[5] [DFN[[CODE[urn:ietf:]]]] は、 [[IETF]] の色々な[[プロトコル]]で使われている
[[URN]] の [[NID]] です。

* 構造

[1] 
:登録版:1
:登録日:1999-04-22
:仕様書:[[RFC 2648]] <urn:ietf:rfc:2648>

,下位名前空間,説明,状態,出典
,[CODE(URI)[[[urn:ietf:fyi]]]],[[IETF]] [[FYI]],[[IETF]] [[情報提供]],[[RFC 2648]]
,[CODE(URI)[[[urn:ietf:bcp]]]],[[IETF]] [[BCP]],[[IETF]] [[情報提供]],[[RFC 2648]]
,[CODE(URI)[[[urn:ietf:id]]]],[[IETF]] [[Internet Draft]],[[IETF]] [[情報提供]],[[RFC 2648]]
,[CODE(URI)[[[urn:ietf:mtg]]]],[[IETF]] 会議報告,[[IETF]] [[情報提供]],[[RFC 2648]]
,[CODE(URI)[[[urn:ietf:params]]]],[[IETF]] 規格の引数,[[IETF]] [[BCP]],[[RFC 3553]]
,[CODE(URI)[[[urn:ietf:rfc]]]],[[IETF]] [[RFC]],[[IETF]] [[情報提供]],[[RFC 2648]]
,[CODE(URI)[[[urn:ietf:std]]]],[[IETF]] [[STD]],[[IETF]] [[情報提供]],[[RFC 2648]]

* 登録簿

[2] 元々登録簿は用意されていませんでしたが、 [[RFC 6924]] で新設されました。

[REFS[
- [3] [CITE@en[RFC 6924 - Registration of Second-Level URN Namespaces under "ietf"]] ([TIME[2013-05-06 19:50:52 +09:00]] 版) <http://tools.ietf.org/html/rfc6924>
- [4] [CITE[Uniform Resource Name (URN) Namespace for IETF Use]] ([TIME[2013-04-13 01:03:06 +09:00]] 版) <http://www.iana.org/assignments/params/params.xhtml#urn-subnamespaces>
]REFS]

* 実装

[8] 
[CODE[urn:ietf:rfc:]] などを [[RFC]] に[[解決][URNの解決]]するような実装はいくつかあります。

* 歴史

[FIG(quote)[ [9] [DFN[RFC 3553]]

Network Working Group                                        M. Mealling
Request for Comments: 3553                                      VeriSign
BCP: 73                                                      L. Masinter
Category: Best Current Practice                            Adobe Systems
[PRE[
                                                               T. Hardie
                                                                Qualcomm
                                                                G. Klyne
                                                            Nine by Nine
                                                               June 2003
]PRE]

[PRE[
      An IETF URN Sub-namespace for Registered Protocol Parameters
]PRE]

Status of this Memo

[PRE[
   This document specifies an Internet Best Current Practices for the
   Internet Community, and requests discussion and suggestions for
   improvements.  Distribution of this memo is unlimited.
]PRE]

Copyright Notice

[PRE[
   Copyright (C) The Internet Society (2003).  All Rights Reserved.
]PRE]


* Abstract

> This document describes a new sub-delegation for the 'ietf' URN
namespace for registered protocol items.  The 'ietf' URN namespace is
defined in RFC 2648 as a root for persistent URIs that refer to
IETF-defined resources.

この文書は、登録プロトコル項目のための
[CODE(URI)[ietf]] URN
名前空間の新しい部分委譲を説明します。
[CODE(URI)[ietf]] URN
名前空間は、 IETF
が定義する資源を参照する永続 URI
の根として [[RFC2648]]
で定義されています。


* 1.  Introduction

> From time to time IETF standards require the registration of various
protocol elements in well known central repository.  The Internet
Assigned Numbers Authority maintains this central repository and
takes direction from the IETF on what, how and when to add items to
it.  The IANA maintains lists of items such as all assigned port
numbers, MIME media types, enterprise numbers, etc.

刻一刻 IETF 標準は種々のプロと尾kる要素の周知の中央 repository
での登録を必要としています。
IANA はこの中央 repository
を維持しており、いついかにそこに項目を追加するかについて
IETF の指示を受けています。
IANA は、すべての割当済みポート番号,
[[MIME]] [[媒体型]], enterprise
番号などの項目の一覧を維持しています。

> Over time there has developed a need to be able to reference these
elements as URIs in various schema.  In the past this was done in a
very ad hoc way that easily led to interoperability problems.  This
document creates a new sub-delegation below the "ietf" [2]URN
namespace [1] called 'params' which acts as a standardized mechanism
for naming the items registered for IETF standards.  Any assignments
below that are specified in an RFC according to the IETF consensus
process and which include the template found in Section 4.

刻々そのような要素を種々の schama
で URI として参照することができるようにする必要が高まっています。
過去にはこれは非常にその場しのぎで簡単に相互運用性の問題を導く方法でなされていました。
この文書は [CODE(URI)[ietf]]
URN 名前空間下の
[CODE(URI)[param]] という新たな部分委譲を作成し、
これを IETF 標準の登録済み項目を命名する標準化した機構として作用させます。
この下の割当は、IETF 
合意過程に従って [[RFC]]
に記述され、
4章にある雛型を含んでいます。


* 2.  Terminology

> 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.


* 3.  IETF Sub-namespace Specifics

> Sub-namespace name:
> params
> Declared registrant of the namespace:
> The Internet Engineering Task Force
> Declaration of structure:
> The namespace is primarily opaque.  The IANA, as operator of the
registry, may take suggestions for names to assign but they
reserve the right to assign whatever name they desire, within
guidelines set by the IESG.  The colon character (":") is used to
denote a very limited concept of hierarchy.  If a colon is present
then the items on both sides of it are valid names.  In general,
if a name has a colon then the item on the left hand side
represents a class of those items that would contain other items
of that class.  For example, a name can be assigned to the entire
list of DNS resource record type codes as well as for each
individual code.  The URN for the list might look like this:

この名前空間は基本的に[[不透明]]です。
IANA は、登録簿の運用者として、
割当る名前に関して提案を行うかもしれませんが、
IESG により設定された指針の範囲内で、
その望む名前は何でも割当てる権利を保留します。
コロン文字 ([CODE(URI)[:]])
は、非常に限定された階層の概念を示すのに使います。
コロンが出現した時は、
その両側が妥当な名前でなければなりません。
通常、名前がコロンを含んでいるときは、左手側の項目は、
その級の他の項目をも含むであろう項目の級を表します。
例えば、名前には DNS
資源記録型符号の完全な一覧が、
それぞれの符号と共に割当られるかもしれません。
この一覧の URN
はこんな感じかもしれません:

>
- urn:ietf:params:dns:rr-type-codes

> while the URN for the SOA records type code might look like this:

で、 [[SOA]] 記録型符号の URN
はこんな感じかもしれません。

>
- urn:ietf:params:dns:rr-type-codes:soa

> Relevant ancillary documentation:
> [3], [2], [1]
> Identifier uniqueness considerations:
> The IESG uses the IETF consensus process to ensure that
sub-namespaces generate unique names within that
sub-namespace.  The IESG delegates to the IANA the task of
ensuring that the sub-namespace names themselves are unique.
Until and unless the IESG specifies differently, the IANA is
directed to ensure uniqueness by comparing the name to be assigned
with the list of previously assigned names.  In the case of a
conflict the IANA is to request a new string from the registrant
until the conflict is resolved.

IESG は部分名前空間がその部分名前空間中で固有な名前を生成することを保証するために
IETF 合意過程を使用します。
IESG は IANA
に部分名前空間自体が固有であることを確認する作業を委譲します。
IESG が違ったように規定するまで、
そして規定しない限り、
IANA は、割当てる名前を以前に割当てた名前の一覧と比較することで固有性を確保することを目指します。
衝突の場合には、 IANA
は衝突が解決されるまで登録者に新しい文字列を要求することとなります。

> Identifier persistence considerations:
> Once a name has been allocated it MUST NOT be re-allocated for a
different purpose.  The rules provided for assignments of values
within a sub-namespace MUST be constructed so that the meaning of
values cannot change.  This registration mechanism is not
appropriate for naming values whose meaning may change over time.
If a value that changes over time the assignment MUST name the
container or concept that contains the value, not the value
itself.  For example, if a parameter called 'foo' has a value that
changes over time, it is valid to create the name
'urn:ietf:params:foo-params:foo' that identifies that 'slot'.  It
is not valid to actually create a name that contains that value
unless it is a persistent and unique value such as a version
number.

いったん名前が割当てられれば、
これは異なる目的に再割当しては'''なりません'''。
部分名前空間中の値の割当てに提供する規則は、
値の意味が変化し得ないように構築しなければ'''なりません'''。
この登録機構は、
時によりその意味が変わる値を命名するのには適当ではありません。
時により値が変わるときは、
割当ては値自体ではなく値を含む含みまたは概念を名づけなければ'''なりません'''。
例えば、 [CODE[foo]]
という引数が時により変わる値を持つ時、
その「スロット」を識別する名前 
[CODE(URI)[urn:ietf:params:foo-params:foo]] 
は妥当です。
その値を含んだ名前を実際に作ることは、
その値が永続的であって版番号のように固有な値でない限り妥当ではありません。

> Process of identifier assignment:
> Identifiers are assigned only after a particular protocol element
or number has been registered with the IANA using standard
policies and procedures, or documented in an RFC describing a
standards track protocol.  This means that the 'gating' function
for assignment is the "IETF Consensus" process documented in RFC
2434 [4].

識別子は特定のプロトコル要素又は番号が標準方針・手続きを使って
IANA に登録されたか、又は標準化過程プロトコルを記述した
RFC に文書化された後にのみ割当てられます。
これは、割当てを「通過検査」
する機能が [[RFC2434]]
に文書化されている「[[IETF合意]]」
過程であることを意味します。

> Process of identifier resolution:
> At this time no resolution mechanism is defined.
> Rules for Lexical Equivalence:
> Lexical equivalence is achieved by exact string match according to
the rules for URN syntax found in RFC 2141 [1].  Specifically, due
to the URN syntax definitions, the 'stringprep' standard found in
RFC 3454 [7] does not apply.

構文的同等性は、
[[RFC2141]] にある URN
構文に対する規則にしたがって文字列全体が一致することで達成されます。
特に、 URN 構文定義により、
[[RFC3454]] にある [[stringprep]]
規格は適用しません。

> Conformance with URN Syntax:
> There are no additional characters reserved.
> Validation mechanism:
> None.
> Scope:
> Global


* 4.  Assigning Names

> The creation of a new registry name will be simple for most flat
registries.  The only required elements will be the registry name, a
reference to relevant documents, a statement about which
current/proposed document repositories contains the authoritative
data for the registry, and a statement specifying which element in
the registry is the value to be used in the URN.  In most cases this
last element will be the index value assigned by the IANA.

新しい登録簿名の作成は、
ほとんどの平坦登録簿には単純です。
必須の要素は登録簿名,
関連文書, 登録簿の管理データを含む現在・提案文書 repository
と登録簿中のどの要素が URN
で使われる値かを規定する言明だけです。
ほとんどの場合、この最後の要素は
IANA により割当てられる索引値になります。

> More complex registries (DNS Parameters for example) will need to
repeat that information for any sub-namespaces.  It should also be
clear as to whether or not a name is assigned to the sub-namespace
itself (i.e., is 'urn:ietf:params:dns:rr-types' valid by itself and
if so, what does it name?).

もっと複雑な登録簿 (例えば DNS
引数) は、部分名前空間に着いての情報を繰り返す必要があるでしょう。
名前が部分名前空間自体に割当てられるか否か
(つまり、 [CODE(URI)[urn:ietf]params:dns:rr-types]]
がそれ自体で妥当か否か、
そうであれば何を名付けたものか)
も明らかにするべきです。

> The template:

[PRE[
   Registry name: -- The name of the sub-namespace.  In many cases this
      should be the same name that the IANA calls the registry itself.
]PRE]

[PRE[
   Specification: -- Relevant IETF published documents that define the
      registry and the items in it.
]PRE]

[PRE[
   Repository: -- A pointer to the 'current' location of the registry in
      the protocol parameters repository or the relevant RFCs that
      document the items being named.  This value will change over time
      as the entity that maintains the repository moves files and or
      fileservers.  It is not meant as a permanent binding to the
      filename but as a hint to the IANA for what the initial mapping
      would be.
]PRE]

[PRE[
   Index value: -- Description of how a registered value is to be
      embedded in the URI form.  This MUST include details of any
      transformations that may be needed for the resulting string to
      conform to URN syntax rules and any canonicalization needed so
      that the case-sensitive string comparison yields the expected
      equivalences.
]PRE]

[PRE[
   The process for requesting that a URN be assigned is currently to put
   the above template or a reference to it in the IANA considerations
   section of the specifying document.  Other more automated processes
   may be proposed at a latter time if demand requires it.
]PRE]


* 5.  Security Considerations

[PRE[
   None not already inherent to using URNs.  Security considerations for
   URNs in general can be found in RFC 2141 [1].  Further security
   considerations for one specific URN resolution method can be found in
   Dynamic Delegation  Discovery System (DDDS) Part Four: The Uniform
   Resource Identifiers (URI) Resolution Application (RFC 3404) [5]
   which is part of a series starting with Dynamic  Delegation Discovery
   System (DDDS) Part One: The Comprehensive DDDS  (RFC 3401) [6].
]PRE]


* 6.  IANA Considerations

[PRE[
   This document puts a new and significant burden on the IANA since it
   may require an additional assignment process to happen for each new
   IANA registry.  To minimize the administrative burden on IANA, any
   parameter namespace registration is very clear about the criteria for
   inclusion in that namespace.
]PRE]

[PRE[
   Defining a registry that fits the constraints of a URN namespace will
   impose extra discipline that should take some of the guess-work about
   creating and maintaining that registry.
]PRE]


* 7.  Intellectual Property Statement

[PRE[
   The IETF takes no position regarding the validity or scope of any
   intellectual property or other rights that might be claimed to
   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
   might or might not be available; neither does it represent that it
   has made any effort to identify any such rights.  Information on the
   IETF's procedures with respect to rights in standards-track and
   standards-related documentation can be found in BCP-11.  Copies of
   claims of rights made available for publication and any assurances of
   licenses to be made available, or the result of an attempt made to
   obtain a general license or permission for the use of such
   proprietary rights by implementors or users of this specification can
   be obtained from the IETF Secretariat.
]PRE]

[PRE[
   The IETF invites any interested party to bring to its attention any
   copyrights, patents or patent applications, or other proprietary
   rights which may cover technology that may be required to practice
   this standard.  Please address the information to the IETF Executive
   Director.
]PRE]

Mealling, et. al.        Best Current Practice                  [Page 5]
[PRE[

RFC 3553                   IANA URN Namespace                  June 2003
]PRE]

8.  Normative References

[PRE[
   [1]  Moats, R., "URN Syntax", RFC 2141, May 1997.
]PRE]

[PRE[
   [2]  Moats, R., "A URN Namespace for IETF Documents", RFC 2648,
        August 1999.
]PRE]

[PRE[
   [3]  Daigle, L., van Gulik, D., Iannella, R. and P. Faltstrom,
        "Uniform Resource Names (URN) Namespace Definition Mechanisms",
        BCP 66, RFC 3406, October 2002.
]PRE]

[PRE[
   [4]  Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
        Considerations Section in RFCs", BCP 26, RFC 2434, October 1998.
]PRE]

[PRE[
   [5]  Mealling, M., "Dynamic Delegation Discovery System (DDDS) Part
        Four: The Uniform Resource Identifiers (URI)", RFC 3404,
        February 2002.
]PRE]

[PRE[
   [6]  Mealling, M., "Dynamic Delegation Discovery System (DDDS) Part
        One: The Comprehensive DDDS", RFC 3401, May 2002.
]PRE]

[PRE[
   [7]  Hoffman, P. and M. Blanchet, "Preparation of Internationalized
        Strings ("stringprep")", RFC 3454, December 2002.
]PRE]

Mealling, et. al.        Best Current Practice                  [Page 6]
[PRE[

RFC 3553                   IANA URN Namespace                  June 2003
]PRE]

9.  Authors' Addresses

[PRE[
   Michael Mealling
   VeriSign
   21345 Ridgetop Circle
   Sterling, VA  20166
   US
]PRE]

[PRE[
   EMail: michael@verisignlabs.com, michael@neonym.net
   URI:   http://www.verisign.com
]PRE]

[PRE[
   Larry Masinter
   Adobe Systems Incorporated
   345 Park Ave
   San Jose, CA  95110
   US
]PRE]

[PRE[
   Phone: +1 408 536-3024
   EMail: LMM@acm.org
   URI:   http://larry.masinter.net
]PRE]

[PRE[
   Ted Hardie
   Qualcomm, Inc.
   675 Campbell Technology Parkway
   Suite 200
   Campbell, CA
   U.S.A.
]PRE]

[PRE[
   EMail: hardie@qualcomm.com
]PRE]

[PRE[
   Graham Klyne
   Nine by Nine
]PRE]

[PRE[
   EMail: GK-IETF@ninebynine.org
   URI:   http://www.ninebynine.net/
]PRE]

* 10.  Full Copyright Statement

[PRE[
   Copyright (C) The Internet Society (2003).  All Rights Reserved.
]PRE]

[PRE[
   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
   or assist in its implementation may be prepared, copied, published
   and distributed, in whole or in part, without restriction of any
   kind, provided that the above copyright notice and this paragraph are
   included on all such copies and derivative works.  However, this
   document itself may not be modified in any way, such as by removing
   the copyright notice or references to the Internet Society or other
   Internet organizations, except as needed for the purpose of
   developing Internet standards in which case the procedures for
   copyrights defined in the Internet Standards process must be
   followed, or as required to translate it into languages other than
   English.
]PRE]

[PRE[
   The limited permissions granted above are perpetual and will not be
   revoked by the Internet Society or its successors or assigns.
]PRE]

[PRE[
   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
   BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION
   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
]PRE]

* Acknowledgement

[PRE[
   Funding for the RFC Editor function is currently provided by the
   Internet Society.
]PRE]
]FIG]