorial changes throughout. 1579 13.2. 2008: Changes in RFC 5226 Relative to RFC 2434 1581 Changes include: 1583 o Major reordering of text to expand descriptions and to better 1584 group topics such as "updating registries" vs. "creating new 1585 registries", in order to make it easier for authors to find the 1586 text most applicable to their needs. 1588 o Numerous editorial changes to improve readability. 1590 o Changed the term "IETF Consensus" to "IETF Review" and added more 1591 clarifications. History has shown that people see the words "IETF 1592 Consensus" (without consulting the actual definition) and are 1593 quick to make incorrect assumptions about what the term means in 1594 the context of IANA Considerations. 1596 o Added "RFC Required" to list of defined policies. 1598 o Much more explicit directions and examples of "what to put in 1599 RFCs". 1601 o "Specification Required" now implies use of a Designated Expert to 1602 evaluate specs for sufficient clarity. 1604 o Significantly changed the wording in the Designated Experts 1605 section. Main purpose is to make clear that Expert Reviewers are 1606 accountable to the community, and to provide some guidance for 1607 review criteria in the default case. 1609 o Changed wording to remove any special appeals path. The normal 1610 RFC 2026 appeals path is used. 1612 o Added a section about reclaiming unused values. 1614 o Added a section on after-the-fact registrations. 1616 o Added a section indicating that mailing lists used to evaluate 1617 possible assignments (such as by a Designated Expert) are subject 1618 to normal IETF rules. 1620 14. Acknowledgments 1622 14.1. Acknowledgments for This Document (2014) 1624 Thomas Narten and Harald Tveit Alvestrand edited the two earlier 1625 editions of this document (RFCs 2434 and 5226), and Thomas continues 1626 his role in this third edition. Much of the text from RFC 5226 1627 remains in this edition. 1629 Thank you to Amanda Baber and Pearl Liang for their multiple reviews 1630 and suggestions for making this document as thorough as possible. 1632 This document has benefited from thorough review and comments by Tony 1633 Hansen, John Klensin, and Mark Nottingham. 1635 Special thanks to Mark Nottingham for reorganizing some of the text 1636 for better organization and readability, and to Tony Hansen for 1637 acting as document shepherd. 1639 14.2. Acknowledgments from the second edition (2008) 1641 The original acknowledgments section in RFC 5226 was: 1643 This document has benefited from specific feedback from Jari Arkko, 1644 Marcelo Bagnulo Braun, Brian Carpenter, Michelle Cotton, Spencer 1645 Dawkins, Barbara Denny, Miguel Garcia, Paul Hoffman, Russ Housley, 1646 John Klensin, Allison Mankin, Blake Ramsdell, Mark Townsley, Magnus 1647 Westerlund, and Bert Wijnen. 1649 14.3. Acknowledgments from the first edition (1998) 1651 The original acknowledgments section in RFC 2434 was: 1653 Jon Postel and Joyce Reynolds provided a detailed explanation on what 1654 IANA needs in order to manage assignments efficiently, and patiently 1655 provided comments on multiple versions of this document. Brian 1656 Carpenter provided helpful comments on earlier versions of the 1657 document. One paragraph in the Security Considerations section was 1658 borrowed from [RFC4288]. 1660 15. References 1661 15.1. Normative References 1663 [RFC2026] Bradner, S., "The Internet Standards Process -- Revision 1664 3", BCP 9, RFC 2026, October 1996. 1666 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1667 Requirement Levels", BCP 14, RFC 2119, March 1997. 1669 15.2. Informative References 1671 [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, September 1672 1981. 1674 [RFC2860] Carpenter, B., Baker, F. and M. Roberts, "Memorandum of 1675 Understanding Concerning the Technical Work of the 1676 Internet Assigned Numbers Authority", RFC 2860, June 2000. 1678 [RFC2939] Droms, R., "Procedures and IANA Guidelines for Definition 1679 of New DHCP Options and Message Types", BCP 43, RFC 2939, 1680 September 2000. 1682 [RFC3228] Fenner, B., "IANA Considerations for IPv4 Internet Group 1683 Management Protocol (IGMP)", BCP 57, RFC 3228, February 1684 2002. 1686 [RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC 1687 Text on Security Considerations", BCP 72, RFC 3552, July 1688 2003. 1690 [RFC3575] Aboba, B., "IANA Considerations for RADIUS (Remote 1691 Authentication Dial In User Service)", RFC 3575, July 1692 2003. 1694 [RFC3692] Narten, T., "Assigning Experimental and Testing Numbers 1695 Considered Useful", BCP 82, RFC 3692, January 2004. 1697 [RFC3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J. and H. 1698 Levkowetz, "Extensible Authentication Protocol (EAP)", RFC 1699 3748, June 2004. 1701 [RFC3942] Volz, B., "Reclassifying Dynamic Host Configuration 1702 Protocol version 4 (DHCPv4) Options", RFC 3942, November 1703 2004. 1705 [RFC3968] Camarillo, G., "The Internet Assigned Number Authority 1706 (IANA) Header Field Parameter Registry for the Session 1707 Initiation Protocol (SIP)", BCP 98, RFC 3968, December 1708 2004. 1710 [RFC4005] Calhoun, P., Zorn, G., Spence, D. and D. Mitton, "Diameter 1711 Network Access Server Application", RFC 4005, August 2005. 1713 [RFC4025] Richardson, M., "A Method for Storing IPsec Keying 1714 Material in DNS", RFC 4025, March 2005. 1716 [RFC4044] McCloghrie, K., "Fibre Channel Management MIB", RFC 4044, 1717 May 2005. 1719 [RFC4124] Le Faucheur, F., "Protocol Extensions for Support of 1720 Diffserv-aware MPLS Traffic Engineering", RFC 4124, June 1721 2005. 1723 [RFC4169] Torvinen, V., Arkko, J. and M. Naslund, "Hypertext 1724 Transfer Protocol (HTTP) Digest Authentication Using 1725 Authentication and Key Agreement (AKA) Version-2", RFC 1726 4169, November 2005. 1728 [RFC4271] Rekhter, Y., Li, T. and S. Hares, "A Border Gateway 1729 Protocol 4 (BGP-4)", RFC 4271, January 2006. 1731 [RFC4283] Patel, A., Leung, K., Khalil, M., Akhtar, H. and K. 1732 Chowdhury, "Mobile Node Identifier Option for Mobile IPv6 1733 (MIPv6)", RFC 4283, November 2005. 1735 [RFC4288] Freed, N. and J. Klensin, "Media Type Specifications and 1736 Registration Procedures", BCP 13, RFC 4288, December 2005. 1738 [RFC4340] Kohler, E., Handley, M. and S. Floyd, "Datagram Congestion 1739 Control Protocol (DCCP)", RFC 4340, March 2006. 1741 [RFC4395] Hansen, T., Hardie, T. and L. Masinter, "Guidelines and 1742 Registration Procedures for New URI Schemes", BCP 35, RFC 1743 4395, February 2006. 1745 [RFC4422] Melnikov, A. and K. Zeilenga, "Simple Authentication and 1746 Security Layer (SASL)", RFC 4422, June 2006. 1748 [RFC4446] Martini, L., "IANA Allocations for Pseudowire Edge to Edge 1749 Emulation (PWE3)", BCP 116, RFC 4446, April 2006. 1751 [RFC4520] Zeilenga, K., "Internet Assigned Numbers Authority (IANA) 1752 Considerations for the Lightweight Directory Access 1753 Protocol (LDAP)", BCP 64, RFC 4520, June 2006. 1755 [RFC4589] Schulzrinne, H. and H. Tschofenig, "Location Types 1756 Registry", RFC 4589, July 2006. 1758 [RFC4727] Fenner, B., "Experimental Values In IPv4, IPv6, ICMPv4, 1759 ICMPv6, UDP, and TCP Headers", RFC 4727, November 2006. 1761 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security 1762 (TLS) Protocol Version 1.2", RFC 5246, August 2008. 1764 [RFC5378] Bradner, S. and J. Contreras, "Rights Contributors Provide 1765 to the IETF Trust", BCP 78, RFC 5378, November 2008. 1767 [RFC5742] Alvestrand, H. and R. Housley, "IESG Procedures for 1768 Handling of Independent and IRTF Stream Submissions", BCP 1769 92, RFC 5742, December 2009. 1771 [RFC5771] Cotton, M., Vegoda, L. and D. Meyer, "IANA Guidelines for 1772 IPv4 Multicast Address Assignments", BCP 51, RFC 5771, 1773 March 2010. 1775 [RFC5795] Sandlund, K., Pelletier, G. and L-E. Jonsson, "The RObust 1776 Header Compression (ROHC) Framework", RFC 5795, March 1777 2010. 1779 [RFC6195] Eastlake, D., "Domain Name System (DNS) IANA 1780 Considerations", BCP 42, RFC 6195, March 2011. 1782 [RFC6275] Perkins, C., Johnson, D. and J. Arkko, "Mobility Support 1783 in IPv6", RFC 6275, July 2011. 1785 [RFC6709] Carpenter, B., Aboba, B. and S. Cheshire, "Design 1786 Considerations for Protocol Extensions", RFC 6709, 1787 September 2012. 1789 [RFC7120] Cotton, M., "Early IANA Allocation of Standards Track Code 1790 Points", BCP 100, RFC 7120, January 2014. 1792 Authors' Addresses 1794 Michelle Cotton 1795 Internet Corporation for Assigned Names and Numbers 1796 12025 Waterfront Drive, Suite 300 1797 Los Angeles, CA 90094-2536 1798 US 1800 Phone: +1 310 823 9358 1801 Email: michelle.cotton@icann.org 1802 URI: http://www.icann.org/ 1804 Barry Leiba 1805 Huawei Technologies 1807 Phone: +1 646 827 0648 1808 Email: barryleiba@computer.org 1809 URI: http://internetmessagingtechnology.org/ 1810 Thomas Narten 1811 IBM Corporation 1812 3039 Cornwallis Ave., PO Box 12195 - BRQA/502 1813 Research Triangle Park, NC 27709-2195 1814 US 1816 Phone: +1 919 254 7798 1817 Email: narten@us.ibm.com