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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: August 10, 2017 IBM Corporation 8 February 08, 2017 10 Guidelines for Writing an IANA Considerations Section in RFCs 11 draft-leiba-cotton-iana-5226bis-20 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, guidance is needed 23 for 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 provided guidance for the IANA Considerations is clear and 28 addresses the various issues that are likely in the operation of a 29 registry. 31 This is the third edition of this document; it obsoletes RFC 5226. 33 Status of this Memo 35 This Internet-Draft is submitted in full conformance with the 36 provisions of BCP 78 and BCP 79. 38 Internet-Drafts are working documents of the Internet Engineering 39 Task Force (IETF). Note that other groups may also distribute 40 working documents as Internet-Drafts. The list of current Internet- 41 Drafts is at http://datatracker.ietf.org/drafts/current/. 43 Internet-Drafts are draft documents valid for a maximum of six months 44 and may be updated, replaced, or obsoleted by other documents at any 45 time. It is inappropriate to use Internet-Drafts as reference 46 material or to cite them other than as "work in progress." 48 This Internet-Draft will expire on August 10, 2017. 50 Copyright Notice 52 Copyright (c) 2017 IETF Trust and the persons identified as the 53 document authors. All rights reserved. 55 This document is subject to BCP 78 and the IETF Trust's Legal 56 Provisions Relating to IETF Documents (http://trustee.ietf.org/ 57 license-info) in effect on the date of publication of this document. 58 Please review these documents carefully, as they describe your rights 59 and restrictions with respect to this document. Code Components 60 extracted from this document must include Simplified BSD License text 61 as described in Section 4.e of the Trust Legal Provisions and are 62 provided without warranty as described in the Simplified BSD License. 64 Table of Contents 66 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 67 1.1. Keep IANA Considerations for IANA . . . . . . . . . . . . 3 68 1.2. For Updated Information . . . . . . . . . . . . . . . . . 4 69 1.3. A Quick Checklist Up Front . . . . . . . . . . . . . . . . 4 70 2. Creating and Revising Registries . . . . . . . . . . . . . . . 6 71 2.1. Organization of Registries . . . . . . . . . . . . . . . . 6 72 2.2. Documentation Requirements for Registries . . . . . . . . 7 73 2.3. Specifying Change Control for a Registry . . . . . . . . . 9 74 2.4. Revising Existing Registries . . . . . . . . . . . . . . . 10 75 3. Registering New Values in an Existing Registry . . . . . . . . 10 76 3.1. Documentation Requirements for Registrations . . . . . . . 10 77 3.2. Updating Existing Registrations . . . . . . . . . . . . . 12 78 3.3. Overriding Registration Procedures . . . . . . . . . . . . 13 79 3.4. Early Allocations . . . . . . . . . . . . . . . . . . . . 13 80 4. Choosing a Registration Policy, and Well-Known Policies . . . 14 81 4.1. Private Use . . . . . . . . . . . . . . . . . . . . . . . 16 82 4.2. Experimental Use . . . . . . . . . . . . . . . . . . . . . 16 83 4.3. Hierarchical Allocation . . . . . . . . . . . . . . . . . 17 84 4.4. First Come First Served . . . . . . . . . . . . . . . . . 17 85 4.5. Expert Review . . . . . . . . . . . . . . . . . . . . . . 18 86 4.6. Specification Required . . . . . . . . . . . . . . . . . . 19 87 4.7. RFC Required . . . . . . . . . . . . . . . . . . . . . . . 20 88 4.8. IETF Review . . . . . . . . . . . . . . . . . . . . . . . 21 89 4.9. Standards Action . . . . . . . . . . . . . . . . . . . . . 21 90 4.10. IESG Approval . . . . . . . . . . . . . . . . . . . . . . 21 91 4.11. Using the Well-Known Registration Policies . . . . . . . . 22 92 4.12. Using Multiple Policies in Combination . . . . . . . . . . 23 93 5. Designated Experts . . . . . . . . . . . . . . . . . . . . . . 24 94 5.1. The Motivation for Designated Experts . . . . . . . . . . 24 95 5.2. The Role of the Designated Expert . . . . . . . . . . . . 25 96 5.2.1. Managing Designated Experts in the IETF . . . . . . . 26 97 5.3. Designated Expert Reviews . . . . . . . . . . . . . . . . 26 98 5.4. Expert Reviews and the Document Lifecycle . . . . . . . . 28 99 6. Well-Known Registration Status Terminology . . . . . . . . . . 28 100 7. Documentation References in IANA Registries . . . . . . . . . 29 101 8. What to Do in "bis" Documents . . . . . . . . . . . . . . . . 30 102 9. Miscellaneous Issues . . . . . . . . . . . . . . . . . . . . . 31 103 9.1. When There Are No IANA Actions . . . . . . . . . . . . . . 31 104 9.2. Namespaces Lacking Documented Guidance . . . . . . . . . . 31 105 9.3. After-the-Fact Registrations . . . . . . . . . . . . . . . 31 106 9.4. Reclaiming Assigned Values . . . . . . . . . . . . . . . . 32 107 9.5. Contact Person vs Assignee or Owner . . . . . . . . . . . 33 108 9.6. Closing or Obsoleting a Registry/Registrations . . . . . . 33 109 10. Appeals . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 110 11. Mailing Lists . . . . . . . . . . . . . . . . . . . . . . . . 34 111 12. Security Considerations . . . . . . . . . . . . . . . . . . . 34 112 13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 34 113 14. Changes Relative to Earlier Editions of BCP 26 . . . . . . . . 35 114 14.1. 2016: Changes in This Document Relative to RFC 5226 . . . 35 115 14.2. 2008: Changes in RFC 5226 Relative to RFC 2434 . . . . . 36 116 15. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 36 117 15.1. Acknowledgments for This Document (2016) . . . . . . . . 36 118 15.2. Acknowledgments from the second edition (2008) . . . . . 37 119 15.3. Acknowledgments from the first edition (1998) . . . . . . 37 120 16. References . . . . . . . . . . . . . . . . . . . . . . . . . . 37 121 16.1. Normative References . . . . . . . . . . . . . . . . . . 37 122 16.2. Informative References . . . . . . . . . . . . . . . . . 37 123 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 40 125 1. Introduction 127 Many protocols make use of points of extensibility that use constants 128 to identify various protocol parameters. To ensure that the values 129 used in these fields do not have conflicting uses, and to promote 130 interoperability, their allocation is often coordinated by a central 131 record keeper. 133 The IETF selects an IANA Functions Operator (IFO) for protocol 134 parameters defined by the IETF. In the contract between the IETF and 135 the current IFO (ICANN), that entity is referred to as the IANA 136 PROTOCOL PARAMETER SERVICES Operator, or IPPSO. For consistency with 137 past practice, the IFO or IPPSO is referred to in this document as 138 "IANA" [RFC2860]. 140 The Protocol field in the IP header [RFC0791] and MIME media types 141 [RFC6838] are two examples of such coordinations. 143 In this document, we call the range of possible values for such a 144 field a "namespace". The binding or association of a specific value 145 with a particular purpose within a namespace is called an assignment 146 (or, variously: an assigned number, assigned value, code point, 147 protocol constant, or protocol parameter). The act of assignment is 148 called a registration, and it takes place in the context of a 149 registry. The terms "assignment" and "registration" are used 150 interchangably throughout this document. 152 To make assignments in a given namespace prudently, guidance is 153 needed for describing the conditions under which new values should be 154 assigned, as well as when and how modifications to existing values 155 can be made. This document defines a framework for the documentation 156 of these guidelines by specification authors, in order to assure that 157 the guidance for the IANA Considerations is clear and addresses the 158 various issues that are likely in the operation of a registry. 160 Typically, this information is recorded in a dedicated section of the 161 specification with the title "IANA Considerations". 163 1.1. Keep IANA Considerations for IANA 164 The purpose of having a dedicated IANA Considerations section is to 165 provide a single place to collect clear and concise information and 166 instructions for IANA. Technical documentation should reside in 167 other parts of the document, and should be included by reference 168 only. Using the IANA Considerations section as primary technical 169 documentation both hides it from the target audience of the document 170 and interferes with IANA's review of the actions they need to take. 172 An ideal IANA Considerations section clearly enumerates and specifies 173 each requested IANA action; includes all information IANA needs, such 174 as the full names of all applicable registries; and includes clear 175 references to elsewhere in the document for other information. 177 The IANA actions are normally phrased as requests for IANA (such as, 178 "IANA is asked to assign the value TBD1 from the Frobozz 179 Registry..."); the RFC Editor will change those sentences to reflect 180 the actions taken ("IANA has assigned the value 83 from the Frobozz 181 Registry..."). 183 1.2. For Updated Information 185 IANA maintains a web page that includes additional clarification 186 information, beyond what is provided here, such as minor updates and 187 summary guidance. Document authors should check that page. Any 188 significant updates to the best current practice will have to feed 189 into updates to BCP 26 (this document), which is definitive. 191 . 193 [[(RFC Editor: Please remove this paragraph.) The initial version of 194 this should contain the bits that are salient to most document 195 authors -- perhaps a table of required elements to create a new 196 registry or update one, a bit about sub-registries, and the listing 197 of well-known registration policies. IANA has text for this, but 198 they need to work on their process to put the page up (transition 199 issues). ]] 201 1.3. A Quick Checklist Up Front 203 It's useful to be familiar with this document as a whole. But when 204 you return for quick reference, here are checklists for the most 205 common things you'll need to do, and references to help with the less 206 common ones. 208 In general... 210 1. Put all the information that IANA will need to know into the 211 "IANA Considerations" section of your document (see Section 1.1). 213 2. Try to keep that section only for information to IANA and to 214 designated expert reviewers, and put significant technical 215 information in the appropriate technical sections of the document 216 (see Section 1.1). 218 3. Note that the IESG has the authority to resolve issues with IANA 219 registrations, and if you have any questions or problems you 220 should consult your document shepherd and/or working group chair, 221 who may ultimately involve an Area Director (see Section 3.3). 223 If you are creating a new registry... 225 1. Give the registry a descriptive name, and provide a brief 226 description of its use (see Section 2.2). 228 2. Identify any registry grouping that it should be part of (see 229 Section 2.1). 231 3. Clearly specify what information is required in order to register 232 new items (see Section 2.2). Be sure to specify data types, 233 lengths, and valid ranges for fields. 235 4. Specify the initial set of items for the registry, if applicable 236 (see Section 2.2). 238 5. Make sure it's clear to IANA what the change control policy is 239 for the registry, in case changes to the format or policies need 240 to be made later (see Section 2.3 and Section 9.5). 242 6. Select a registration policy -- or a set of policies -- to use 243 for future registrations (see Section 4, and especially note 244 Section 4.11 and Section 4.12). 246 7. If you're using a policy that requires a Designated Expert 247 (Expert Review or Specification Required), understand Section 5 248 Section 5, and provide review guidance to the Designated Expert 249 (see Section 5.3). 251 8. If any items or ranges in your registry need to be reserved for 252 special use or are otherwise unavailable for assignment, see 253 Section 6. 255 If you are registering into an existing registry... 257 1. Clearly identify the registry by its exact name, and optionally 258 by its URL (see Section 3.1). 260 2. If the registry has multiple ranges from which assignments can be 261 made, make it clear which range is requested (see Section 3.1). 263 3. Avoid using specific values for numeric or bit assignments, and 264 let IANA pick a suitable value at registration time (see Section 265 3.1). This will avoid registration conflicts among multiple 266 documents. 268 4. For "reference" fields, use the document that provides the best, 269 most current documentation for the item being registered, and 270 include section numbers to make it easier for readers to locate 271 the relevant documentation (see Section 3.1 and Section 7). 273 5. Look up (in the registry's reference document) what information 274 is required for the registry and accurately provide all the 275 necessary information (see Section 3.1). 277 6. Look up (in the registry's reference document) any special rules 278 or processes there may be for the registry, such as posting to a 279 particular mailing list for comment, and be sure to follow the 280 process (see Section 3.1). 282 7. If the registration policy for the registry does not already 283 dictate the change control policy, make sure it's clear to IANA 284 what the change control policy is for the item, in case changes 285 to the registration need to be made later (see Section 9.5). 287 If you're writing a "bis" document or otherwise making older 288 documents obsolete, see Section 8. 290 If you need to make an early registration, such as for supporting 291 test implementations during document development, rather than waiting 292 for your document to be finished and approved, see [RFC7120]. 294 If you need to change the format/contents or policies for an existing 295 registry, see Section 2.4. 297 If you need to update an existing registration, see Section 3.2. 299 If you need to close down a registry because it is no longer needed, 300 see Section 9.6. 302 2. Creating and Revising Registries 304 Defining a registry involves describing the namespaces to be created, 305 listing an initial set of assignments (if applicable), and 306 documenting guidelines on how future assignments are to be made. 308 When defining a registry, consider structuring the namespace in such 309 a way that only top-level assignments need to be made with central 310 coordination, and those assignments can delegate lower-level 311 assignments so coordination for them can be distributed. This 312 lessens the burden on IANA for dealing with assignments, and is 313 particularly useful in situations where distributed coordinators have 314 better knowledge of their portion of the namespace and are better 315 suited to handling those assignments. 317 2.1. Organization of Registries 319 All registries are anchored from the IANA "Protocol Registries" page: 321 . 323 That page lists registries in protocol category groups, placing 324 related registries together and making it easier for users of the 325 registries to find the necessary information. Clicking on the title 326 of one of the registries on the IANA Protocol Registries page will 327 take the reader to the details page for that registry. 329 Unfortunately, we have been inconsistent in how we refer to these 330 entities. The group names, as they are referred to here, have been 331 variously called "protocol category groups", "groups", "top-level 332 registries", or just "registries". The registries under them have 333 been called "registries" or "sub-registries". 335 Regardless of the terminology used, document authors should pay 336 attention to the registry groupings, should request that related 337 registries be grouped together to make related registries easier to 338 find, and, when creating a new registry, should check whether that 339 registry might best be included in an existing group. That grouping 340 information should be clearly communicated to IANA in the registry 341 creation request. 343 2.2. Documentation Requirements for Registries 345 Documents that create a new namespace (or modify the definition of an 346 existing space) and that expect IANA to play a role in maintaining 347 that space (serving as a repository for registered values) must 348 provide clear instructions on details of the namespace, either in the 349 IANA Considerations section, or referenced from it. 351 In particular, such instructions must include: 353 The name of the registry 355 This name will appear on the IANA web page and will be referred to 356 in future documents that need to allocate a value from the new 357 space. The full name (and abbreviation, if appropriate) should be 358 provided. It is highly desirable that the chosen name not be 359 easily confused with the name of another registry. 361 When creating a registry, the group that it is a part of must be 362 identified using its full name, exactly as it appears in the 363 Protocol Registries list. 365 Providing a URL to precisely identify the registry helps IANA 366 understand the request. Such URLs can be removed from the RFC 367 prior to final publication, or left in the document for reference. 368 If you include iana.org URLs, IANA will provide corrections, if 369 necessary, during their review. 371 Required information for registrations 372 This tells registrants what information they have to include in 373 their registration requests. Some registries require only the 374 requested value and a reference to a document where use of the 375 value is defined. Other registries require a more detailed 376 registration template that describes relevant security 377 considerations, internationalization considerations, and other 378 such information. 380 Applicable registration policy 382 The policy that will apply to all future requests for 383 registration. See Section 4. 385 Size, format and syntax of registry entries 387 What fields to record in the registry, any technical requirements 388 on registry entries (valid ranges for integers, length limitations 389 on strings, and such), and the exact format in which registry 390 values should be displayed. For numeric assignments, one should 391 specify whether values are to be recorded in decimal, in 392 hexadecimal, or in some other format. 394 Strings are expected to be ASCII, and it should be clearly 395 specified whether case matters, and whether, for example, strings 396 should be shown in the registry in upper case or lower case. 398 Strings that represent protocol parameters will rarely, if ever, 399 need to contain non-ASCII characters. If non-ASCII characters are 400 really necessary, instructions should make it very clear that they 401 are allowed and that the non-ASCII characters should be 402 represented as Unicode characters using the "(U+XXXX)" convention. 403 Anyone creating such a registry should think carefully about this 404 and consider internationalization advice such as that in [RFC7564] 405 Section 10. 407 Initial assignments and reservations 409 Any initial assignments or registrations to be included. In 410 addition, any ranges that are to be reserved for "Private Use", 411 "Reserved", "Unassigned", etc. (see Section 6) should be 412 indicated. 414 For example, a document might specify a new registry by including: 416 --------------------------------------------------------------- 418 X. IANA Considerations 420 This document defines a new DHCP option, entitled "FooBar" (see 421 Section y), assigned a value of TBD1 from the DHCP Option space 422 423 [RFC2132] [RFC2939]: 424 Data 425 Tag Name Length Meaning 426 ---- ---- ------ ------- 427 TBD1 FooBar N FooBar server 429 The FooBar option also defines an 8-bit FooType field, for which 430 IANA is to create and maintain a new registry entitled 431 "FooType values" used by the FooBar option. Initial values for the 432 DHCP FooBar FooType registry are given below; future assignments 433 are to be made through Expert Review [BCP26]. 434 Assignments consist of a DHCP FooBar FooType name and its 435 associated value. 437 Value DHCP FooBar FooType Name Definition 438 ---- ------------------------ ---------- 439 0 Reserved 440 1 Frobnitz RFCXXXX, Section y.1 441 2 NitzFrob RFCXXXX, Section y.2 442 3-254 Unassigned 443 255 Reserved 444 --------------------------------------------------------------- 446 For examples of documents that establish registries, consult 447 [RFC3575], [RFC3968], and [RFC4520]. 449 Any time IANA includes names and contact information in the public 450 registry, some individuals might prefer that their contact 451 information not be made public. In such cases, arrangements can be 452 made with IANA to keep the contact information private. 454 2.3. Specifying Change Control for a Registry 456 Registry definitions and registrations within registries often need 457 to be changed after they are created. The process of making such 458 changes is complicated when it is unclear who is authorized to make 459 the changes. For registries created by RFCs in the IETF stream, 460 change control for the registry lies by default with the IETF, via 461 the IESG. The same is true for value registrations made in IETF- 462 stream RFCs. 464 Because registries can be created and registrations can be made 465 outside the IETF stream, it can sometimes be desirable to have change 466 control outside the IETF and IESG, and clear specification of change 467 control policies is always helpful. 469 It is advised, therefore, that all registries that are created 470 clearly specify a change control policy and a change controller. It 471 is also advised that registries that allow registrations from outside 472 the IETF stream include, for each value, the designation of a change 473 controller for that value. If the definition or reference for a 474 registered value ever needs to change, or if a registered value needs 475 to be deprecated, it is critical that IANA know who is authorized to 476 make the change. Example: the Media Types registry [RFC6838] 477 includes a "Change Controller" in its registration template. See 478 also Section 9.5. 480 2.4. Revising Existing Registries 482 Updating the registration process or making changes to the format of 483 an already existing (previously created) registry (whether created 484 explicitly or implicitly) follows a process similar to that used when 485 creating a new registry. That is, a document is produced that makes 486 reference to the existing namespace and then provides detailed 487 guidance for handling assignments in the registry, or detailed 488 instructions about the changes required. 490 If a change requires a new column in the registry, the instructions 491 need to be clear about how to populate that column for the existing 492 entries. Other changes may require similar clarity. 494 Such documents are normally processed with the same document status 495 as the document that created the registry. Under some circumstances, 496 such as with a straightforward change that is clearly needed (such as 497 adding a "status" column), or when an earlier error needs to be 498 corrected, the IESG may approve an update to a registry without 499 requiring a new document. 501 Example documents that updated the guidelines for assignments in pre- 502 existing registries include: [RFC6195], [RFC3228], and [RFC3575]. 504 3. Registering New Values in an Existing Registry 506 3.1. Documentation Requirements for Registrations 508 Often, documents request an assignment in an existing registry (one 509 created by a previously published document). 511 Such documents should clearly identify the registry into which each 512 value is to be registered. Use the exact registry name as listed on 513 the IANA web page, and cite the RFC where the registry is defined. 514 When referring to an existing registry, providing a URL to precisely 515 identify the registry is helpful (see Section 2.2). 517 There is no need to mention what the assignment policy is when making 518 new assignments in existing registries, as that should be clear from 519 the references. However, if multiple assignment policies might 520 apply, as in registries with different ranges that have different 521 policies, it is important to make it clear which range is being 522 requested, so that IANA will know which policy applies and can assign 523 a value in the correct range. 525 Be sure to provide all the information required for a registration, 526 and follow any special processes that are set out for the registry. 527 Registries sometimes require the completion of a registration 528 template for registration, or ask registrants to post their request 529 to a particular mailing list for discussion prior to registration. 530 Look up the registry's reference document: the required information 531 and special processes should be documented there. 533 Normally, numeric values to be used are chosen by IANA when the 534 document is approved, and drafts should not specify final values. 535 Instead, placeholders such as "TBD1" and "TBD2" should be used 536 consistently throughout the document, giving each item to be 537 registered a different placeholder. The IANA Considerations should 538 ask the RFC Editor to replace the placeholder names with the IANA- 539 assigned values. When drafts need to specify numeric values for 540 testing or early implementations, they will either request early 541 allocation (see Section 3.4) or use values that have already been set 542 aside for testing or experimentation (if the registry in question 543 allows that without explicit assignment). It is important that 544 drafts not choose their own values, lest IANA assign one of those 545 values to another document in the meantime. A draft can request a 546 specific value in the IANA Considerations section, and IANA will 547 accommodate such requests when that's possible, but the proposed 548 number might have been assigned to some other use by the time the 549 draft is approved. 551 Normally, text-string values to be used are specified in the 552 document, as collisions are less likely with text strings. IANA will 553 consult with the authors if there is, in fact, a collision, and a 554 different value has to be used. When drafts need to specify string 555 values for testing or early implementations, they sometimes use the 556 expected final value. But it is often useful to use a draft value 557 instead, possibly including the draft version number. This allows 558 the early implementations to be distinguished from those implementing 559 the final version. A document that intends to use "foobar" in the 560 final version might use "foobar-testing-draft-05" for the -05 version 561 of the draft, for example. 563 For some registries, there is a long-standing policy prohibiting 564 assignment of names or codes on a vanity or organization-name basis. 565 For example, codes might always be assigned sequentially unless there 566 is a strong reason for making an exception. Nothing in this document 567 is intended to change those policies or prevent their future 568 application. 570 As an example, the following text could be used to request assignment 571 of a DHCPv6 option number: 573 IANA is asked to assign an option code value of TBD1 to the DNS 574 Recursive Name Server option and an option code value of TBD2 to 575 the Domain Search List option from the DHCP option code space 576 defined in Section 24.3 of RFC 3315. 578 The IANA Considerations section should summarize all of the IANA 579 actions, with pointers to the relevant sections elsewhere in the 580 document as appropriate. Including section numbers is especially 581 useful when the reference document is large; the section numbers will 582 make it easier for those searching the reference document to find the 583 relevant information. 585 When multiple values are requested, it is generally helpful to 586 include a summary table of the additions/changes. It is also helpful 587 for this table to be in the same format as it appears or will appear 588 on the IANA web site. For example: 590 Value Description Reference 591 -------- ------------------- --------- 592 TBD1 Foobar this RFC, Section 3.2 593 TBD2 Gumbo this RFC, Section 3.3 594 TBD3 Banana this RFC, Section 3.4 596 Note: In cases where authors feel that including the full table of 597 changes is too verbose or repetitive, authors should still include 598 the table in the draft, but may include a note asking that the table 599 be removed prior to publication of the final RFC. 601 3.2. Updating Existing Registrations 603 Even after a number has been assigned, some types of registrations 604 contain additional information that may need to be updated over time. 606 For example, MIME media types, character sets, and language tags 607 typically include more information than just the registered value 608 itself, and may need updates to items such as point-of-contact 609 information, security issues, pointers to updates, and literature 610 references. 612 In such cases, the document defining the namespace must clearly state 613 who is responsible for maintaining and updating a registration. 614 Depending on the registry, it may be appropriate to specify one or 615 more of: 617 o Letting registrants and/or nominated change controllers update 618 their own registrations, subject to the same constraints and 619 review as with new registrations. 621 o Allowing attachment of comments to the registration. This can be 622 useful in cases where others have significant objections to a 623 registration, but the author does not agree to change the 624 registration. 626 o Designating the IESG, a designated expert, or another entity as 627 having the right to change the registrant associated with a 628 registration and any requirements or conditions on doing so. This 629 is mainly to get around the problem when a registrant cannot be 630 reached in order to make necessary updates. 632 3.3. Overriding Registration Procedures 634 Experience has shown that the documented IANA considerations for 635 individual protocols do not always adequately cover the reality of 636 registry operation, or are not sufficiently clear. In addition, 637 documented IANA considerations are sometimes found to be too 638 stringent to allow even working group documents (for which there is 639 strong consensus) to perform a registration in advance of actual RFC 640 publication. 642 In order to allow assignments in such cases, the IESG is granted 643 authority to override registration procedures and approve assignments 644 on a case-by-case basis. 646 The intention here is not to overrule properly documented procedures, 647 or to obviate the need for protocols to properly document their IANA 648 considerations. Rather, it is to permit assignments in specific 649 cases where it is obvious that the assignment should just be made, 650 but updating the IANA process beforehand is too onerous. 652 When the IESG is required to take action as described above, it is a 653 strong indicator that the applicable registration procedures should 654 be updated, possibly in parallel with the work that instigated it. 656 IANA always has the discretion to ask the IESG for advice or 657 intervention when they feel it is needed, such as in cases where 658 policies or procedures are unclear to them, where they encounter 659 issues or questions they are unable to resolve, or where registration 660 requests or patterns of requests appear to be unusual or abusive. 662 3.4. Early Allocations 664 IANA normally takes its actions when a document is approved for 665 publication. There are times, though, when early allocation of a 666 value is important for the development of a technology: for example, 667 when early implementations are created while the document is still 668 under development. 670 IANA has a mechanism for handling such early allocations in some 671 cases. See [RFC7120] for details. It is usually not necessary to 672 explicitly mark a registry as allowing early allocation, because the 673 general rules will apply. 675 4. Choosing a Registration Policy, and Well-Known Policies 677 A registration policy is the policy that controls how new assignments 678 in a registry are accepted. There are several issues to consider 679 when defining the registration policy. 681 If the registry's namespace is limited, assignments will need to be 682 made carefully to prevent exhaustion. 684 Even when the space is essentially unlimited, it is still often 685 desirable to have at least a minimal review prior to assignment in 686 order to: 688 o prevent the hoarding of or unnecessary wasting of values. For 689 example, if the space consists of text strings, it may be 690 desirable to prevent entities from obtaining large sets of strings 691 that correspond to desirable names (existing company names, for 692 example). 694 o provide a sanity check that the request actually makes sense and 695 is necessary. Experience has shown that some level of minimal 696 review from a subject matter expert is useful to prevent 697 assignments in cases where the request is malformed or not 698 actually needed (for example, an existing assignment for an 699 essentially equivalent service already exists). 701 Perhaps most importantly, unreviewed extensions can impact 702 interoperability and security. See [RFC6709]. 704 When the namespace is essentially unlimited and there are no 705 potential interoperability or security issues, assigned numbers can 706 usually be given out to anyone without any subjective review. In 707 such cases, IANA can make assignments directly, provided that IANA is 708 given detailed instructions on what types of requests it should 709 grant, and it is able to do so without exercising subjective 710 judgement. 712 When this is not the case, some level of review is required. 713 However, it's important to balance adequate review and ease of 714 registration. In many cases, those making registrations will not be 715 IETF participants; requests often come from other standards 716 organizations, from organizations not directly involved in standards, 717 from ad-hoc community work (from an open-source project, for 718 example), and so on. Registration must not be unnecessarily 719 difficult, unnecessarily costly (in terms of time and other 720 resources), nor unnecessarily subject to denial. 722 While it is sometimes necessary to restrict what gets registered 723 (e.g., for limited resources such as bits in a byte, or for items for 724 which unsupported values can be damaging to protocol operation), in 725 many cases having what's in use represented in the registry is more 726 important. Overly strict review criteria and excessive cost (in time 727 and effort) discourage people from even attempting to make a 728 registration. If a registry fails to reflect the protocol elements 729 actually in use, it can adversely affect deployment of protocols on 730 the Internet, and the registry itself is devalued. 732 Therefore, it is important to think specifically about the 733 registration policy, and not just pick one arbitrarily nor copy text 734 from another document. Working groups and other document developers 735 should use care in selecting appropriate registration policies when 736 their documents create registries. They should select the least 737 strict policy that suits a registry's needs, and look for specific 738 justification for policies that require significant community 739 involvement (those stricter than Expert Review or Specification 740 Required, in terms of the well-known policies). The needs here will 741 vary from registry to registry, and, indeed, over time, and this BCP 742 will not be the last word on the subject. 744 The following policies are defined for common usage. These cover a 745 range of typical policies that have been used to describe the 746 procedures for assigning new values in a namespace. It is not 747 strictly required that documents use these terms; the actual 748 requirement is that the instructions to IANA be clear and 749 unambiguous. However, use of these terms is strongly recommended 750 because their meanings are widely understood. Newly minted policies, 751 including ones that combine the elements of procedures associated 752 with these terms in novel ways, may be used if none of these policies 753 are suitable; it will help the review process if an explanation is 754 included as to why that is the case. The terms are fully explained 755 in the following subsections. 757 1. Private Use 758 2. Experimental Use 759 3. Hierarchical Allocation 760 4. First Come First Served 761 5. Expert Review 762 6. Specification Required 763 7. RFC Required 764 8. IETF Review 765 9. Standards Action 766 10. IESG Approval 768 It should be noted that it often makes sense to partition a namespace 769 into multiple categories, with assignments within each category 770 handled differently. Many protocols now partition namespaces into 771 two or more parts, with one range reserved for Private or 772 Experimental Use while other ranges are reserved for globally unique 773 assignments assigned following some review process. Dividing a 774 namespace into ranges makes it possible to have different policies in 775 place for different ranges and different use cases. 777 Similarly, it will often be useful to specify multiple policies in 778 parallel, with each policy being used under different circumstances. 779 For more discussion of that topic, see Section 4.12. 781 Examples of RFCs that specify multiple policies in parallel: 783 LDAP [RFC4520] 784 TLS ClientCertificateType Identifiers [RFC5246] (as detailed in 785 the subsections below) 786 MPLS Pseudowire Types Registry [RFC4446] 788 4.1. Private Use 790 For private or local use only, with the type and purpose defined by 791 the local site. No attempt is made to prevent multiple sites from 792 using the same value in different (and incompatible) ways. IANA does 793 not record assignments from registries or ranges with this policy 794 (and therefore there is no need for IANA to review them) and 795 assignments are not generally useful for broad interoperability. It 796 is the responsibility of the sites making use of the Private Use 797 range to ensure that no conflicts occur (within the intended scope of 798 use). 800 Examples: 802 Site-specific options in DHCP [RFC2939] 803 Fibre Channel Port Type Registry [RFC4044] 804 TLS ClientCertificateType Identifiers 224-255 [RFC5246] 806 4.2. Experimental Use 808 Experimental Use is similar to Private Use, but with the purpose 809 being to facilitate experimentation. See [RFC3692] for details. 810 IANA does not record assignments from registries or ranges with this 811 policy (and therefore there is no need for IANA to review them) and 812 assignments are not generally useful for broad interoperability. 814 Unless the registry explicitly allows it, it is not appropriate for 815 documents to select explicit values from registries or ranges with 816 this policy. Specific experiments will select a value to use during 817 the experiment. 819 When code points are set aside for experimental use, it's important 820 to make clear any expected restrictions on experimental scope. For 821 example, say whether it's acceptable to run experiments using those 822 code points over the open Internet, or whether such experiments 823 should be confined to more closed environments. See [RFC6994] for an 824 example of such considerations. 826 Example: 828 Experimental Values in IPv4, IPv6, ICMPv4, ICMPv6, UDP, and TCP 829 Headers [RFC4727] 831 4.3. Hierarchical Allocation 833 With Hierarchical Allocation, delegated administrators are given 834 control over part of the namespace, and can assign values in that 835 part of the namespace. IANA makes allocations in the higher levels 836 of the namespace according to one of the other policies. 838 Examples: 840 - DNS names. IANA manages the top-level domains (TLDs), and, as 841 [RFC1591] says: 843 Under each TLD may be created a hierarchy of names. Generally, 844 under the generic TLDs the structure is very flat. That is, 845 many organizations are registered directly under the TLD, and 846 any further structure is up to the individual organizations. 848 - Object Identifiers, defined by ITU-T recommendation X.208. 849 According to , some registries 850 include 852 * IANA, which hands out OIDs the "Private Enterprises" branch, 853 * ANSI, which hands out OIDs under the "US Organizations" branch, 854 and 855 * BSI, which hands out OIDs under the "UK Organizations" branch. 857 - URN namespaces. IANA registers URN Namespace IDs (NIDs [RFC3406]), 858 and the organization registering an NID is responsible for 859 allocations of URNs within that namespace. 861 4.4. First Come First Served 862 For the First Come First Served policy, assignments are made to 863 anyone on a first come, first served basis. There is no substantive 864 review of the request, other than to ensure that it is well-formed 865 and doesn't duplicate an existing assignment. However, requests must 866 include a minimal amount of clerical information, such as a point of 867 contact (including an email address, and sometimes a postal address) 868 and a brief description of how the value will be used. Additional 869 information specific to the type of value requested may also need to 870 be provided, as defined by the namespace. For numbers, IANA 871 generally assigns the next in-sequence unallocated value, but other 872 values may be requested and assigned if an extenuating circumstance 873 exists. With names, specific text strings can usually be requested. 875 When creating a new registry with First Come First Served as the 876 registration policy, in addition to the contact person field or 877 reference, the registry should contain a field for change controller. 878 Having a change controller for each entry for these types of 879 registrations makes authorization of future modifications more clear. 880 See Section 2.3. 882 It is important that changes to the registration of a First Come 883 First Served code point retain compatibility with the current usage 884 of that code point, and so changes need to be made with care. The 885 change controller should not, in most cases, be requesting 886 incompatible changes nor repurposing a registered code point. See 887 also Section 9.4 and Section 9.5. 889 A working group or any other entity that is developing a protocol 890 based on a First Come First Served code point has to be extremely 891 careful that the protocol retains wire compatibility with current use 892 of the code point. Once that is no longer true, the new work needs 893 to change to a different code point (and register that use at the 894 appropriate time). 896 It is also important to understand that First Come First Served 897 really has no filtering. Essentially, any well formed request is 898 accepted. 900 Examples: 902 SASL mechanism names [RFC4422] 903 LDAP Protocol Mechanisms and LDAP Syntax [RFC4520] 905 4.5. Expert Review 907 For the Expert Review policy, review and approval by a designated 908 expert (see Section 5) is required. While this does not necessarily 909 require formal documentation, information needs to be provided with 910 the request for the designated expert to evaluate. The registry's 911 definition needs to make clear to registrants what information is 912 necessary. The actual process for requesting registrations is 913 administered by IANA (see Section 1.2 to find details). 915 (This policy was also called "Designated Expert" in earlier editions 916 of this document. The current term is "Expert Review".) 918 The required documentation and review criteria, giving clear guidance 919 to the designated expert, should be provided when defining the 920 registry. It is particularly important to lay out what should be 921 considered when performing an evaluation and reasons for rejecting a 922 request. It is also a good idea to include, when possible, a sense 923 of whether many registrations are expected over time, or if the 924 registry is expected to be updated infrequently or in exceptional 925 circumstances only. 927 Thorough understanding of Section 5 is important when deciding on an 928 Expert Review policy and designing the guidance to the designated 929 expert. 931 Good examples of guidance to designated experts: 933 Extensible Authentication Protocol (EAP) [RFC3748], Sections 6 and 934 7.2 935 North-Bound Distribution of Link-State and TE Information using 936 BGP [RFC7752], Section 5.1 938 When creating a new registry with Expert Review as the registration 939 policy, in addition to the contact person field or reference, the 940 registry should contain a field for change controller. Having a 941 change controller for each entry for these types of registrations 942 makes authorization of future modifications more clear. See Section 943 2.3 945 Examples: 947 EAP Method Types [RFC3748] 948 HTTP Digest AKA algorithm versions [RFC4169] 949 URI schemes [RFC4395] 950 GEOPRIV Location Types [RFC4589] 952 4.6. Specification Required 953 For the Specification Required policy, review and approval by a 954 designated expert (see Section 5) is required, and the values and 955 their meanings must be documented in a permanent and readily 956 available public specification, in sufficient detail so that 957 interoperability between independent implementations is possible. 958 This policy is the same as Expert Review, with the additional 959 requirement of a formal public specification. In addition to the 960 normal review of such a request, the designated expert will review 961 the public specification and evaluate whether it is sufficiently 962 stable and permanent, and sufficiently clear and technically sound to 963 allow interoperable implementations. 965 The intention behind "permanent and readily available" is that a 966 document can reasonably be expected to be findable and retrievable 967 long after IANA assignment of the requested value. Publication of an 968 RFC is an ideal means of achieving this requirement, but 969 Specification Required is intended to also cover the case of a 970 document published outside of the RFC path, including informal 971 documentation. 973 For RFC publication, formal review by the designated expert is still 974 requested, but the normal RFC review process is expected to provide 975 the necessary review for interoperability. The designated expert's 976 review is still important, but it's equally important to note that 977 when there is IETF consensus, the expert can sometimes be "in the 978 rough" (see also the last paragraph of Section 5.4). 980 As with Expert Review (Section 4.5), clear guidance to the designated 981 expert, should be provided when defining the registry, and thorough 982 understanding of Section 5 is important. 984 When specifying this policy, just use the term "Specification 985 Required". Some specifications have chosen to refer to it as "Expert 986 Review with Specification Required", and that only causes confusion. 988 Examples: 990 Diffserv-aware TE Bandwidth Constraints Model Identifiers 991 [RFC4124] 992 TLS ClientCertificateType Identifiers 64-223 [RFC5246] 993 ROHC Profile Identifiers [RFC5795] 995 4.7. RFC Required 997 With the RFC Required policy, the registration request, along with 998 associated documentation, must be published in an RFC. The RFC need 999 not be in the IETF stream, but may be in any RFC stream (currently an 1000 RFC may be in the IETF, IRTF, or IAB stream, or an RFC Editor 1001 Independent Submission [RFC5742]). 1003 Unless otherwise specified, any type of RFC is sufficient (currently 1004 Standards Track, BCP, Informational, Experimental, or Historic). 1006 Examples: 1008 DNSSEC DNS Security Algorithm Numbers [RFC6014] 1009 Media Control Channel Framework registries [RFC6230] 1010 DANE TLSA Certificate Usages [RFC6698] 1012 4.8. IETF Review 1014 (Formerly called "IETF Consensus" in the first edition of this 1015 document.) With the IETF Review policy, new values are assigned only 1016 through RFCs in the IETF Stream -- those that have been shepherded 1017 through the IESG as AD-Sponsored or IETF working group Documents 1018 [RFC2026] [RFC5378], have gone through IETF last call, and that the 1019 IESG has approved as having IETF consensus. 1021 The intent is that the document and proposed assignment will be 1022 reviewed by the IETF community (including appropriate IETF working 1023 groups, directorates, and other experts) and by the IESG, to ensure 1024 that the proposed assignment will not negatively affect 1025 interoperability or otherwise extend IETF protocols in an 1026 inappropriate or damaging manner. 1028 Unless otherwise specified, any type of RFC is sufficient (currently 1029 Standards Track, BCP, Informational, Experimental, or Historic). 1031 Examples: 1033 IPSECKEY Algorithm Types [RFC4025] 1034 Accounting-Auth-Method AVP values in DIAMETER [RFC4005] 1035 TLS Extension Types [RFC5246] 1037 4.9. Standards Action 1039 For the Standards Action policy, values are assigned only through 1040 Standards Track or Best Current Practice RFCs in the IETF Stream. 1042 Examples: 1044 BGP message types [RFC4271] 1045 Mobile Node Identifier option types [RFC4283] 1046 TLS ClientCertificateType Identifiers 0-63 [RFC5246] 1047 DCCP Packet Types [RFC4340] 1049 4.10. IESG Approval 1051 New assignments may be approved by the IESG. Although there is no 1052 requirement that the request be documented in an RFC, the IESG has 1053 discretion to request documents or other supporting materials on a 1054 case-by-case basis. 1056 IESG Approval is not intended to be used often or as a "common case"; 1057 indeed, it has seldom been used in practice. Rather, it is intended 1058 to be available in conjunction with other policies as a fall-back 1059 mechanism in the case where one of the other allowable approval 1060 mechanisms cannot be employed in a timely fashion or for some other 1061 compelling reason. IESG Approval is not intended to circumvent the 1062 public review processes implied by other policies that could have 1063 been employed for a particular assignment. IESG Approval would be 1064 appropriate, however, in cases where expediency is desired and there 1065 is strong consensus (such as from a working group) for making the 1066 assignment. 1068 Before approving a request, the IESG might consider consulting the 1069 community, via a "call for comments" that provides as much 1070 information as is reasonably possible about the request. 1072 Examples: 1074 IPv4 Multicast address assignments [RFC5771] 1075 IPv4 IGMP Type and Code values [RFC3228] 1076 Mobile IPv6 Mobility Header Type and Option values [RFC6275] 1078 4.11. Using the Well-Known Registration Policies 1080 Because the well-known policies benefit from both community 1081 experience and wide understanding, their use is encouraged, and the 1082 making up of new policies needs to be accompanied by reasonable 1083 justification. 1085 It is also acceptable to cite one or more well-known policies and 1086 include additional guidelines for what kind of considerations should 1087 be taken into account by the review process. 1089 For example, for media-type registrations [RFC6838], a number of 1090 different situations are covered that involve the use of IETF Review 1091 and Specification Required, while also including specific additional 1092 criteria the Designated Expert should follow. This is not meant to 1093 represent a registration procedures, but shows an example of what can 1094 be done when special circumstances need to be covered. 1096 The well-known policies from "First Come First Served" to "Standards 1097 Action" specify a range of policies in increasing order of strictness 1098 (using the numbering from the full list in Section 4): 1100 4. First Come First Served 1101 No review, minimal documentation. 1103 5/6. Expert Review / Specification Required 1104 Expert review with sufficient documentation for review. / 1105 Significant stable public documentation sufficient for 1106 interoperability. 1108 7. RFC Required 1109 Any RFC publication, IETF or a non-IETF Stream. 1111 8. IETF Review 1112 RFC publication, IETF Stream only, but need not be Standards 1113 Track. 1115 9. Standards Action 1116 RFC publication, IETF Stream, Standards Track or BCP only. 1118 Examples of situations that might merit IETF Review or Standards 1119 Action include the following: 1121 o When a resource is limited, such as bits in a byte (or in two 1122 bytes, or four), or numbers in a limited range. In these cases, 1123 allowing registrations that haven't been carefully reviewed and 1124 agreed by community consensus could too quickly deplete the 1125 allowable values. 1127 o When thorough community review is necessary to avoid extending or 1128 modifying the protocol in ways that could be damaging. One 1129 example is in defining new command codes, as opposed to options 1130 that use existing command codes: the former might require a strict 1131 policy, where a more relaxed policy could be adequate for the 1132 latter. Another example is in defining protocol elements that 1133 change the semantics of existing operations. 1135 o When there are security implications with respect to the resource, 1136 and thorough review is needed to ensure that the new usage is 1137 sound. Examples of this include lists of acceptable hashing and 1138 cryptographic algorithms, and assignment of transport ports in the 1139 system range. 1141 When reviewing a document that asks IANA to create a new registry or 1142 change a registration policy to any policy more stringent than Expert 1143 Review or Specification Required, the IESG should ask for 1144 justification to ensure that more relaxed policies have been 1145 considered and that the strict policy is the right one. 1147 Accordingly, document developers need to anticipate this and document 1148 their considerations for selecting the specified policy (ideally, in 1149 the document itself; failing that, in the shepherd writeup). 1150 Likewise, the document shepherd should ensure that the selected 1151 policies have been justified before sending the document to the IESG. 1153 When specifications are revised, registration policies should be 1154 reviewed in light of experience since the policies were set. 1156 4.12. Using Multiple Policies in Combination 1157 In some situations, it is necessary to define multiple registration 1158 policies. For example, registrations through the normal IETF process 1159 might use one policy, while registrations from outside the process 1160 would have a different policy applied. 1162 Thus, a particular registry might want to use a policy such as "RFC 1163 Required" or "IETF Review" sometimes, with a designated expert 1164 checking a "Specification Required" policy at other times. 1166 The alternative to using a combination requires either that all 1167 requests come through RFCs or that requests in RFCs go through review 1168 by the designated expert, even though they already have IETF review 1169 and consensus. 1171 This can be documented in the IANA Considerations section when the 1172 registry is created: 1174 IANA is asked to create the registry "Fruit Access Flags" under 1175 the "Fruit Parameters" group. New registrations will be permitted 1176 through either the IETF Review policy or the Specification 1177 Required policy [BCP26]. The latter should be used only for 1178 registrations requested by SDOs outside the IETF. Registrations 1179 requested in IETF documents will be subject to IETF review. 1181 Such combinations will commonly use one of {Standards Action, IETF 1182 Review, RFC Required} in combination with one of {Specification 1183 Required, Expert Review}. Guidance should be provided about when 1184 each policy is appropriate, as in the example above. 1186 5. Designated Experts 1188 5.1. The Motivation for Designated Experts 1190 Discussion on a mailing list can provide valuable technical feedback, 1191 but opinions often vary and discussions may continue for some time 1192 without clear resolution. In addition, IANA cannot participate in 1193 all of these mailing lists and cannot determine if or when such 1194 discussions reach consensus. Therefore, IANA relies on a "designated 1195 expert" for advice regarding the specific question of whether an 1196 assignment should be made. The designated expert is an individual 1197 who is responsible for carrying out an appropriate evaluation and 1198 returning a recommendation to IANA. 1200 It should be noted that a key motivation for having designated 1201 experts is for the IETF to provide IANA with a subject matter expert 1202 to whom the evaluation process can be delegated. IANA forwards 1203 requests for an assignment to the expert for evaluation, and the 1204 expert (after performing the evaluation) informs IANA as to whether 1205 or not to make the assignment or registration. In most cases, the 1206 registrants do not work directly with the designated experts. The 1207 list of designated experts for a registry is listed in the registry. 1209 It will often be useful to use a designated expert only some of the 1210 time, as a supplement to other processes. For more discussion of 1211 that topic, see Section 4.12. 1213 5.2. The Role of the Designated Expert 1215 The designated expert is responsible for coordinating the appropriate 1216 review of an assignment request. The review may be wide or narrow, 1217 depending on the situation and the judgment of the designated expert. 1218 This may involve consultation with a set of technology experts, 1219 discussion on a public mailing list, consultation with a working 1220 group (or its mailing list if the working group has disbanded), etc. 1221 Ideally, the designated expert follows specific review criteria as 1222 documented with the protocol that creates or uses the namespace. See 1223 the IANA Considerations sections of [RFC3748] and [RFC3575] for 1224 specific examples. 1226 Designated experts are expected to be able to defend their decisions 1227 to the IETF community, and the evaluation process is not intended to 1228 be secretive or bestow unquestioned power on the expert. Experts are 1229 expected to apply applicable documented review or vetting procedures, 1230 or in the absence of documented criteria, follow generally accepted 1231 norms such as those in Section 5.3. Designated experts are generally 1232 not expected to be "gatekeepers", setting out to make registrations 1233 difficult to obtain, unless the guidance in the defining document 1234 specifies that they should act as such. Absent stronger guidance, 1235 the experts should be evaluating registration requests for 1236 completeness, interoperability, and conflicts with existing protocols 1237 and options. 1239 It has proven useful to have multiple designated experts for some 1240 registries. Sometimes those experts work together in evaluating a 1241 request, while in other cases additional experts serve as backups, 1242 acting only when the primary expert is unavailable. In registries 1243 with a pool of experts, the pool often has a single chair responsible 1244 for defining how requests are to be assigned to and reviewed by 1245 experts. In other cases, IANA might assign requests to individual 1246 members in sequential or approximate random order. The document 1247 defining the registry can, if it's appropriate for the situation, 1248 specify how the group should work -- for example, it might be 1249 appropriate to specify rough consensus on a mailing list, within a 1250 related working group, or among a pool of designated experts. 1252 In cases of disagreement among multiple experts, it is the 1253 responsibility of those experts to make a single clear recommendation 1254 to IANA. It is not appropriate for IANA to resolve disputes among 1255 experts. In extreme situations, such as deadlock, the designating 1256 body may need to step in to resolve the problem. 1258 If a designated expert has a conflict of interest for a particular 1259 review (is, for example, an author or significant proponent of a 1260 specification related to the registration under review), that expert 1261 should recuse himself. In the event that all the designated experts 1262 are conflicted, they should ask that a temporary expert be designated 1263 for the conflicted review. The responsible AD may then appoint 1264 someone, or the AD may handle the review. 1266 This document defines the designated expert mechanism with respect to 1267 documents in the IETF stream only. If other streams want to use 1268 registration policies that require designated experts, it is up to 1269 those streams (or those documents) to specify how those designated 1270 experts are appointed and managed. What is described below, with 1271 management by the IESG, is only appropriate for the IETF stream. 1273 5.2.1. Managing Designated Experts in the IETF 1275 Designated experts for registries created by the IETF are appointed 1276 by the IESG, normally upon recommendation by the relevant Area 1277 Director. They may be appointed at the time a document creating or 1278 updating a namespace is approved by the IESG, or subsequently, when 1279 the first registration request is received. Because experts 1280 originally appointed may later become unavailable, the IESG will 1281 appoint replacements as necessary. The IESG may remove any 1282 designated expert that it appointed, at its discretion. 1284 The normal appeals process, as described in [RFC2026], Section 6.5.1, 1285 applies to issues that arise with the designated expert team. For 1286 this purpose, the designated expert team takes the place of the 1287 working group in that description. 1289 5.3. Designated Expert Reviews 1291 In the years since RFC 2434 was published and has been put to use, 1292 experience has led to the following observations: 1294 o A designated expert must respond in a timely fashion, normally 1295 within a week for simple requests to a few weeks for more complex 1296 ones. Unreasonable delays can cause significant problems for 1297 those needing assignments, such as when products need code points 1298 to ship. This is not to say that all reviews can be completed 1299 under a firm deadline, but they must be started, and the requester 1300 and IANA should have some transparency into the process if an 1301 answer cannot be given quickly. 1303 o If a designated expert does not respond to IANA's requests within 1304 a reasonable period of time, either with a response or with a 1305 reasonable explanation for the delay (some requests may be 1306 particularly complex), and if this is a recurring event, IANA must 1307 raise the issue with the IESG. Because of the problems caused by 1308 delayed evaluations and assignments, the IESG should take 1309 appropriate actions to ensure that the expert understands and 1310 accepts his or her responsibilities, or appoint a new expert. 1312 o The designated expert is not required to personally bear the 1313 burden of evaluating and deciding all requests, but acts as a 1314 shepherd for the request, enlisting the help of others as 1315 appropriate. In the case that a request is denied, and rejecting 1316 the request is likely to be controversial, the expert should have 1317 the support of other subject matter experts. That is, the expert 1318 must be able to defend a decision to the community as a whole. 1320 When a designated expert is used, the documentation should give clear 1321 guidance to the designated expert, laying out criteria for performing 1322 an evaluation and reasons for rejecting a request. In the case where 1323 there are no specific documented criteria, the presumption should be 1324 that a code point should be granted unless there is a compelling 1325 reason to the contrary (and see also Section 5.4). Reasons that have 1326 been used to deny requests have included these: 1328 o Scarcity of code points, where the finite remaining code points 1329 should be prudently managed, or where a request for a large number 1330 of code points is made and a single code point is the norm. 1332 o Documentation is not of sufficient clarity to evaluate or ensure 1333 interoperability. 1335 o The code point is needed for a protocol extension, but the 1336 extension is not consistent with the documented (or generally 1337 understood) architecture of the base protocol being extended, and 1338 would be harmful to the protocol if widely deployed. It is not 1339 the intent that "inconsistencies" refer to minor differences "of a 1340 personal preference nature". Instead, they refer to significant 1341 differences such as inconsistencies with the underlying security 1342 model, implying a change to the semantics of an existing message 1343 type or operation, requiring unwarranted changes in deployed 1344 systems (compared with alternate ways of achieving a similar 1345 result), etc. 1347 o The extension would cause problems with existing deployed systems. 1349 o The extension would conflict with one under active development by 1350 the IETF, and having both would harm rather than foster 1351 interoperability. 1353 Documents must not name the designated expert(s) in the document 1354 itself; instead, any suggested names should be relayed to the 1355 appropriate Area Director at the time the document is sent to the 1356 IESG for approval. This is usually done in the document shepherd 1357 writeup. 1359 If the request should also be reviewed on a specific public mailing 1360 list, its address should be specified. 1362 5.4. Expert Reviews and the Document Lifecycle 1364 Review by the designated expert is necessarily done at a particular 1365 point in time, and represents review of a particular version of the 1366 document. While reviews are generally done around the time of IETF 1367 last call, deciding when the review should take place is a question 1368 of good judgment. And while re-reviews might be done when it's 1369 acknowledged that the documentation of the registered item has 1370 changed substantially, making sure that re-review happens requires 1371 attention and care. 1373 It is possible, through carelessness, accident, inattentiveness, or 1374 even willful disregard, that changes might be made after the 1375 designated expert's review and approval that would, if the document 1376 were re-reviewed, cause the expert not to approve the registration. 1377 It is up to the IESG, with the token held by the responsible Area 1378 Director, to be alert to such situations and to recognize that such 1379 changes need to be checked. 1381 For registrations made from documents on the Standards Track, there 1382 is often expert review required (by the registration policy) in 1383 addition to IETF consensus (for approval as a Standards Track RFC). 1384 In such cases, the review by the designated expert needs to be 1385 timely, submitted before the IESG evaluates the document. The IESG 1386 should generally not hold the document up waiting for late review. 1387 It is also not intended for the expert review to override IETF 1388 consensus: the IESG should consider the review in its own evaluation, 1389 as it would do for other last-call reviews. 1391 6. Well-Known Registration Status Terminology 1393 The following labels describe the status of an assignment or range of 1394 assignments: 1396 Private Use: Private use only (not assigned), as described in 1397 Section 4.1. 1399 Experimental: Available for general experimental use as described 1400 in [RFC3692]. IANA does not record specific assignments for 1401 any particular use. 1403 Unassigned: Not currently assigned, and available for assignment 1404 via documented procedures. While it's generally clear that 1405 any values that are not registered are unassigned and 1406 available for assignment, it is sometimes useful to 1407 explicitly specify that situation. Note that this is 1408 distinctly different from "Reserved". 1410 Reserved: Not assigned and not available for assignment. Reserved 1411 values are held for special uses, such as to extend the 1412 namespace when it becomes exhausted. "Reserved" is also 1413 sometimes used to designate values that had been assigned 1414 but are no longer in use, keeping them set aside as long as 1415 other unassigned values are available. Note that this is 1416 distinctly different from "Unassigned". 1418 Reserved values can be released for assignment by the change 1419 controller for the registry (this is often the IESG, for 1420 registries created by RFCs in the IETF stream). 1422 Known Unregistered Use: It's known that the assignment or range is 1423 in use without having been defined in accordance with 1424 reasonable practice. Documentation for use of the 1425 assignment or range may be unavailable, inadequate, or 1426 conflicting. This is a warning against use, as well as an 1427 alert to network operators, who might see these values in 1428 use on their networks. 1430 7. Documentation References in IANA Registries 1432 Usually, registries and registry entries include references to 1433 documentation (RFCs or other documents). The purpose of these 1434 references is to provide pointers for implementors to find details 1435 necessary for implementation, NOT to simply note what document 1436 created the registry or entry. Therefore: 1438 o If a document registers an item that is defined and explained 1439 elsewhere, the registered reference should be to the document 1440 containing the definition, not to the document that is merely 1441 performing the registration. 1443 o If the registered item is defined and explained in the current 1444 document, it is important to include sufficient information to 1445 enable implementors to understand the item and to create a proper 1446 implementation. 1448 o If the registered item is explained primarily in a specific 1449 section of the reference document, it is useful to include a 1450 section reference. For example, "[RFC4637], Section 3.2", rather 1451 than just "[RFC4637]". 1453 o For documentation of a new registry, the reference should provide 1454 information about the registry itself, not just a pointer to the 1455 creation of it. Useful information includes the purpose of the 1456 registry, a rationale for its creation, documentation of the 1457 process and policy for new registrations, guidelines for new 1458 registrants or designated experts, and other such related 1459 information. But note that, while it's important to include this 1460 information in the document, it needn't all be in the IANA 1461 Considerations section. See Section 1.1. 1463 8. What to Do in "bis" Documents 1465 On occasion, an RFC is issued that obsoletes a previous edition of 1466 the same document. We sometimes call these "bis" documents, such as 1467 when RFC 4637 is obsoleted by draft-ietf-foo-rfc4637bis. When the 1468 original document created registries and/or registered entries, there 1469 is a question of how to handle the IANA Considerations section in the 1470 "bis" document. 1472 If the registrations specify the original document as a reference, 1473 those registrations should be updated to point to the current (not 1474 obsolete) documentation for those items. Usually, that will mean 1475 changing the reference to be the "bis" document. 1477 There will, though, be times when a document updates another, but 1478 does not make it obsolete, and the definitive reference is changed 1479 for some items but not for others. Be sure that the references are 1480 always set to point to the correct, current documentation for each 1481 item. 1483 For example, suppose RFC 4637 registered the "BANANA" flag in the 1484 "Fruit Access Flags" registry, and the documentation for that flag is 1485 in Section 3.2. 1487 The current registry might look, in part, like this: 1489 Name Description Reference 1490 -------- ------------------- --------- 1491 BANANA Flag for bananas [RFC4637], Section 3.2 1493 If draft-ietf-foo-rfc4637bis obsoletes RFC 4637 and, because of some 1494 rearrangement, now documents the flag in Section 4.1.2, the IANA 1495 Considerations of the bis document might contain text such as this: 1497 IANA is asked to change the registration information for the 1498 BANANA flag in the "Fruit Access Flags" registry to the following: 1500 Name Description Reference 1501 -------- ------------------- --------- 1502 BANANA Flag for bananas [[this RFC]], Section 4.2.1 1504 In many cases, if there are a number of registered references to the 1505 original RFC and the document organization has not changed the 1506 registered section numbering much, it may simply be reasonable to do 1507 this: 1509 Because this document obsoletes RFC 4637, IANA is asked to change 1510 all registration information that references [RFC4637] to instead 1511 reference [[this RFC]]. 1513 If information for registered items has been or is being moved to 1514 other documents, then the registration information should be changed 1515 to point to those other documents. In most cases, documentation 1516 references should not be left pointing to the obsoleted document for 1517 registries or registered items that are still in current use. For 1518 registries or registered items that are no longer in current use, it 1519 will usually make sense to leave the references pointing to the old 1520 document -- the last current reference for the obsolete items. The 1521 main point is to make sure that the reference pointers are as useful 1522 and current as is reasonable, and authors should consider that as 1523 they write the IANA Considerations for the new document. As always: 1524 do the right thing, and there is flexibility to allow for that. 1526 It is extremely important to be clear in your instructions regarding 1527 updating references, especially in cases where some references need 1528 to be updated and others do not. 1530 9. Miscellaneous Issues 1532 9.1. When There Are No IANA Actions 1534 Before an Internet-Draft can be published as an RFC, IANA needs to 1535 know what actions (if any) it needs to perform. Experience has shown 1536 that it is not always immediately obvious whether a document has no 1537 IANA actions, without reviewing the document in some detail. In 1538 order to make it clear to IANA that it has no actions to perform (and 1539 that the author has consciously made such a determination), such 1540 documents should, after the authors confirm that this is the case, 1541 include an IANA Considerations section that states: 1543 This document has no IANA actions. 1545 IANA prefers that these "empty" IANA Considerations sections be left 1546 in the document for the record: it makes it clear later on that the 1547 document explicitly said that no IANA actions were needed (and that 1548 it wasn't just omitted). This is a change from the prior practice of 1549 requesting that such sections be removed by the RFC Editor, and 1550 authors are asked to accommodate this change. 1552 9.2. Namespaces Lacking Documented Guidance 1554 For all existing RFCs that either explicitly or implicitly rely on 1555 IANA to make assignments without specifying a precise assignment 1556 policy, IANA will work with the IESG to decide what policy is 1557 appropriate. Changes to existing policies can always be initiated 1558 through the normal IETF consensus process, or through the IESG when 1559 appropriate. 1561 All future RFCs that either explicitly or implicitly rely on IANA to 1562 register or otherwise administer namespace assignments must provide 1563 guidelines for administration of the namespace. 1565 9.3. After-the-Fact Registrations 1566 Occasionally, the IETF becomes aware that an unassigned value from a 1567 namespace is in use on the Internet or that an assigned value is 1568 being used for a different purpose than it was registered for. The 1569 IETF does not condone such misuse; procedures of the type described 1570 in this document need to be applied to such cases, and it might not 1571 always be possible to formally assign the desired value. In the 1572 absence of specifications to the contrary, values may only be 1573 reassigned for a different purpose with the consent of the original 1574 assignee (when possible) and with due consideration of the impact of 1575 such a reassignment. In cases of likely controversy, consultation 1576 with the IESG is advised. 1578 This is part of the reason for the advice in Section 3.1 about using 1579 placeholder values, such as "TBD1", during document development: open 1580 use of unregistered values after results from well-meant, early 1581 implementations, where the implementations retained the use of 1582 developmental code points that never proceeded to a final IANA 1583 assignment. 1585 9.4. Reclaiming Assigned Values 1587 Reclaiming previously assigned values for reuse is tricky, because 1588 doing so can lead to interoperability problems with deployed systems 1589 still using the assigned values. Moreover, it can be extremely 1590 difficult to determine the extent of deployment of systems making use 1591 of a particular value. However, in cases where the namespace is 1592 running out of unassigned values and additional ones are needed, it 1593 may be desirable to attempt to reclaim unused values. When 1594 reclaiming unused values, the following (at a minimum) should be 1595 considered: 1597 o Attempts should be made to contact the original party to which a 1598 value is assigned, to determine if the value was ever used, and if 1599 so, the extent of deployment. (In some cases, products were never 1600 shipped or have long ceased being used. In other cases, it may be 1601 known that a value was never actually used at all.) 1603 o Reassignments should not normally be made without the concurrence 1604 of the original requester. Reclamation under such conditions 1605 should only take place where there is strong evidence that a value 1606 is not widely used, and the need to reclaim the value outweighs 1607 the cost of a hostile reclamation. In any case, IESG Approval is 1608 needed in this case. 1610 o It may be appropriate to write up the proposed action and solicit 1611 comments from relevant user communities. In some cases, it may be 1612 appropriate to write an RFC that goes through a formal IETF 1613 process (including IETF Last Call) as was done when DHCP reclaimed 1614 some of its "Private Use" options [RFC3942]. 1616 o It may be useful to differentiate between revocation, release, and 1617 transfer. Revocation occurs when IANA removes an assignment, 1618 release occurs when the assignee initiates that removal, and 1619 transfer occurs when either revocation or release is coupled with 1620 immediate reassignment. It may be useful to specify procedures 1621 for each of these, or to explicitly prohibit combinations that are 1622 not desired. 1624 9.5. Contact Person vs Assignee or Owner 1626 Many registries include designation of a technical or administrative 1627 contact associated with each entry. Often, this is recorded as 1628 contact information for an individual. It is unclear, though, what 1629 role the individual has with respect to the registration: is this 1630 item registered on behalf of the individual, the company the 1631 individual worked for, or perhaps another organization the individual 1632 was acting for? 1634 This matters because some time later, when the individual has changed 1635 jobs or roles, and perhaps can no longer be contacted, someone might 1636 want to update the registration. IANA has no way to know what 1637 company, organization, or individual should be allowed to take the 1638 registration over. For registrations rooted in RFCs, the stream 1639 owner (such as the IESG or the IAB) can make an overriding decision. 1640 But in other cases, there is no recourse. 1642 Registries can include, in addition to a "Contact" field, an 1643 "Assignee" or "Owner" field (also referred to as "Change Controller") 1644 that can be used to address this situation, giving IANA clear 1645 guidance as to the actual owner of the registration. This is 1646 strongly advised especially for registries that do not require RFCs 1647 to manage their information (registries with policies such as First 1648 Come First Served Section 4.4, Expert Review Section 4.5, and 1649 Specification Required Section 4.6). Alternatively, organizations 1650 can put an organizational role into the "Contact" field in order to 1651 make their ownership clear. 1653 9.6. Closing or Obsoleting a Registry/Registrations 1655 Sometimes there is a request to "close" a registry to further 1656 registrations. When a registry is closed, no further registrations 1657 will be accepted. The information in the registry will still be 1658 valid and registrations already in the registry can still be updated. 1660 A closed registry can also be marked as "obsolete", as an indication 1661 that the information in the registry is no longer in current use. 1663 Specific entries in a registry can be marked as "obsolete" (no longer 1664 in use) or "deprecated" (use is not recommended). 1666 Such changes to registries and registered values are subject to 1667 normal change controls (see Section 2.3). Any closure, obsolescence, 1668 or deprecation serves to annotate the registry involved; the 1669 information in the registry remains there for informational and 1670 historic purposes. 1672 10. Appeals 1674 Appeals of protocol parameter registration decisions can be made 1675 using the normal IETF appeals process as described in [RFC2026], 1676 Section 6.5. That is, an initial appeal should be directed to the 1677 IESG, followed (if necessary) by an appeal to the IAB. 1679 11. Mailing Lists 1681 All IETF mailing lists associated with evaluating or discussing 1682 assignment requests as described in this document are subject to 1683 whatever rules of conduct and methods of list management are 1684 currently defined by Best Current Practices or by IESG decision. 1686 12. Security Considerations 1688 Information that creates or updates a registration needs to be 1689 authenticated and authorized. IANA updates registries according to 1690 instructions in published RFCs and from the IESG. It also may accept 1691 clarifications from document authors, relevant working group chairs, 1692 Designated Experts, and mail list participants, too. 1694 Information concerning possible security vulnerabilities of a 1695 protocol may change over time. Likewise, security vulnerabilities 1696 related to how an assigned number is used may change as well. As new 1697 vulnerabilities are discovered, information about such 1698 vulnerabilities may need to be attached to existing registrations, so 1699 that users are not misled as to the true security issues surrounding 1700 the use of a registered number. 1702 Security needs to be considered as part of the selection of a 1703 registration policy. For some protocols, registration of certain 1704 parameters will have security implications, and registration policies 1705 for the relevant registries must ensure that requests get appropriate 1706 review with those security implications in mind. 1708 An analysis of security issues is generally required for all 1709 protocols that make use of parameters (data types, operation codes, 1710 keywords, etc.) used in IETF protocols or registered by IANA. Such 1711 security considerations are usually included in the protocol document 1712 [RFC3552]. It is the responsibility of the IANA considerations 1713 associated with a particular registry to specify whether value- 1714 specific security considerations must be provided when assigning new 1715 values, and the process for reviewing such claims. 1717 13. IANA Considerations 1718 IANA is asked to update any references to RFC 5226 to now point to 1719 this document. 1721 14. Changes Relative to Earlier Editions of BCP 26 1723 14.1. 2016: Changes in This Document Relative to RFC 5226 1725 Significant additions: 1727 o Removed RFC 2119 key words, boilerplate, and reference, preferring 1728 plain English -- this is not a protocol specification. 1730 o Added Section 1.1, Keep IANA Considerations for IANA 1732 o Added Section 1.2, For More Information 1734 o Added Section 2.1, Hierarchical Registry Structure 1736 o Added best practice for selecting an appropriate policy into 1737 Section 4. 1739 o Added Section 4.12, Using Multiple Policies in Combination. 1741 o Added Section 2.3, Specifying Change Control for a Registry 1743 o Added Section 3.4, Early Allocations 1745 o Moved well-known policies into a separate section for each, 1746 subsections of Section 4. 1748 o Added Section 5.4, Expert Reviews and the Document Lifecycle 1750 o Added Section 7, Documentation References in IANA Registries 1752 o Added Section 8, What to Do in "bis" Documents 1754 o Added Section 9.5, Contact Person vs Assignee or Owner 1756 o Added Section 9.6, Closing or Obsoleting a Registry 1758 Clarifications and such: 1760 o Some reorganization -- moved text around for clarity and easier 1761 reading. 1763 o Made clarifications about identification of IANA registries and 1764 use of URLs for them. 1766 o Clarified the distinction between "Unassigned" and "Reserved". 1768 o Made some clarifications in "Expert Review" about instructions to 1769 the designated expert. 1771 o Made some clarifications in "Specification Required" about how to 1772 declare this policy. 1774 o Assorted minor clarifications and editorial changes throughout. 1776 14.2. 2008: Changes in RFC 5226 Relative to RFC 2434 1778 Changes include: 1780 o Major reordering of text to expand descriptions and to better 1781 group topics such as "updating registries" vs. "creating new 1782 registries", in order to make it easier for authors to find the 1783 text most applicable to their needs. 1785 o Numerous editorial changes to improve readability. 1787 o Changed the term "IETF Consensus" to "IETF Review" and added more 1788 clarifications. History has shown that people see the words "IETF 1789 Consensus" (without consulting the actual definition) and are 1790 quick to make incorrect assumptions about what the term means in 1791 the context of IANA Considerations. 1793 o Added "RFC Required" to list of defined policies. 1795 o Much more explicit directions and examples of "what to put in 1796 RFCs". 1798 o "Specification Required" now implies use of a Designated Expert to 1799 evaluate specs for sufficient clarity. 1801 o Significantly changed the wording in the Designated Experts 1802 section. Main purpose is to make clear that Expert Reviewers are 1803 accountable to the community, and to provide some guidance for 1804 review criteria in the default case. 1806 o Changed wording to remove any special appeals path. The normal 1807 RFC 2026 appeals path is used. 1809 o Added a section about reclaiming unused values. 1811 o Added a section on after-the-fact registrations. 1813 o Added a section indicating that mailing lists used to evaluate 1814 possible assignments (such as by a Designated Expert) are subject 1815 to normal IETF rules. 1817 15. Acknowledgments 1819 15.1. Acknowledgments for This Document (2016) 1820 Thomas Narten and Harald Tveit Alvestrand edited the two earlier 1821 editions of this document (RFCs 2434 and 5226), and Thomas continues 1822 his role in this third edition. Much of the text from RFC 5226 1823 remains in this edition. 1825 Thank you to Amanda Baber and Pearl Liang for their multiple reviews 1826 and suggestions for making this document as thorough as possible. 1828 This document has benefited from thorough review and comments by many 1829 people, including Benoit Claise, Alissa Cooper, Adrian Farrel, 1830 Stephen Farrell, Tony Hansen, John Klensin, Kathleen Moriarty, Mark 1831 Nottingham, Pete Resnick, and Joe Touch. 1833 Special thanks to Mark Nottingham for reorganizing some of the text 1834 for better organization and readability, to Tony Hansen for acting as 1835 document shepherd, and to Brian Haberman and Terry Manderson for 1836 acting as sponsoring ADs. 1838 15.2. Acknowledgments from the second edition (2008) 1840 The original acknowledgments section in RFC 5226 was: 1842 This document has benefited from specific feedback from Jari Arkko, 1843 Marcelo Bagnulo Braun, Brian Carpenter, Michelle Cotton, Spencer 1844 Dawkins, Barbara Denny, Miguel Garcia, Paul Hoffman, Russ Housley, 1845 John Klensin, Allison Mankin, Blake Ramsdell, Mark Townsley, Magnus 1846 Westerlund, and Bert Wijnen. 1848 15.3. Acknowledgments from the first edition (1998) 1850 The original acknowledgments section in RFC 2434 was: 1852 Jon Postel and Joyce Reynolds provided a detailed explanation on what 1853 IANA needs in order to manage assignments efficiently, and patiently 1854 provided comments on multiple versions of this document. Brian 1855 Carpenter provided helpful comments on earlier versions of the 1856 document. One paragraph in the Security Considerations section was 1857 borrowed from RFC 4288. 1859 16. References 1861 16.1. Normative References 1863 [RFC2026] Bradner, S., "The Internet Standards Process -- Revision 1864 3", BCP 9, RFC 2026, October 1996. 1866 16.2. Informative References 1868 [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, September 1869 1981. 1871 [RFC1591] Postel, J., "Domain Name System Structure and Delegation", 1872 RFC 1591, DOI 10.17487/RFC1591, March 1994, . 1875 [RFC2860] Carpenter, B., Baker, F. and M. Roberts, "Memorandum of 1876 Understanding Concerning the Technical Work of the 1877 Internet Assigned Numbers Authority", RFC 2860, June 2000. 1879 [RFC2939] Droms, R., "Procedures and IANA Guidelines for Definition 1880 of New DHCP Options and Message Types", BCP 43, RFC 2939, 1881 September 2000. 1883 [RFC3228] Fenner, B., "IANA Considerations for IPv4 Internet Group 1884 Management Protocol (IGMP)", BCP 57, RFC 3228, February 1885 2002. 1887 [RFC3406] Daigle, L., van Gulik, D., Iannella, R. and P. Faltstrom, 1888 "Uniform Resource Names (URN) Namespace Definition 1889 Mechanisms", BCP 66, RFC 3406, DOI 10.17487/RFC3406, 1890 October 2002, . 1892 [RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC 1893 Text on Security Considerations", BCP 72, RFC 3552, July 1894 2003. 1896 [RFC3575] Aboba, B., "IANA Considerations for RADIUS (Remote 1897 Authentication Dial In User Service)", RFC 3575, July 1898 2003. 1900 [RFC3692] Narten, T., "Assigning Experimental and Testing Numbers 1901 Considered Useful", BCP 82, RFC 3692, January 2004. 1903 [RFC3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J. and H. 1904 Levkowetz, "Extensible Authentication Protocol (EAP)", RFC 1905 3748, June 2004. 1907 [RFC3942] Volz, B., "Reclassifying Dynamic Host Configuration 1908 Protocol version 4 (DHCPv4) Options", RFC 3942, November 1909 2004. 1911 [RFC3968] Camarillo, G., "The Internet Assigned Number Authority 1912 (IANA) Header Field Parameter Registry for the Session 1913 Initiation Protocol (SIP)", BCP 98, RFC 3968, December 1914 2004. 1916 [RFC4005] Calhoun, P., Zorn, G., Spence, D. and D. Mitton, "Diameter 1917 Network Access Server Application", RFC 4005, August 2005. 1919 [RFC4025] Richardson, M., "A Method for Storing IPsec Keying 1920 Material in DNS", RFC 4025, March 2005. 1922 [RFC4044] McCloghrie, K., "Fibre Channel Management MIB", RFC 4044, 1923 May 2005. 1925 [RFC4124] Le Faucheur, F., "Protocol Extensions for Support of 1926 Diffserv-aware MPLS Traffic Engineering", RFC 4124, June 1927 2005. 1929 [RFC4169] Torvinen, V., Arkko, J. and M. Naslund, "Hypertext 1930 Transfer Protocol (HTTP) Digest Authentication Using 1931 Authentication and Key Agreement (AKA) Version-2", RFC 1932 4169, November 2005. 1934 [RFC4271] Rekhter, Y., Li, T. and S. Hares, "A Border Gateway 1935 Protocol 4 (BGP-4)", RFC 4271, January 2006. 1937 [RFC4283] Patel, A., Leung, K., Khalil, M., Akhtar, H. and K. 1938 Chowdhury, "Mobile Node Identifier Option for Mobile IPv6 1939 (MIPv6)", RFC 4283, November 2005. 1941 [RFC4340] Kohler, E., Handley, M. and S. Floyd, "Datagram Congestion 1942 Control Protocol (DCCP)", RFC 4340, March 2006. 1944 [RFC4395] Hansen, T., Hardie, T. and L. Masinter, "Guidelines and 1945 Registration Procedures for New URI Schemes", BCP 35, RFC 1946 4395, February 2006. 1948 [RFC4422] Melnikov, A. and K. Zeilenga, "Simple Authentication and 1949 Security Layer (SASL)", RFC 4422, June 2006. 1951 [RFC4446] Martini, L., "IANA Allocations for Pseudowire Edge to Edge 1952 Emulation (PWE3)", BCP 116, RFC 4446, April 2006. 1954 [RFC4520] Zeilenga, K., "Internet Assigned Numbers Authority (IANA) 1955 Considerations for the Lightweight Directory Access 1956 Protocol (LDAP)", BCP 64, RFC 4520, June 2006. 1958 [RFC4589] Schulzrinne, H. and H. Tschofenig, "Location Types 1959 Registry", RFC 4589, July 2006. 1961 [RFC4727] Fenner, B., "Experimental Values In IPv4, IPv6, ICMPv4, 1962 ICMPv6, UDP, and TCP Headers", RFC 4727, November 2006. 1964 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security 1965 (TLS) Protocol Version 1.2", RFC 5246, August 2008. 1967 [RFC5378] Bradner, S. and J. Contreras, "Rights Contributors Provide 1968 to the IETF Trust", BCP 78, RFC 5378, November 2008. 1970 [RFC5742] Alvestrand, H. and R. Housley, "IESG Procedures for 1971 Handling of Independent and IRTF Stream Submissions", BCP 1972 92, RFC 5742, December 2009. 1974 [RFC5771] Cotton, M., Vegoda, L. and D. Meyer, "IANA Guidelines for 1975 IPv4 Multicast Address Assignments", BCP 51, RFC 5771, 1976 March 2010. 1978 [RFC5795] Sandlund, K., Pelletier, G. and L-E. Jonsson, "The RObust 1979 Header Compression (ROHC) Framework", RFC 5795, March 1980 2010. 1982 [RFC6014] Hoffman, P., "Cryptographic Algorithm Identifier 1983 Allocation for DNSSEC", RFC 6014, DOI 10.17487/RFC6014, 1984 November 2010, . 1986 [RFC6195] Eastlake, D., "Domain Name System (DNS) IANA 1987 Considerations", BCP 42, RFC 6195, March 2011. 1989 [RFC6230] Boulton, C., Melanchuk, T. and S. McGlashan, "Media 1990 Control Channel Framework", RFC 6230, DOI 10.17487/ 1991 RFC6230, May 2011, . 1994 [RFC6275] Perkins, C., Johnson, D. and J. Arkko, "Mobility Support 1995 in IPv6", RFC 6275, July 2011. 1997 [RFC6698] Hoffman, P. and J. Schlyter, "The DNS-Based Authentication 1998 of Named Entities (DANE) Transport Layer Security (TLS) 1999 Protocol: TLSA", RFC 6698, DOI 10.17487/RFC6698, August 2000 2012, . 2002 [RFC6709] Carpenter, B., Aboba, B. and S. Cheshire, "Design 2003 Considerations for Protocol Extensions", RFC 6709, 2004 September 2012. 2006 [RFC6838] Freed, N., Klensin, J. and T. Hansen, "Media Type 2007 Specifications and Registration Procedures", BCP 13, RFC 2008 6838, DOI 10.17487/RFC6838, January 2013, . 2011 [RFC6994] Touch, J., "Shared Use of Experimental TCP Options", RFC 2012 6994, DOI 10.17487/RFC6994, August 2013, . 2015 [RFC7120] Cotton, M., "Early IANA Allocation of Standards Track Code 2016 Points", BCP 100, RFC 7120, January 2014. 2018 [RFC7564] Saint-Andre, P. and M. Blanchet, "PRECIS Framework: 2019 Preparation, Enforcement, and Comparison of 2020 Internationalized Strings in Application Protocols", RFC 2021 7564, DOI 10.17487/RFC7564, May 2015, . 2024 [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A. and 2025 S. Ray, "North-Bound Distribution of Link-State and 2026 Traffic Engineering (TE) Information Using BGP", RFC 7752, 2027 DOI 10.17487/RFC7752, March 2016, . 2030 Authors' Addresses 2031 Michelle Cotton 2032 Internet Corporation for Assigned Names and Numbers 2033 12025 Waterfront Drive, Suite 300 2034 Los Angeles, CA 90094-2536 2035 US 2037 Phone: +1 310 823 9358 2038 Email: michelle.cotton@icann.org 2039 URI: https://www.icann.org/ 2041 Barry Leiba 2042 Huawei Technologies 2044 Phone: +1 646 827 0648 2045 Email: barryleiba@computer.org 2046 URI: http://internetmessagingtechnology.org/ 2048 Thomas Narten 2049 IBM Corporation 2050 3039 Cornwallis Ave., PO Box 12195 - BRQA/502 2051 Research Triangle Park, NC 27709-2195 2052 US 2054 Phone: +1 919 254 7798 2055 Email: narten@us.ibm.com