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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: October 05, 2016 IBM Corporation 8 April 05, 2016 10 Guidelines for Writing an IANA Considerations Section in RFCs 11 draft-leiba-cotton-iana-5226bis-12 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 record keeper. For IETF protocols, that role is filled by the 20 Internet Assigned Numbers Authority (IANA). 22 To make assignments in a given registry 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 of this document; it 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 October 05, 2016. 49 Copyright Notice 51 Copyright (c) 2016 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 2. Creating and Revising Registries . . . . . . . . . . . . . . . 4 69 2.1. Organization of Registries . . . . . . . . . . . . . . . . 4 70 2.2. Documentation Requirements for Registries . . . . . . . . 6 71 2.3. Specifying Change Control for a Registry . . . . . . . . . 8 72 2.4. Revising Existing Registries . . . . . . . . . . . . . . . 9 73 3. Registering New Values in an Existing Registry . . . . . . . . 9 74 3.1. Documentation Requirements for Registrations . . . . . . . 9 75 3.2. Updating Existing Registrations . . . . . . . . . . . . . 11 76 3.3. Overriding Registration Procedures . . . . . . . . . . . . 12 77 3.4. Early Allocations . . . . . . . . . . . . . . . . . . . . 12 78 4. Choosing a Registration Policy, and Well-Known Policies . . . 13 79 4.1. Private Use . . . . . . . . . . . . . . . . . . . . . . . 15 80 4.2. Experimental Use . . . . . . . . . . . . . . . . . . . . . 15 81 4.3. Hierarchical Allocation . . . . . . . . . . . . . . . . . 16 82 4.4. First Come First Served . . . . . . . . . . . . . . . . . 16 83 4.5. Expert Review . . . . . . . . . . . . . . . . . . . . . . 17 84 4.6. Specification Required . . . . . . . . . . . . . . . . . . 18 85 4.7. RFC Required . . . . . . . . . . . . . . . . . . . . . . . 19 86 4.8. IETF Review . . . . . . . . . . . . . . . . . . . . . . . 19 87 4.9. Standards Action . . . . . . . . . . . . . . . . . . . . . 19 88 4.10. IESG Approval . . . . . . . . . . . . . . . . . . . . . . 20 89 4.11. Using the Well-Known Registration Policies . . . . . . . . 20 90 4.12. Using Multiple Policies in Combination . . . . . . . . . . 21 91 5. Designated Experts . . . . . . . . . . . . . . . . . . . . . . 22 92 5.1. The Motivation for Designated Experts . . . . . . . . . . 22 93 5.2. The Role of the Designated Expert . . . . . . . . . . . . 23 94 5.2.1. Managing Designated Experts in the IETF . . . . . . . 23 95 5.3. Designated Expert Reviews . . . . . . . . . . . . . . . . 24 96 5.4. Expert Reviews and the Document Lifecycle . . . . . . . . 25 97 6. Well-Known Registration Status Terminology . . . . . . . . . . 26 98 7. Documentation References in IANA Registries . . . . . . . . . 26 99 8. What to Do in "bis" Documents . . . . . . . . . . . . . . . . 27 100 9. Miscellaneous Issues . . . . . . . . . . . . . . . . . . . . . 28 101 9.1. When There Are No IANA Actions . . . . . . . . . . . . . . 28 102 9.2. Namespaces Lacking Documented Guidance . . . . . . . . . . 29 103 9.3. After-the-Fact Registrations . . . . . . . . . . . . . . . 29 104 9.4. Reclaiming Assigned Values . . . . . . . . . . . . . . . . 29 105 9.5. Contact Person vs Assignee or Owner . . . . . . . . . . . 30 106 9.6. Closing or Obsoleting a Registry . . . . . . . . . . . . . 30 108 10. Appeals . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 109 11. Mailing Lists . . . . . . . . . . . . . . . . . . . . . . . . 31 110 12. Security Considerations . . . . . . . . . . . . . . . . . . . 31 111 13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 31 112 14. Changes Relative to Earlier Editions of BCP 26 . . . . . . . . 31 113 14.1. 2014: Changes in This Document Relative to RFC 5226 . . . 32 114 14.2. 2008: Changes in RFC 5226 Relative to RFC 2434 . . . . . 33 115 15. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 33 116 15.1. Acknowledgments for This Document (2014) . . . . . . . . 33 117 15.2. Acknowledgments from the second edition (2008) . . . . . 34 118 15.3. Acknowledgments from the first edition (1998) . . . . . . 34 119 16. References . . . . . . . . . . . . . . . . . . . . . . . . . . 34 120 16.1. Normative References . . . . . . . . . . . . . . . . . . 34 121 16.2. Informative References . . . . . . . . . . . . . . . . . 34 122 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 37 124 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 record keeper. For IETF protocols, that role is filled by the 131 Internet Assigned Numbers Authority (IANA) [RFC2860]. 133 The Protocol field in the IP header [RFC0791] and MIME media types 134 [RFC4288] are two examples of such coordinations. 136 In this document, we call the range of possible values for such a 137 field a "namespace". The binding or association of a specific value 138 with a particular purpose within a namespace is called an assignment 139 (or, variously: an assigned number, assigned value, code point, 140 protocol constant, or protocol parameter). The act of assignment is 141 called a registration, and it takes place in the context of a 142 registry. The terms "assignment" and "registration" are used 143 interchangably throughout this document. 145 To make assignments in a given namespace prudently, IANA needs 146 guidance describing the conditions under which new values should be 147 assigned, as well as when and how modifications to existing values 148 can be made. This document defines a framework for the documentation 149 of these guidelines by specification authors, in order to assure that 150 the guidance given to IANA is clear and addresses the various issues 151 that are likely in the operation of a registry. 153 Typically, this information is recorded in a dedicated section of the 154 specification with the title "IANA Considerations". 156 1.1. Keep IANA Considerations for IANA 157 The purpose of having a dedicated IANA Considerations section is to 158 provide a single place to collect clear and concise information and 159 instructions for IANA. Technical documentation should reside in 160 other parts of the document, and should be included by reference 161 only. Using the IANA Considerations section as primary technical 162 documentation both hides it from the target audience of the document 163 and interferes with IANA's review of the actions they need to take. 165 An ideal IANA Considerations section clearly enumerates and specifies 166 each requested IANA action; includes all information IANA needs, such 167 as the full names of all applicable registries; and includes clear 168 references to elsewhere in the document for other information. 170 1.2. For More Information 172 IANA maintains a web page that includes current important information 173 from IANA. Document authors should check that page for additional 174 information, beyond what is provided here. 176 . 178 [[The initial version of this should contain the bits that are 179 salient to most document authors -- perhaps a table of required 180 elements to create a new registry or update one, a bit about sub- 181 registries, and the listing of well-known registration policies. ]] 183 2. Creating and Revising Registries 185 Defining a registry involves describing the namespaces to be created, 186 listing an initial set of assignments (if applicable), and 187 documenting guidelines on how future assignments are to be made. 189 When defining a registry, consider structuring the namespace in such 190 a way that only top-level assignments need to be made with central 191 coordination, and those assignments can delegate lower-level 192 assignments so coordination for them can be distributed. This 193 lessens the burden on IANA for dealing with assignments, and is 194 particularly useful in situations where distributed coordinators have 195 better knowledge of their portion of the namespace and are better 196 suited to handling those assignments. 198 2.1. Organization of Registries 200 All registries are anchored from the IANA "Protocol Registries" page: 202 . 204 That page lists registries in protocol category groups, like this: 206 --------------------------------------------------------------- 207 Author Domain Signing Practices (ADSP) Parameters 209 ADSP Outbound Signing Practices RFC 5617 210 IETF Review 212 ADSP Specification Tags RFC 5617 213 IETF Review 215 Automatic Responses to Electronic Mail Parameters 217 Auto-Submitted Header Field RFC 5436 218 Keywords Specification Required 220 Auto-Submitted header field RFC 3834 221 optional parameters IETF Consensus 223 Autonomous System (AS) Numbers 225 16-bit Autonomous System Numbers RFC 1930, RFC 5398, RFC 6996 226 RIR request to the IANA 227 or IETF Review 229 32-bit Autonomous System Numbers RFC 1930, RFC 5398, RFC 6793, 230 RFC 6996 231 RIR request to the IANA 232 or IETF Review 233 --------------------------------------------------------------- 235 The grouping allows related registries to be placed together, making 236 it easier for users of the registries to find the necessary 237 information. In the example section above, all registries related to 238 the ADSP protocol are placed in the "ADSP Parameters" group. 240 Within the "ADSP Parameters" group are two registries: "ADSP Outbound 241 Signing Practices" and "ADSP Specification Tags". Clicking on the 242 title of one of these registries on the IANA Protocol Registries page 243 will take the reader to the details page for that registry. Often, 244 multiple registries are shown on the same details page. 246 Unfortunately, we have been inconsistent in how we refer to these 247 entities. The group names, as they are referred to here, have been 248 variously called "protocol category groups", "groups", "top-level 249 registries", or just "registries". The registries under them have 250 been called "registries" or "sub-registries". 252 Regardless of the terminology used, document authors should pay 253 attention to the registry groupings, should request that related 254 registries be grouped together to make related registries easier to 255 find, and, when creating a new registry, should check whether that 256 registry might best be included in an existing group. That grouping 257 information should be clearly communicated to IANA in the registry 258 creation request. 260 2.2. Documentation Requirements for Registries 262 Documents that create a new namespace (or modify the definition of an 263 existing space) and that expect IANA to play a role in maintaining 264 that space (serving as a repository for registered values) must 265 provide clear instructions on details of the namespace, either in the 266 IANA Considerations section, or referenced from it. 268 In particular, such instructions must include: 270 The name of the registry 271 This name will appear on the IANA web page and will be referred to 272 in future documents that need to allocate a value from the new 273 space. The full name (and abbreviation, if appropriate) should be 274 provided. It is highly desirable that the chosen name not be 275 easily confused with the name of another registry. 277 When creating a registry, the group that it is a part of must be 278 identified using its full name, exactly as it appears in the IANA 279 registry list. 281 Providing a URL to precisely identify the registry helps IANA 282 understand the request. Such URLs can be removed from the RFC 283 prior to final publication. If they are to be left in, it is 284 important that they be permanent links. IANA intends to include 285 the permalink for each registry in the registry header. Until 286 that is done, IANA can answer questions about the correct URLs to 287 use. 289 For example, a document could contain something like this: 291 This registration should be made in the Foobar Operational 292 Parameters registry, located at . 295 It might be tempting to use the URL that appears in your web 296 browser's address bar, which might look something like this for 297 the example above: 299 https://www.iana.org/assignments/foobar-registry/foobar- 300 registry.xml 302 ...but that is not the permanent link to the registry. 304 Required information for registrations 305 This tells registrants what information they have to include in 306 their registration requests. Some registries require only the 307 requested value and a reference to a document where use of the 308 value is defined. Other registries require a more detailed 309 registration template that describes relevant security 310 considerations, internationalization considerations, and other 311 such information. 313 Applicable registration policy 315 The policy that will apply to all future requests for 316 registration. See Section 4. 318 Size, format and syntax of registry entries 320 What fields to record in the registry, any technical requirements 321 on registry entries (valid ranges for integers, length limitations 322 on strings, and such), and the exact format in which registry 323 values should be displayed. For numeric assignments, one should 324 specify whether values are to be recorded in decimal, in 325 hexadecimal, or in some other format. 327 Strings are expected to be ASCII, and it should be clearly 328 specified whether case matters, and whether, for example, strings 329 should be shown in the registry in upper case or lower case. 331 Strings that represent protocol parameters will rarely, if ever, 332 need to contain non-ASCII characters. If non-ASCII characters are 333 really necessary, instructions should make it very clear that they 334 are allowed and that the non-ASCII characters should be 335 represented as Unicode characters using the "(U+XXXX)" convention. 336 Anyone creating such a registry should think carefully about this 337 and consider internationalization advice such as that in [RFC7564] 338 Section 10. 340 Initial assignments and reservations 342 Any initial assignments or registrations to be included. In 343 addition, any ranges that are to be reserved for "Private Use", 344 "Reserved", "Unassigned", etc. (see Section 6) should be 345 indicated. 347 For example, a document might specify a new registry by including: 349 --------------------------------------------------------------- 351 X. IANA Considerations 353 This document defines a new DHCP option, entitled "FooBar" (see 354 Section y), assigned a value of TBD1 from the DHCP Option space 355 356 [RFC2132] [RFC2939]: 357 Data 358 Tag Name Length Meaning 359 ---- ---- ------ ------- 360 TBD1 FooBar N FooBar server 362 The FooBar option also defines an 8-bit FooType field, for which 363 IANA is to create and maintain a new registry entitled 364 "FooType values" used by the FooBar option. Initial values for the 365 DHCP FooBar FooType registry are given below; future assignments 366 are to be made through Expert Review [BCP26]. 367 Assignments consist of a DHCP FooBar FooType name and its 368 associated value. 370 Value DHCP FooBar FooType Name Definition 371 ---- ------------------------ ---------- 372 0 Reserved 373 1 Frobnitz See Section y.1 374 2 NitzFrob See Section y.2 375 3-254 Unassigned 376 255 Reserved 377 --------------------------------------------------------------- 379 For examples of documents that establish registries, consult 380 [RFC3575], [RFC3968], and [RFC4520]. 382 2.3. Specifying Change Control for a Registry 384 Registry definitions and registrations within registries often need 385 to be changed after they are created. The process of making such 386 changes is complicated when it is unclear who is authorized to make 387 the changes. For registries created by RFCs in the IETF stream, 388 change control for the registry lies by default with the IETF, via 389 the IESG. The same is true for value registrations made in IETF- 390 stream RFCs. 392 Because registries can be created and registrations can be made 393 outside the IETF stream, it can sometimes be desirable to have change 394 control outside the IETF and IESG, and clear specification of change 395 control policies is always helpful. 397 It is advised, therefore, that all registries that are created 398 clearly specify a change control policy and a change controller. It 399 is also advised that registries that allow registrations from outside 400 the IETF stream include, for each value, the designation of a change 401 controller for that value. If the definition or reference for a 402 registered value ever needs to change, or if a registered value needs 403 to be deprecated, it is critical that IANA know who is authorized to 404 make the change. See also Section 9.5. 406 While IANA normally includes information about change control in the 407 public registry, some change controllers might prefer that their 408 identities or contact information not be made public. In such cases, 409 arrangements can be made with IANA to keep the information private, 410 to use an alias or role-based contact address, or to otherwise 411 protect the change controller's privacy. 413 2.4. Revising Existing Registries 415 Updating the registration process or making changes to the format of 416 an already existing (previously created) registry (whether created 417 explicitly or implicitly) follows a process similar to that used when 418 creating a new registry. That is, a document is produced that makes 419 reference to the existing namespace and then provides detailed 420 guidance for handling assignments in the registry, or detailed 421 instructions about the changes required. 423 If a change requires a new column in the registry, the instructions 424 need to be clear about how to populate that column for the existing 425 entries. Other changes may require similar clarity. 427 Such documents are normally processed with the same document status 428 as the document that created the registry. 430 Example documents that updated the guidelines for assignments in pre- 431 existing registries include: [RFC6195], [RFC3228], and [RFC3575]. 433 3. Registering New Values in an Existing Registry 435 3.1. Documentation Requirements for Registrations 437 Often, documents request an assignment in an existing registry (one 438 created by a previously published document). 440 Such documents should clearly identify the registry into which each 441 value is to be registered. Use the exact registry name as listed on 442 the IANA web page, and cite the RFC where the registry is defined. 444 There is no need to mention what the assignment policy is when making 445 new assignments in existing registries, as that should be clear from 446 the references. However, if multiple assignment policies might 447 apply, as in registries with different ranges that have different 448 policies, it is important to make it clear which range is being 449 requested, so that IANA will know which policy applies and can assign 450 a value in the correct range. 452 When referring to an existing registry, providing a URL to precisely 453 identify the registry is helpful. See Section 2.2 for details on 454 specifying the correct URL. 456 For example, a document could contain something like this: 458 This registration should be made in the Foobar Operational 459 Parameters registry, located at . 462 Normally, numeric values to be used are chosen by IANA when the 463 document is approved, and drafts should not specify final values. 464 Instead, placeholders such as "TBD1" and "TBD2" should be used 465 consistently throughout the document, giving each item to be 466 registered a different placeholder. The IANA Considerations should 467 ask the RFC Editor to replace the placeholder names with the IANA- 468 assigned values. When drafts need to specify numeric values for 469 testing or early implementations, they will either request early 470 allocation (see Section 3.4) or use values that have already been set 471 aside for testing or experimentation (if the registry in question 472 allows that without explicit assignment). It is important that 473 drafts not choose their own values, lest IANA assign one of those 474 values to another document in the meantime. A draft can request a 475 specific value in the IANA Considerations section, and IANA will 476 accommodate such requests when that's possible, but the proposed 477 number might have been assigned to some other use by the time the 478 draft is approved. 480 Normally, text-string values to be used are specified in the 481 document, as collisions are less likely with text strings. IANA will 482 consult with the authors if there is, in fact, a collision, and a 483 different value has to be used. When drafts need to specify string 484 values for testing or early implementations, they sometimes use the 485 expected final value. But it is often useful to use a draft value 486 instead, possibly including the draft version number. This allows 487 the early implementations to be distinguished from those implementing 488 the final version. A document that intends to use "foobar" in the 489 final version might use "foobar-testing-draft-05" for the -05 version 490 of the draft, for example. 492 For some registries, IANA has a long-standing policy prohibiting 493 assignment of names or codes on a vanity or organization-name basis. 494 For example, codes might always be assigned sequentially unless there 495 is a strong reason for making an exception. Nothing in this document 496 is intended to change those policies or prevent their future 497 application. 499 As an example, the following text could be used to request assignment 500 of a DHCPv6 option number: 502 IANA is asked to assign an option code value of TBD1 to the DNS 503 Recursive Name Server option and an option code value of TBD2 to 504 the Domain Search List option from the DHCP option code space 505 defined in Section 24.3 of RFC 3315. 507 The IANA Considerations section should summarize all of the IANA 508 actions, with pointers to the relevant sections elsewhere in the 509 document as appropriate. Including section numbers is especially 510 useful when the reference document is large; the section numbers will 511 make it easier for those searching the reference document to find the 512 relevant information. 514 When multiple values are requested, it is generally helpful to 515 include a summary table of the additions/changes. It is also helpful 516 for this table to be in the same format as it appears or will appear 517 on the IANA web site. For example: 519 Value Description Reference 520 -------- ------------------- --------- 521 TBD1 Foobar [[this RFC, Section 3.2]] 522 TBD2 Gumbo [[this RFC, Section 3.3]] 523 TBD3 Banana [[this RFC, Section 3.4]] 525 Note: In cases where authors feel that including the full table of 526 changes is too verbose or repetitive, authors should still include 527 the table in the draft, but may include a note asking that the table 528 be removed prior to publication of the final RFC. 530 3.2. Updating Existing Registrations 532 Even after a number has been assigned, some types of registrations 533 contain additional information that may need to be updated over time. 535 For example, MIME media types, character sets, and language tags 536 typically include more information than just the registered value 537 itself, and may need updates to items such as point-of-contact 538 information, security issues, pointers to updates, and literature 539 references. 541 In such cases, the document defining the namespace must clearly state 542 who is responsible for maintaining and updating a registration. 543 Depending on the registry, it may be appropriate to specify one or 544 more of: 546 o Letting registrants and/or nominated change controllers update 547 their own registrations, subject to the same constraints and 548 review as with new registrations. 550 o Allowing attachment of comments to the registration. This can be 551 useful in cases where others have significant objections to a 552 registration, but the author does not agree to change the 553 registration. 555 o Designating the IESG, a designated expert, or another entity as 556 having the right to change the registrant associated with a 557 registration and any requirements or conditions on doing so. This 558 is mainly to get around the problem when a registrant cannot be 559 reached in order to make necessary updates. 561 3.3. Overriding Registration Procedures 563 Experience has shown that the documented IANA considerations for 564 individual protocols do not always adequately cover the reality of 565 registry operation, or are not sufficiently clear. In addition, 566 documented IANA considerations are sometimes found to be too 567 stringent to allow even working group documents (for which there is 568 strong consensus) to perform a registration in advance of actual RFC 569 publication. 571 In order to allow assignments in such cases, the IESG is granted 572 authority to override registration procedures and approve assignments 573 on a case-by-case basis. 575 The intention here is not to overrule properly documented procedures, 576 or to obviate the need for protocols to properly document their IANA 577 considerations. Rather, it is to permit assignments in specific 578 cases where it is obvious that the assignment should just be made, 579 but updating the IANA process beforehand is too onerous. 581 When the IESG is required to take action as described above, it is a 582 strong indicator that the applicable registration procedures should 583 be updated, possibly in parallel with the work that instigated it. 585 IANA always has the discretion to ask the IESG for advice or 586 intervention when they feel it is needed, such as in cases where 587 policies or procedures are unclear to them, where they encounter 588 issues or questions they are unable to resolve, or where registration 589 requests or patterns of requests appear to be unusual or abusive. 591 3.4. Early Allocations 592 IANA normally takes its actions when a document is approved for 593 publication. There are times, though, when early allocation of a 594 value is important for the development of a technology: for example, 595 when early implementations are created while the document is still 596 under development. 598 IANA has a mechanism for handling such early allocations in some 599 cases. See [RFC7120] for details. It is usually not necessary to 600 explicitly mark a registry as allowing early allocation, because the 601 general rules will apply. 603 4. Choosing a Registration Policy, and Well-Known Policies 605 A registration policy is the policy that controls how new assignments 606 in a registry are accepted. There are several issues to consider 607 when defining the registration policy. 609 If the registry's namespace is limited, assignments will need to be 610 made carefully to prevent exhaustion. 612 Even when the space is essentially unlimited, it is still often 613 desirable to have at least a minimal review prior to assignment in 614 order to: 616 o prevent the hoarding of or unnecessary wasting of values. For 617 example, if the space consists of text strings, it may be 618 desirable to prevent entities from obtaining large sets of strings 619 that correspond to desirable names (existing company names, for 620 example). 622 o provide a sanity check that the request actually makes sense and 623 is necessary. Experience has shown that some level of minimal 624 review from a subject matter expert is useful to prevent 625 assignments in cases where the request is malformed or not 626 actually needed (for example, an existing assignment for an 627 essentially equivalent service already exists). 629 Perhaps most importantly, unreviewed extensions can impact 630 interoperability and security. See [RFC6709]. 632 When the namespace is essentially unlimited and there are no 633 potential interoperability or security issues, assigned numbers can 634 usually be given out to anyone without any subjective review. In 635 such cases, IANA can make assignments directly, provided that IANA is 636 given detailed instructions on what types of requests it should 637 grant, and it is able to do so without exercising subjective 638 judgement. 640 When this is not the case, some level of review is required. 641 However, it's important to balance adequate review and ease of 642 registration. In many cases, those making registrations will not be 643 IETF participants; requests often come from other standards 644 organizations, from organizations not directly involved in standards, 645 from ad-hoc community work (from an open-source project, for 646 example), and so on. Registration must not be unnecessarily 647 difficult, unnecessarily costly (in terms of time and other 648 resources), nor unnecessarily subject to denial. 650 While it is sometimes necessary to restrict what gets registered 651 (e.g., for limited resources such as bits in a byte, or for items for 652 which unsupported values can be damaging to protocol operation), in 653 many cases having what's in use represented in the registry is more 654 important. Overly strict review criteria and excessive cost (in time 655 and effort) discourage people from even attempting to make a 656 registration. If a registry fails to reflect the protocol elements 657 actually in use, it can adversely affect deployment of protocols on 658 the Internet, and the registry itself is devalued. 660 Therefore, working groups and other document developers should use 661 care in selecting appropriate registration policies when their 662 documents create registries. They should select the least strict 663 policy that suits a registry's needs, and look for specific 664 justification for policies that require significant community 665 involvement (those stricter than Expert Review or Specification 666 Required, in terms of the well-known policies). 668 The following policies are defined for common usage. These cover a 669 range of typical policies that have been used to describe the 670 procedures for assigning new values in a namespace. It is not 671 strictly required that documents use these terms; the actual 672 requirement is that the instructions to IANA be clear and 673 unambiguous. However, use of these terms is strongly recommended 674 because their meanings are widely understood, and newly minted 675 policies should not be used without good reason and explanation. The 676 terms are fully explained in the following subsections. 678 1. Private Use 679 2. Experimental Use 680 3. Hierarchical Allocation 681 4. First Come First Served 682 5. Expert Review 683 6. Specification Required 684 7. RFC Required 685 8. IETF Review 686 9. Standards Action 687 10. IESG Approval 689 It should be noted that it often makes sense to partition a namespace 690 into multiple categories, with assignments within each category 691 handled differently. Many protocols now partition namespaces into 692 two or more parts, with one range reserved for Private or 693 Experimental Use while other ranges are reserved for globally unique 694 assignments assigned following some review process. Dividing a 695 namespace into ranges makes it possible to have different policies in 696 place for different ranges and different use cases. 698 Similarly, it will often be useful to specify multiple policies in 699 parallel, with each policy being used under different circumstances. 700 For more discussion of that topic, see Section 4.12. 702 Examples of RFCs that specify multiple policies in parallel: 704 LDAP [RFC4520] 705 TLS ClientCertificateType Identifiers [RFC5246] (as detailed in 706 the subsections below) 707 MPLS Pseudowire Types Registry [RFC4446] 709 4.1. Private Use 711 For private or local use only, with the type and purpose defined by 712 the local site. No attempt is made to prevent multiple sites from 713 using the same value in different (and incompatible) ways. IANA does 714 not record assignments from registries or ranges with this policy 715 (and therefore there is no need for IANA to review them) and 716 assignments are not generally useful for broad interoperability. It 717 is the responsibility of the sites making use of the Private Use 718 range to ensure that no conflicts occur (within the intended scope of 719 use). 721 Examples: 723 Site-specific options in DHCP [RFC2939] 724 Fibre Channel Port Type Registry [RFC4044] 725 TLS ClientCertificateType Identifiers 224-255 [RFC5246] 727 4.2. Experimental Use 729 Experimental Use is similar to Private Use, but with the purpose 730 being to facilitate experimentation. See [RFC3692] for details. 731 IANA does not record assignments from registries or ranges with this 732 policy (and therefore there is no need for IANA to review them) and 733 assignments are not generally useful for broad interoperability. 734 Unless the registry explicitly allows it, it is not appropriate for 735 documents to select explicit values from registries or ranges with 736 this policy. Specific experiments will select a value to use during 737 the experiment. 739 Example: 741 Experimental Values in IPv4, IPv6, ICMPv4, ICMPv6, UDP, and TCP 742 Headers [RFC4727] 744 4.3. Hierarchical Allocation 746 With Hierarchical Allocation, delegated administrators are given 747 control over part of the namespace, and can assign values in that 748 part of the namespace. IANA makes allocations in the higher levels 749 of the namespace according to one of the other policies. 751 Examples: 753 - DNS names. IANA manages the top-level domains (TLDs), and, as 754 [RFC1591] says: 756 Under each TLD may be created a hierarchy of names. Generally, 757 under the generic TLDs the structure is very flat. That is, 758 many organizations are registered directly under the TLD, and 759 any further structure is up to the individual organizations. 761 - Object Identifiers, defined by ITU-T recommendation X.208. 762 According to , some registries 763 include 765 * IANA, which hands out OIDs the "Private Enterprises" branch, 766 * ANSI, which hands out OIDs under the "US Organizations" branch, 767 and 768 * BSI, which hands out OIDs under the "UK Organizations" branch. 770 - URN namespaces. IANA registers URN Namespace IDs (NIDs [RFC3406]), 771 and the organization registering an NID is responsible for 772 allocations of URNs within that namespace. 774 4.4. First Come First Served 776 For the First Come First Served policy, assignments are made to 777 anyone on a first come, first served basis. There is no substantive 778 review of the request, other than to ensure that it is well-formed 779 and doesn't duplicate an existing assignment. However, requests must 780 include a minimal amount of clerical information, such as a point of 781 contact (including an email address, and sometimes a postal address) 782 and a brief description of how the value will be used. Additional 783 information specific to the type of value requested may also need to 784 be provided, as defined by the namespace. For numbers, the exact 785 value is generally assigned by IANA; with names, specific text 786 strings can usually be requested. 788 When creating a new registry with First Come First Served as the 789 registration policy, in addition to the contact person field or 790 reference, the registry should contain a field for change controller. 791 Having a change controller for each entry for these types of 792 registrations makes authorization of future modifications more clear. 793 See Section 2.3. It is important that changes to the registration of 794 a First Come First Served code point retain compatibility with the 795 current usage of that code point, and so changes need to be made with 796 care. 798 It is also important to understand that First Come First Served 799 really has no filtering. Essentially, any well formed request is 800 accepted. 802 A working group or any other entity that is developing a protocol 803 based on a First Come First Served code point has to be extremely 804 careful that the protocol retains wire compatibility with current use 805 of the code point. Once that is no longer true, the new work needs 806 to change to a different code point (and register that use at the 807 appropriate time). 809 Examples: 811 SASL mechanism names [RFC4422] 812 LDAP Protocol Mechanisms and LDAP Syntax [RFC4520] 814 4.5. Expert Review 816 (Also called "Designated Expert" in earlier editions of this 817 document.) For the Expert Review policy, review and approval by a 818 designated expert (see Section 5) is required. 820 The required documentation and review criteria, giving clear guidance 821 to the designated expert, should be provided when defining the 822 registry. It is particularly important to lay out what should be 823 considered when performing an evaluation and reasons for rejecting a 824 request. It is also a good idea to include, when possible, a sense 825 of whether many registrations are expected over time, or if the 826 registry is expected to be updated infrequently or in exceptional 827 circumstances only. 829 Good examples of guidance to designated experts: 831 Extensible Authentication Protocol (EAP) [RFC3748], Sections 6 and 832 7.2 833 North-Bound Distribution of Link-State and TE Information using 834 BGP [RFC7752], Section 5.1 836 When creating a new registry with Expert Review as the registration 837 policy, in addition to the contact person field or reference, the 838 registry should contain a field for change controller. Having a 839 change controller for each entry for these types of registrations 840 makes authorization of future modifications more clear. See Section 841 2.3 843 Examples: 845 EAP Method Types [RFC3748] 846 HTTP Digest AKA algorithm versions [RFC4169] 847 URI schemes [RFC4395] 848 GEOPRIV Location Types [RFC4589] 850 4.6. Specification Required 852 For the Specification Required policy, review and approval by a 853 designated expert (see Section 5) is required, and the values and 854 their meanings must be documented in a permanent and readily 855 available public specification, in sufficient detail so that 856 interoperability between independent implementations is possible. 857 The designated expert will review the public specification and 858 evaluate whether it is sufficiently stable and permanent, and 859 sufficiently clear to allow interoperable implementations. 861 The intention behind "permanent and readily available" is that a 862 document can reasonably be expected to be findable and retrievable 863 long after IANA assignment of the requested value. Publication of an 864 RFC is an ideal means of achieving this requirement, but 865 Specification Required is intended to also cover the case of a 866 document published outside of the RFC path, including informal 867 documentation. 869 For RFC publication, the normal RFC review process is expected to 870 provide the necessary review for interoperability, though the 871 designated expert may be a particularly well-qualified person to 872 perform such a review. 874 As with Expert Review (Section 4.5), clear guidance to the designated 875 expert, should be provided when defining the registry. 877 When specifying this policy, just use the term "Specification 878 Required". Some specifications have chosen to refer to it as "Expert 879 Review with Specification Required", and that only causes confusion. 881 Examples: 883 Diffserv-aware TE Bandwidth Constraints Model Identifiers 884 [RFC4124] 885 TLS ClientCertificateType Identifiers 64-223 [RFC5246] 886 ROHC Profile Identifiers [RFC5795] 888 4.7. RFC Required 890 With the RFC Required policy, the registration request, along with 891 associated documentation, must be published in an RFC. The RFC need 892 not be in the IETF stream, but may be in any RFC stream (currently an 893 RFC may be in the IETF, IRTF, or IAB stream, or an RFC Editor 894 Independent Submission [RFC5742]). 896 Unless otherwise specified, any type of RFC is sufficient (currently 897 Standards Track, BCP, Informational, Experimental, or Historic). 899 4.8. IETF Review 901 (Formerly called "IETF Consensus" in the first edition of this 902 document.) With the IETF Review policy, new values are assigned only 903 through RFCs in the IETF Stream -- those that have been shepherded 904 through the IESG as AD-Sponsored or IETF working group Documents 905 [RFC2026] [RFC5378], have gone through IETF last call, and that the 906 IESG has approved as having IETF consensus. 908 The intent is that the document and proposed assignment will be 909 reviewed by the IETF community (including appropriate IETF working 910 groups, directorates, and other experts) and by the IESG, to ensure 911 that the proposed assignment will not negatively affect 912 interoperability or otherwise extend IETF protocols in an 913 inappropriate or damaging manner. To ensure adequate community 914 review, such documents will always undergo an IETF Last Call. 916 Unless otherwise specified, any type of RFC is sufficient (currently 917 Standards Track, BCP, Informational, Experimental, or Historic). 919 Examples: 921 IPSECKEY Algorithm Types [RFC4025] 922 Accounting-Auth-Method AVP values in DIAMETER [RFC4005] 923 TLS Extension Types [RFC5246] 925 4.9. Standards Action 927 For the Standards Action policy, values are assigned only through 928 Standards Track or Best Current Practice RFCs approved by the IESG. 930 Examples: 932 BGP message types [RFC4271] 933 Mobile Node Identifier option types [RFC4283] 934 TLS ClientCertificateType Identifiers 0-63 [RFC5246] 935 DCCP Packet Types [RFC4340] 937 4.10. IESG Approval 939 New assignments may be approved by the IESG. Although there is no 940 requirement that the request be documented in an RFC, the IESG has 941 discretion to request documents or other supporting materials on a 942 case-by-case basis. 944 IESG Approval is not intended to be used often or as a "common case"; 945 indeed, it has seldom been used in practice. Rather, it is intended 946 to be available in conjunction with other policies as a fall-back 947 mechanism in the case where one of the other allowable approval 948 mechanisms cannot be employed in a timely fashion or for some other 949 compelling reason. IESG Approval is not intended to circumvent the 950 public review processes implied by other policies that could have 951 been employed for a particular assignment. IESG Approval would be 952 appropriate, however, in cases where expediency is desired and there 953 is strong consensus (such as from a working group) for making the 954 assignment. 956 Before approving a request, the IESG might consider consulting the 957 community, via a "call for comments" that provides as much 958 information as is reasonably possible about the request. 960 Examples: 962 IPv4 Multicast address assignments [RFC5771] 963 IPv4 IGMP Type and Code values [RFC3228] 964 Mobile IPv6 Mobility Header Type and Option values [RFC6275] 966 4.11. Using the Well-Known Registration Policies 968 Because the well-known policies benefit from both community 969 experience and wide understanding, their use is encouraged, and the 970 making up of new policies needs to be accompanied by reasonable 971 justification. 973 It is also acceptable to cite one of the well-known policies and 974 include additional guidelines for what kind of considerations should 975 be taken into account by the review process. 977 For example, RADIUS [RFC3575] specifies the use of a Designated 978 Expert, but includes specific additional criteria the Designated 979 Expert should follow. 981 The well-known policies from "First Come First Served" to "Standards 982 Action" specify a range of policies in increasing order of strictness 983 (using the numbering from the full list in Section 4): 985 4. First Come First Served 986 No review, minimal documentation. 988 5/6. Expert Review / Specification Required 989 Expert review with sufficient documentation for review. / 990 Significant stable public documentation sufficient for 991 interoperability. 993 7. RFC Required 994 Any RFC publication, IETF or a non-IETF Stream. 996 8. IETF Review 997 RFC publication, IETF Stream only, but need not be Standards 998 Track. 1000 9. Standards Action 1001 RFC publication, IETF Stream, Standards Track only. 1003 Examples of situations that might merit IETF Review or Standards 1004 Action include the following: 1006 o When a resource is limited, such as bits in a byte (or in two 1007 bytes, or four), or numbers in a limited range. In these cases, 1008 allowing registrations that haven't been carefully reviewed and 1009 agreed by community consensus could too quickly deplete the 1010 allowable values. 1012 o When thorough community review is necessary to avoid extending or 1013 modifying the protocol in ways that could be damaging. One 1014 example is in defining new command codes, as opposed to options 1015 that use existing command codes: the former might require a strict 1016 policy, where a more relaxed policy could be adequate for the 1017 latter. Another example is in defining protocol elements that 1018 change the semantics of existing operations. 1020 When reviewing a document that asks IANA to create a new registry or 1021 change a registration policy to any policy more stringent than Expert 1022 Review or Specification Required, the IESG should ask for 1023 justification to ensure that more relaxed policies have been 1024 considered and that the strict policy is the right one. 1026 Accordingly, document developers need to anticipate this and document 1027 their considerations for selecting the specified policy (ideally, in 1028 the document itself; failing that, in the shepherd writeup). 1029 Likewise, the document shepherd should ensure that the selected 1030 policies have been justified before sending the document to the IESG. 1032 When specifications are revised, registration policies should be 1033 reviewed in light of experience since the policies were set. 1035 4.12. Using Multiple Policies in Combination 1037 In some situations, it is necessary to define multiple registration 1038 policies. For example, registrations through the normal IETF process 1039 might use one policy, while registrations from outside the process 1040 would have a different policy applied. 1042 Thus, a particular registry might want to use a policy such as "RFC 1043 Required" or "IETF Review" sometimes, with a designated expert 1044 checking a "Specification Required" policy at other times. 1046 The alternative to using a combination requires either that all 1047 requests come through RFCs or that requests in RFCs go through review 1048 by the designated expert, even though they already have IETF review 1049 and consensus. 1051 This can be documented in the IANA Considerations section when the 1052 registry is created: 1054 IANA is asked to create the registry "Fruit Access Flags" under 1055 the "Fruit Parameters" group. New registrations will be permitted 1056 through either the IETF Review policy or the Specification 1057 Required policy [BCP26]. The latter should be used only for 1058 registrations requested by SDOs outside the IETF. Registrations 1059 requested in IETF documents will be subject to IETF review. 1061 Such combinations will commonly use one of {Standards Action, IETF 1062 Review, RFC Required} in combination with one of {Specification 1063 Required, Expert Review}. Guidance should be provided about when 1064 each policy is appropriate, as in the example above. 1066 5. Designated Experts 1068 5.1. The Motivation for Designated Experts 1070 Discussion on a mailing list can provide valuable technical feedback, 1071 but opinions often vary and discussions may continue for some time 1072 without clear resolution. In addition, IANA cannot participate in 1073 all of these mailing lists and cannot determine if or when such 1074 discussions reach consensus. Therefore, IANA relies on a "designated 1075 expert" for advice regarding the specific question of whether an 1076 assignment should be made. The designated expert is an individual 1077 who is responsible for carrying out an appropriate evaluation and 1078 returning a recommendation to IANA. 1080 It should be noted that a key motivation for having designated 1081 experts is for the IETF to provide IANA with a subject matter expert 1082 to whom the evaluation process can be delegated. IANA forwards 1083 requests for an assignment to the expert for evaluation, and the 1084 expert (after performing the evaluation) informs IANA as to whether 1085 or not to make the assignment or registration. In most cases, the 1086 registrants do not work directly with the designated experts. The 1087 list of designated experts for a registry is listed in the registry. 1089 It will often be useful to use a designated expert only some of the 1090 time, as a supplement to other processes. For more discussion of 1091 that topic, see Section 4.12. 1093 5.2. The Role of the Designated Expert 1095 The designated expert is responsible for coordinating the appropriate 1096 review of an assignment request. The review may be wide or narrow, 1097 depending on the situation and the judgment of the designated expert. 1098 This may involve consultation with a set of technology experts, 1099 discussion on a public mailing list, consultation with a working 1100 group (or its mailing list if the working group has disbanded), etc. 1101 Ideally, the designated expert follows specific review criteria as 1102 documented with the protocol that creates or uses the namespace. See 1103 the IANA Considerations sections of [RFC3748] and [RFC3575] for 1104 specific examples. 1106 Designated experts are expected to be able to defend their decisions 1107 to the IETF community, and the evaluation process is not intended to 1108 be secretive or bestow unquestioned power on the expert. Experts are 1109 expected to apply applicable documented review or vetting procedures, 1110 or in the absence of documented criteria, follow generally accepted 1111 norms such as those in Section 5.3. 1113 It has proven useful to have multiple designated experts for some 1114 registries. Sometimes those experts work together in evaluating a 1115 request, while in other cases additional experts serve as backups, 1116 acting only when the primary expert is unavailable. In registries 1117 with a pool of experts, the pool often has a single chair responsible 1118 for defining how requests are to be assigned to and reviewed by 1119 experts. In other cases, IANA might assign requests to individual 1120 members in sequential or approximate random order. 1122 In cases of disagreement among multiple experts, it is the 1123 responsibility of those experts to make a single clear recommendation 1124 to IANA. It is not appropriate for IANA to resolve disputes among 1125 experts. In extreme situations, such as deadlock, the designating 1126 body may need to step in to resolve the problem. 1128 If a designated expert is conflicted for a particular review (is, for 1129 example, an author or significant proponent of a specification 1130 related to the registration under review), that expert should recuse 1131 himself. In the event that all the designated experts are 1132 conflicted, they should ask that a temporary expert be designated for 1133 the conflicted review. 1135 This document defines the designated expert mechanism with respect to 1136 documents in the IETF stream only. Documents in other streams may 1137 use a registration policy that requires a designated expert only if 1138 those streams (or those documents) specify how designated experts are 1139 appointed and managed. What is described below, with management by 1140 the IESG, is only appropriate for the IETF stream. 1142 5.2.1. Managing Designated Experts in the IETF 1143 Designated experts for registries created by the IETF are appointed 1144 by the IESG, normally upon recommendation by the relevant Area 1145 Director. They may be appointed at the time a document creating or 1146 updating a namespace is approved by the IESG, or subsequently, when 1147 the first registration request is received. Because experts 1148 originally appointed may later become unavailable, the IESG will 1149 appoint replacements as necessary. The IESG may remove any 1150 designated expert that it appointed, at its discretion. 1152 The normal appeals process, as described in [RFC2026], Section 6.5.1, 1153 applies to issues that arise with the designated expert team. For 1154 this purpose, the designated expert team takes the place of the 1155 working group in that description. 1157 5.3. Designated Expert Reviews 1159 In the years since RFC 2434 was published and has been put to use, 1160 experience has led to the following observations: 1162 o A designated expert must respond in a timely fashion, normally 1163 within a week for simple requests to a few weeks for more complex 1164 ones. Unreasonable delays can cause significant problems for 1165 those needing assignments, such as when products need code points 1166 to ship. This is not to say that all reviews can be completed 1167 under a firm deadline, but they must be started, and the requester 1168 and IANA should have some transparency into the process if an 1169 answer cannot be given quickly. 1171 o If a designated expert does not respond to IANA's requests within 1172 a reasonable period of time, either with a response or with a 1173 reasonable explanation for the delay (some requests may be 1174 particularly complex), and if this is a recurring event, IANA must 1175 raise the issue with the IESG. Because of the problems caused by 1176 delayed evaluations and assignments, the IESG should take 1177 appropriate actions to ensure that the expert understands and 1178 accepts his or her responsibilities, or appoint a new expert. 1180 o The designated expert is not required to personally bear the 1181 burden of evaluating and deciding all requests, but acts as a 1182 shepherd for the request, enlisting the help of others as 1183 appropriate. In the case that a request is denied, and rejecting 1184 the request is likely to be controversial, the expert should have 1185 the support of other subject matter experts. That is, the expert 1186 must be able to defend a decision to the community as a whole. 1188 When a designated expert is used, the documentation should give clear 1189 guidance to the designated expert, laying out criteria for performing 1190 an evaluation and reasons for rejecting a request. In the case where 1191 there are no specific documented criteria, the presumption should be 1192 that a code point should be granted unless there is a compelling 1193 reason to the contrary. Reasons that have been used to deny requests 1194 have included these: 1196 o Scarcity of code points, where the finite remaining code points 1197 should be prudently managed, or where a request for a large number 1198 of code points is made and a single code point is the norm. 1200 o Documentation is not of sufficient clarity to evaluate or ensure 1201 interoperability. 1203 o The code point is needed for a protocol extension, but the 1204 extension is not consistent with the documented (or generally 1205 understood) architecture of the base protocol being extended, and 1206 would be harmful to the protocol if widely deployed. It is not 1207 the intent that "inconsistencies" refer to minor differences "of a 1208 personal preference nature". Instead, they refer to significant 1209 differences such as inconsistencies with the underlying security 1210 model, implying a change to the semantics of an existing message 1211 type or operation, requiring unwarranted changes in deployed 1212 systems (compared with alternate ways of achieving a similar 1213 result), etc. 1215 o The extension would cause problems with existing deployed systems. 1217 o The extension would conflict with one under active development by 1218 the IETF, and having both would harm rather than foster 1219 interoperability. 1221 When a designated expert is used, documents must not name the 1222 designated expert in the document itself; instead, any suggested 1223 names should be relayed to the appropriate Area Director at the time 1224 the document is sent to the IESG for approval. This is usually done 1225 in the document shepherd writeup. 1227 If the request should also be reviewed on a specific public mailing 1228 list, its address should be specified. 1230 5.4. Expert Reviews and the Document Lifecycle 1232 Review by the designated expert is necessarily done at a particular 1233 point in time, and represents review of a particular version of the 1234 document. While reviews are generally done around the time of IETF 1235 last call, deciding when the review should take place is a question 1236 of good judgment. And while re-reviews might be done when it's 1237 acknowledged that the documentation of the registered item has 1238 changed substantially, making sure that re-review happens requires 1239 attention and care. 1241 It is possible, through carelessness, accident, inattentiveness, or 1242 even willful disregard, that changes might be made after the 1243 designated expert's review and approval that would, if the document 1244 were re-reviewed, cause the expert not to approve the registration. 1245 It is up to the IESG, with the token held by the responsible Area 1246 Director, to be alert to such situations and to recognize that such 1247 changes need to be checked. 1249 For registrations made from documents on the Standards Track, there 1250 is often expert review required (by the registration policy) in 1251 addition to IETF consensus (for approval as a Standards Track RFC). 1252 In such cases, the review by the designated expert needs to be 1253 timely, submitted before the IESG evaluates the document. The IESG 1254 should generally not hold the document up waiting for late review. 1255 It is also not intended for the expert review to override IETF 1256 consensus: the IESG should consider the review in its own evaluation, 1257 as it would do for other last-call reviews. 1259 6. Well-Known Registration Status Terminology 1261 The following labels describe the status of an assignment or range of 1262 assignments: 1264 Private Use: Private use only (not assigned), as described in 1265 Section 4.1. 1267 Experimental: Available for general experimental use as described 1268 in [RFC3692]. IANA does not record specific assignments for 1269 any particular use. 1271 Unassigned: Not currently assigned, and available for assignment 1272 via documented procedures. While it's generally clear that 1273 any values that are not registered are unassigned and 1274 available for assignment, it is sometimes useful to 1275 explicitly specify that situation. Note that this is 1276 distinctly different from "Reserved". 1278 Reserved: Not assigned and not available for assignment. Reserved 1279 values are held for special uses, such as to extend the 1280 namespace when it becomes exhausted. Note that this is 1281 distinctly different from "Unassigned". 1283 Reserved values can be released for assignment by the change 1284 controller for the registry (this is often the IESG, for 1285 registries created by RFCs in the IETF stream). 1287 7. Documentation References in IANA Registries 1289 Usually, registries and registry entries include references to 1290 documentation (RFCs or other documents). The purpose of these 1291 references is to provide pointers for implementors to find details 1292 necessary for implementation, NOT to simply note what document 1293 created the registry or entry. Therefore: 1295 o If a document registers an item that is defined and explained 1296 elsewhere, the registered reference should be to the document 1297 containing the definition, not to the document that is merely 1298 performing the registration. 1300 o If the registered item is defined and explained in the current 1301 document, it is important to include sufficient information to 1302 enable implementors to understand the item and to create a proper 1303 implementation. 1305 o If the registered item is explained primarily in a specific 1306 section of the reference document, it is useful to include a 1307 section reference. For example, "[RFC9876], Section 3.2", rather 1308 than just "[RFC9876]". 1310 o For documentation of a new registry, the reference should provide 1311 information about the registry itself, not just a pointer to the 1312 creation of it. Useful information includes the purpose of the 1313 registry, a rationale for its creation, documentation of the 1314 process and policy for new registrations, guidelines for new 1315 registrants or designated experts, and other such related 1316 information. But note that, while it's important to include this 1317 information in the document, it needn't all be in the IANA 1318 Considerations section. See Section 1.1. 1320 8. What to Do in "bis" Documents 1322 On occasion, an RFC is issued that obsoletes a previous edition of 1323 the same document. We sometimes call these "bis" documents, such as 1324 when RFC 9876 is obsoleted by draft-ietf-foo-rfc9876bis. When the 1325 original document created registries and/or registered entries, there 1326 is a question of how to handle the IANA Considerations section in the 1327 "bis" document. 1329 If the registrations specify the original document as a reference, 1330 those registrations should be updated to point to the current (not 1331 obsolete) documentation for those items. Usually, that will mean 1332 changing the reference to be the "bis" document. 1334 There will, though, be times when a document updates another, but 1335 does not make it obsolete, and the definitive reference is changed 1336 for some items but not for others. Be sure that the references are 1337 always set to point to the correct, current documentation for each 1338 item. 1340 For example, suppose RFC 9876 registered the "BANANA" flag in the 1341 "Fruit Access Flags" registry, and the documentation for that flag is 1342 in Section 3.2. 1344 The current registry might look, in part, like this: 1346 Name Description Reference 1347 -------- ------------------- --------- 1348 BANANA Flag for bananas [RFC9876], Section 3.2 1349 If draft-ietf-foo-rfc9876bis obsoletes RFC 9876 and, because of some 1350 rearrangement, now documents the flag in Section 4.1.2, the IANA 1351 Considerations of the bis document might contain text such as this: 1353 IANA is asked to change the registration information for the 1354 BANANA flag in the "Fruit Access Flags" registry to the following: 1356 Name Description Reference 1357 -------- ------------------- --------- 1358 BANANA Flag for bananas [[this RFC]], Section 4.2.1 1360 In many cases, if there are a number of registered references to the 1361 original RFC and the document organization has not changed the 1362 registered section numbering much, it may simply be reasonable to do 1363 this: 1365 Because this document obsoletes RFC 9876, IANA is asked to change 1366 all registration information that references [RFC9876] to instead 1367 reference [[this RFC]]. 1369 If information for registered items has been or is being moved to 1370 other documents, then, of course, the registration information should 1371 be changed to point to those other documents. In no case is it 1372 reasonable to leave documentation pointers to the obsoleted document 1373 for any registries or registered items that are still in current use. 1375 It is extremely important to be clear in your instructions regarding 1376 updating references, especially in cases where some references need 1377 to be updated and others do not. 1379 9. Miscellaneous Issues 1381 9.1. When There Are No IANA Actions 1383 Before an Internet-Draft can be published as an RFC, IANA needs to 1384 know what actions (if any) it needs to perform. Experience has shown 1385 that it is not always immediately obvious whether a document has no 1386 IANA actions, without reviewing the document in some detail. In 1387 order to make it clear to IANA that it has no actions to perform (and 1388 that the author has consciously made such a determination), such 1389 documents should, after the authors confirm that this is the case, 1390 include an IANA Considerations section that states: 1392 This document has no IANA actions. 1394 IANA prefers that these "empty" IANA Considerations sections be left 1395 in the document for the record: it makes it clear later on that the 1396 document explicitly said that no IANA actions were needed (and that 1397 it wasn't just omitted). This is a change from the prior practice of 1398 requesting that such sections be removed by the RFC Editor, and 1399 authors are asked to accommodate this change. 1401 9.2. Namespaces Lacking Documented Guidance 1403 For all existing RFCs that either explicitly or implicitly rely on 1404 IANA to make assignments without specifying a precise assignment 1405 policy, IANA (in consultation with the IESG) will continue to decide 1406 what policy is appropriate. Changes to existing policies can always 1407 be initiated through the normal IETF consensus process, or through 1408 the IESG when appropriate. 1410 All future RFCs that either explicitly or implicitly rely on IANA to 1411 register or otherwise administer namespace assignments must provide 1412 guidelines for administration of the namespace. 1414 9.3. After-the-Fact Registrations 1416 Occasionally, the IETF becomes aware that an unassigned value from a 1417 namespace is in use on the Internet or that an assigned value is 1418 being used for a different purpose than it was registered for. The 1419 IETF does not condone such misuse; procedures of the type described 1420 in this document need to be applied to such cases. In the absence of 1421 specifications to the contrary, values may only be reassigned for a 1422 different purpose with the consent of the original assignee (when 1423 possible) and with due consideration of the impact of such a 1424 reassignment. In cases of likely controversy, consultation with the 1425 IESG is advised. 1427 9.4. Reclaiming Assigned Values 1429 Reclaiming previously assigned values for reuse is tricky, because 1430 doing so can lead to interoperability problems with deployed systems 1431 still using the assigned values. Moreover, it can be extremely 1432 difficult to determine the extent of deployment of systems making use 1433 of a particular value. However, in cases where the namespace is 1434 running out of unassigned values and additional ones are needed, it 1435 may be desirable to attempt to reclaim unused values. When 1436 reclaiming unused values, the following (at a minimum) should be 1437 considered: 1439 o Attempts should be made to contact the original party to which a 1440 value is assigned, to determine if the value was ever used, and if 1441 so, the extent of deployment. (In some cases, products were never 1442 shipped or have long ceased being used. In other cases, it may be 1443 known that a value was never actually used at all.) 1445 o Reassignments should not normally be made without the concurrence 1446 of the original requester. Reclamation under such conditions 1447 should only take place where there is strong evidence that a value 1448 is not widely used, and the need to reclaim the value outweighs 1449 the cost of a hostile reclamation. In any case, IESG Approval is 1450 needed in this case. 1452 o It may be appropriate to write up the proposed action and solicit 1453 comments from relevant user communities. In some cases, it may be 1454 appropriate to write an RFC that goes through a formal IETF 1455 process (including IETF Last Call) as was done when DHCP reclaimed 1456 some of its "Private Use" options [RFC3942]. 1458 9.5. Contact Person vs Assignee or Owner 1460 Many registries include designation of a technical or administrative 1461 contact associated with each entry. Often, this is recorded as 1462 contact information for an individual. It is unclear, though, what 1463 role the individual has with respect to the registration: is this 1464 item registered on behalf of the individual, the company the 1465 individual worked for, or perhaps another organization the individual 1466 was acting for? 1468 This matters because some time later, when the individual has changed 1469 jobs or roles, and perhaps can no longer be contacted, someone might 1470 want to update the registration. IANA has no way to know what 1471 company, organization, or individual should be allowed to take the 1472 registration over. For registrations rooted in RFCs, the stream 1473 owner (such as the IESG or the IAB) can make an overriding decision. 1474 But in other cases, there is no recourse. 1476 Registries can include, in addition to a "Contact" field, an 1477 "Assignee" or "Owner" field that can be used to address this 1478 situation, giving IANA clear guidance as to the actual owner of the 1479 registration. This is strongly advised especially for registries 1480 that do not require RFCs to manage their information (registries with 1481 policies such as First Come First Served Section 4.4, Expert Review 1482 Section 4.5, and Specification Required Section 4.6). Alternatively, 1483 organizations can put an organizational role into the "Contact" field 1484 in order to make their ownership clear. 1486 9.6. Closing or Obsoleting a Registry 1488 Sometimes there is a request to "close" a registry to further 1489 registrations. When a registry is closed, no further registrations 1490 will be accepted. The information in the registry will still be 1491 valid and registrations already in the registry can still be updated. 1493 A closed registry can also be marked as "obsolete", as an indication 1494 that the information in the registry is no longer in current use. 1496 Specific entries in a registry can be marked as "obsolete" (no longer 1497 in use) or "deprecated" (use is not recommended). 1499 Such changes to registries and registered values are subject to 1500 normal change controls (see Section 2.3). Any closure, obsolescence, 1501 or deprecation serves to annotate the registry involved; the 1502 information in the registry remains there for informational and 1503 historic purposes. 1505 10. Appeals 1507 Appeals of protocol parameter registration decisions can be made 1508 using the normal IETF appeals process as described in [RFC2026], 1509 Section 6.5. That is, an initial appeal should be directed to the 1510 IESG, followed (if necessary) by an appeal to the IAB. 1512 11. Mailing Lists 1514 All IETF mailing lists associated with evaluating or discussing 1515 assignment requests as described in this document are subject to 1516 whatever rules of conduct and methods of list management are 1517 currently defined by Best Current Practices or by IESG decision. 1519 12. Security Considerations 1521 Information that creates or updates a registration needs to be 1522 authenticated and authorized. IANA updates registries according to 1523 instructions in published RFCs and from the IESG. It also may accept 1524 clarifications from document authors, relevant working group chairs, 1525 Designated Experts, and mail list participants, too. 1527 Information concerning possible security vulnerabilities of a 1528 protocol may change over time. Likewise, security vulnerabilities 1529 related to how an assigned number is used may change as well. As new 1530 vulnerabilities are discovered, information about such 1531 vulnerabilities may need to be attached to existing registrations, so 1532 that users are not misled as to the true security issues surrounding 1533 the use of a registered number. 1535 Security needs to be considered as part of the selection of a 1536 registration policy. For some protocols, registration of certain 1537 parameters will have security implications, and registration policies 1538 for the relevant registries must ensure that requests get appropriate 1539 review with those security implications in mind. 1541 An analysis of security issues is generally required for all 1542 protocols that make use of parameters (data types, operation codes, 1543 keywords, etc.) used in IETF protocols or registered by IANA. Such 1544 security considerations are usually included in the protocol document 1545 [RFC3552]. It is the responsibility of the IANA considerations 1546 associated with a particular registry to specify whether value- 1547 specific security considerations must be provided when assigning new 1548 values, and the process for reviewing such claims. 1550 13. IANA Considerations 1552 In accordance with Section 9.1: 1554 This document has no IANA actions. 1556 14. Changes Relative to Earlier Editions of BCP 26 1557 14.1. 2014: Changes in This Document Relative to RFC 5226 1559 Significant additions: 1561 o Removed RFC 2119 key words, boilerplate, and reference, preferring 1562 plain English -- this is not a protocol specification. 1564 o Added Section 1.1, Keep IANA Considerations for IANA 1566 o Added Section 1.2, For More Information 1568 o Added Section 2.1, Hierarchical Registry Structure 1570 o Added best practice for selecting an appropriate policy into 1571 Section 4. 1573 o Added Section 4.12, Using Multiple Policies in Combination. 1575 o Added Section 2.3, Specifying Change Control for a Registry 1577 o Added Section 3.4, Early Allocations 1579 o Moved well-known policies into a separate section for each, 1580 subsections of Section 4. 1582 o Added Section 5.4, Expert Reviews and the Document Lifecycle 1584 o Added Section 7, Documentation References in IANA Registries 1586 o Added Section 8, What to Do in "bis" Documents 1588 o Added Section 9.5, Contact Person vs Assignee or Owner 1590 o Added Section 9.6, Closing or Obsoleting a Registry 1592 Clarifications and such: 1594 o Some reorganization -- moved text around for clarity and easier 1595 reading. 1597 o Made clarifications about identification of IANA registries and 1598 use of URLs for them. 1600 o Clarified the distinction between "Unassigned" and "Reserved". 1602 o Made some clarifications in "Expert Review" about instructions to 1603 the designated expert. 1605 o Made some clarifications in "Specification Required" about how to 1606 declare this policy. 1608 o Assorted minor clarifications and editorial changes throughout. 1610 14.2. 2008: Changes in RFC 5226 Relative to RFC 2434 1612 Changes include: 1614 o Major reordering of text to expand descriptions and to better 1615 group topics such as "updating registries" vs. "creating new 1616 registries", in order to make it easier for authors to find the 1617 text most applicable to their needs. 1619 o Numerous editorial changes to improve readability. 1621 o Changed the term "IETF Consensus" to "IETF Review" and added more 1622 clarifications. History has shown that people see the words "IETF 1623 Consensus" (without consulting the actual definition) and are 1624 quick to make incorrect assumptions about what the term means in 1625 the context of IANA Considerations. 1627 o Added "RFC Required" to list of defined policies. 1629 o Much more explicit directions and examples of "what to put in 1630 RFCs". 1632 o "Specification Required" now implies use of a Designated Expert to 1633 evaluate specs for sufficient clarity. 1635 o Significantly changed the wording in the Designated Experts 1636 section. Main purpose is to make clear that Expert Reviewers are 1637 accountable to the community, and to provide some guidance for 1638 review criteria in the default case. 1640 o Changed wording to remove any special appeals path. The normal 1641 RFC 2026 appeals path is used. 1643 o Added a section about reclaiming unused values. 1645 o Added a section on after-the-fact registrations. 1647 o Added a section indicating that mailing lists used to evaluate 1648 possible assignments (such as by a Designated Expert) are subject 1649 to normal IETF rules. 1651 15. Acknowledgments 1653 15.1. Acknowledgments for This Document (2014) 1655 Thomas Narten and Harald Tveit Alvestrand edited the two earlier 1656 editions of this document (RFCs 2434 and 5226), and Thomas continues 1657 his role in this third edition. Much of the text from RFC 5226 1658 remains in this edition. 1660 Thank you to Amanda Baber and Pearl Liang for their multiple reviews 1661 and suggestions for making this document as thorough as possible. 1663 This document has benefited from thorough review and comments by Tony 1664 Hansen, John Klensin, and Mark Nottingham. 1666 Special thanks to Mark Nottingham for reorganizing some of the text 1667 for better organization and readability, and to Tony Hansen for 1668 acting as document shepherd. 1670 15.2. Acknowledgments from the second edition (2008) 1672 The original acknowledgments section in RFC 5226 was: 1674 This document has benefited from specific feedback from Jari Arkko, 1675 Marcelo Bagnulo Braun, Brian Carpenter, Michelle Cotton, Spencer 1676 Dawkins, Barbara Denny, Miguel Garcia, Paul Hoffman, Russ Housley, 1677 John Klensin, Allison Mankin, Blake Ramsdell, Mark Townsley, Magnus 1678 Westerlund, and Bert Wijnen. 1680 15.3. Acknowledgments from the first edition (1998) 1682 The original acknowledgments section in RFC 2434 was: 1684 Jon Postel and Joyce Reynolds provided a detailed explanation on what 1685 IANA needs in order to manage assignments efficiently, and patiently 1686 provided comments on multiple versions of this document. Brian 1687 Carpenter provided helpful comments on earlier versions of the 1688 document. One paragraph in the Security Considerations section was 1689 borrowed from [RFC4288]. 1691 16. References 1693 16.1. Normative References 1695 [RFC2026] Bradner, S., "The Internet Standards Process -- Revision 1696 3", BCP 9, RFC 2026, October 1996. 1698 16.2. Informative References 1700 [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, September 1701 1981. 1703 [RFC1591] Postel, J., "Domain Name System Structure and Delegation", 1704 RFC 1591, DOI 10.17487/RFC1591, March 1994, . 1707 [RFC2860] Carpenter, B., Baker, F. and M. Roberts, "Memorandum of 1708 Understanding Concerning the Technical Work of the 1709 Internet Assigned Numbers Authority", RFC 2860, June 2000. 1711 [RFC2939] Droms, R., "Procedures and IANA Guidelines for Definition 1712 of New DHCP Options and Message Types", BCP 43, RFC 2939, 1713 September 2000. 1715 [RFC3228] Fenner, B., "IANA Considerations for IPv4 Internet Group 1716 Management Protocol (IGMP)", BCP 57, RFC 3228, February 1717 2002. 1719 [RFC3406] Daigle, L., van Gulik, D., Iannella, R. and P. Faltstrom, 1720 "Uniform Resource Names (URN) Namespace Definition 1721 Mechanisms", BCP 66, RFC 3406, DOI 10.17487/RFC3406, 1722 October 2002, . 1724 [RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC 1725 Text on Security Considerations", BCP 72, RFC 3552, July 1726 2003. 1728 [RFC3575] Aboba, B., "IANA Considerations for RADIUS (Remote 1729 Authentication Dial In User Service)", RFC 3575, July 1730 2003. 1732 [RFC3692] Narten, T., "Assigning Experimental and Testing Numbers 1733 Considered Useful", BCP 82, RFC 3692, January 2004. 1735 [RFC3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J. and H. 1736 Levkowetz, "Extensible Authentication Protocol (EAP)", RFC 1737 3748, June 2004. 1739 [RFC3942] Volz, B., "Reclassifying Dynamic Host Configuration 1740 Protocol version 4 (DHCPv4) Options", RFC 3942, November 1741 2004. 1743 [RFC3968] Camarillo, G., "The Internet Assigned Number Authority 1744 (IANA) Header Field Parameter Registry for the Session 1745 Initiation Protocol (SIP)", BCP 98, RFC 3968, December 1746 2004. 1748 [RFC4005] Calhoun, P., Zorn, G., Spence, D. and D. Mitton, "Diameter 1749 Network Access Server Application", RFC 4005, August 2005. 1751 [RFC4025] Richardson, M., "A Method for Storing IPsec Keying 1752 Material in DNS", RFC 4025, March 2005. 1754 [RFC4044] McCloghrie, K., "Fibre Channel Management MIB", RFC 4044, 1755 May 2005. 1757 [RFC4124] Le Faucheur, F., "Protocol Extensions for Support of 1758 Diffserv-aware MPLS Traffic Engineering", RFC 4124, June 1759 2005. 1761 [RFC4169] Torvinen, V., Arkko, J. and M. Naslund, "Hypertext 1762 Transfer Protocol (HTTP) Digest Authentication Using 1763 Authentication and Key Agreement (AKA) Version-2", RFC 1764 4169, November 2005. 1766 [RFC4271] Rekhter, Y., Li, T. and S. Hares, "A Border Gateway 1767 Protocol 4 (BGP-4)", RFC 4271, January 2006. 1769 [RFC4283] Patel, A., Leung, K., Khalil, M., Akhtar, H. and K. 1770 Chowdhury, "Mobile Node Identifier Option for Mobile IPv6 1771 (MIPv6)", RFC 4283, November 2005. 1773 [RFC4288] Freed, N. and J. Klensin, "Media Type Specifications and 1774 Registration Procedures", BCP 13, RFC 4288, December 2005. 1776 [RFC4340] Kohler, E., Handley, M. and S. Floyd, "Datagram Congestion 1777 Control Protocol (DCCP)", RFC 4340, March 2006. 1779 [RFC4395] Hansen, T., Hardie, T. and L. Masinter, "Guidelines and 1780 Registration Procedures for New URI Schemes", BCP 35, RFC 1781 4395, February 2006. 1783 [RFC4422] Melnikov, A. and K. Zeilenga, "Simple Authentication and 1784 Security Layer (SASL)", RFC 4422, June 2006. 1786 [RFC4446] Martini, L., "IANA Allocations for Pseudowire Edge to Edge 1787 Emulation (PWE3)", BCP 116, RFC 4446, April 2006. 1789 [RFC4520] Zeilenga, K., "Internet Assigned Numbers Authority (IANA) 1790 Considerations for the Lightweight Directory Access 1791 Protocol (LDAP)", BCP 64, RFC 4520, June 2006. 1793 [RFC4589] Schulzrinne, H. and H. Tschofenig, "Location Types 1794 Registry", RFC 4589, July 2006. 1796 [RFC4727] Fenner, B., "Experimental Values In IPv4, IPv6, ICMPv4, 1797 ICMPv6, UDP, and TCP Headers", RFC 4727, November 2006. 1799 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security 1800 (TLS) Protocol Version 1.2", RFC 5246, August 2008. 1802 [RFC5378] Bradner, S. and J. Contreras, "Rights Contributors Provide 1803 to the IETF Trust", BCP 78, RFC 5378, November 2008. 1805 [RFC5742] Alvestrand, H. and R. Housley, "IESG Procedures for 1806 Handling of Independent and IRTF Stream Submissions", BCP 1807 92, RFC 5742, December 2009. 1809 [RFC5771] Cotton, M., Vegoda, L. and D. Meyer, "IANA Guidelines for 1810 IPv4 Multicast Address Assignments", BCP 51, RFC 5771, 1811 March 2010. 1813 [RFC5795] Sandlund, K., Pelletier, G. and L-E. Jonsson, "The RObust 1814 Header Compression (ROHC) Framework", RFC 5795, March 1815 2010. 1817 [RFC6195] Eastlake, D., "Domain Name System (DNS) IANA 1818 Considerations", BCP 42, RFC 6195, March 2011. 1820 [RFC6275] Perkins, C., Johnson, D. and J. Arkko, "Mobility Support 1821 in IPv6", RFC 6275, July 2011. 1823 [RFC6709] Carpenter, B., Aboba, B. and S. Cheshire, "Design 1824 Considerations for Protocol Extensions", RFC 6709, 1825 September 2012. 1827 [RFC7120] Cotton, M., "Early IANA Allocation of Standards Track Code 1828 Points", BCP 100, RFC 7120, January 2014. 1830 [RFC7564] Saint-Andre, P. and M. Blanchet, "PRECIS Framework: 1831 Preparation, Enforcement, and Comparison of 1832 Internationalized Strings in Application Protocols", RFC 1833 7564, DOI 10.17487/RFC7564, May 2015, . 1836 [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A. and 1837 S. Ray, "North-Bound Distribution of Link-State and 1838 Traffic Engineering (TE) Information Using BGP", RFC 7752, 1839 DOI 10.17487/RFC7752, March 2016, . 1842 Authors' Addresses 1844 Michelle Cotton 1845 Internet Corporation for Assigned Names and Numbers 1846 12025 Waterfront Drive, Suite 300 1847 Los Angeles, CA 90094-2536 1848 US 1850 Phone: +1 310 823 9358 1851 Email: michelle.cotton@icann.org 1852 URI: https://www.icann.org/ 1854 Barry Leiba 1855 Huawei Technologies 1857 Phone: +1 646 827 0648 1858 Email: barryleiba@computer.org 1859 URI: http://internetmessagingtechnology.org/ 1861 Thomas Narten 1862 IBM Corporation 1863 3039 Cornwallis Ave., PO Box 12195 - BRQA/502 1864 Research Triangle Park, NC 27709-2195 1865 US 1867 Phone: +1 919 254 7798 1868 Email: narten@us.ibm.com