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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: December 07, 2016 IBM Corporation 8 June 07, 2016 10 Guidelines for Writing an IANA Considerations Section in RFCs 11 draft-leiba-cotton-iana-5226bis-16 13 Abstract 15 Many protocols make use of points of extensibility that use constants 16 to identify various protocol parameters. To ensure that the values 17 used in these fields do not have conflicting uses, and to promote 18 interoperability, their allocation is often coordinated by a central 19 record keeper. For IETF protocols, that role is filled by the 20 Internet Assigned Numbers Authority (IANA). 22 To make assignments in a given registry prudently, IANA needs 23 guidance describing the conditions under which new values should be 24 assigned, as well as when and how modifications to existing values 25 can be made. This document defines a framework for the documentation 26 of these guidelines by specification authors, in order to assure that 27 the guidance given to IANA is clear and addresses the various issues 28 that are likely in the operation of a registry. 30 This is the third edition of this document; it obsoletes RFC 5226. 32 Status of this Memo 34 This Internet-Draft is submitted in full conformance with the 35 provisions of BCP 78 and BCP 79. 37 Internet-Drafts are working documents of the Internet Engineering 38 Task Force (IETF). Note that other groups may also distribute 39 working documents as Internet-Drafts. The list of current Internet- 40 Drafts is at http://datatracker.ietf.org/drafts/current/. 42 Internet-Drafts are draft documents valid for a maximum of six months 43 and may be updated, replaced, or obsoleted by other documents at any 44 time. It is inappropriate to use Internet-Drafts as reference 45 material or to cite them other than as "work in progress." 47 This Internet-Draft will expire on December 07, 2016. 49 Copyright Notice 51 Copyright (c) 2016 IETF Trust and the persons identified as the 52 document authors. All rights reserved. 54 This document is subject to BCP 78 and the IETF Trust's Legal 55 Provisions Relating to IETF Documents (http://trustee.ietf.org/ 56 license-info) in effect on the date of publication of this document. 57 Please review these documents carefully, as they describe your rights 58 and restrictions with respect to this document. Code Components 59 extracted from this document must include Simplified BSD License text 60 as described in Section 4.e of the Trust Legal Provisions and are 61 provided without warranty as described in the Simplified BSD License. 63 Table of Contents 65 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 66 1.1. Keep IANA Considerations for IANA . . . . . . . . . . . . 3 67 1.2. For Updated Information . . . . . . . . . . . . . . . . . 4 68 2. Creating and Revising Registries . . . . . . . . . . . . . . . 4 69 2.1. Organization of Registries . . . . . . . . . . . . . . . . 5 70 2.2. Documentation Requirements for Registries . . . . . . . . 5 71 2.3. Specifying Change Control for a Registry . . . . . . . . . 7 72 2.4. Revising Existing Registries . . . . . . . . . . . . . . . 8 73 3. Registering New Values in an Existing Registry . . . . . . . . 8 74 3.1. Documentation Requirements for Registrations . . . . . . . 8 75 3.2. Updating Existing Registrations . . . . . . . . . . . . . 10 76 3.3. Overriding Registration Procedures . . . . . . . . . . . . 11 77 3.4. Early Allocations . . . . . . . . . . . . . . . . . . . . 12 78 4. Choosing a Registration Policy, and Well-Known Policies . . . 12 79 4.1. Private Use . . . . . . . . . . . . . . . . . . . . . . . 14 80 4.2. Experimental Use . . . . . . . . . . . . . . . . . . . . . 14 81 4.3. Hierarchical Allocation . . . . . . . . . . . . . . . . . 15 82 4.4. First Come First Served . . . . . . . . . . . . . . . . . 15 83 4.5. Expert Review . . . . . . . . . . . . . . . . . . . . . . 16 84 4.6. Specification Required . . . . . . . . . . . . . . . . . . 17 85 4.7. RFC Required . . . . . . . . . . . . . . . . . . . . . . . 18 86 4.8. IETF Review . . . . . . . . . . . . . . . . . . . . . . . 18 87 4.9. Standards Action . . . . . . . . . . . . . . . . . . . . . 19 88 4.10. IESG Approval . . . . . . . . . . . . . . . . . . . . . . 19 89 4.11. Using the Well-Known Registration Policies . . . . . . . . 20 90 4.12. Using Multiple Policies in Combination . . . . . . . . . . 21 91 5. Designated Experts . . . . . . . . . . . . . . . . . . . . . . 22 92 5.1. The Motivation for Designated Experts . . . . . . . . . . 22 93 5.2. The Role of the Designated Expert . . . . . . . . . . . . 22 94 5.2.1. Managing Designated Experts in the IETF . . . . . . . 23 95 5.3. Designated Expert Reviews . . . . . . . . . . . . . . . . 24 96 5.4. Expert Reviews and the Document Lifecycle . . . . . . . . 25 97 6. Well-Known Registration Status Terminology . . . . . . . . . . 26 98 7. Documentation References in IANA Registries . . . . . . . . . 27 99 8. What to Do in "bis" Documents . . . . . . . . . . . . . . . . 27 100 9. Miscellaneous Issues . . . . . . . . . . . . . . . . . . . . . 29 101 9.1. When There Are No IANA Actions . . . . . . . . . . . . . . 29 102 9.2. Namespaces Lacking Documented Guidance . . . . . . . . . . 29 103 9.3. After-the-Fact Registrations . . . . . . . . . . . . . . . 29 104 9.4. Reclaiming Assigned Values . . . . . . . . . . . . . . . . 30 105 9.5. Contact Person vs Assignee or Owner . . . . . . . . . . . 31 106 9.6. Closing or Obsoleting a Registry/Registrations . . . . . . 31 108 10. Appeals . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 109 11. Mailing Lists . . . . . . . . . . . . . . . . . . . . . . . . 32 110 12. Security Considerations . . . . . . . . . . . . . . . . . . . 32 111 13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 32 112 14. Changes Relative to Earlier Editions of BCP 26 . . . . . . . . 33 113 14.1. 2016: Changes in This Document Relative to RFC 5226 . . . 33 114 14.2. 2008: Changes in RFC 5226 Relative to RFC 2434 . . . . . 34 115 15. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 34 116 15.1. Acknowledgments for This Document (2016) . . . . . . . . 34 117 15.2. Acknowledgments from the second edition (2008) . . . . . 35 118 15.3. Acknowledgments from the first edition (1998) . . . . . . 35 119 16. References . . . . . . . . . . . . . . . . . . . . . . . . . . 35 120 16.1. Normative References . . . . . . . . . . . . . . . . . . 35 121 16.2. Informative References . . . . . . . . . . . . . . . . . 35 122 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 38 124 1. Introduction 126 Many protocols make use of points of extensibility that use constants 127 to identify various protocol parameters. To ensure that the values 128 used in these fields do not have conflicting uses, and to promote 129 interoperability, their allocation is often coordinated by a central 130 record keeper. For IETF protocols, that role is filled by the 131 Internet Assigned Numbers Authority (IANA) [RFC2860]. 133 The Protocol field in the IP header [RFC0791] and MIME media types 134 [RFC6838] are two examples of such coordinations. 136 In this document, we call the range of possible values for such a 137 field a "namespace". The binding or association of a specific value 138 with a particular purpose within a namespace is called an assignment 139 (or, variously: an assigned number, assigned value, code point, 140 protocol constant, or protocol parameter). The act of assignment is 141 called a registration, and it takes place in the context of a 142 registry. The terms "assignment" and "registration" are used 143 interchangably throughout this document. 145 To make assignments in a given namespace prudently, IANA needs 146 guidance describing the conditions under which new values should be 147 assigned, as well as when and how modifications to existing values 148 can be made. This document defines a framework for the documentation 149 of these guidelines by specification authors, in order to assure that 150 the guidance given to IANA is clear and addresses the various issues 151 that are likely in the operation of a registry. 153 Typically, this information is recorded in a dedicated section of the 154 specification with the title "IANA Considerations". 156 1.1. Keep IANA Considerations for IANA 157 The purpose of having a dedicated IANA Considerations section is to 158 provide a single place to collect clear and concise information and 159 instructions for IANA. Technical documentation should reside in 160 other parts of the document, and should be included by reference 161 only. Using the IANA Considerations section as primary technical 162 documentation both hides it from the target audience of the document 163 and interferes with IANA's review of the actions they need to take. 165 An ideal IANA Considerations section clearly enumerates and specifies 166 each requested IANA action; includes all information IANA needs, such 167 as the full names of all applicable registries; and includes clear 168 references to elsewhere in the document for other information. 170 The IANA actions are normally phrased as requests for IANA (such as, 171 "IANA is asked to assign the value TBD1 from the Frobozz 172 Registry..."); the RFC Editor will change those sentences to reflect 173 the actions taken ("IANA has assigned the value 83 from the Frobozz 174 Registry..."). 176 1.2. For Updated Information 178 IANA maintains a web page that includes current important information 179 from IANA. Document authors should check that page for additional 180 information, beyond what is provided here: current clarifications, 181 minor updates, and summary guidance. Any significant updates to the 182 best current practice will have to feed into updates to BCP 26 (this 183 document), which is definitive. 185 . 187 [[(RFC Editor: Please remove this paragraph.) The initial version of 188 this should contain the bits that are salient to most document 189 authors -- perhaps a table of required elements to create a new 190 registry or update one, a bit about sub-registries, and the listing 191 of well-known registration policies. IANA has text for this, but 192 they need to work on their process to put the page up (transition 193 issues). We might host the first version on the IETF site, with the 194 URL above set to redirect to it. ]] 196 2. Creating and Revising Registries 198 Defining a registry involves describing the namespaces to be created, 199 listing an initial set of assignments (if applicable), and 200 documenting guidelines on how future assignments are to be made. 202 When defining a registry, consider structuring the namespace in such 203 a way that only top-level assignments need to be made with central 204 coordination, and those assignments can delegate lower-level 205 assignments so coordination for them can be distributed. This 206 lessens the burden on IANA for dealing with assignments, and is 207 particularly useful in situations where distributed coordinators have 208 better knowledge of their portion of the namespace and are better 209 suited to handling those assignments. 211 2.1. Organization of Registries 213 All registries are anchored from the IANA "Protocol Registries" page: 215 . 217 That page lists registries in protocol category groups, placing 218 related registries together and making it easier for users of the 219 registries to find the necessary information. Clicking on the title 220 of one of the registries on the IANA Protocol Registries page will 221 take the reader to the details page for that registry. 223 Unfortunately, we have been inconsistent in how we refer to these 224 entities. The group names, as they are referred to here, have been 225 variously called "protocol category groups", "groups", "top-level 226 registries", or just "registries". The registries under them have 227 been called "registries" or "sub-registries". 229 Regardless of the terminology used, document authors should pay 230 attention to the registry groupings, should request that related 231 registries be grouped together to make related registries easier to 232 find, and, when creating a new registry, should check whether that 233 registry might best be included in an existing group. That grouping 234 information should be clearly communicated to IANA in the registry 235 creation request. 237 2.2. Documentation Requirements for Registries 239 Documents that create a new namespace (or modify the definition of an 240 existing space) and that expect IANA to play a role in maintaining 241 that space (serving as a repository for registered values) must 242 provide clear instructions on details of the namespace, either in the 243 IANA Considerations section, or referenced from it. 245 In particular, such instructions must include: 247 The name of the registry 249 This name will appear on the IANA web page and will be referred to 250 in future documents that need to allocate a value from the new 251 space. The full name (and abbreviation, if appropriate) should be 252 provided. It is highly desirable that the chosen name not be 253 easily confused with the name of another registry. 255 When creating a registry, the group that it is a part of must be 256 identified using its full name, exactly as it appears in the IANA 257 registry list. 259 Providing a URL to precisely identify the registry helps IANA 260 understand the request. Such URLs can be removed from the RFC 261 prior to final publication, or left in the document for reference. 262 If you include IANA URLs, IANA will provide corrections, if 263 necessary, during their review. 265 Required information for registrations 267 This tells registrants what information they have to include in 268 their registration requests. Some registries require only the 269 requested value and a reference to a document where use of the 270 value is defined. Other registries require a more detailed 271 registration template that describes relevant security 272 considerations, internationalization considerations, and other 273 such information. 275 Applicable registration policy 277 The policy that will apply to all future requests for 278 registration. See Section 4. 280 Size, format and syntax of registry entries 282 What fields to record in the registry, any technical requirements 283 on registry entries (valid ranges for integers, length limitations 284 on strings, and such), and the exact format in which registry 285 values should be displayed. For numeric assignments, one should 286 specify whether values are to be recorded in decimal, in 287 hexadecimal, or in some other format. 289 Strings are expected to be ASCII, and it should be clearly 290 specified whether case matters, and whether, for example, strings 291 should be shown in the registry in upper case or lower case. 293 Strings that represent protocol parameters will rarely, if ever, 294 need to contain non-ASCII characters. If non-ASCII characters are 295 really necessary, instructions should make it very clear that they 296 are allowed and that the non-ASCII characters should be 297 represented as Unicode characters using the "(U+XXXX)" convention. 298 Anyone creating such a registry should think carefully about this 299 and consider internationalization advice such as that in [RFC7564] 300 Section 10. 302 Initial assignments and reservations 304 Any initial assignments or registrations to be included. In 305 addition, any ranges that are to be reserved for "Private Use", 306 "Reserved", "Unassigned", etc. (see Section 6) should be 307 indicated. 309 For example, a document might specify a new registry by including: 311 --------------------------------------------------------------- 313 X. IANA Considerations 315 This document defines a new DHCP option, entitled "FooBar" (see 316 Section y), assigned a value of TBD1 from the DHCP Option space 317 318 [RFC2132] [RFC2939]: 319 Data 320 Tag Name Length Meaning 321 ---- ---- ------ ------- 322 TBD1 FooBar N FooBar server 324 The FooBar option also defines an 8-bit FooType field, for which 325 IANA is to create and maintain a new registry entitled 326 "FooType values" used by the FooBar option. Initial values for the 327 DHCP FooBar FooType registry are given below; future assignments 328 are to be made through Expert Review [BCP26]. 329 Assignments consist of a DHCP FooBar FooType name and its 330 associated value. 332 Value DHCP FooBar FooType Name Definition 333 ---- ------------------------ ---------- 334 0 Reserved 335 1 Frobnitz RFCXXXX, Section y.1 336 2 NitzFrob RFCXXXX, Section y.2 337 3-254 Unassigned 338 255 Reserved 339 --------------------------------------------------------------- 341 For examples of documents that establish registries, consult 342 [RFC3575], [RFC3968], and [RFC4520]. 344 2.3. Specifying Change Control for a Registry 346 Registry definitions and registrations within registries often need 347 to be changed after they are created. The process of making such 348 changes is complicated when it is unclear who is authorized to make 349 the changes. For registries created by RFCs in the IETF stream, 350 change control for the registry lies by default with the IETF, via 351 the IESG. The same is true for value registrations made in IETF- 352 stream RFCs. 354 Because registries can be created and registrations can be made 355 outside the IETF stream, it can sometimes be desirable to have change 356 control outside the IETF and IESG, and clear specification of change 357 control policies is always helpful. 359 It is advised, therefore, that all registries that are created 360 clearly specify a change control policy and a change controller. It 361 is also advised that registries that allow registrations from outside 362 the IETF stream include, for each value, the designation of a change 363 controller for that value. If the definition or reference for a 364 registered value ever needs to change, or if a registered value needs 365 to be deprecated, it is critical that IANA know who is authorized to 366 make the change. Example: the Media Types registry [RFC6838] 367 includes a "Change Controller" in its registration template. See 368 also Section 9.5. 370 While IANA normally includes information about change control in the 371 public registry, some change controllers might prefer that their 372 identities or contact information not be made public. In such cases, 373 arrangements can be made with IANA to keep the information private, 374 to use an alias or role-based contact address, or to otherwise 375 protect the change controller's privacy. 377 2.4. Revising Existing Registries 379 Updating the registration process or making changes to the format of 380 an already existing (previously created) registry (whether created 381 explicitly or implicitly) follows a process similar to that used when 382 creating a new registry. That is, a document is produced that makes 383 reference to the existing namespace and then provides detailed 384 guidance for handling assignments in the registry, or detailed 385 instructions about the changes required. 387 If a change requires a new column in the registry, the instructions 388 need to be clear about how to populate that column for the existing 389 entries. Other changes may require similar clarity. 391 Such documents are normally processed with the same document status 392 as the document that created the registry. Under some circumstances, 393 such as with a straightforward change that is clearly needed (such as 394 adding a "status" column), or when an earlier error needs to be 395 corrected, the IESG may approve an update to a registry without 396 requiring a new document. 398 Example documents that updated the guidelines for assignments in pre- 399 existing registries include: [RFC6195], [RFC3228], and [RFC3575]. 401 3. Registering New Values in an Existing Registry 403 3.1. Documentation Requirements for Registrations 405 Often, documents request an assignment in an existing registry (one 406 created by a previously published document). 408 Such documents should clearly identify the registry into which each 409 value is to be registered. Use the exact registry name as listed on 410 the IANA web page, and cite the RFC where the registry is defined. 411 When referring to an existing registry, providing a URL to precisely 412 identify the registry is helpful (see Section 2.2). 414 There is no need to mention what the assignment policy is when making 415 new assignments in existing registries, as that should be clear from 416 the references. However, if multiple assignment policies might 417 apply, as in registries with different ranges that have different 418 policies, it is important to make it clear which range is being 419 requested, so that IANA will know which policy applies and can assign 420 a value in the correct range. 422 Normally, numeric values to be used are chosen by IANA when the 423 document is approved, and drafts should not specify final values. 424 Instead, placeholders such as "TBD1" and "TBD2" should be used 425 consistently throughout the document, giving each item to be 426 registered a different placeholder. The IANA Considerations should 427 ask the RFC Editor to replace the placeholder names with the IANA- 428 assigned values. When drafts need to specify numeric values for 429 testing or early implementations, they will either request early 430 allocation (see Section 3.4) or use values that have already been set 431 aside for testing or experimentation (if the registry in question 432 allows that without explicit assignment). It is important that 433 drafts not choose their own values, lest IANA assign one of those 434 values to another document in the meantime. A draft can request a 435 specific value in the IANA Considerations section, and IANA will 436 accommodate such requests when that's possible, but the proposed 437 number might have been assigned to some other use by the time the 438 draft is approved. 440 Normally, text-string values to be used are specified in the 441 document, as collisions are less likely with text strings. IANA will 442 consult with the authors if there is, in fact, a collision, and a 443 different value has to be used. When drafts need to specify string 444 values for testing or early implementations, they sometimes use the 445 expected final value. But it is often useful to use a draft value 446 instead, possibly including the draft version number. This allows 447 the early implementations to be distinguished from those implementing 448 the final version. A document that intends to use "foobar" in the 449 final version might use "foobar-testing-draft-05" for the -05 version 450 of the draft, for example. 452 For some registries, there is a long-standing policy prohibiting 453 assignment of names or codes on a vanity or organization-name basis. 454 For example, codes might always be assigned sequentially unless there 455 is a strong reason for making an exception. Nothing in this document 456 is intended to change those policies or prevent their future 457 application. 459 As an example, the following text could be used to request assignment 460 of a DHCPv6 option number: 462 IANA is asked to assign an option code value of TBD1 to the DNS 463 Recursive Name Server option and an option code value of TBD2 to 464 the Domain Search List option from the DHCP option code space 465 defined in Section 24.3 of RFC 3315. 467 The IANA Considerations section should summarize all of the IANA 468 actions, with pointers to the relevant sections elsewhere in the 469 document as appropriate. Including section numbers is especially 470 useful when the reference document is large; the section numbers will 471 make it easier for those searching the reference document to find the 472 relevant information. 474 When multiple values are requested, it is generally helpful to 475 include a summary table of the additions/changes. It is also helpful 476 for this table to be in the same format as it appears or will appear 477 on the IANA web site. For example: 479 Value Description Reference 480 -------- ------------------- --------- 481 TBD1 Foobar this RFC, Section 3.2 482 TBD2 Gumbo this RFC, Section 3.3 483 TBD3 Banana this RFC, Section 3.4 485 Note: In cases where authors feel that including the full table of 486 changes is too verbose or repetitive, authors should still include 487 the table in the draft, but may include a note asking that the table 488 be removed prior to publication of the final RFC. 490 3.2. Updating Existing Registrations 492 Even after a number has been assigned, some types of registrations 493 contain additional information that may need to be updated over time. 495 For example, MIME media types, character sets, and language tags 496 typically include more information than just the registered value 497 itself, and may need updates to items such as point-of-contact 498 information, security issues, pointers to updates, and literature 499 references. 501 In such cases, the document defining the namespace must clearly state 502 who is responsible for maintaining and updating a registration. 504 Depending on the registry, it may be appropriate to specify one or 505 more of: 507 o Letting registrants and/or nominated change controllers update 508 their own registrations, subject to the same constraints and 509 review as with new registrations. 511 o Allowing attachment of comments to the registration. This can be 512 useful in cases where others have significant objections to a 513 registration, but the author does not agree to change the 514 registration. 516 o Designating the IESG, a designated expert, or another entity as 517 having the right to change the registrant associated with a 518 registration and any requirements or conditions on doing so. This 519 is mainly to get around the problem when a registrant cannot be 520 reached in order to make necessary updates. 522 3.3. Overriding Registration Procedures 524 Experience has shown that the documented IANA considerations for 525 individual protocols do not always adequately cover the reality of 526 registry operation, or are not sufficiently clear. In addition, 527 documented IANA considerations are sometimes found to be too 528 stringent to allow even working group documents (for which there is 529 strong consensus) to perform a registration in advance of actual RFC 530 publication. 532 In order to allow assignments in such cases, the IESG is granted 533 authority to override registration procedures and approve assignments 534 on a case-by-case basis. 536 The intention here is not to overrule properly documented procedures, 537 or to obviate the need for protocols to properly document their IANA 538 considerations. Rather, it is to permit assignments in specific 539 cases where it is obvious that the assignment should just be made, 540 but updating the IANA process beforehand is too onerous. 542 When the IESG is required to take action as described above, it is a 543 strong indicator that the applicable registration procedures should 544 be updated, possibly in parallel with the work that instigated it. 546 IANA always has the discretion to ask the IESG for advice or 547 intervention when they feel it is needed, such as in cases where 548 policies or procedures are unclear to them, where they encounter 549 issues or questions they are unable to resolve, or where registration 550 requests or patterns of requests appear to be unusual or abusive. 552 3.4. Early Allocations 554 IANA normally takes its actions when a document is approved for 555 publication. There are times, though, when early allocation of a 556 value is important for the development of a technology: for example, 557 when early implementations are created while the document is still 558 under development. 560 IANA has a mechanism for handling such early allocations in some 561 cases. See [RFC7120] for details. It is usually not necessary to 562 explicitly mark a registry as allowing early allocation, because the 563 general rules will apply. 565 4. Choosing a Registration Policy, and Well-Known Policies 567 A registration policy is the policy that controls how new assignments 568 in a registry are accepted. There are several issues to consider 569 when defining the registration policy. 571 If the registry's namespace is limited, assignments will need to be 572 made carefully to prevent exhaustion. 574 Even when the space is essentially unlimited, it is still often 575 desirable to have at least a minimal review prior to assignment in 576 order to: 578 o prevent the hoarding of or unnecessary wasting of values. For 579 example, if the space consists of text strings, it may be 580 desirable to prevent entities from obtaining large sets of strings 581 that correspond to desirable names (existing company names, for 582 example). 584 o provide a sanity check that the request actually makes sense and 585 is necessary. Experience has shown that some level of minimal 586 review from a subject matter expert is useful to prevent 587 assignments in cases where the request is malformed or not 588 actually needed (for example, an existing assignment for an 589 essentially equivalent service already exists). 591 Perhaps most importantly, unreviewed extensions can impact 592 interoperability and security. See [RFC6709]. 594 When the namespace is essentially unlimited and there are no 595 potential interoperability or security issues, assigned numbers can 596 usually be given out to anyone without any subjective review. In 597 such cases, IANA can make assignments directly, provided that IANA is 598 given detailed instructions on what types of requests it should 599 grant, and it is able to do so without exercising subjective 600 judgement. 602 When this is not the case, some level of review is required. 603 However, it's important to balance adequate review and ease of 604 registration. In many cases, those making registrations will not be 605 IETF participants; requests often come from other standards 606 organizations, from organizations not directly involved in standards, 607 from ad-hoc community work (from an open-source project, for 608 example), and so on. Registration must not be unnecessarily 609 difficult, unnecessarily costly (in terms of time and other 610 resources), nor unnecessarily subject to denial. 612 While it is sometimes necessary to restrict what gets registered 613 (e.g., for limited resources such as bits in a byte, or for items for 614 which unsupported values can be damaging to protocol operation), in 615 many cases having what's in use represented in the registry is more 616 important. Overly strict review criteria and excessive cost (in time 617 and effort) discourage people from even attempting to make a 618 registration. If a registry fails to reflect the protocol elements 619 actually in use, it can adversely affect deployment of protocols on 620 the Internet, and the registry itself is devalued. 622 Therefore, it is important to think specifically about the 623 registration policy, and not just pick one arbitrarily nor copy text 624 from another document. Working groups and other document developers 625 should use care in selecting appropriate registration policies when 626 their documents create registries. They should select the least 627 strict policy that suits a registry's needs, and look for specific 628 justification for policies that require significant community 629 involvement (those stricter than Expert Review or Specification 630 Required, in terms of the well-known policies). The needs here will 631 vary from registry to registry, and, indeed, over time, and this BCP 632 will not be the last word on the subject. 634 The following policies are defined for common usage. These cover a 635 range of typical policies that have been used to describe the 636 procedures for assigning new values in a namespace. It is not 637 strictly required that documents use these terms; the actual 638 requirement is that the instructions to IANA be clear and 639 unambiguous. However, use of these terms is strongly recommended 640 because their meanings are widely understood. Newly minted policies, 641 including ones that combine the elements of procedures associated 642 with these terms in novel ways, may be used if none of these policies 643 are suitable; it will help the review process if an explanation is 644 included as to why that is the case. The terms are fully explained 645 in the following subsections. 647 1. Private Use 648 2. Experimental Use 649 3. Hierarchical Allocation 650 4. First Come First Served 651 5. Expert Review 652 6. Specification Required 653 7. RFC Required 654 8. IETF Review 655 9. Standards Action 656 10. IESG Approval 658 It should be noted that it often makes sense to partition a namespace 659 into multiple categories, with assignments within each category 660 handled differently. Many protocols now partition namespaces into 661 two or more parts, with one range reserved for Private or 662 Experimental Use while other ranges are reserved for globally unique 663 assignments assigned following some review process. Dividing a 664 namespace into ranges makes it possible to have different policies in 665 place for different ranges and different use cases. 667 Similarly, it will often be useful to specify multiple policies in 668 parallel, with each policy being used under different circumstances. 669 For more discussion of that topic, see Section 4.12. 671 Examples of RFCs that specify multiple policies in parallel: 673 LDAP [RFC4520] 674 TLS ClientCertificateType Identifiers [RFC5246] (as detailed in 675 the subsections below) 676 MPLS Pseudowire Types Registry [RFC4446] 678 4.1. Private Use 680 For private or local use only, with the type and purpose defined by 681 the local site. No attempt is made to prevent multiple sites from 682 using the same value in different (and incompatible) ways. IANA does 683 not record assignments from registries or ranges with this policy 684 (and therefore there is no need for IANA to review them) and 685 assignments are not generally useful for broad interoperability. It 686 is the responsibility of the sites making use of the Private Use 687 range to ensure that no conflicts occur (within the intended scope of 688 use). 690 Examples: 692 Site-specific options in DHCP [RFC2939] 693 Fibre Channel Port Type Registry [RFC4044] 694 TLS ClientCertificateType Identifiers 224-255 [RFC5246] 696 4.2. Experimental Use 698 Experimental Use is similar to Private Use, but with the purpose 699 being to facilitate experimentation. See [RFC3692] for details. 700 IANA does not record assignments from registries or ranges with this 701 policy (and therefore there is no need for IANA to review them) and 702 assignments are not generally useful for broad interoperability. 703 Unless the registry explicitly allows it, it is not appropriate for 704 documents to select explicit values from registries or ranges with 705 this policy. Specific experiments will select a value to use during 706 the experiment. 708 When code points are set aside for experimental use, it's important 709 to make clear any expected restrictions on experimental scope. For 710 example, say whether it's acceptable to run experiments using those 711 code points over the open Internet, or whether such experiments 712 should be confined to more closed environments. See [RFC6994] for an 713 example of such considerations. 715 Example: 717 Experimental Values in IPv4, IPv6, ICMPv4, ICMPv6, UDP, and TCP 718 Headers [RFC4727] 720 4.3. Hierarchical Allocation 722 With Hierarchical Allocation, delegated administrators are given 723 control over part of the namespace, and can assign values in that 724 part of the namespace. IANA makes allocations in the higher levels 725 of the namespace according to one of the other policies. 727 Examples: 729 - DNS names. IANA manages the top-level domains (TLDs), and, as 730 [RFC1591] says: 732 Under each TLD may be created a hierarchy of names. Generally, 733 under the generic TLDs the structure is very flat. That is, 734 many organizations are registered directly under the TLD, and 735 any further structure is up to the individual organizations. 737 - Object Identifiers, defined by ITU-T recommendation X.208. 738 According to , some registries 739 include 741 * IANA, which hands out OIDs the "Private Enterprises" branch, 742 * ANSI, which hands out OIDs under the "US Organizations" branch, 743 and 744 * BSI, which hands out OIDs under the "UK Organizations" branch. 746 - URN namespaces. IANA registers URN Namespace IDs (NIDs [RFC3406]), 747 and the organization registering an NID is responsible for 748 allocations of URNs within that namespace. 750 4.4. First Come First Served 751 For the First Come First Served policy, assignments are made to 752 anyone on a first come, first served basis. There is no substantive 753 review of the request, other than to ensure that it is well-formed 754 and doesn't duplicate an existing assignment. However, requests must 755 include a minimal amount of clerical information, such as a point of 756 contact (including an email address, and sometimes a postal address) 757 and a brief description of how the value will be used. Additional 758 information specific to the type of value requested may also need to 759 be provided, as defined by the namespace. For numbers, IANA 760 generally assigns the next in-sequence unallocated value, but other 761 values may be requested and assigned if an extenuating circumstance 762 exists. With names, specific text strings can usually be requested. 764 When creating a new registry with First Come First Served as the 765 registration policy, in addition to the contact person field or 766 reference, the registry should contain a field for change controller. 767 Having a change controller for each entry for these types of 768 registrations makes authorization of future modifications more clear. 769 See Section 2.3. 771 It is important that changes to the registration of a First Come 772 First Served code point retain compatibility with the current usage 773 of that code point, and so changes need to be made with care. The 774 change controller should not, in most cases, be requesting 775 incompatible changes nor repurposing a registered code point. See 776 also Section 9.4 and Section 9.5. 778 A working group or any other entity that is developing a protocol 779 based on a First Come First Served code point has to be extremely 780 careful that the protocol retains wire compatibility with current use 781 of the code point. Once that is no longer true, the new work needs 782 to change to a different code point (and register that use at the 783 appropriate time). 785 It is also important to understand that First Come First Served 786 really has no filtering. Essentially, any well formed request is 787 accepted. 789 Examples: 791 SASL mechanism names [RFC4422] 792 LDAP Protocol Mechanisms and LDAP Syntax [RFC4520] 794 4.5. Expert Review 796 (Also called "Designated Expert" in earlier editions of this 797 document.) For the Expert Review policy, review and approval by a 798 designated expert (see Section 5) is required. 800 The required documentation and review criteria, giving clear guidance 801 to the designated expert, should be provided when defining the 802 registry. It is particularly important to lay out what should be 803 considered when performing an evaluation and reasons for rejecting a 804 request. It is also a good idea to include, when possible, a sense 805 of whether many registrations are expected over time, or if the 806 registry is expected to be updated infrequently or in exceptional 807 circumstances only. 809 Thorough understanding of Section 5 is important when deciding on an 810 Expert Review policy and designing the guidance to the designated 811 expert. 813 Good examples of guidance to designated experts: 815 Extensible Authentication Protocol (EAP) [RFC3748], Sections 6 and 816 7.2 817 North-Bound Distribution of Link-State and TE Information using 818 BGP [RFC7752], Section 5.1 820 When creating a new registry with Expert Review as the registration 821 policy, in addition to the contact person field or reference, the 822 registry should contain a field for change controller. Having a 823 change controller for each entry for these types of registrations 824 makes authorization of future modifications more clear. See Section 825 2.3 827 Examples: 829 EAP Method Types [RFC3748] 830 HTTP Digest AKA algorithm versions [RFC4169] 831 URI schemes [RFC4395] 832 GEOPRIV Location Types [RFC4589] 834 4.6. Specification Required 836 For the Specification Required policy, review and approval by a 837 designated expert (see Section 5) is required, and the values and 838 their meanings must be documented in a permanent and readily 839 available public specification, in sufficient detail so that 840 interoperability between independent implementations is possible. 841 The designated expert will review the public specification and 842 evaluate whether it is sufficiently stable and permanent, and 843 sufficiently clear to allow interoperable implementations. 845 The intention behind "permanent and readily available" is that a 846 document can reasonably be expected to be findable and retrievable 847 long after IANA assignment of the requested value. Publication of an 848 RFC is an ideal means of achieving this requirement, but 849 Specification Required is intended to also cover the case of a 850 document published outside of the RFC path, including informal 851 documentation. 853 For RFC publication, formal review by the designated expert is still 854 requested, but the normal RFC review process is expected to provide 855 the necessary review for interoperability. The designated expert's 856 review is still important, but it's equally important to note that 857 when there is IETF consensus, the expert can sometimes be "in the 858 rough" (see also the last paragraph of Section 5.4). 860 As with Expert Review (Section 4.5), clear guidance to the designated 861 expert, should be provided when defining the registry, and thorough 862 understanding of Section 5 is important. 864 When specifying this policy, just use the term "Specification 865 Required". Some specifications have chosen to refer to it as "Expert 866 Review with Specification Required", and that only causes confusion. 868 Examples: 870 Diffserv-aware TE Bandwidth Constraints Model Identifiers 871 [RFC4124] 872 TLS ClientCertificateType Identifiers 64-223 [RFC5246] 873 ROHC Profile Identifiers [RFC5795] 875 4.7. RFC Required 877 With the RFC Required policy, the registration request, along with 878 associated documentation, must be published in an RFC. The RFC need 879 not be in the IETF stream, but may be in any RFC stream (currently an 880 RFC may be in the IETF, IRTF, or IAB stream, or an RFC Editor 881 Independent Submission [RFC5742]). 883 Unless otherwise specified, any type of RFC is sufficient (currently 884 Standards Track, BCP, Informational, Experimental, or Historic). 886 Examples: 888 DNSSEC DNS Security Algorithm Numbers [RFC6014] 889 Media Control Channel Framework registries [RFC6230] 890 DANE TLSA Certificate Usages [RFC6698] 892 4.8. IETF Review 894 (Formerly called "IETF Consensus" in the first edition of this 895 document.) With the IETF Review policy, new values are assigned only 896 through RFCs in the IETF Stream -- those that have been shepherded 897 through the IESG as AD-Sponsored or IETF working group Documents 898 [RFC2026] [RFC5378], have gone through IETF last call, and that the 899 IESG has approved as having IETF consensus. 901 The intent is that the document and proposed assignment will be 902 reviewed by the IETF community (including appropriate IETF working 903 groups, directorates, and other experts) and by the IESG, to ensure 904 that the proposed assignment will not negatively affect 905 interoperability or otherwise extend IETF protocols in an 906 inappropriate or damaging manner. 908 Unless otherwise specified, any type of RFC is sufficient (currently 909 Standards Track, BCP, Informational, Experimental, or Historic). 911 Examples: 913 IPSECKEY Algorithm Types [RFC4025] 914 Accounting-Auth-Method AVP values in DIAMETER [RFC4005] 915 TLS Extension Types [RFC5246] 917 4.9. Standards Action 919 For the Standards Action policy, values are assigned only through 920 Standards Track or Best Current Practice RFCs in the IETF Stream. 922 Examples: 924 BGP message types [RFC4271] 925 Mobile Node Identifier option types [RFC4283] 926 TLS ClientCertificateType Identifiers 0-63 [RFC5246] 927 DCCP Packet Types [RFC4340] 929 4.10. IESG Approval 931 New assignments may be approved by the IESG. Although there is no 932 requirement that the request be documented in an RFC, the IESG has 933 discretion to request documents or other supporting materials on a 934 case-by-case basis. 936 IESG Approval is not intended to be used often or as a "common case"; 937 indeed, it has seldom been used in practice. Rather, it is intended 938 to be available in conjunction with other policies as a fall-back 939 mechanism in the case where one of the other allowable approval 940 mechanisms cannot be employed in a timely fashion or for some other 941 compelling reason. IESG Approval is not intended to circumvent the 942 public review processes implied by other policies that could have 943 been employed for a particular assignment. IESG Approval would be 944 appropriate, however, in cases where expediency is desired and there 945 is strong consensus (such as from a working group) for making the 946 assignment. 948 Before approving a request, the IESG might consider consulting the 949 community, via a "call for comments" that provides as much 950 information as is reasonably possible about the request. 952 Examples: 954 IPv4 Multicast address assignments [RFC5771] 955 IPv4 IGMP Type and Code values [RFC3228] 956 Mobile IPv6 Mobility Header Type and Option values [RFC6275] 958 4.11. Using the Well-Known Registration Policies 960 Because the well-known policies benefit from both community 961 experience and wide understanding, their use is encouraged, and the 962 making up of new policies needs to be accompanied by reasonable 963 justification. 965 It is also acceptable to cite one or more well-known policies and 966 include additional guidelines for what kind of considerations should 967 be taken into account by the review process. 969 For example, for media-type registrations [RFC6838], a number of 970 different situations are covered that involve the use of IETF Review 971 and Specification Required, while also including specific additional 972 criteria the Designated Expert should follow. This is not meant to 973 represent a registration procedures, but shows an example of what can 974 be done when special circumstances need to be covered. 976 The well-known policies from "First Come First Served" to "Standards 977 Action" specify a range of policies in increasing order of strictness 978 (using the numbering from the full list in Section 4): 980 4. First Come First Served 981 No review, minimal documentation. 983 5/6. Expert Review / Specification Required 984 Expert review with sufficient documentation for review. / 985 Significant stable public documentation sufficient for 986 interoperability. 988 7. RFC Required 989 Any RFC publication, IETF or a non-IETF Stream. 991 8. IETF Review 992 RFC publication, IETF Stream only, but need not be Standards 993 Track. 995 9. Standards Action 996 RFC publication, IETF Stream, Standards Track or BCP only. 998 Examples of situations that might merit IETF Review or Standards 999 Action include the following: 1001 o When a resource is limited, such as bits in a byte (or in two 1002 bytes, or four), or numbers in a limited range. In these cases, 1003 allowing registrations that haven't been carefully reviewed and 1004 agreed by community consensus could too quickly deplete the 1005 allowable values. 1007 o When thorough community review is necessary to avoid extending or 1008 modifying the protocol in ways that could be damaging. One 1009 example is in defining new command codes, as opposed to options 1010 that use existing command codes: the former might require a strict 1011 policy, where a more relaxed policy could be adequate for the 1012 latter. Another example is in defining protocol elements that 1013 change the semantics of existing operations. 1015 o When there are security implications with respect to the resource, 1016 and thorough review is needed to ensure that the new usage is 1017 sound. Examples of this include lists of acceptable hashing and 1018 cryptographic algorithms, and assignment of transport ports in the 1019 system range. 1021 When reviewing a document that asks IANA to create a new registry or 1022 change a registration policy to any policy more stringent than Expert 1023 Review or Specification Required, the IESG should ask for 1024 justification to ensure that more relaxed policies have been 1025 considered and that the strict policy is the right one. 1027 Accordingly, document developers need to anticipate this and document 1028 their considerations for selecting the specified policy (ideally, in 1029 the document itself; failing that, in the shepherd writeup). 1030 Likewise, the document shepherd should ensure that the selected 1031 policies have been justified before sending the document to the IESG. 1033 When specifications are revised, registration policies should be 1034 reviewed in light of experience since the policies were set. 1036 4.12. Using Multiple Policies in Combination 1038 In some situations, it is necessary to define multiple registration 1039 policies. For example, registrations through the normal IETF process 1040 might use one policy, while registrations from outside the process 1041 would have a different policy applied. 1043 Thus, a particular registry might want to use a policy such as "RFC 1044 Required" or "IETF Review" sometimes, with a designated expert 1045 checking a "Specification Required" policy at other times. 1047 The alternative to using a combination requires either that all 1048 requests come through RFCs or that requests in RFCs go through review 1049 by the designated expert, even though they already have IETF review 1050 and consensus. 1052 This can be documented in the IANA Considerations section when the 1053 registry is created: 1055 IANA is asked to create the registry "Fruit Access Flags" under 1056 the "Fruit Parameters" group. New registrations will be permitted 1057 through either the IETF Review policy or the Specification 1058 Required policy [BCP26]. The latter should be used only for 1059 registrations requested by SDOs outside the IETF. Registrations 1060 requested in IETF documents will be subject to IETF review. 1062 Such combinations will commonly use one of {Standards Action, IETF 1063 Review, RFC Required} in combination with one of {Specification 1064 Required, Expert Review}. Guidance should be provided about when 1065 each policy is appropriate, as in the example above. 1067 5. Designated Experts 1069 5.1. The Motivation for Designated Experts 1071 Discussion on a mailing list can provide valuable technical feedback, 1072 but opinions often vary and discussions may continue for some time 1073 without clear resolution. In addition, IANA cannot participate in 1074 all of these mailing lists and cannot determine if or when such 1075 discussions reach consensus. Therefore, IANA relies on a "designated 1076 expert" for advice regarding the specific question of whether an 1077 assignment should be made. The designated expert is an individual 1078 who is responsible for carrying out an appropriate evaluation and 1079 returning a recommendation to IANA. 1081 It should be noted that a key motivation for having designated 1082 experts is for the IETF to provide IANA with a subject matter expert 1083 to whom the evaluation process can be delegated. IANA forwards 1084 requests for an assignment to the expert for evaluation, and the 1085 expert (after performing the evaluation) informs IANA as to whether 1086 or not to make the assignment or registration. In most cases, the 1087 registrants do not work directly with the designated experts. The 1088 list of designated experts for a registry is listed in the registry. 1090 It will often be useful to use a designated expert only some of the 1091 time, as a supplement to other processes. For more discussion of 1092 that topic, see Section 4.12. 1094 5.2. The Role of the Designated Expert 1096 The designated expert is responsible for coordinating the appropriate 1097 review of an assignment request. The review may be wide or narrow, 1098 depending on the situation and the judgment of the designated expert. 1099 This may involve consultation with a set of technology experts, 1100 discussion on a public mailing list, consultation with a working 1101 group (or its mailing list if the working group has disbanded), etc. 1102 Ideally, the designated expert follows specific review criteria as 1103 documented with the protocol that creates or uses the namespace. See 1104 the IANA Considerations sections of [RFC3748] and [RFC3575] for 1105 specific examples. 1107 Designated experts are expected to be able to defend their decisions 1108 to the IETF community, and the evaluation process is not intended to 1109 be secretive or bestow unquestioned power on the expert. Experts are 1110 expected to apply applicable documented review or vetting procedures, 1111 or in the absence of documented criteria, follow generally accepted 1112 norms such as those in Section 5.3. Designated experts are generally 1113 not expected to be "gatekeepers", setting out to make registrations 1114 difficult to obtain, unless the guidance in the defining document 1115 specifies that they should act as such. Absent stronger guidance, 1116 the experts should be evaluating registration requests for 1117 completeness, interoperability, and conflicts with existing protocols 1118 and options. 1120 It has proven useful to have multiple designated experts for some 1121 registries. Sometimes those experts work together in evaluating a 1122 request, while in other cases additional experts serve as backups, 1123 acting only when the primary expert is unavailable. In registries 1124 with a pool of experts, the pool often has a single chair responsible 1125 for defining how requests are to be assigned to and reviewed by 1126 experts. In other cases, IANA might assign requests to individual 1127 members in sequential or approximate random order. The document 1128 defining the registry can, if it's appropriate for the situation, 1129 specify how the group should work -- for example, it might be 1130 appropriate to specify rough consensus on a mailing list, within a 1131 related working group, or among a pool of designated experts. 1133 In cases of disagreement among multiple experts, it is the 1134 responsibility of those experts to make a single clear recommendation 1135 to IANA. It is not appropriate for IANA to resolve disputes among 1136 experts. In extreme situations, such as deadlock, the designating 1137 body may need to step in to resolve the problem. 1139 If a designated expert has a conflict of interest for a particular 1140 review (is, for example, an author or significant proponent of a 1141 specification related to the registration under review), that expert 1142 should recuse himself. In the event that all the designated experts 1143 are conflicted, they should ask that a temporary expert be designated 1144 for the conflicted review. The responsible AD may then appoint 1145 someone, or the AD may handle the review. 1147 This document defines the designated expert mechanism with respect to 1148 documents in the IETF stream only. If other streams want to use 1149 registration policies that require designated experts, it is up to 1150 those streams (or those documents) to specify how those designated 1151 experts are appointed and managed. What is described below, with 1152 management by the IESG, is only appropriate for the IETF stream. 1154 5.2.1. Managing Designated Experts in the IETF 1155 Designated experts for registries created by the IETF are appointed 1156 by the IESG, normally upon recommendation by the relevant Area 1157 Director. They may be appointed at the time a document creating or 1158 updating a namespace is approved by the IESG, or subsequently, when 1159 the first registration request is received. Because experts 1160 originally appointed may later become unavailable, the IESG will 1161 appoint replacements as necessary. The IESG may remove any 1162 designated expert that it appointed, at its discretion. 1164 The normal appeals process, as described in [RFC2026], Section 6.5.1, 1165 applies to issues that arise with the designated expert team. For 1166 this purpose, the designated expert team takes the place of the 1167 working group in that description. 1169 5.3. Designated Expert Reviews 1171 In the years since RFC 2434 was published and has been put to use, 1172 experience has led to the following observations: 1174 o A designated expert must respond in a timely fashion, normally 1175 within a week for simple requests to a few weeks for more complex 1176 ones. Unreasonable delays can cause significant problems for 1177 those needing assignments, such as when products need code points 1178 to ship. This is not to say that all reviews can be completed 1179 under a firm deadline, but they must be started, and the requester 1180 and IANA should have some transparency into the process if an 1181 answer cannot be given quickly. 1183 o If a designated expert does not respond to IANA's requests within 1184 a reasonable period of time, either with a response or with a 1185 reasonable explanation for the delay (some requests may be 1186 particularly complex), and if this is a recurring event, IANA must 1187 raise the issue with the IESG. Because of the problems caused by 1188 delayed evaluations and assignments, the IESG should take 1189 appropriate actions to ensure that the expert understands and 1190 accepts his or her responsibilities, or appoint a new expert. 1192 o The designated expert is not required to personally bear the 1193 burden of evaluating and deciding all requests, but acts as a 1194 shepherd for the request, enlisting the help of others as 1195 appropriate. In the case that a request is denied, and rejecting 1196 the request is likely to be controversial, the expert should have 1197 the support of other subject matter experts. That is, the expert 1198 must be able to defend a decision to the community as a whole. 1200 When a designated expert is used, the documentation should give clear 1201 guidance to the designated expert, laying out criteria for performing 1202 an evaluation and reasons for rejecting a request. In the case where 1203 there are no specific documented criteria, the presumption should be 1204 that a code point should be granted unless there is a compelling 1205 reason to the contrary (and see also Section 5.4). Reasons that have 1206 been used to deny requests have included these: 1208 o Scarcity of code points, where the finite remaining code points 1209 should be prudently managed, or where a request for a large number 1210 of code points is made and a single code point is the norm. 1212 o Documentation is not of sufficient clarity to evaluate or ensure 1213 interoperability. 1215 o The code point is needed for a protocol extension, but the 1216 extension is not consistent with the documented (or generally 1217 understood) architecture of the base protocol being extended, and 1218 would be harmful to the protocol if widely deployed. It is not 1219 the intent that "inconsistencies" refer to minor differences "of a 1220 personal preference nature". Instead, they refer to significant 1221 differences such as inconsistencies with the underlying security 1222 model, implying a change to the semantics of an existing message 1223 type or operation, requiring unwarranted changes in deployed 1224 systems (compared with alternate ways of achieving a similar 1225 result), etc. 1227 o The extension would cause problems with existing deployed systems. 1229 o The extension would conflict with one under active development by 1230 the IETF, and having both would harm rather than foster 1231 interoperability. 1233 Documents must not name the designated expert(s) in the document 1234 itself; instead, any suggested names should be relayed to the 1235 appropriate Area Director at the time the document is sent to the 1236 IESG for approval. This is usually done in the document shepherd 1237 writeup. 1239 If the request should also be reviewed on a specific public mailing 1240 list, its address should be specified. 1242 5.4. Expert Reviews and the Document Lifecycle 1244 Review by the designated expert is necessarily done at a particular 1245 point in time, and represents review of a particular version of the 1246 document. While reviews are generally done around the time of IETF 1247 last call, deciding when the review should take place is a question 1248 of good judgment. And while re-reviews might be done when it's 1249 acknowledged that the documentation of the registered item has 1250 changed substantially, making sure that re-review happens requires 1251 attention and care. 1253 It is possible, through carelessness, accident, inattentiveness, or 1254 even willful disregard, that changes might be made after the 1255 designated expert's review and approval that would, if the document 1256 were re-reviewed, cause the expert not to approve the registration. 1257 It is up to the IESG, with the token held by the responsible Area 1258 Director, to be alert to such situations and to recognize that such 1259 changes need to be checked. 1261 For registrations made from documents on the Standards Track, there 1262 is often expert review required (by the registration policy) in 1263 addition to IETF consensus (for approval as a Standards Track RFC). 1264 In such cases, the review by the designated expert needs to be 1265 timely, submitted before the IESG evaluates the document. The IESG 1266 should generally not hold the document up waiting for late review. 1267 It is also not intended for the expert review to override IETF 1268 consensus: the IESG should consider the review in its own evaluation, 1269 as it would do for other last-call reviews. 1271 6. Well-Known Registration Status Terminology 1273 The following labels describe the status of an assignment or range of 1274 assignments: 1276 Private Use: Private use only (not assigned), as described in 1277 Section 4.1. 1279 Experimental: Available for general experimental use as described 1280 in [RFC3692]. IANA does not record specific assignments for 1281 any particular use. 1283 Unassigned: Not currently assigned, and available for assignment 1284 via documented procedures. While it's generally clear that 1285 any values that are not registered are unassigned and 1286 available for assignment, it is sometimes useful to 1287 explicitly specify that situation. Note that this is 1288 distinctly different from "Reserved". 1290 Reserved: Not assigned and not available for assignment. Reserved 1291 values are held for special uses, such as to extend the 1292 namespace when it becomes exhausted. "Reserved" is also 1293 sometimes used to designate values that had been assigned 1294 but are no longer in use, keeping them set aside as long as 1295 other unassigned values are available. Note that this is 1296 distinctly different from "Unassigned". 1298 Reserved values can be released for assignment by the change 1299 controller for the registry (this is often the IESG, for 1300 registries created by RFCs in the IETF stream). 1302 Known Unregistered Use: It's known that the assignment or range is 1303 in use without having been defined in accordance with 1304 reasonable practice. Documentation for use of the 1305 assignment or range may be unavailable, inadequate, or 1306 conflicting. This is a warning against use, as well as an 1307 alert to network operators, who might see these values in 1308 use on their networks. 1310 7. Documentation References in IANA Registries 1312 Usually, registries and registry entries include references to 1313 documentation (RFCs or other documents). The purpose of these 1314 references is to provide pointers for implementors to find details 1315 necessary for implementation, NOT to simply note what document 1316 created the registry or entry. Therefore: 1318 o If a document registers an item that is defined and explained 1319 elsewhere, the registered reference should be to the document 1320 containing the definition, not to the document that is merely 1321 performing the registration. 1323 o If the registered item is defined and explained in the current 1324 document, it is important to include sufficient information to 1325 enable implementors to understand the item and to create a proper 1326 implementation. 1328 o If the registered item is explained primarily in a specific 1329 section of the reference document, it is useful to include a 1330 section reference. For example, "[RFC4637], Section 3.2", rather 1331 than just "[RFC4637]". 1333 o For documentation of a new registry, the reference should provide 1334 information about the registry itself, not just a pointer to the 1335 creation of it. Useful information includes the purpose of the 1336 registry, a rationale for its creation, documentation of the 1337 process and policy for new registrations, guidelines for new 1338 registrants or designated experts, and other such related 1339 information. But note that, while it's important to include this 1340 information in the document, it needn't all be in the IANA 1341 Considerations section. See Section 1.1. 1343 8. What to Do in "bis" Documents 1345 On occasion, an RFC is issued that obsoletes a previous edition of 1346 the same document. We sometimes call these "bis" documents, such as 1347 when RFC 4637 is obsoleted by draft-ietf-foo-rfc4637bis. When the 1348 original document created registries and/or registered entries, there 1349 is a question of how to handle the IANA Considerations section in the 1350 "bis" document. 1352 If the registrations specify the original document as a reference, 1353 those registrations should be updated to point to the current (not 1354 obsolete) documentation for those items. Usually, that will mean 1355 changing the reference to be the "bis" document. 1357 There will, though, be times when a document updates another, but 1358 does not make it obsolete, and the definitive reference is changed 1359 for some items but not for others. Be sure that the references are 1360 always set to point to the correct, current documentation for each 1361 item. 1363 For example, suppose RFC 4637 registered the "BANANA" flag in the 1364 "Fruit Access Flags" registry, and the documentation for that flag is 1365 in Section 3.2. 1367 The current registry might look, in part, like this: 1369 Name Description Reference 1370 -------- ------------------- --------- 1371 BANANA Flag for bananas [RFC4637], Section 3.2 1373 If draft-ietf-foo-rfc4637bis obsoletes RFC 4637 and, because of some 1374 rearrangement, now documents the flag in Section 4.1.2, the IANA 1375 Considerations of the bis document might contain text such as this: 1377 IANA is asked to change the registration information for the 1378 BANANA flag in the "Fruit Access Flags" registry to the following: 1380 Name Description Reference 1381 -------- ------------------- --------- 1382 BANANA Flag for bananas [[this RFC]], Section 4.2.1 1384 In many cases, if there are a number of registered references to the 1385 original RFC and the document organization has not changed the 1386 registered section numbering much, it may simply be reasonable to do 1387 this: 1389 Because this document obsoletes RFC 4637, IANA is asked to change 1390 all registration information that references [RFC4637] to instead 1391 reference [[this RFC]]. 1393 If information for registered items has been or is being moved to 1394 other documents, then the registration information should be changed 1395 to point to those other documents. In most cases, documentation 1396 references should not be left pointing to the obsoleted document for 1397 registries or registered items that are still in current use. For 1398 registries or registered items that are no longer in current use, it 1399 will usually make sense to leave the references pointing to the old 1400 document -- the last current reference for the obsolete items. The 1401 main point is to make sure that the reference pointers are as useful 1402 and current as is reasonable, and authors should consider that as 1403 they write the IANA Considerations for the new document. As always: 1404 do the right thing, and there is flexibility to allow for that. 1406 It is extremely important to be clear in your instructions regarding 1407 updating references, especially in cases where some references need 1408 to be updated and others do not. 1410 9. Miscellaneous Issues 1412 9.1. When There Are No IANA Actions 1414 Before an Internet-Draft can be published as an RFC, IANA needs to 1415 know what actions (if any) it needs to perform. Experience has shown 1416 that it is not always immediately obvious whether a document has no 1417 IANA actions, without reviewing the document in some detail. In 1418 order to make it clear to IANA that it has no actions to perform (and 1419 that the author has consciously made such a determination), such 1420 documents should, after the authors confirm that this is the case, 1421 include an IANA Considerations section that states: 1423 This document has no IANA actions. 1425 IANA prefers that these "empty" IANA Considerations sections be left 1426 in the document for the record: it makes it clear later on that the 1427 document explicitly said that no IANA actions were needed (and that 1428 it wasn't just omitted). This is a change from the prior practice of 1429 requesting that such sections be removed by the RFC Editor, and 1430 authors are asked to accommodate this change. 1432 9.2. Namespaces Lacking Documented Guidance 1434 For all existing RFCs that either explicitly or implicitly rely on 1435 IANA to make assignments without specifying a precise assignment 1436 policy, IANA will work with the IESG to decide what policy is 1437 appropriate. Changes to existing policies can always be initiated 1438 through the normal IETF consensus process, or through the IESG when 1439 appropriate. 1441 All future RFCs that either explicitly or implicitly rely on IANA to 1442 register or otherwise administer namespace assignments must provide 1443 guidelines for administration of the namespace. 1445 9.3. After-the-Fact Registrations 1447 Occasionally, the IETF becomes aware that an unassigned value from a 1448 namespace is in use on the Internet or that an assigned value is 1449 being used for a different purpose than it was registered for. The 1450 IETF does not condone such misuse; procedures of the type described 1451 in this document need to be applied to such cases, and it might not 1452 always be possible to formally assign the desired value. In the 1453 absence of specifications to the contrary, values may only be 1454 reassigned for a different purpose with the consent of the original 1455 assignee (when possible) and with due consideration of the impact of 1456 such a reassignment. In cases of likely controversy, consultation 1457 with the IESG is advised. 1459 This is part of the reason for the advice in Section 3.1 about using 1460 placeholder values, such as "TBD1", during document development: open 1461 use of unregistered values after results from well-meant, early 1462 implementations, where the implementations retained the use of 1463 developmental code points that never proceeded to a final IANA 1464 assignment. 1466 9.4. Reclaiming Assigned Values 1468 Reclaiming previously assigned values for reuse is tricky, because 1469 doing so can lead to interoperability problems with deployed systems 1470 still using the assigned values. Moreover, it can be extremely 1471 difficult to determine the extent of deployment of systems making use 1472 of a particular value. However, in cases where the namespace is 1473 running out of unassigned values and additional ones are needed, it 1474 may be desirable to attempt to reclaim unused values. When 1475 reclaiming unused values, the following (at a minimum) should be 1476 considered: 1478 o Attempts should be made to contact the original party to which a 1479 value is assigned, to determine if the value was ever used, and if 1480 so, the extent of deployment. (In some cases, products were never 1481 shipped or have long ceased being used. In other cases, it may be 1482 known that a value was never actually used at all.) 1484 o Reassignments should not normally be made without the concurrence 1485 of the original requester. Reclamation under such conditions 1486 should only take place where there is strong evidence that a value 1487 is not widely used, and the need to reclaim the value outweighs 1488 the cost of a hostile reclamation. In any case, IESG Approval is 1489 needed in this case. 1491 o It may be appropriate to write up the proposed action and solicit 1492 comments from relevant user communities. In some cases, it may be 1493 appropriate to write an RFC that goes through a formal IETF 1494 process (including IETF Last Call) as was done when DHCP reclaimed 1495 some of its "Private Use" options [RFC3942]. 1497 o It may be useful to differentiate between revocation, release, and 1498 transfer. Revocation occurs when IANA removes an assignment, 1499 release occurs when the assignee initiates that removal, and 1500 transfer occurs when either revocation or release is coupled with 1501 immediate reassignment. It may be useful to specify procedures 1502 for each of these, or to explicitly prohibit combinations that are 1503 not desired. 1505 9.5. Contact Person vs Assignee or Owner 1507 Many registries include designation of a technical or administrative 1508 contact associated with each entry. Often, this is recorded as 1509 contact information for an individual. It is unclear, though, what 1510 role the individual has with respect to the registration: is this 1511 item registered on behalf of the individual, the company the 1512 individual worked for, or perhaps another organization the individual 1513 was acting for? 1515 This matters because some time later, when the individual has changed 1516 jobs or roles, and perhaps can no longer be contacted, someone might 1517 want to update the registration. IANA has no way to know what 1518 company, organization, or individual should be allowed to take the 1519 registration over. For registrations rooted in RFCs, the stream 1520 owner (such as the IESG or the IAB) can make an overriding decision. 1521 But in other cases, there is no recourse. 1523 Registries can include, in addition to a "Contact" field, an 1524 "Assignee" or "Owner" field (also referred to as "Change Controller") 1525 that can be used to address this situation, giving IANA clear 1526 guidance as to the actual owner of the registration. This is 1527 strongly advised especially for registries that do not require RFCs 1528 to manage their information (registries with policies such as First 1529 Come First Served Section 4.4, Expert Review Section 4.5, and 1530 Specification Required Section 4.6). Alternatively, organizations 1531 can put an organizational role into the "Contact" field in order to 1532 make their ownership clear. 1534 9.6. Closing or Obsoleting a Registry/Registrations 1536 Sometimes there is a request to "close" a registry to further 1537 registrations. When a registry is closed, no further registrations 1538 will be accepted. The information in the registry will still be 1539 valid and registrations already in the registry can still be updated. 1541 A closed registry can also be marked as "obsolete", as an indication 1542 that the information in the registry is no longer in current use. 1544 Specific entries in a registry can be marked as "obsolete" (no longer 1545 in use) or "deprecated" (use is not recommended). 1547 Such changes to registries and registered values are subject to 1548 normal change controls (see Section 2.3). Any closure, obsolescence, 1549 or deprecation serves to annotate the registry involved; the 1550 information in the registry remains there for informational and 1551 historic purposes. 1553 10. Appeals 1555 Appeals of protocol parameter registration decisions can be made 1556 using the normal IETF appeals process as described in [RFC2026], 1557 Section 6.5. That is, an initial appeal should be directed to the 1558 IESG, followed (if necessary) by an appeal to the IAB. 1560 11. Mailing Lists 1562 All IETF mailing lists associated with evaluating or discussing 1563 assignment requests as described in this document are subject to 1564 whatever rules of conduct and methods of list management are 1565 currently defined by Best Current Practices or by IESG decision. 1567 12. Security Considerations 1569 Information that creates or updates a registration needs to be 1570 authenticated and authorized. IANA updates registries according to 1571 instructions in published RFCs and from the IESG. It also may accept 1572 clarifications from document authors, relevant working group chairs, 1573 Designated Experts, and mail list participants, too. 1575 Information concerning possible security vulnerabilities of a 1576 protocol may change over time. Likewise, security vulnerabilities 1577 related to how an assigned number is used may change as well. As new 1578 vulnerabilities are discovered, information about such 1579 vulnerabilities may need to be attached to existing registrations, so 1580 that users are not misled as to the true security issues surrounding 1581 the use of a registered number. 1583 Security needs to be considered as part of the selection of a 1584 registration policy. For some protocols, registration of certain 1585 parameters will have security implications, and registration policies 1586 for the relevant registries must ensure that requests get appropriate 1587 review with those security implications in mind. 1589 An analysis of security issues is generally required for all 1590 protocols that make use of parameters (data types, operation codes, 1591 keywords, etc.) used in IETF protocols or registered by IANA. Such 1592 security considerations are usually included in the protocol document 1593 [RFC3552]. It is the responsibility of the IANA considerations 1594 associated with a particular registry to specify whether value- 1595 specific security considerations must be provided when assigning new 1596 values, and the process for reviewing such claims. 1598 13. IANA Considerations 1599 IANA is asked to update any references to RFC 5226 to now point to 1600 this document. 1602 14. Changes Relative to Earlier Editions of BCP 26 1604 14.1. 2016: Changes in This Document Relative to RFC 5226 1606 Significant additions: 1608 o Removed RFC 2119 key words, boilerplate, and reference, preferring 1609 plain English -- this is not a protocol specification. 1611 o Added Section 1.1, Keep IANA Considerations for IANA 1613 o Added Section 1.2, For More Information 1615 o Added Section 2.1, Hierarchical Registry Structure 1617 o Added best practice for selecting an appropriate policy into 1618 Section 4. 1620 o Added Section 4.12, Using Multiple Policies in Combination. 1622 o Added Section 2.3, Specifying Change Control for a Registry 1624 o Added Section 3.4, Early Allocations 1626 o Moved well-known policies into a separate section for each, 1627 subsections of Section 4. 1629 o Added Section 5.4, Expert Reviews and the Document Lifecycle 1631 o Added Section 7, Documentation References in IANA Registries 1633 o Added Section 8, What to Do in "bis" Documents 1635 o Added Section 9.5, Contact Person vs Assignee or Owner 1637 o Added Section 9.6, Closing or Obsoleting a Registry 1639 Clarifications and such: 1641 o Some reorganization -- moved text around for clarity and easier 1642 reading. 1644 o Made clarifications about identification of IANA registries and 1645 use of URLs for them. 1647 o Clarified the distinction between "Unassigned" and "Reserved". 1649 o Made some clarifications in "Expert Review" about instructions to 1650 the designated expert. 1652 o Made some clarifications in "Specification Required" about how to 1653 declare this policy. 1655 o Assorted minor clarifications and editorial changes throughout. 1657 14.2. 2008: Changes in RFC 5226 Relative to RFC 2434 1659 Changes include: 1661 o Major reordering of text to expand descriptions and to better 1662 group topics such as "updating registries" vs. "creating new 1663 registries", in order to make it easier for authors to find the 1664 text most applicable to their needs. 1666 o Numerous editorial changes to improve readability. 1668 o Changed the term "IETF Consensus" to "IETF Review" and added more 1669 clarifications. History has shown that people see the words "IETF 1670 Consensus" (without consulting the actual definition) and are 1671 quick to make incorrect assumptions about what the term means in 1672 the context of IANA Considerations. 1674 o Added "RFC Required" to list of defined policies. 1676 o Much more explicit directions and examples of "what to put in 1677 RFCs". 1679 o "Specification Required" now implies use of a Designated Expert to 1680 evaluate specs for sufficient clarity. 1682 o Significantly changed the wording in the Designated Experts 1683 section. Main purpose is to make clear that Expert Reviewers are 1684 accountable to the community, and to provide some guidance for 1685 review criteria in the default case. 1687 o Changed wording to remove any special appeals path. The normal 1688 RFC 2026 appeals path is used. 1690 o Added a section about reclaiming unused values. 1692 o Added a section on after-the-fact registrations. 1694 o Added a section indicating that mailing lists used to evaluate 1695 possible assignments (such as by a Designated Expert) are subject 1696 to normal IETF rules. 1698 15. Acknowledgments 1700 15.1. Acknowledgments for This Document (2016) 1701 Thomas Narten and Harald Tveit Alvestrand edited the two earlier 1702 editions of this document (RFCs 2434 and 5226), and Thomas continues 1703 his role in this third edition. Much of the text from RFC 5226 1704 remains in this edition. 1706 Thank you to Amanda Baber and Pearl Liang for their multiple reviews 1707 and suggestions for making this document as thorough as possible. 1709 This document has benefited from thorough review and comments by many 1710 people, including Benoit Claise, Alissa Cooper, Adrian Farrel, 1711 Stephen Farrell, Tony Hansen, John Klensin, Kathleen Moriarty, Mark 1712 Nottingham, Pete Resnick, and Joe Touch. 1714 Special thanks to Mark Nottingham for reorganizing some of the text 1715 for better organization and readability, to Tony Hansen for acting as 1716 document shepherd, and to Brian Haberman and Terry Manderson for 1717 acting as sponsoring ADs. 1719 15.2. Acknowledgments from the second edition (2008) 1721 The original acknowledgments section in RFC 5226 was: 1723 This document has benefited from specific feedback from Jari Arkko, 1724 Marcelo Bagnulo Braun, Brian Carpenter, Michelle Cotton, Spencer 1725 Dawkins, Barbara Denny, Miguel Garcia, Paul Hoffman, Russ Housley, 1726 John Klensin, Allison Mankin, Blake Ramsdell, Mark Townsley, Magnus 1727 Westerlund, and Bert Wijnen. 1729 15.3. Acknowledgments from the first edition (1998) 1731 The original acknowledgments section in RFC 2434 was: 1733 Jon Postel and Joyce Reynolds provided a detailed explanation on what 1734 IANA needs in order to manage assignments efficiently, and patiently 1735 provided comments on multiple versions of this document. Brian 1736 Carpenter provided helpful comments on earlier versions of the 1737 document. One paragraph in the Security Considerations section was 1738 borrowed from RFC 4288. 1740 16. References 1742 16.1. Normative References 1744 [RFC2026] Bradner, S., "The Internet Standards Process -- Revision 1745 3", BCP 9, RFC 2026, October 1996. 1747 16.2. Informative References 1749 [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, September 1750 1981. 1752 [RFC1591] Postel, J., "Domain Name System Structure and Delegation", 1753 RFC 1591, DOI 10.17487/RFC1591, March 1994, . 1756 [RFC2860] Carpenter, B., Baker, F. and M. Roberts, "Memorandum of 1757 Understanding Concerning the Technical Work of the 1758 Internet Assigned Numbers Authority", RFC 2860, June 2000. 1760 [RFC2939] Droms, R., "Procedures and IANA Guidelines for Definition 1761 of New DHCP Options and Message Types", BCP 43, RFC 2939, 1762 September 2000. 1764 [RFC3228] Fenner, B., "IANA Considerations for IPv4 Internet Group 1765 Management Protocol (IGMP)", BCP 57, RFC 3228, February 1766 2002. 1768 [RFC3406] Daigle, L., van Gulik, D., Iannella, R. and P. Faltstrom, 1769 "Uniform Resource Names (URN) Namespace Definition 1770 Mechanisms", BCP 66, RFC 3406, DOI 10.17487/RFC3406, 1771 October 2002, . 1773 [RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC 1774 Text on Security Considerations", BCP 72, RFC 3552, July 1775 2003. 1777 [RFC3575] Aboba, B., "IANA Considerations for RADIUS (Remote 1778 Authentication Dial In User Service)", RFC 3575, July 1779 2003. 1781 [RFC3692] Narten, T., "Assigning Experimental and Testing Numbers 1782 Considered Useful", BCP 82, RFC 3692, January 2004. 1784 [RFC3748] Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J. and H. 1785 Levkowetz, "Extensible Authentication Protocol (EAP)", RFC 1786 3748, June 2004. 1788 [RFC3942] Volz, B., "Reclassifying Dynamic Host Configuration 1789 Protocol version 4 (DHCPv4) Options", RFC 3942, November 1790 2004. 1792 [RFC3968] Camarillo, G., "The Internet Assigned Number Authority 1793 (IANA) Header Field Parameter Registry for the Session 1794 Initiation Protocol (SIP)", BCP 98, RFC 3968, December 1795 2004. 1797 [RFC4005] Calhoun, P., Zorn, G., Spence, D. and D. Mitton, "Diameter 1798 Network Access Server Application", RFC 4005, August 2005. 1800 [RFC4025] Richardson, M., "A Method for Storing IPsec Keying 1801 Material in DNS", RFC 4025, March 2005. 1803 [RFC4044] McCloghrie, K., "Fibre Channel Management MIB", RFC 4044, 1804 May 2005. 1806 [RFC4124] Le Faucheur, F., "Protocol Extensions for Support of 1807 Diffserv-aware MPLS Traffic Engineering", RFC 4124, June 1808 2005. 1810 [RFC4169] Torvinen, V., Arkko, J. and M. Naslund, "Hypertext 1811 Transfer Protocol (HTTP) Digest Authentication Using 1812 Authentication and Key Agreement (AKA) Version-2", RFC 1813 4169, November 2005. 1815 [RFC4271] Rekhter, Y., Li, T. and S. Hares, "A Border Gateway 1816 Protocol 4 (BGP-4)", RFC 4271, January 2006. 1818 [RFC4283] Patel, A., Leung, K., Khalil, M., Akhtar, H. and K. 1819 Chowdhury, "Mobile Node Identifier Option for Mobile IPv6 1820 (MIPv6)", RFC 4283, November 2005. 1822 [RFC4340] Kohler, E., Handley, M. and S. Floyd, "Datagram Congestion 1823 Control Protocol (DCCP)", RFC 4340, March 2006. 1825 [RFC4395] Hansen, T., Hardie, T. and L. Masinter, "Guidelines and 1826 Registration Procedures for New URI Schemes", BCP 35, RFC 1827 4395, February 2006. 1829 [RFC4422] Melnikov, A. and K. Zeilenga, "Simple Authentication and 1830 Security Layer (SASL)", RFC 4422, June 2006. 1832 [RFC4446] Martini, L., "IANA Allocations for Pseudowire Edge to Edge 1833 Emulation (PWE3)", BCP 116, RFC 4446, April 2006. 1835 [RFC4520] Zeilenga, K., "Internet Assigned Numbers Authority (IANA) 1836 Considerations for the Lightweight Directory Access 1837 Protocol (LDAP)", BCP 64, RFC 4520, June 2006. 1839 [RFC4589] Schulzrinne, H. and H. Tschofenig, "Location Types 1840 Registry", RFC 4589, July 2006. 1842 [RFC4727] Fenner, B., "Experimental Values In IPv4, IPv6, ICMPv4, 1843 ICMPv6, UDP, and TCP Headers", RFC 4727, November 2006. 1845 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security 1846 (TLS) Protocol Version 1.2", RFC 5246, August 2008. 1848 [RFC5378] Bradner, S. and J. Contreras, "Rights Contributors Provide 1849 to the IETF Trust", BCP 78, RFC 5378, November 2008. 1851 [RFC5742] Alvestrand, H. and R. Housley, "IESG Procedures for 1852 Handling of Independent and IRTF Stream Submissions", BCP 1853 92, RFC 5742, December 2009. 1855 [RFC5771] Cotton, M., Vegoda, L. and D. Meyer, "IANA Guidelines for 1856 IPv4 Multicast Address Assignments", BCP 51, RFC 5771, 1857 March 2010. 1859 [RFC5795] Sandlund, K., Pelletier, G. and L-E. Jonsson, "The RObust 1860 Header Compression (ROHC) Framework", RFC 5795, March 1861 2010. 1863 [RFC6014] Hoffman, P., "Cryptographic Algorithm Identifier 1864 Allocation for DNSSEC", RFC 6014, DOI 10.17487/RFC6014, 1865 November 2010, . 1867 [RFC6195] Eastlake, D., "Domain Name System (DNS) IANA 1868 Considerations", BCP 42, RFC 6195, March 2011. 1870 [RFC6230] Boulton, C., Melanchuk, T. and S. McGlashan, "Media 1871 Control Channel Framework", RFC 6230, DOI 10.17487/ 1872 RFC6230, May 2011, . 1875 [RFC6275] Perkins, C., Johnson, D. and J. Arkko, "Mobility Support 1876 in IPv6", RFC 6275, July 2011. 1878 [RFC6698] Hoffman, P. and J. Schlyter, "The DNS-Based Authentication 1879 of Named Entities (DANE) Transport Layer Security (TLS) 1880 Protocol: TLSA", RFC 6698, DOI 10.17487/RFC6698, August 1881 2012, . 1883 [RFC6709] Carpenter, B., Aboba, B. and S. Cheshire, "Design 1884 Considerations for Protocol Extensions", RFC 6709, 1885 September 2012. 1887 [RFC6838] Freed, N., Klensin, J. and T. Hansen, "Media Type 1888 Specifications and Registration Procedures", BCP 13, RFC 1889 6838, DOI 10.17487/RFC6838, January 2013, . 1892 [RFC6994] Touch, J., "Shared Use of Experimental TCP Options", RFC 1893 6994, DOI 10.17487/RFC6994, August 2013, . 1896 [RFC7120] Cotton, M., "Early IANA Allocation of Standards Track Code 1897 Points", BCP 100, RFC 7120, January 2014. 1899 [RFC7564] Saint-Andre, P. and M. Blanchet, "PRECIS Framework: 1900 Preparation, Enforcement, and Comparison of 1901 Internationalized Strings in Application Protocols", RFC 1902 7564, DOI 10.17487/RFC7564, May 2015, . 1905 [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A. and 1906 S. Ray, "North-Bound Distribution of Link-State and 1907 Traffic Engineering (TE) Information Using BGP", RFC 7752, 1908 DOI 10.17487/RFC7752, March 2016, . 1911 Authors' Addresses 1912 Michelle Cotton 1913 Internet Corporation for Assigned Names and Numbers 1914 12025 Waterfront Drive, Suite 300 1915 Los Angeles, CA 90094-2536 1916 US 1918 Phone: +1 310 823 9358 1919 Email: michelle.cotton@icann.org 1920 URI: https://www.icann.org/ 1922 Barry Leiba 1923 Huawei Technologies 1925 Phone: +1 646 827 0648 1926 Email: barryleiba@computer.org 1927 URI: http://internetmessagingtechnology.org/ 1929 Thomas Narten 1930 IBM Corporation 1931 3039 Cornwallis Ave., PO Box 12195 - BRQA/502 1932 Research Triangle Park, NC 27709-2195 1933 US 1935 Phone: +1 919 254 7798 1936 Email: narten@us.ibm.com