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Versions: (RFC 5226) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 RFC 8126

Network Working Group                                          M. Cotton
Internet-Draft                                 Internet Assigned Numbers
Obsoletes: 5226 (if approved)                           Authority (IANA)
Intended status: BCP                                            B. Leiba
Expires: February 2, 2013                            Huawei Technologies
                                                               T. Narten
                                                         IBM Corporation
                                                          August 1, 2012


     Guidelines for Writing an IANA Considerations Section in RFCs
                   draft-leiba-cotton-iana-5226bis-00

Abstract

   Many protocols make use of identifiers consisting of constants and
   other well-known values.  Even after a protocol has been defined and
   deployment has begun, new values may need to be assigned (such as for
   a new option type in DHCP, or a new encryption or authentication
   transform for IPsec).  To ensure that such quantities have consistent
   values and interpretations across all implementations, their
   assignment must be administered by a central authority.  For IETF
   protocols, that role is provided by the Internet Assigned Numbers
   Authority (IANA).

   In order for IANA to manage a given namespace prudently, it needs
   guidelines describing the conditions under which new values can be
   assigned or when modifications to existing values can be made.  If
   IANA is expected to play a role in the management of a namespace,
   IANA must be given clear and concise instructions describing that
   role.  This document discusses issues that should be considered in
   formulating a policy for assigning values to a namespace and provides
   guidelines for authors on the specific text that must be included in
   documents that place demands on IANA.

   This document obsoletes RFC 5226.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months



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   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on February 2, 2013.

Copyright Notice

   Copyright (c) 2012 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.































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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  5
     1.1.  Terminology Used In This Document  . . . . . . . . . . . .  5
   2.  Why Management of a Namespace May Be Necessary . . . . . . . .  6
   3.  Designated Experts . . . . . . . . . . . . . . . . . . . . . .  7
     3.1.  The Motivation for Designated Experts  . . . . . . . . . .  7
     3.2.  The Role of the Designated Expert  . . . . . . . . . . . .  8
     3.3.  Designated Expert Reviews  . . . . . . . . . . . . . . . .  9
     3.4.  Expert Reviews and the Document Lifecycle  . . . . . . . . 10
   4.  Creating a Registry  . . . . . . . . . . . . . . . . . . . . . 11
     4.1.  Well-Known IANA Policy Definitions . . . . . . . . . . . . 11
       4.1.1.  Policy: Private Use  . . . . . . . . . . . . . . . . . 12
       4.1.2.  Policy: Experimental Use . . . . . . . . . . . . . . . 12
       4.1.3.  Policy: Hierarchical Allocation  . . . . . . . . . . . 13
       4.1.4.  Policy: First Come First Served  . . . . . . . . . . . 13
       4.1.5.  Policy: Expert Review  . . . . . . . . . . . . . . . . 13
       4.1.6.  Policy: Specification Required . . . . . . . . . . . . 14
       4.1.7.  Policy: RFC Required . . . . . . . . . . . . . . . . . 14
       4.1.8.  Policy: IETF Review  . . . . . . . . . . . . . . . . . 14
       4.1.9.  Policy: Standards Action . . . . . . . . . . . . . . . 15
       4.1.10. Policy: IESG Approval  . . . . . . . . . . . . . . . . 15
     4.2.  Best Practice for Selecting an Appropriate Policy  . . . . 16
     4.3.  What to Put in Documents That Create a Registry  . . . . . 19
     4.4.  Updating IANA Guidelines for Existing Registries . . . . . 21
   5.  Registering New Values in an Existing Registry . . . . . . . . 22
     5.1.  What to Put in Documents When Registering Values . . . . . 22
     5.2.  Updating Registrations . . . . . . . . . . . . . . . . . . 23
     5.3.  Overriding Registration Procedures . . . . . . . . . . . . 24
   6.  Documentation References in IANA Registries  . . . . . . . . . 25
   7.  What to Do in "bis" Documents  . . . . . . . . . . . . . . . . 25
   8.  Miscellaneous Issues . . . . . . . . . . . . . . . . . . . . . 26
     8.1.  When There Are No IANA Actions . . . . . . . . . . . . . . 26
     8.2.  Namespaces Lacking Documented Guidance . . . . . . . . . . 27
     8.3.  After-the-Fact Registrations . . . . . . . . . . . . . . . 27
     8.4.  Reclaiming Assigned Values . . . . . . . . . . . . . . . . 28
     8.5.  Contact Person vs Assignee or Owner  . . . . . . . . . . . 28
     8.6.  BCP 78/79 Issues in Registries . . . . . . . . . . . . . . 29
   9.  Appeals  . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
   10. Mailing Lists  . . . . . . . . . . . . . . . . . . . . . . . . 29
   11. Security Considerations  . . . . . . . . . . . . . . . . . . . 29
   12. Changes Relative to Earlier Editions of BCP 26 . . . . . . . . 30
     12.1. 2012: Changes in This Document Relative to RFC 5226  . . . 30
     12.2. 2008: Changes in RFC 5226 Relative to RFC 2434 . . . . . . 31
   13. Acknowledgments  . . . . . . . . . . . . . . . . . . . . . . . 31
     13.1. Acknowledgments for This Document (2012) . . . . . . . . . 31
     13.2. Acknowledgments from the second edition (2008) . . . . . . 32
     13.3. Acknowledgments from the first edition (1998)  . . . . . . 32



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   14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 32
     14.1. Normative References . . . . . . . . . . . . . . . . . . . 32
     14.2. Informative References . . . . . . . . . . . . . . . . . . 32
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 35















































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1.  Introduction

   Many protocols make use of fields that contain constants and other
   well-known values (such as the Protocol field in the IP header
   [RFC0791] and MIME media types [RFC4288]).  Even after a protocol has
   been defined and deployment has begun, new values may need to be
   assigned (such as a new option type in DHCP [RFC2132] or a new
   encryption or authentication transform for IPsec [RFC4301]).  To
   ensure that such fields have consistent values and interpretations in
   different implementations, their assignment must be administered by a
   central authority.  For IETF protocols, that role is provided by the
   Internet Assigned Numbers Authority (IANA) [RFC2860].

   In this document, we call the set of possible values for such a field
   a "namespace"; its actual value may be a text string, a number, or
   another kind of value.  The binding or association of a specific
   value with a particular purpose within a namespace is called an
   assigned number (or assigned value, or sometimes a "code point",
   "protocol constant", or "protocol parameter").  Each assignment of a
   value in a namespace is called a registration.

   In order for IANA to manage a given namespace prudently, it needs
   guidelines describing the conditions under which new values should be
   assigned or when (and how) modifications to existing values can be
   made.  This document provides guidelines to authors on what sort of
   text should be added to their documents in order to provide IANA
   clear guidelines, and it reviews issues that should be considered in
   formulating an appropriate policy for assigning numbers to name
   spaces.

   Not all namespaces require centralized administration.  In some
   cases, it is possible to delegate a namespace in such a way that
   further assignments can be made independently and with no further
   (central) coordination.  In the Domain Name System, for example, IANA
   only deals with assignments at the higher levels, while subdomains
   are administered by the organization to which the space has been
   delegated.  As another example, Object Identifiers (OIDs) as defined
   by the ITU are also delegated [RFC3232]; IANA manages the subtree
   rooted at "iso.org.dod.internet" (1.3.6.1) .  When a namespace is
   delegated, the scope of IANA is limited to the parts of the namespace
   where IANA has authority.

1.1.  Terminology Used In This Document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].
   For this document, "the specification" as used by RFC 2119 refers to



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   the processing of protocol documents within the IETF standards
   process.


2.  Why Management of a Namespace May Be Necessary

   One issue to consider in managing a namespace is its size.  If the
   space is small and limited in size, assignments must be made
   carefully to prevent exhaustion of the space.  If the space is
   essentially unlimited, on the other hand, potential exhaustion will
   probably not be a practical concern at all.  Even when the space is
   essentially unlimited, however, it is usually desirable to have at
   least a minimal review prior to assignment in order to:

   o  prevent the hoarding of or unnecessary wasting of values.  For
      example, if the space consists of text strings, it may be
      desirable to prevent entities from obtaining large sets of strings
      that correspond to desirable names (existing company names, for
      example).

   o  provide a sanity check that the request actually makes sense and
      is necessary.  Experience has shown that some level of minimal
      review from a subject matter expert is useful to prevent
      assignments in cases where the request is malformed or not
      actually needed (for example, an existing assignment for an
      essentially equivalent service already exists).

   A second consideration is whether it makes sense to delegate the
   namespace in some manner.  This route should be pursued when
   appropriate, as it lessens the burden on IANA for dealing with
   assignments.

   A third, and perhaps most important, consideration concerns potential
   impact on the interoperability of unreviewed extensions.  Proposed
   protocol extensions generally benefit from community review; indeed,
   review is often essential to avoid future interoperability problems
   [I-D.iab-extension-recs].

   When the namespace is essentially unlimited and there are no
   potential interoperability issues, assigned numbers can safely be
   given out to anyone without any subjective review.  In such cases,
   IANA can make assignments directly, provided that IANA is given
   specific instructions on what types of requests it should grant, and
   what information must be provided as part of a well-formed request
   for an assigned number.






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3.  Designated Experts

3.1.  The Motivation for Designated Experts

   It should be noted that IANA does not create or define assignment
   policy itself; rather, it carries out policies that have been defined
   by others and published in RFCs.  IANA must be given a set of
   guidelines that allow it to make allocation decisions with minimal
   subjectivity and without requiring any technical expertise with
   respect to the protocols that make use of a registry.

   In many cases, some review of prospective allocations is appropriate,
   and the question becomes who should perform the review and what is
   the purpose of the review.  One might think that an IETF working
   group familiar with the namespace at hand should be consulted.  In
   practice, however, working groups eventually disband, so they cannot
   be considered a permanent evaluator.  It is also possible for
   namespaces to be created through individual submission documents, for
   which no working group is ever formed.

   One way to ensure community review of prospective assignments is to
   have the requester submit a document for publication as an RFC.  Such
   an action helps ensure that the specification is publicly and
   permanently available, and it allows some review of the specification
   prior to publication and assignment of the requested code points.
   This is the preferred way of ensuring review, and is particularly
   important if any potential interoperability issues can arise.  For
   example, some assignments are not just assignments, but also involve
   an element of protocol specification.  A new option may define fields
   that need to be parsed and acted on, which (if specified poorly) may
   not fit cleanly with the architecture of other options or the base
   protocols on which they are built.

   In some cases, however, the burden of publishing an RFC in order to
   get an assignment is excessive.  However, it is generally still
   useful (and sometimes necessary) to discuss proposed additions on a
   mailing list dedicated to the purpose (such as the
   media-types@iana.org for media types) or on a more general mailing
   list (such as that of a current or former IETF working group).  Such
   a mailing list provides a way for new registrations to be publicly
   reviewed prior to getting assigned, or gives advice to persons
   wanting help in understanding what a proper registration should
   contain.

   While discussion on a mailing list can provide valuable technical
   feedback, opinions may vary and discussions may continue for some
   time without clear resolution.  In addition, IANA cannot participate
   in all of these mailing lists and cannot determine if or when such



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   discussions reach consensus.  Therefore, IANA relies on a "designated
   expert" for advice regarding the specific question of whether an
   assignment should be made.  The designated expert is an individual
   who is responsible for carrying out an appropriate evaluation and
   returning a recommendation to IANA.

   It should be noted that a key motivation for having designated
   experts is for the IETF to provide IANA with a subject matter expert
   to whom the evaluation process can be delegated.  IANA forwards
   requests for an assignment to the expert for evaluation, and the
   expert (after performing the evaluation) informs IANA as to whether
   or not to make the assignment or registration.

3.2.  The Role of the Designated Expert

   The designated expert is responsible for initiating and coordinating
   the appropriate review of an assignment request.  The review may be
   wide or narrow, depending on the situation and the judgment of the
   designated expert.  This may involve consultation with a set of
   technology experts, discussion on a public mailing list, consultation
   with a working group (or its mailing list if the working group has
   disbanded), etc.  Ideally, the designated expert follows specific
   review criteria as documented with the protocol that creates or uses
   the namespace.  See the IANA Considerations sections of [RFC3748] and
   [RFC3575] for examples that have been done for specific namespaces.

   Designated experts are expected to be able to defend their decisions
   to the IETF community, and the evaluation process is not intended to
   be secretive or bestow unquestioned power on the expert.  Experts are
   expected to apply applicable documented review or vetting procedures,
   or in the absence of documented criteria, follow generally accepted
   norms such as those in Section 3.3.

   Section 5.2 discusses disputes and appeals in more detail.

   Designated experts are appointed by the IESG (normally upon
   recommendation by the relevant Area Director).  They are typically
   named at the time a document creating or updating a namespace is
   approved by the IESG, but as experts originally appointed may later
   become unavailable, the IESG will appoint replacements if necessary.

   For some registries, it has proven useful to have multiple designated
   experts.  Sometimes those experts work together in evaluating a
   request, while in other cases additional experts serve as backups.
   In cases of disagreement among those experts, it is the
   responsibility of those experts to make a single clear recommendation
   to IANA.  It is not appropriate for IANA to resolve disputes among
   experts.  In extreme situations, such as deadlock, the IESG may need



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   to step in to resolve the problem.

   In registries where a pool of experts evaluates requests, the pool
   should have a single chair responsible for defining how requests are
   to be assigned to and reviewed by experts.  In some cases, the expert
   pool may consist of a primary and backups, with the backups involved
   only when the primary expert is unavailable.  In other cases, IANA
   might assign requests to individual members in sequential or
   approximate random order.  In the event that IANA finds itself having
   received conflicting advice from its experts, it is the
   responsibility of the pool's chair to resolve the issue and provide
   IANA with clear instructions.

   Since the designated experts are appointed by the IESG, they may be
   removed by the IESG.

3.3.  Designated Expert Reviews

   In the years since RFC 2434 was published and has been put to use,
   experience has led to the following observations:

   o  A designated expert must respond in a timely fashion, normally
      within a week for simple requests to a few weeks for more complex
      ones.  Unreasonable delays can cause significant problems for
      those needing assignments, such as when products need code points
      to ship.  This is not to say that all reviews can be completed
      under a firm deadline, but they must be started, and the requester
      and IANA should have some transparency into the process if an
      answer cannot be given quickly.

   o  If a designated expert does not respond to IANA's requests within
      a reasonable period of time, either with a response or with a
      reasonable explanation for the delay (some requests may be
      particularly complex), and if this is a recurring event, IANA must
      raise the issue with the IESG.  Because of the problems caused by
      delayed evaluations and assignments, the IESG should take
      appropriate actions to ensure that the expert understands and
      accepts his or her responsibilities, or appoint a new expert.

   o  The designated expert is not required to personally bear the
      burden of evaluating and deciding all requests, but acts as a
      shepherd for the request, enlisting the help of others as
      appropriate.  In the case that a request is denied, and rejecting
      the request is likely to be controversial, the expert should have
      the support of other subject matter experts.  That is, the expert
      must be able to defend a decision to the community as a whole.

   When a designated expert is used, the documentation should give clear



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   guidance to the designated expert, laying out criteria for performing
   an evaluation and reasons for rejecting a request.  In the case where
   there are no specific documented criteria, the presumption should be
   that a code point should be granted unless there is a compelling
   reason to the contrary.  Possible reasons to deny a request include
   these:

   o  Scarcity of code points, where the finite remaining code points
      should be prudently managed, or when a request for a large number
      of code points is made, when a single code point is the norm.

   o  Documentation is not of sufficient clarity to evaluate or ensure
      interoperability.

   o  The code point is needed for a protocol extension, but the
      extension is not consistent with the documented (or generally
      understood) architecture of the base protocol being extended, and
      would be harmful to the protocol if widely deployed.  It is not
      the intent that "inconsistencies" refer to minor differences "of a
      personal preference nature".  Instead, they refer to significant
      differences such as inconsistencies with the underlying security
      model, implying a change to the semantics of an existing message
      type or operation, requiring unwarranted changes in deployed
      systems (compared with alternate ways of achieving a similar
      result), etc.

   o  The extension would cause problems with existing deployed systems.

   o  The extension would conflict with one under active development by
      the IETF, and having both would harm rather than foster
      interoperability.

3.4.  Expert Reviews and the Document Lifecycle

   Review by the designated expert is necessarily done at a particular
   point in time, and represents review of a particular version of the
   document.  Deciding when the review should take place is a question
   of good judgment.  And while re-reviews might be done when it's
   acknowledged that the documentation of the registered item has
   changed substantially, making sure that re-review happens requires
   attention and care.

   It is possible, through carelessness, accident, inattentiveness, or
   even willful disregard, that changes might be made after the
   designated expert's review and approval that would, if the document
   were re-reviewed, cause the expert not to approve the registration.
   It is up to the IESG, with the token held by the responsible Area
   Director, to be alert to such situations and to recognize that such



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   changes need to be checked.


4.  Creating a Registry

   Creating a registry involves describing the namespaces to be created,
   an initial set of assignments (if appropriate), and guidelines on how
   future assignments are to be made.

   Once a registry has been created, IANA records assignments that have
   been made.  The following labels describe the status of an individual
   (or range) of assignments:



      Private Use:  Private use only (not assigned), as described in
            Section 4.1.1.

      Experimental:  Available for general experimental use as described
            in [RFC3692].  IANA does not record specific assignments for
            any particular use.

      Unassigned:  Not currently assigned, and available for assignment
            via documented procedures.  While it's generally clear that
            any values that are not registered are unassigned and
            available for assignment, it is sometimes useful to
            explicitly specify that situation.  Note that this is
            distinctly different from "Reserved".

      Reserved:  Not assigned and not available for assignment.
            Reserved values are held for special uses, such as to extend
            the namespace when it becomes exhausted.  Note that this is
            distinctly different from "Unassigned".

4.1.  Well-Known IANA Policy Definitions

   The following are some defined policies, most of which are in use
   today.  These cover a range of typical policies that have been used
   to describe the procedure for assigning new values in a namespace.
   It is not strictly required that documents use these terms; the
   actual requirement is that the instructions to IANA be clear and
   unambiguous.  However, use of these terms is strongly RECOMMENDED,
   because their meanings are widely understood.  The terms are fully
   explained in the following subsections.







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      1.   Private Use
      2.   Experimental Use
      3.   Hierarchical Allocation
      4.   First Come First Served
      5.   Expert Review
      6.   Specification Required
      7.   RFC Required
      8.   IETF Review
      9.   Standards Action
      10.  IESG Approval

   It should be noted that it often makes sense to partition a namespace
   into multiple categories, with assignments within each category
   handled differently.  Many protocols now partition namespaces into
   two or more parts, with one range reserved for Private or
   Experimental Use while other ranges are reserved for globally unique
   assignments assigned following some review process.  Dividing a
   namespace into ranges makes it possible to have different policies in
   place for different ranges and different use cases.

   Examples:
      LDAP [RFC4520]
      TLS ClientCertificateType Identifiers [RFC5246] (as detailed in
      the subsections below)
      Pseudowire Edge to Edge Emulation (PWE3) [RFC4446]

4.1.1.  Policy: Private Use

   For private or local use only, with the type and purpose defined by
   the local site.  No attempt is made to prevent multiple sites from
   using the same value in different (and incompatible) ways.  There is
   no need for IANA to review such assignments (since IANA does not
   record them) and assignments are not generally useful for broad
   interoperability.  It is the responsibility of the sites making use
   of the Private Use range to ensure that no conflicts occur (within
   the intended scope of use).

   Examples:
      Site-specific options in DHCP [RFC2939]
      Fibre Channel Port Type Registry [RFC4044]
      TLS ClientCertificateType Identifiers 224-255 [RFC5246]

4.1.2.  Policy: Experimental Use

   Similar to private or local use only, with the purpose being to
   facilitate experimentation.  See [RFC3692] for details.

   Example:



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      Experimental Values in IPv4, IPv6, ICMPv4, ICMPv6, UDP, and TCP
      Headers [RFC4727]

4.1.3.  Policy: Hierarchical Allocation

   Delegated managers can assign values provided they have been given
   control over that part of the namespace.  IANA controls the higher
   levels of the namespace according to one of the other policies.

   Examples:
      DNS names
      Object Identifiers
      IP addresses

4.1.4.  Policy: First Come First Served

   Assignments are made to anyone on a first come, first served basis.
   There is no substantive review of the request, other than to ensure
   that it is well-formed and doesn't duplicate an existing assignment.
   However, requests must include a minimal amount of clerical
   information, such as a point of contact (including an email address)
   and a brief description of how the value will be used.  Additional
   information specific to the type of value requested may also need to
   be provided, as defined by the namespace.  For numbers, the exact
   value is generally assigned by IANA; with names, specific text
   strings can usually be requested.

   Examples:
      SASL mechanism names [RFC4422]
      LDAP Protocol Mechanisms and LDAP Syntax [RFC4520]

4.1.5.  Policy: Expert Review

   (Sometimes also called "Designated Expert" in earlier editions of
   this document.)  Approval by a designated expert is required.  The
   required documentation and review criteria for use by the designated
   expert should be provided when defining the registry.  For example,
   see Sections 6 and 7.2 in [RFC3748].

   It is particularly important, when using a designated expert, to give
   clear guidance to the expert, laying out criteria for performing an
   evaluation and reasons for rejecting a request.  When specifying a
   policy that involves a designated expert, the IANA Considerations
   SHOULD contain such guidance.  It is also a good idea to include,
   when possible, a sense of whether many registrations are expected
   over time, or if the registry is expected to be updated infrequently
   or in exceptional circumstances only.




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   Examples:
      EAP Method Types [RFC3748]
      HTTP Digest AKA algorithm versions [RFC4169]
      URI schemes [RFC4395]
      GEOPRIV Location Types [RFC4589]

4.1.6.  Policy: Specification Required

   Values and their meanings must be documented in a permanent and
   readily available public specification, in sufficient detail so that
   interoperability between independent implementations is possible.
   When used, Specification Required also implies use of a Designated
   Expert (see Section 4.1.5), who will review the public specification
   and evaluate whether it is sufficiently clear to allow interoperable
   implementations.  The intention behind "permanent and readily
   available" is that a document can reasonably be expected to be
   findable and retrievable long after IANA assignment of the requested
   value.  Publication of an RFC is an ideal means of achieving this
   requirement, but Specification Required is intended to also cover the
   case of a document published outside of the RFC path.  For RFC
   publication, the normal RFC review process is expected to provide the
   necessary review for interoperability, though the designated expert
   may be a particularly well-qualified person to perform such a review.

   When specifying this policy, just use the term "Specification
   Required".  Some specifications have chosen to refer to it as "Expert
   Review with Specification Required", and that only causes confusion.

   Examples:
      Diffserv-aware TE Bandwidth Constraints Model Identifiers
      [RFC4124]
      TLS ClientCertificateType Identifiers 64-223 [RFC5246]
      ROHC Profile Identifiers [RFC5795]

4.1.7.  Policy: RFC Required

   RFC publication suffices, as an IETF submission or in any other
   stream (currently an RFC Editor Independent Submission [RFC5742] or
   an RFC in the IRTF or IAB Stream).  Unless otherwise specified, any
   type of RFC is sufficient (currently Standards Track, BCP,
   Informational, Experimental, Historic).

4.1.8.  Policy: IETF Review

   (Formerly called "IETF Consensus" in the first edition of this
   document.)  New values are assigned only through RFCs in the IETF
   Stream -- those that have been shepherded through the IESG as AD-
   Sponsored or IETF working group Documents [RFC2026] [RFC5378].  The



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   intention is that the document and proposed assignment will be
   reviewed by the IESG and appropriate IETF working groups (or experts,
   if suitable working groups no longer exist) to ensure that the
   proposed assignment will not negatively impact interoperability or
   otherwise extend IETF protocols in an inappropriate or damaging
   manner.

   To ensure adequate community review, such documents are shepherded
   through the IESG as AD-sponsored or working group documents with an
   IETF Last Call.

   Examples:
      IPSECKEY Algorithm Types [RFC4025]
      Accounting-Auth-Method AVP values in DIAMETER [RFC4005]
      TLS Extension Types [RFC5246]

4.1.9.  Policy: Standards Action

   Values are assigned only for Standards Track RFCs approved by the
   IESG.

   Examples:
      BGP message types [RFC4271]
      Mobile Node Identifier option types [RFC4283]
      TLS ClientCertificateType Identifiers 0-63 [RFC5246]
      DCCP Packet Types [RFC4340]

4.1.10.  Policy: IESG Approval

   New assignments may be approved by the IESG.  Although there is no
   requirement that the request be documented in an RFC, the IESG has
   discretion to request documents or other supporting materials on a
   case-by-case basis.

   IESG Approval is not intended to be used often or as a "common case";
   indeed, it has seldom been used in practice during the period RFC
   2434 was in effect.  Rather, it is intended to be available in
   conjunction with other policies as a fall-back mechanism in the case
   where one of the other allowable approval mechanisms cannot be
   employed in a timely fashion or for some other compelling reason.
   IESG Approval is not intended to circumvent the public review
   processes implied by other policies that could have been employed for
   a particular assignment.  IESG Approval would be appropriate,
   however, in cases where expediency is desired and there is strong
   consensus (such as from a working group) for making the assignment.

   The following guidelines are suggested for any evaluation under IESG
   Approval:



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   o  The IESG can (and should) reject a request if another path for
      registration is available that is more appropriate and there is no
      compelling reason not to use that path.

   o  Before approving a request, the community should be consulted, via
      a "call for comments" that provides as much information as is
      reasonably possible about the request.

   Examples:
      IPv4 Multicast address assignments [RFC5771]
      IPv4 IGMP Type and Code values [RFC3228]
      Mobile IPv6 Mobility Header Type and Option values [RFC6275]

4.2.  Best Practice for Selecting an Appropriate Policy

   The definitions above from "First Come First Served" to "Standards
   Action" specify a range of policies in increasing order of
   strictness:

   4.   First Come First Served:
        No review, minimal documentation.

   5.   Expert Review:
        Expert review, sufficient documentation for review.

   6.   Specification Required:
        Expert review, significant, stable public documentation.

   7.   RFC Required:
        Any RFC publication, IETF or a non-IETF Stream.

   8.   IETF Review:
        RFC publication, IETF Stream only, but need not be Standards
        Track.

   9.   Standards Action:
        RFC publication, IETF Stream, Standards Track only.

   In considering which of those policies to apply, it's important to
   get the right balance of review and ease of registration.  In many
   cases, those needing to register items will not be IETF participants;
   requests often come from other standards organizations, from
   organizations not directly involved in standards, from ad-hoc
   community work (from an open-source project, for example), and so on.
   We must not make registration policies and procedures unnecessarily
   difficult to navigate, unnecessarily costly (in terms of time and
   other resources), nor unnecessarily subject to denial.




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   While it is sometimes necessary to restrict what gets registered (for
   limited resources such as bits in a byte or numbers within a
   relatively small range, or for items for which unsupported values can
   be damaging to protocol operation), in many cases having items
   registered is more important than putting restrictions on the
   registration.  A pattern of denial through overly strict review
   criteria, or because of excessive cost in time and effort to get
   through the process, discourages people from even attempting to
   register their items.  And failure to have in-use items registered
   adversely affects the protocols in use on the Internet.

   In particular, because policies 7 through 9 require involvement of
   working groups, directorates, and/or communities of former working-
   group participants to be actively involved and to support the effort,
   requests frequently run into concerns that "it's not worth doing a
   Standards-Track RFC for something this trivial," when, in fact, that
   requirement was created by the working group in the first place, with
   its selection of a Standards Action policy for the registry.  Indeed,
   publishing any RFC is costly, and a Standards Track RFC is especially
   so, requiring a great deal of community time for review and
   discussion, IETF-wide last call, involvement of the entire IESG as
   well as concentrated time and review from the sponsoring AD, review
   and action by IANA, and RFC-Editor processing.

   Working groups and other document developers should use care in
   selecting appropriate registration policies when their documents
   create registries.  They should select the least strict policy that
   suits a registry's needs, and look for specific justification for
   policies stricter than Specification Required.  Examples of
   situations that might merit RFC Required, IETF Review, or Standards
   Action include the following.

   o  Registries of limited resources, such as bits in a byte (or in two
      bytes, or four), or numbers in a limited range.  In these cases,
      allowing registrations that haven't been carefully reviewed and
      agreed by community consensus could too quickly deplete the
      allowable values.

   o  Registries for which thorough community review is necessary to
      avoid extending or modifying the protocol in ways that could be
      damaging.  One example is in defining new command codes, as
      opposed to options that use existing command codes: the former
      might require a strict policy, where a more relaxed policy could
      be adequate for the latter.  Another example is in defining things
      that change the semantics of existing operations.

   There will be other cases, as well, of course; much assessment and
   judgment is needed.  It's not the intent here to put limits on the



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   applicability of particular registration policies, but to recommend
   laxity, rather than strictness, in general, and to encourage document
   developers to think carefully about each registry before deciding on
   policies.

   The description in Section 4.1.10 of "IESG Approval" suggests that
   the IESG "can (and should) reject a request if another path for
   registration is available that is more appropriate and there is no
   compelling reason not to use that path."  The IESG should give
   similar consideration to any registration policy more stringent than
   Specification Required, asking for justification and ensuring that
   more relaxed policies have been considered, and the strict policy is
   the right one.  This is a situation that will -- and should --
   involve a substantive discussion between the IESG and the working
   group, chairs, document editors, and/or document shepherd.  The
   important point, again, is not to relax the registration policy just
   to get the document through quickly, but to carefully choose the
   right policy for each registry.

   Accordingly, document developers need to anticipate this and document
   their considerations for selecting the specified policy.  Ideally,
   they should include that in the document.  At the least, it should be
   included in the shepherd writeup for the document, and in any case
   the document shepherd should ensure that the selected policies have
   been justified before sending the document to the IESG.

   When specifications are revised, registration policies should be
   reviewed in light of experience since the policies were set.  It is
   also possible to produce a small document at any time, which
   "updates" the original specification and changes registration
   policies.  In either case, a policy can be relaxed or made more
   strict, as appropriate to the actual situation.

   Once again, it cannot be stressed enough that this must not be a
   mechanical process, but one to which the document developers apply
   thought, consideration, assessment, and judgment in choosing the
   right policy for each registry.

   The recommendations in this section apply whether the well-defined
   policy names defined herein are used, or whether the document
   contains other policy definitions.  The point, again, is not to limit
   registration policies, but to ensure that the policies selected are
   appropriate, and that proper consideration has been given to the
   level of strictness required by them.







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4.3.  What to Put in Documents That Create a Registry

   The previous sections presented some issues that should be considered
   in formulating a policy for assigning values in namespaces.  It is
   the working group and/or document author's job to formulate an
   appropriate policy and specify it in the appropriate document.  In
   almost all cases, having an explicit "IANA Considerations" section is
   appropriate.  The following and later sections define what is needed
   for the different types of IANA actions.

   Documents that create a new namespace (or modify the definition of an
   existing space) and that expect IANA to play a role in maintaining
   that space (serving as a repository for registered values) MUST
   provide clear instructions on details of the namespace.  In
   particular, instructions MUST include:

   1.  The name of the registry (or sub-registry) being created and/or
       maintained.
       The name will appear on the IANA web page and will be referred to
       in future documents that need to allocate a value from the new
       space.  The full name (and abbreviation, if appropriate) should
       be provided.  It is highly desirable that the chosen name not be
       easily confusable with the name of another registry.  When
       creating a sub-registry, the registry that it is a part of must
       be clearly identified using its exact name (look it up, to be
       sure).  Providing a URL to precisely identify the registry is
       helpful.  Such URLs will be removed from the RFC prior to final
       publication, but help to ensure that IANA will understand exactly
       what is being requested.  For example, a document could contain
       something like this:

          [TO BE REMOVED: This registration should be made in the Foobar
          Operational Parameters registry, located at
          http://www.iana.org/assignments/foobar-registry]

   2.  What information must be provided as part of a request in order
       to assign a new value.  This information may include the need to
       document relevant security considerations, if any.

   3.  The review process that will apply to all future requests for a
       value from the namespace.

       Note: When a designated expert is used, documents MUST NOT name
       the designated expert in the document itself; instead, any
       suggested names should be relayed to the appropriate Area
       Director at the time the document is sent to the IESG for
       approval.  This is usually done in the document shepherd writeup.




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       If the request should also be reviewed on a specific public
       mailing list (such as the media-types@iana.org for media types),
       that mailing address should be specified.  Note, however, that
       when mailing lists are specified, the requirement for a
       designated expert MUST also be specified (see Section 3).

       If IANA is expected to make assignments without requiring an
       outside review, sufficient guidance MUST be provided so that the
       requests can be evaluated with minimal subjectivity.

   4.  The size, format, and syntax of registry entries.  When creating
       a new name/number space, authors must describe any technical
       requirements on registry (and sub-registry) values (valid ranges
       for integers, length limitations on strings, etc.) as well as the
       exact format in which registry values should be displayed.  For
       number assignments, one should specify whether values are to be
       recorded in decimal, hexadecimal, or some other format.  For
       strings, the encoding format should be specified (ASCII, UTF8,
       etc.).  Authors should also clearly specify what fields to record
       in the registry.

   5.  Initial assignments and reservations.  Clear instructions should
       be provided to identify any initial assignments or registrations.
       In addition, any ranges that are to be reserved for "Private
       Use", "Reserved", "Unassigned", etc. should be clearly indicated.

   When specifying the process for making future assignments, it is
   quite acceptable to pick one (or more) of the example policies listed
   in Section 4.1 and refer to it by name.  Indeed, this is the
   preferred mechanism in those cases where the sample policies provide
   the desired level of review.  It is also acceptable to cite one of
   the above policies and include additional guidelines for what kind of
   considerations should be taken into account by the review process.
   For example, RADIUS [RFC3575] specifies the use of a Designated
   Expert, but includes specific additional criteria the Designated
   Expert should follow.

   For example, a document could say something like this:













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       ---------------------------------------------------------------
       This document defines a new DHCP option, entitled "FooBar" (see
       Section y), assigned a value of TBD1 from the DHCP Option space
       [to be removed upon publication:
       http://www.iana.org/assignments/bootp-dhcp-parameters]
       [RFC2132] [RFC2939]:
                                      Data
             Tag     Name            Length      Meaning
             ----    ----            ------      -------
             TBD1    FooBar          N           FooBar server

       The FooBar option also defines an 8-bit FooType field, for which
       IANA is to create and maintain a new sub-registry entitled
       "FooType values" under the FooBar option.  Initial values for the
       DHCP FooBar FooType registry are given below; future assignments
       are to be made through Expert Review [BCP26].
       Assignments consist of a DHCP FooBar FooType name and its
       associated value.

             Value    DHCP FooBar FooType Name        Definition
             ----     ------------------------        ----------
             0        Reserved
             1        Frobnitz                        See Section y.1
             2        NitzFrob                        See Section y.2
             3-254    Unassigned
             255      Reserved
       ---------------------------------------------------------------

   For examples of documents that provide detailed guidance to IANA on
   the issue of assigning numbers, consult [RFC6195], [RFC3575],
   [RFC3968], and [RFC4520].

4.4.  Updating IANA Guidelines for Existing Registries

   Updating the registration process for an already existing (previously
   created) namespace (whether created explicitly or implicitly) follows
   a process similar to that used when creating a new namespace.  That
   is, a document is produced that makes reference to the existing
   namespace and then provides detailed guidelines for handling
   assignments in each individual namespace.  Such documents are
   normally processed as Best Current Practices (BCPs) [RFC2026].

   Example documents that updated the guidelines for managing (then)
   pre-existing registries include: [RFC6195], [RFC3228], and [RFC3575].







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5.  Registering New Values in an Existing Registry

5.1.  What to Put in Documents When Registering Values

   Often, documents request an assignment from an already existing
   namespace (one created by a previously published document).  In such
   cases:

   o  Documents should clearly identify the namespace in which each
      value is to be registered.  If the registration goes into a sub-
      registry, the author should clearly describe where the assignment
      or registration should go.  It is helpful to use the *exact*
      namespace name as listed on the IANA web page (please look it up,
      and don't guess), and cite the RFC where the namespace is defined.

      Note 1: There is no need to mention what the assignment policy for
      new assignments is, as that should be clear from the references.

      Note 2: When referring to an existing registry, providing a URL to
      precisely identify the registry is helpful.  Such URLs, however,
      should usually be removed from the RFC prior to final publication,
      since IANA URLs are not guaranteed to be stable in the future.  In
      cases where it is important to include a URL in the document, IANA
      should concur on its inclusion.

      For example, a document could contain something like this:

         [TO BE REMOVED: This registration should be made in the Foobar
         Operational Parameters registry, located at
         http://www.iana.org/assignments/foobar-registry]

   o  Each value requested should be given a unique reference.  When the
      value is numeric, use the notation: TBD1, TBD2, etc.  Throughout
      the document where an actual IANA-assigned value should be filled
      in, use the "TBDx" notation.  This helps ensure that the final RFC
      has the correct assigned values inserted in all of the relevant
      places where the value is expected to appear in the final
      document.  For values that are text strings, a specific name can
      be suggested.  IANA will normally assign the name, unless it
      conflicts with a name already in use.

   o  Normally, the values to be used are chosen by IANA and documents
      should specify values of "TBD".  However, in some cases, a value
      may have been used for testing or in early implementations.  In
      such cases, it is acceptable to include text suggesting what
      specific value should be used (together with the reason for the
      choice).  For example, one might include the text "the value XXX
      is suggested as it is used in implementations".  However, it



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      should be noted that suggested values are just that; IANA will
      attempt to assign them, but may find that impossible, if the
      proposed number has already been assigned for some other use.  For
      some registries, IANA has a long-standing policy prohibiting
      assignment of names or codes on a vanity or organization-name
      basis.  For example, codes are always assigned sequentially unless
      there is a strong reason for making an exception.  Nothing in this
      document is intended to change those policies or prevent their
      future application.

   o  The IANA Considerations section should summarize all of the IANA
      actions, with pointers to the relevant sections elsewhere in the
      document as appropriate.  When multiple values are requested, it
      is generally helpful to include a summary table.  It is also
      helpful for this table to be in the same format as it appears or
      will appear on the IANA web site.  For example:


               Value     Description          Reference
               --------  -------------------  ---------
               TBD1      Foobar               [[this RFC]]


      Note: In cases where authors feel that including the full table is
      too verbose or repetitive, authors should still include the table
      in the draft, but may include a note asking that the table be
      removed prior to publication of the final RFC.

   As an example, the following text could be used to request assignment
   of a DHCPv6 option number:

      IANA has assigned an option code value of TBD1 to the DNS
      Recursive Name Server option and an option code value of TBD2 to
      the Domain Search List option from the DHCP option code space
      defined in Section 24.3 of RFC 3315.

5.2.  Updating Registrations

   Registrations are a request to assign a new value, including the
   related information needed to evaluate and document the request.
   Even after a number has been assigned, some types of registrations
   contain additional information that may need to be updated over time.
   For example, MIME media types, character sets, and language tags,
   etc. typically include more information than just the registered
   value itself.  Example information can include point-of-contact
   information, security issues, pointers to updates, literature
   references, etc.  In such cases, the document defining the namespace
   must clearly state who is responsible for maintaining and updating a



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   registration.  In different cases, it may be appropriate to specify
   one or more of the following:

   o  Let the author update the registration, subject to the same
      constraints and review as with new registrations.

   o  Allow some mechanism to attach comments to the registration, for
      cases where others have significant objections to claims in a
      registration, but the author does not agree to change the
      registration.

   o  Designate the IESG, a designated expert, or another entity as
      having the right to change the registrant associated with a
      registration and any requirements or conditions on doing so.  This
      is mainly to get around the problem when a registrant cannot be
      reached in order to make necessary updates.

5.3.  Overriding Registration Procedures

   Since RFC 2434 was published, experience has shown that the
   documented IANA considerations for individual protocols do not always
   adequately cover the reality after the protocol is deployed.  For
   example, many older routing protocols do not have documented,
   detailed IANA considerations.  In addition, documented IANA
   considerations are sometimes found to be too stringent to allow even
   working group documents (for which there is strong consensus) to
   obtain code points from IANA in advance of actual RFC publication.
   In other cases, the documented procedures are unclear or neglected to
   cover all the cases.  In order to allow assignments in individual
   cases where there is strong IETF consensus that an allocation should
   go forward, but the documented procedures do not support such an
   assignment, the IESG is granted authority to approve assignments in
   such cases.  The intention is not to overrule properly documented
   procedures, or to obviate the need for protocols to properly document
   their IANA considerations.  Instead, the intention is to permit
   assignments in individual cases where it is obvious that the
   assignment should just be made, but updating the IANA process just to
   assign a particular code point is viewed as too heavy a burden.

   In general, the IETF would like to see deficient IANA registration
   procedures for a namespace revised through the IETF standards
   process, but not at the cost of unreasonable delay for needed
   assignments.  If the IESG has had to take the action in this section,
   it is a strong indicator that the IANA registration procedures should
   be updated, possibly in parallel with ongoing protocol work.






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6.  Documentation References in IANA Registries

   Usually, registries and registry entries include references to
   documentation (RFCs or other documents).  The purpose of these
   references is to provide pointers for implementors to find details
   necessary for implementation, NOT to simply note what document
   created the registry or entry.  Therefore:

   o  If a document registers an item that is defined and explained
      elsewhere, the registered reference should be to that document,
      and not to the document that is merely performing the
      registration.

   o  If the registered item is defined and explained in the current
      document, it is important to include sufficient information to
      enable implementors to understand the item and to create a proper
      implementation.

   o  If the registered item is explained primarily in a specific
      section of the reference document, it is useful to include a
      section reference.  For example, "[RFC9876], Section 3.2", rather
      than just "[RFC9876]".

   o  For documentation of a new registry, the reference should provide
      information about the registry itself, not just a pointer to the
      creation of it.  Useful information includes the purpose of the
      registry, a rationale for its creation, documentation of the
      process and policy for new registrations, guidelines for new
      registrants or designated experts, and other such related
      information.


7.  What to Do in "bis" Documents

   We often produce a new edition of an RFC, which obsoletes the
   previous edition (we sometimes call these "bis" documents, such as
   when RFC 9876 is updated by draft-ietf-foo-rfc9876bis).  When the
   original document created registries and/or registered entries, there
   is a question of how to handle the IANA Considerations section in the
   "bis" document.

   If the registrations specify the original document as a reference,
   those registrations should be updated to point to the current (not
   obsolete) documentation for those items.  Usually, that will mean
   changing the reference to be the "bis" document.

   For example, suppose RFC 9876 registered the "BANANA" flag in the
   "Fruit Access Flags" registry, and the documentation for that flag is



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   in Section 3.2.  The current registry might look, in part, like this:

      Name      Description          Reference
      --------  -------------------  ---------
      BANANA    Flag for bananas     [RFC9876], Section 3.2

   If draft-ietf-foo-rfc9876bis obsoletes RFC 9876 and, because of some
   rearrangement, now documents the flag in Section 4.1.2, the IANA
   Considerations of the bis document might contain text such as this:


      IANA is asked to change the registration information for the
      BANANA flag in the "Fruit Access Flags" registry to the following:

      Name      Description          Reference
      --------  -------------------  ---------
      BANANA    Flag for bananas     [[this RFC]], Section 4.2.1

   In many cases, if there are a number of registered references to the
   original RFC and the document organization has not changed the
   registered section numbering much, it may simply be reasonable to do
   this:

      Because this document obsoletes RFC 9876, IANA is asked to change
      all registration information that references [RFC9876] to instead
      reference [[this RFC]].

   If information for registered items has been or is being moved to
   other documents, then, of course, the registration information should
   be changed to point to those other documents.  In no case is it
   reasonable to leave documentation pointers to the obsoleted document
   for any registries or registered items that are still in current use.


8.  Miscellaneous Issues

8.1.  When There Are No IANA Actions

   Before an Internet-Draft can be published as an RFC, IANA needs to
   know what actions (if any) it needs to perform.  Experience has shown
   that it is not always immediately obvious whether a document has no
   IANA actions, without reviewing the document in some detail.  In
   order to make it clear to IANA that it has no actions to perform (and
   that the author has consciously made such a determination), such
   documents should include an IANA Considerations section that states:

      This document has no IANA actions.




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   This statement, or an equivalent, must only be inserted after the
   working group or individual submitter has carefully verified it to be
   true.  Using such wording as a matter of "boilerplate" or without
   careful consideration can lead to incomplete or incorrect IANA
   actions being performed.

   If a specification makes use of values from a namespace that is not
   managed by IANA, it may be useful to note this fact, with wording
   such as this:

      The values of the Foobar parameter are assigned by the Barfoo
      registry on behalf of the Rabfoo Forum.  Therefore, this document
      has no IANA actions.

   In some cases, the absence of IANA-assigned values may be considered
   valuable information for future readers; in other cases, it may be
   considered of no value once the document has been approved, and may
   be removed before archival publication.  This choice should be made
   clear in the draft, for example, by including a sentence such as

      [RFC Editor: please remove this section prior to publication.]

   or

      [RFC Editor: please do not remove this section.]

8.2.  Namespaces Lacking Documented Guidance

   For all existing RFCs that either explicitly or implicitly rely on
   IANA to evaluate assignments without specifying a precise evaluation
   policy, IANA (in consultation with the IESG) will continue to decide
   what policy is appropriate.  Changes to existing policies can always
   be initiated through the normal IETF consensus process.

   All future RFCs that either explicitly or implicitly rely on IANA to
   register or otherwise manage namespace assignments MUST provide
   guidelines for managing the namespace.

8.3.  After-the-Fact Registrations

   Occasionally, IANA becomes aware that an unassigned value from a
   managed namespace is in use on the Internet or that an assigned value
   is being used for a different purpose than originally registered.
   IANA will not condone such misuse; procedures of the type described
   in this document MUST be applied to such cases.  In the absence of
   specifications to the contrary, values may only be reassigned for a
   different purpose with the consent of the original assignee (when
   possible) and with due consideration of the impact of such a



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   reassignment.  In cases of likely controversy, consultation with the
   IESG is advised.

8.4.  Reclaiming Assigned Values

   Reclaiming previously assigned values for reuse is tricky, because
   doing so can lead to interoperability problems with deployed systems
   still using the assigned values.  Moreover, it can be extremely
   difficult to determine the extent of deployment of systems making use
   of a particular value.  However, in cases where the namespace is
   running out of unassigned values and additional ones are needed, it
   may be desirable to attempt to reclaim unused values.  When
   reclaiming unused values, the following (at a minimum) should be
   considered:

   o  Attempts should be made to contact the original party to which a
      value is assigned, to determine if the value was ever used, and if
      so, the extent of deployment.  (In some cases, products were never
      shipped or have long ceased being used.  In other cases, it may be
      known that a value was never actually used at all.)

   o  Reassignments should not normally be made without the concurrence
      of the original requester.  Reclamation under such conditions
      should only take place where there is strong evidence that a value
      is not widely used, and the need to reclaim the value outweighs
      the cost of a hostile reclamation.  In any case, IESG Approval is
      needed in this case.

   o  It may be appropriate to write up the proposed action and solicit
      comments from relevant user communities.  In some cases, it may be
      appropriate to write an RFC that goes through a formal IETF
      process (including IETF Last Call) as was done when DHCP reclaimed
      some of its "Private Use" options [RFC3942].

8.5.  Contact Person vs Assignee or Owner

   Many registries include designation of a technical or administrative
   contact associated with each entry.  Often, this is recorded as
   contact information for an individual.  It is unclear, though, what
   role the individual has with respect to the registration: is this
   item registered on behalf of the individual, the company the
   individual worked for, or perhaps another organization the individual
   was acting for?

   This matters because some time later, when the individual has changed
   jobs or roles, and perhaps can no longer be contacted, someone might
   want to update the registration.  IANA has no way to know what
   company, organization, or individual should be allowed to take the



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   registration over.  For registrations rooted in RFCs, the stream
   owner (such as the IESG or the IAB) can make an overriding decision.
   But in other cases, there is no recourse.

   Registries can include, in addition to a "Contact" field, an
   "Assignee" or "Owner" field that can be used to address this
   situation, giving IANA clear guidance as to the actual owner of the
   registration.  Alternatively, organizations can put an organizational
   role into the "Contact" field in order to make their ownership clear.

8.6.  BCP 78/79 Issues in Registries

   [[anchor2: This section needs to be resolved before publication.]]


9.  Appeals

   Appeals of registration decisions made by IANA can be made using the
   normal IETF appeals process as described in Section 6.5 of [RFC2026].
   Specifically, appeals should be directed to the IESG, followed (if
   necessary) by an appeal to the IAB, etc.


10.  Mailing Lists

   All IETF mailing lists associated with evaluating or discussing
   assignment requests as described in this document are subject to
   whatever rules of conduct and methods of list management are
   currently defined by Best Current Practices or by IESG decision.


11.  Security Considerations

   Information that creates or updates a registration needs to be
   authenticated and authorized.  IANA updates registries according to
   instructions in published RFCs and from the IESG.  It also may accept
   clarifications from document authors, relevant working group chairs,
   Designated Experts, and mail list participants, too.

   Information concerning possible security vulnerabilities of a
   protocol may change over time.  Likewise, security vulnerabilities
   related to how an assigned number is used may change as well.  As new
   vulnerabilities are discovered, information about such
   vulnerabilities may need to be attached to existing registrations, so
   that users are not misled as to the true security issues surrounding
   the use of a registered number.

   An analysis of security issues is generally required for all



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   protocols that make use of parameters (data types, operation codes,
   keywords, etc.) used in IETF protocols or registered by IANA.  Such
   security considerations are usually included in the protocol document
   [RFC3552].  It is the responsibility of the IANA considerations
   associated with a particular registry to specify what (if any)
   security considerations must be provided when assigning new values,
   and the process for reviewing such claims.


12.  Changes Relative to Earlier Editions of BCP 26

12.1.  2012: Changes in This Document Relative to RFC 5226

   Significant additions:

   o  Added Section 3.4, Expert Reviews and the Document Lifecycle

   o  Moved well-known policies into a separate section for each,
      subsections of Section 4.1.

   o  Added Section 4.2, Best Practice for Selecting an Appropriate
      Policy.

   o  Added Section 6, Documentation References in IANA Registries

   o  Added Section 7, What to Do in "bis" Documents

   o  Added Section 8.5, Contact Person vs Assignee or Owner

   o  Added Section 8.6, BCP 78/79 Issues in Registries

   Clarifications and such:

   o  Made clarifications about identification of IANA registries and
      use of URLs for them.

   o  Clarified the distinction between "Unassigned" and "Reserved".

   o  Made some clarifications in "Expert Review" about instructions to
      the designated expert.

   o  Made some clarifications in "Specification Required" about how to
      declare this policy.

   o  Assorted minor clarifications and editorial changes throughout.






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12.2.  2008: Changes in RFC 5226 Relative to RFC 2434

   Changes include:

   o  Major reordering of text to expand descriptions and to better
      group topics such as "updating registries" vs. "creating new
      registries", in order to make it easier for authors to find the
      text most applicable to their needs.

   o  Numerous editorial changes to improve readability.

   o  Changed the term "IETF Consensus" to "IETF Review" and added more
      clarifications.  History has shown that people see the words "IETF
      Consensus" (without consulting the actual definition) and are
      quick to make incorrect assumptions about what the term means in
      the context of IANA Considerations.

   o  Added "RFC Required" to list of defined policies.

   o  Much more explicit directions and examples of "what to put in
      RFCs".

   o  "Specification Required" now implies use of a Designated Expert to
      evaluate specs for sufficient clarity.

   o  Significantly changed the wording in the Designated Experts
      section.  Main purpose is to make clear that Expert Reviewers are
      accountable to the community, and to provide some guidance for
      review criteria in the default case.

   o  Changed wording to remove any special appeals path.  The normal
      RFC 2026 appeals path is used.

   o  Added a section about reclaiming unused value.

   o  Added a section on after-the-fact registrations.

   o  Added a section indicating that mailing lists used to evaluate
      possible assignments (such as by a Designated Expert) are subject
      to normal IETF rules.


13.  Acknowledgments

13.1.  Acknowledgments for This Document (2012)

   Thomas Narten and Harald Tveit Alvestrand edited the two earlier
   editions of this document (RFCs 2434 and 5226), and Thomas continues



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   his role in this third edition.  Most of the text from RFC 5226
   remains in this edition.

13.2.  Acknowledgments from the second edition (2008)

   The original acknowledgments section in RFC 5226 was:

   This document has benefited from specific feedback from Jari Arkko,
   Marcelo Bagnulo Braun, Brian Carpenter, Michelle Cotton, Spencer
   Dawkins, Barbara Denny, Miguel Garcia, Paul Hoffman, Russ Housley,
   John Klensin, Allison Mankin, Blake Ramsdell, Mark Townsley, Magnus
   Westerlund, and Bert Wijnen.

13.3.  Acknowledgments from the first edition (1998)

   The original acknowledgments section in RFC 2434 was:

   Jon Postel and Joyce Reynolds provided a detailed explanation on what
   IANA needs in order to manage assignments efficiently, and patiently
   provided comments on multiple versions of this document.  Brian
   Carpenter provided helpful comments on earlier versions of the
   document.  One paragraph in the Security Considerations section was
   borrowed from [RFC4288].


14.  References

14.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

14.2.  Informative References

   [I-D.iab-extension-recs]
              Carpenter, B., Aboba, B., and S. Cheshire, "Design
              Considerations for Protocol Extensions",
              draft-iab-extension-recs-10 (work in progress),
              February 2012.

   [RFC0791]  Postel, J., "Internet Protocol", STD 5, RFC 791,
              September 1981.

   [RFC2026]  Bradner, S., "The Internet Standards Process -- Revision
              3", BCP 9, RFC 2026, October 1996.

   [RFC2132]  Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
              Extensions", RFC 2132, March 1997.



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   [RFC2860]  Carpenter, B., Baker, F., and M. Roberts, "Memorandum of
              Understanding Concerning the Technical Work of the
              Internet Assigned Numbers Authority", RFC 2860, June 2000.

   [RFC2939]  Droms, R., "Procedures and IANA Guidelines for Definition
              of New DHCP Options and Message Types", BCP 43, RFC 2939,
              September 2000.

   [RFC3228]  Fenner, B., "IANA Considerations for IPv4 Internet Group
              Management Protocol (IGMP)", BCP 57, RFC 3228,
              February 2002.

   [RFC3232]  Reynolds, J., "Assigned Numbers: RFC 1700 is Replaced by
              an On-line Database", RFC 3232, January 2002.

   [RFC3552]  Rescorla, E. and B. Korver, "Guidelines for Writing RFC
              Text on Security Considerations", BCP 72, RFC 3552,
              July 2003.

   [RFC3575]  Aboba, B., "IANA Considerations for RADIUS (Remote
              Authentication Dial In User Service)", RFC 3575,
              July 2003.

   [RFC3692]  Narten, T., "Assigning Experimental and Testing Numbers
              Considered Useful", BCP 82, RFC 3692, January 2004.

   [RFC3748]  Aboba, B., Blunk, L., Vollbrecht, J., Carlson, J., and H.
              Levkowetz, "Extensible Authentication Protocol (EAP)",
              RFC 3748, June 2004.

   [RFC3942]  Volz, B., "Reclassifying Dynamic Host Configuration
              Protocol version 4 (DHCPv4) Options", RFC 3942,
              November 2004.

   [RFC3968]  Camarillo, G., "The Internet Assigned Number Authority
              (IANA) Header Field Parameter Registry for the Session
              Initiation Protocol (SIP)", BCP 98, RFC 3968,
              December 2004.

   [RFC4005]  Calhoun, P., Zorn, G., Spence, D., and D. Mitton,
              "Diameter Network Access Server Application", RFC 4005,
              August 2005.

   [RFC4025]  Richardson, M., "A Method for Storing IPsec Keying
              Material in DNS", RFC 4025, March 2005.

   [RFC4044]  McCloghrie, K., "Fibre Channel Management MIB", RFC 4044,
              May 2005.



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   [RFC4124]  Le Faucheur, F., "Protocol Extensions for Support of
              Diffserv-aware MPLS Traffic Engineering", RFC 4124,
              June 2005.

   [RFC4169]  Torvinen, V., Arkko, J., and M. Naslund, "Hypertext
              Transfer Protocol (HTTP) Digest Authentication Using
              Authentication and Key Agreement (AKA) Version-2",
              RFC 4169, November 2005.

   [RFC4271]  Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
              Protocol 4 (BGP-4)", RFC 4271, January 2006.

   [RFC4283]  Patel, A., Leung, K., Khalil, M., Akhtar, H., and K.
              Chowdhury, "Mobile Node Identifier Option for Mobile IPv6
              (MIPv6)", RFC 4283, November 2005.

   [RFC4288]  Freed, N. and J. Klensin, "Media Type Specifications and
              Registration Procedures", BCP 13, RFC 4288, December 2005.

   [RFC4301]  Kent, S. and K. Seo, "Security Architecture for the
              Internet Protocol", RFC 4301, December 2005.

   [RFC4340]  Kohler, E., Handley, M., and S. Floyd, "Datagram
              Congestion Control Protocol (DCCP)", RFC 4340, March 2006.

   [RFC4395]  Hansen, T., Hardie, T., and L. Masinter, "Guidelines and
              Registration Procedures for New URI Schemes", BCP 35,
              RFC 4395, February 2006.

   [RFC4422]  Melnikov, A. and K. Zeilenga, "Simple Authentication and
              Security Layer (SASL)", RFC 4422, June 2006.

   [RFC4446]  Martini, L., "IANA Allocations for Pseudowire Edge to Edge
              Emulation (PWE3)", BCP 116, RFC 4446, April 2006.

   [RFC4520]  Zeilenga, K., "Internet Assigned Numbers Authority (IANA)
              Considerations for the Lightweight Directory Access
              Protocol (LDAP)", BCP 64, RFC 4520, June 2006.

   [RFC4589]  Schulzrinne, H. and H. Tschofenig, "Location Types
              Registry", RFC 4589, July 2006.

   [RFC4727]  Fenner, B., "Experimental Values In IPv4, IPv6, ICMPv4,
              ICMPv6, UDP, and TCP Headers", RFC 4727, November 2006.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246, August 2008.




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   [RFC5378]  Bradner, S. and J. Contreras, "Rights Contributors Provide
              to the IETF Trust", BCP 78, RFC 5378, November 2008.

   [RFC5742]  Alvestrand, H. and R. Housley, "IESG Procedures for
              Handling of Independent and IRTF Stream Submissions",
              BCP 92, RFC 5742, December 2009.

   [RFC5771]  Cotton, M., Vegoda, L., and D. Meyer, "IANA Guidelines for
              IPv4 Multicast Address Assignments", BCP 51, RFC 5771,
              March 2010.

   [RFC5795]  Sandlund, K., Pelletier, G., and L-E. Jonsson, "The RObust
              Header Compression (ROHC) Framework", RFC 5795,
              March 2010.

   [RFC6195]  Eastlake, D., "Domain Name System (DNS) IANA
              Considerations", BCP 42, RFC 6195, March 2011.

   [RFC6275]  Perkins, C., Johnson, D., and J. Arkko, "Mobility Support
              in IPv6", RFC 6275, July 2011.


Authors' Addresses

   Michelle Cotton
   Internet Assigned Numbers Authority (IANA)
   4676 Admiralty Way, Suite 330
   Marina del Rey, CA  90292
   USA

   Phone: +1 310 301 5812
   Email: michelle.cotton@icann.org


   Barry Leiba
   Huawei Technologies

   Phone: +1 646 827 0648
   Email: barryleiba@computer.org
   URI:   http://internetmessagingtechnology.org/











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   Thomas Narten
   IBM Corporation
   3039 Cornwallis Ave., PO Box 12195 - BRQA/502
   Research Triangle Park, NC  27709-2195
   USA

   Phone: +1 919 254 7798
   Email: narten@us.ibm.com











































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