Network Working Group J. Goodwin

Network Working Group J. Goodwin
Request for Comments: 5141 H. Apel
Category: Informational ISO
March 2008

A Uniform Resource Name (URN) Namespace for
the International Organization for Standardization (ISO)

Status of This Memo

This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.

Abstract

This document describes a Uniform Resource Name Namespace
Identification (URN NID) for the International Organization for
Standardization (ISO). This URN NID is intended for use for the
identification of persistent resources published by the ISO standards
body (including documents, document metadata, extracted resources
such as standard schemata and standard value sets, and other
resources).

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Table of Contents

1. Introduction ....................................................2
2. Specification Template ..........................................4
2.1. Namespace ID ...............................................4
2.2. Registration Information ...................................4
2.3. Declared Registrant of the Namespace .......................4
2.4. Declaration of Structure ...................................4
2.4.1. Definition ..........................................4
2.4.2. Examples ...........................................12
2.5. Relevant Ancillary Documentation ..........................15
2.6. Identifier Uniqueness Considerations ......................15
2.7. Identifier Persistence Considerations .....................15
2.8. Process for Identifier Resolution .........................16
2.9. Rules for Lexical Equivalence .............................16
2.10. Conformance with URN Syntax ..............................17
2.11. Validation Mechanism .....................................17
2.12. Scope ....................................................17
3. Namespace Considerations .......................................17
4. Community Considerations .......................................18
5. IANA Considerations ............................................20
6. Security Considerations ........................................20
7. References .....................................................21
7.1. Normative References ......................................21
7.2. Informative References ....................................21
Appendix A. Alternative Naming Schemes ............................23
Appendix B. ABNF Definition of Namespace ID = "iso"
(Informative) .........................................24

1. Introduction

The International Organization for Standardization (ISO) was created
by international agreement in 1947. ISO is a network of the national
standards institutes of many countries, on the basis of one member
per country, with a Central Secretariat in Geneva, Switzerland, that
coordinates the system. ISO acts as a bridging organization in which
a consensus can be reached on solutions that meet both the
requirements of business and the broader needs of society, such as
the needs of stakeholder groups like consumers and users.

Further information is provided at http://www.iso.org/iso/about.htm.

The core mission of ISO is to develop technical standards
constituting technical agreements that provide the framework for
compatible technology worldwide. ISO standards contribute to making
the development, manufacturing, and supply of products and services
more efficient, safer, and cleaner. They make trade between
countries easier and fairer.

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Every participating ISO member institute (full members) has the right
to take part in the development of any standard that it judges to be
important to its country's economy. No matter what the size or
strength of that economy, each participating member in ISO has one
vote. ISO's activities are thus carried out in a democratic
framework where each country is on an equal footing to influence the
direction of ISO's work at the strategic level, as well as the
technical content of its individual standards. Although the ISO
standards are voluntary, the fact that they are developed in response
to market demand, and are based on consensus among the interested
parties, ensures widespread applicability of the standards.
Consensus, like technology, evolves and ISO takes account of both
evolving technology and evolving interests by requiring a review of
its standards at least every five years to decide whether they should
be maintained, updated, or withdrawn.

ISO publishes International Standards and other technical
specifications that are cited in the definitions of required or
expected practices in many industries in many nations. These
specifications contain dictionaries of standard terms, catalogues of
reference values, definitions of formal languages, formal schemata
for information capture and exchange, specifications for standard
practices, and other information resources of general use to
international trade and industry. ISO wishes to create and manage
globally unique, persistent, location-independent identifiers for
these resources.

This specification defines the syntax for URNs that identify
documents developed by the International Organization for
Standardization (ISO) in accordance with the standards development
procedures defined in the ISO/IEC Directives, Part 1 [ISODIR-1] and
the ISO supplement [ISODIR-S] and processed by the ISO Central
Secretariat. The syntax extends to identify document metadata and
resources related to these documents or otherwise associated with
them. It does not extend to products derived from these documents
and published by ISO (e.g., handbooks, compendia) or documents at or
below the Technical Committee level. Revisions of this specification
may define syntax for URNs in this namespace that identify other ISO
objects, when the ISO community defines a requirement for such
identifiers.

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2. Specification Template

2.1. Namespace ID

"iso"

2.2. Registration Information

Version 2.1
Date: 2007-12-13

2.3. Declared Registrant of the Namespace

J. Goodwin
ISO Central Secretariat
International Organization for Standardization (ISO)
Case Postale 56
CH-1211 Geneva 20
Switzerland

E-mail: [email protected]

2.4. Declaration of Structure

2.4.1. Definition

The Namespace Specific Strings (NSSs) of all URNs assigned by ISO
will conform to the syntax defined in Section 2.2 of [RFC2141].

The NSS has the following ABNF [RFC5234] specification:

NSS = std-nss

All URNs conforming to this specification begin the NSS with the
prefix "std:" to denote the restriction to documents developed by
the ISO standards development procedures as defined in the ISO/IEC
Directives, Part 1 [ISODIR-1] and the ISO Supplement [ISODIR-S].
Prefixes that identify ISO objects of other kinds may be defined
in future revisions of this specification.

std-nss = "std:" docidentifier *supplement *docelement
[addition]

The prefix "std:" distinguishes an <std-nss>. An <std-nss>
identifies the ISO document that is designated by the
<docidentifier>, as extended or modified by any identified
<supplement>. (An <std-nss> that identifies all parts of a
multipart ISO document is a special case as described under the

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element <partnumber>.) If the <std-nss> contains an <addition>
element, the NSS identifies a resource extracted from the ISO
document or otherwise associated with it (see below).

docidentifier = originator [":" type] ":" docnumber [":" partnumber]
[[":" status] ":" edition]
[":" docversion] [":" language]

<docidentifier> provides the complete identification of an ISO
document. Each of its component elements is described below.

originator = "iso" / "iso-iec" / "iso-cie" / "iso-astm" /
"iso-ieee" / "iec"

<originator> is the organization (usually an international body)
from which a document emanates.

Current values:

iso = International Organization for Standardization

iec = International Electrotechnical Commission (IEC), or
Commission Electrotechnique Internationale

iso-iec = jointly developed by ISO and IEC

iso-cie = jointly developed by ISO and the Commission
Internationale d'Eclairage (CIE)

iso-astm = jointly developed by ISO and the American Society for
Testing and Materials (ASTM) International

iso-ieee = jointly developed by ISO and the Institute for
Electrical and Electronics Engineers (IEEE)

Revisions of this specification may define additional values.

type = "data" / "guide" / "isp" / "iwa" /
"pas" / "r" / "tr" / "ts" / "tta"

<type> designates the ISO deliverable type. If the <type> element
is not present, the classification is "international standard".
Other current values:

data = Data (document type no longer published)

guide = Guide

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isp = International Standardized Profile

iwa = International Workshop Agreement

pas = Publicly Available Specification

r = Recommendation (document type no longer published)

tr = Technical Report

ts = Technical Specification

tta = Technology Trends Assessment

docnumber = DIGITS

<docnumber> is the reference number assigned to the document by
ISO and/or IEC. An ISO document may comprise a single document,
or two or more separate parts each of which is identified by
<partnumber>.

partnumber = "-" 1*( DIGIT / ALPHA / "-" )

<partnumber> is the reference number that identifies a part of a
multipart standard.

Where it is required to refer to a multipart ISO document in its
entirety, this can be designated by omitting the <partnumber>
element. However, this precludes the possibility of using any
further elements except <addition>.

NOTE: The option to refer to a multipart ISO document by omitting
the <partnumber> element has been included to align with the
provision in the ISO/IEC Directives, Part 2, 2004 [ISODIR-2]
subclause 6.2.2 of making an undated reference to all parts of an
ISO document. It is only permissible to use this option where the
URN is referring to a multipart ISO document in its entirety.
Since the use of this option precludes the designation of the
elements <status> and <edition>, it is implicit that the URN needs
to remain valid irrespective of any future changes to the
multipart document (see the rules for undated references given in
the ISO/IEC Directives, Part 2, 2004 [ISODIR-2] subclause
6.6.7.5.2). This shall be taken into consideration in the use
(and maintenance) of any URN specification employing this option.

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NOTE: In the case where the multipart document comprises different
types of ISO deliverable, the <type> of the core part (usually
part 1) applies. See the example "Reference to a resource related
to all parts of a multipart document".

Except for the case where it is required to refer to a multipart
document in its entirety, the element <partnumber> is required if
the identified resource is a part of an ISO document. Otherwise,
this element is not used.

status = ( "draft" / "cancelled" ) / stage

<status> indicates the publication status of the document. When
the <status> element is not present, the NSS refers to a published
document. Other values:

draft = document that has not yet been accepted for
publication by international ballot

cancelled = document that has been deleted or withdrawn

stage = "stage-" stagecode ["." iteration]

<stage> indicates the stage code and iteration of the document.

stagecode = DIGIT DIGIT "." DIGIT DIGIT

<stagecode> is the harmonized stage code in accordance with ISO
Guide 69:1999, "Harmonized Stage Code system (Edition 2) --
Principles and guidelines for use" [ISOGUIDE69].

iteration = "v" DIGITS

<iteration> is a sequential number that refers to a specific
iteration of the project's lifecycle through the designated stage.

If no <iteration> is specified, the reference is to the highest
iteration available for the specified stagecode.

NOTE: In the ISO Central Secretariat project management database,
the <iteration> is referred to as the "project version".

edition = "ed-" DIGITS

<edition> designates a specific edition of the document. (DIGITS
is the (sequential) edition number.) If no <edition> is
specified, the NSS refers to the latest edition.

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docversion = "v" (simpleversion / isoversion)

simpleversion = DIGITS

<docversion> designates the version number of a document's
<edition>. It is altered by correction (corrected version;
Technical Corrigendum) or amendment (Amendment; Addendum) and is
distinct from a revision, which changes the edition number.

In the <simpleversion>, the first version published is 1, and each
subsequent correction or amendment increases the version number by
1.

If no <docversion> is specified, the reference is to the highest
version number available for the denoted <edition>.

Current values of <simpleversion>:

1 - first version published

2 - corrected version published

isoversion = baseversion *includedsuppl

baseversion = DIGITS

includedsuppl = "-" suppltype supplnumber [ "." supplversion ]

An <isoversion> can be linked to a simpleversion by defining an
existing simpleversion as baseversion and listing all the
<supplement> elements (corrections and amendments) incorporated
into that version.

Examples for the <isoversion> (internal ISO version) scheme:

1 = first version of standard

1-amd1.v1 = first version of standard incorporating first
version of Amendment 1

1-amd1.v1-amd2.v1 = first version of standard incorporating
first version of Amendment 1 and first version of Amendment 2

1-amd1.v2-amd2.v1-amd3 = first version of standard
incorporating corrected version of Amendment 1, first version
of Amendment 2, and highest version of Amendment 3

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1-cor3 = first version of standard incorporating highest
version of Technical Corrigendum 3

1-amd1-cor3 = first version of standard incorporating highest
version of Amendment 1 and highest version of Technical
Corrigendum 3

language = monolingual / bilingual / trilingual

monolingual = "en" / "fr" / "ru" / "es" / "ar"

bilingual = "en,fr" / "en,ru" / "fr,ru"

trilingual = "en,fr,ru"

<language> designates the official ISO language(s), or the
language of an official translation, in which the document
(object) is processed and published by ISO (excluding languages
that constitute only specific elements of the content). The value
is one or more alpha-2 codes, each of which designates a language,
as specified in ISO 639-1 [ISO639-1]. If no language element is
specified, <en> is assumed.

NOTE: Although [ISO639-1] recommends that language codes be
written in lowercase, this ABNF definition allows the use of
uppercase language codes because in ABNF [RFC5234], terminal
symbols defined as literal strings are explicitly
case-insensitive. This case distinction does not carry any
meaning (see Section 2.9) and it is recommended to use language
codes in lowercase. For additional information about the usage of
language tags in information objects, see [RFC4646].

supplement = ":" suppltype ":" supplnumber
[":" supplversion ] [":" language ]

suppltype = "amd" / "cor" / "add"

supplnumber = DIGITS

supplversion = "v" DIGITS

<supplement> designates a technical alteration of or addition to
an ISO standard that does not result in a new <edition> or
<version>. Each <supplement> may be one of the three types,
designated by <suppltype>:

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amd = Amendment -- a document that alters and/or adds to
previously agreed upon technical provisions in an existing
ISO document; an amendment is subject to acceptance by
ballot in accordance with the ISO/IEC Directives, Part 1,
2004 [ISODIR-1] subclause 2.10.3

cor = Technical Corrigendum -- a document that corrects a
technical error or ambiguity, or updates the ISO document in
such a way that the modification has no effect on the
technical normative elements; a Technical Corrigendum is not
balloted -- see the ISO/IEC Directives, Part 1, 2004
[ISODIR-1] subclause 2.10.2

add = Addendum -- (document type no longer published) Addenda were
documents that changed (by correction, addition, or
deletion) the technical requirements of an ISO document; an
addendum was subject to acceptance by ballot in accordance
with the ISO/IEC Directives, Part 1. (Addenda are included
in this RFC because some of them are still valid.)

Supplements are numbered consecutively per ISO document, and
within each supplement type.

<supplnumber> identifies the number of the supplement.

<supplversion> designates the version of a published supplement.
At present, only two versions are used in practice: when a
supplement is published, it is version 1. If that supplement is
subsequently corrected by issuing a corrected version, as
designated by the term "Corrected" on the cover page together with
a date, the corrected version is version 2.

The language of a supplement can be different from that of the
document. For example, a supplement may apply to only one of the
languages of a bilingual document. For such cases, the language
of a supplement can be identified using the <language> element
defined above. The interpretation is the same, except that it
applies only to the supplement.

docelement = ":" ( "clause" / "figure" / "table" / "term" ) ":"
elementnumber / elementrange
*( "," elementnumber / elementrange )

elementnumber = ( ALPHA / DIGITS ) *( "." DIGITS )

elementrange = elementnumber "-" elementnumber

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<docelement> identifies one or more numbered subdivisions of a
document. Types of numbered subdivision are specified in the ISO/
IEC Directives, Part 2 [ISODIR-2]. This RFC currently specifies
forms for reference to clauses, figures, tables, and terms only.
It does not provide for reference to subfigures. Revisions of
this specification may define additional values.

<clause> represents the selection of one or more clauses or
subclauses of the document. <figure> represents the selection of
one or more figures of the document. <table> represents the
selection of one or more tables of the document. <term> represents
the selection of one or more terms of the document.

<elementnumber> designates a numbered subdivision in a document,
where the type of subdivision is identified by the literal
"clause", "figure", "table", or "term". When the first character
of <elementnumber> is a digit, the reference is to the subdivision
designated by that digit string and by any additional digit
strings separated by periods. When the first character of
<elementnumber> is alphabetical, the reference is to the
corresponding Annex, and to the subdivisions designated by
additional digit strings.

The form <elementnumber> HYPHEN <elementnumber> designates a range
of subdivisions, and the form <elementnumber> COMMA
<elementnumber> designates a list. A list can contain ranges.

addition = techdefined / isodefined

techdefined = ":tech" *techelement

techelement = <unspecified>

isodefined = <unspecified>

<addition> is an additional element of the NSS intended to
identify a representation of an ISO document, an extract from an
ISO document, or some related information set, as a resource in
its own right.

<techdefined> represents an associated or embedded resource
defined by the committee that develops or maintains the identified
document. All such <addition> elements begin with the prefix
":tech".

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<isodefined> represents associated or embedded resources defined
by the ISO Central Secretariat. The definition of an <addition>
element beginning with any symbol other than <tech> is reserved to
the ISO Central Secretariat.

The syntax of the <addition> element is not specified in this RFC.
Specific syntax for this element will be specified as needed by
the ISO Central Secretariat, or by the individual committee that
has the responsibility for developing or maintaining the
identified document. It is necessary that these definitions
comply with the rules for lexical equivalence specified in Section
2.9 and take into account the process for identifier resolution as
discussed in Section 2.8.

DIGITS = DIGIT *DIGIT

DIGIT = %x30-39 ; 0-9

ALPHA = %x41-5A / %x61-7A ; A-Z / a-z

Basics of the ABNF notation used :

" " literals (terminal character strings); terms not in quotes are
non-terminals

/ alternatives

[] indicates an optional rule

() indicates a sequence group, used as a single alternative or as a
single repeating group

<a>*<b> indicates that the following term or group can repeat at
least <a> and at most <b> times; default values are 0 and
infinity, respectively

; comment

2.4.2. Examples

o Language handling:

urn:iso:std:iso:9999:-1:ed-1:en
refers to the 1st edition of ISO 9999-1, in English

urn:iso:std:iso:9999:-1:ed-1:en,fr
refers to the 1st edition of ISO 9999-1, in English/French
(bilingual document)

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o Originators/document type:

urn:iso:std:iso-iec:tr:9999:-1:ed-1:en
refers to the 1st edition of ISO/IEC TR 9999-1, in English

o Status:

urn:iso:std:iso-iec:9075:-3:cancelled:ed-2:en
urn:iso:std:iso-iec:9075:-3:stage-95.99:ed-2:en
both refer to the cancelled 2nd edition of ISO/IEC 9075-3, in
English

urn:iso:std:iso-iec:9075:-3:draft:ed-4:en
urn:iso:std:iso-iec:9075:-3:stage-30.60:ed-4:en
both refer to the draft 4th edition of ISO/IEC 9075-3, in English

urn:iso:std:iso:128:-20:en
urn:iso:std:iso:128:-20:stage-90.20:ed-1:en
both refer to the published (90.20 = under 2nd periodic review)
1st edition of ISO 128-20, in English

urn:iso:std:iso:128:-71:cancelled:ed-1:en
urn:iso:std:iso:128:-71:stage-30.98.v2:ed-1:en
both refer to the cancelled (30.98 = project deleted) 1st edition
of ISO 128-71, in English; the second example refers specifically
to the 2nd iteration (projectversion) at stage 30

o Non-numeric part number:

urn:iso:std:iso:9999:-A02:ed-1:en
refers to the 1st edition of ISO 9999-A02, in English

o Reference to a resource related to all parts of a multipart
document:

urn:iso:std:iso:20022:tech:xsd:camt.001.001.01
refers to a "techdefined" resource (i.e., a resource defined by
the committee that develops or maintains the identified document)
associated with ISO 20022 in its entirety; in this example, the
techdefined part comprises ":xsd:camt.001.001.01"

NOTE: At the time of drafting of this schema, ISO 20022 comprises
5 parts: parts 1 and 2 are International Standards; parts 3 to 5
are Technical Specifications. Therefore, the <doctype>
"international standard" is used in the URN.

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o Docversion handling:

urn:iso:std:iso:9999:-1:ed-1:v2:en
refers to the corrected English version of the 1st edition of ISO
9999-1

urn:iso:std:iso:9999:-1:ed-1:v1-amd1:en
refers to the version comprising the 1st edition of ISO 9999-1,
incorporating the latest version of Amendment 1, in English

urn:iso:std:iso:9999:-1:ed-1:v1:en,fr:amd:1:v2:en
refers to the 2nd version of Amendment 1, in English, which amends
the 1st version of edition 1 of ISO 9999-1, in English/French
(bilingual document)

urn:iso:std:iso:9999:-1:ed-1:v1-amd1.v1:en,fr:amd:2:v2:en
(isoversion scheme)
refers to the corrected version of Amendment 2, in English, which
amends the document comprising the 1st version of edition 1 of ISO
9999-1 incorporating the 1st version of Amendment 1, in English/
French (bilingual document)

urn:iso:std:iso:5817:ed-2:v2:en:cor:1:en
refers to the 1st version of Technical Corrigendum 1, in English,
which amends the corrected version of edition 2 of ISO 5817, in
English

o Supplement handling:

urn:iso:std:iso:9999:-1:ed-2:en:amd:1
refers to Amendment 1 to the 2nd edition of ISO 9999-1, in English

urn:iso:std:iso:9999:-1:ed-2:en:amd:1:v2
refers to the corrected version of Amendment 1 to the 2nd edition
of ISO 9999-1, in English

urn:iso:std:iso:9999:1:ed-2:en,fr:amd:2:en
refers to Amendment 2 in English to the 2nd edition of ISO 9999-1,
in English/French (bilingual document)

urn:iso:std:iso:9999:-1:ed-2:en:amd:1:cor:1
refers to Corrigendum 1 to Amendment 1 to the 2nd edition of ISO
9999-1, in English

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o Docelement handling:

urn:iso:std:iso:105:-c12:ed-1:en:clause:a.1,a.2
urn:iso:std:iso:105:-c12:ed-1:en:clause:a.1-a.2
both refer to clauses A.1 and A.2 in the 1st edition of ISO
105-C12, in English

urn:iso:std:iso:9999:-1:ed-1:v1-
amd1.v1:en,fr:amd:2:v2:en:clause:3.1,a.2-b.9 (isoversion scheme)
refers to (sub)clauses 3.1 and A.2 to B.9 in the corrected version
of Amendment 2, in English, which amends the document comprising
the 1st version of edition 1 of ISO 9999-1 incorporating the 1st
version of Amendment 1, in English/French (bilingual document)

urn:iso:std:iso:9999:-1:ed-2:en:amd:1:term:3.2,3.3,3.4.1-
3.4.4,3.12
refers to the terms 3.2, 3.3, 3.4.1 to 3.4.4, and 3.12 in
Amendment 1 to the 2nd edition of ISO 9999-1, in English

2.5. Relevant Ancillary Documentation

ISO/IEC Directives, Part 1 [ISODIR-1] and Part 2 [ISODIR-2], and ISO
supplement [ISODIR-S].

2.6. Identifier Uniqueness Considerations

Assignment of URNs for documents in the requested namespace will be
managed by the ISO Central Secretariat, which will ensure that the
assigned URNs are consistent with the ISO Directives for unique
identification of ISO documents.

Assignment of URNs for Technical Committee resources related to ISO
documents will be managed by the Technical Committees developing or
maintaining those documents. As indicated above, each such URN will
extend the URN for the containing document via the element
<addition>. The responsibility of the Technical Committee will
therefore be to ensure the uniqueness of the techdefined <addition>
element that constitutes the identifier for the resource within the
document namespace, and thus the uniqueness of the overall resource
identifier within the requested namespace.

2.7. Identifier Persistence Considerations

Assigned URNs will not be reused and will remain valid beyond the
lifecycle of the referenced resources. However, it should be noted
that although the URNs remain valid, the status of the referenced
resource may change.

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2.8. Process for Identifier Resolution

Resolving document identifiers:

This schema has been developed with the intent that a URN
identifying an ISO document can be transformed to a valid http URI
by replacing the requested URN namespace prefix ("iso") and the
"std:" prefix with the domain name "standards.iso.org", replacing
all occurrences of ":" within the identifier with "/", and
converting characters to lowercase. (ISO is planning to develop a
website implementation to support these URIs.)

Examples:

urn:iso:std:iso:9999:-1:ed-1:en: corresponds to
http://standards.iso.org/iso/9999/-1/ed-1/en/

urn:iso:std:iso-iec:tr:9999:-1:ed-1:en: corresponds to
http://standards.iso.org/iso-iec/tr/9999/-1/ed-1/en/

urn:iso:std:iso:9999:-1:ed-2:en,fr:amd:2: corresponds to
http://standards.iso.org/iso/9999/-1/ed-2/en,fr/amd/2/

Resolving identifiers for <addition> resources:

For URNs in the requested namespace that refer to additional
resources related to ISO documents, the ISO Central Secretariat
will specify the resolution procedure at the time it defines the
syntax for the corresponding <addition> to the <std-nss>. In most
cases, those resources will be maintained on an ISO website, as
extensions to the http URIs described above.

2.9. Rules for Lexical Equivalence

URNs are lexically equivalent if they are octet-by-octet equal after
the following preprocessing:

1. normalize the case of the leading "urn:" token

2. normalize the case of the NID

3. normalize the case of any %-escaping

4. normalize the case of all elements

Further information is specified in [RFC2141], Section 5.

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2.10. Conformance with URN Syntax

No special considerations.

2.11. Validation Mechanism

None specified.

2.12. Scope

Global.

3. Namespace Considerations

The ISO-specific requirements are as follows:

o globally unique, persistent identifiers

o location-independent identifiers

o human-interpretable identifiers

o a scheme applicable to paper documents as well as machine-readable
documents

o a scheme applicable to conceptual documents and explicit forms of
documents

o a scheme applicable to resources extracted from documents

o a scheme applicable to "metadata" associated with documents

o a scheme in which the identifier assignment is managed by the ISO
Central Secretariat

Location-independence: Because the publication of ISO standards is a
complex arrangement involving multiple development organizations and
national standards institutes, a given ISO document may be available
in a number of forms from a number of sources. This makes it
important to have a document identifier that is global in scope,
widely and uniformly used, and independent of the text source used by
any given reference.

Human-interpretable: Many, perhaps most, references to documents
appear in text generated by human authors. It is important that an
author familiar with the scheme be able to generate a correct URN for
a document for which the author has the ISO reference (or document
identifier). Conversely, it is important that a reader unfamiliar

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with the scheme be able to identify the URN as a reference to an ISO
document, particularly an ISO standard, and also to recognize
identifiers for forms, languages, or metadata sets.

Paper documents: Older ISO standards that are commonly used as
industrial references exist only in paper form or in earlier
machine-readable forms that are not commonly used on the Internet.
It is important to have a document identifier scheme that extends to
these resources as well. (In fact, many of these have been converted
to Internet forms, and others are being converted, but it is
important that the identifier be independent of the form in which the
document can be obtained at any given time.)

Conceptual documents vs. representation forms: Because ISO documents
are regularly maintained and re-published in multiple forms, it is
important to have document identifiers that denote the conceptual
document, without regard to publication form. At the same time, it
is necessary for certain types of use to be able to refer to specific
editions, or specific publication forms (for example, editions in
different languages, or to PDF or HTML versions). This URN
specification allows for the identification of these different types
of use in the <isodefined> part of the <addition> element.

Document extracts: ISO standards may contain formal specifications in
machine-processable languages, or formal specifications that also
have representations in machine-processable languages. It is useful
to be able to extract these specifications in machine-processable
form as separate resources, and therefore it is necessary to give
these "extracted resources" global identifiers derived from the
document identifier using a consistent identification scheme.

Document metadata: Certain uses of documents and document text,
primarily bibliographic, also extract information from the documents,
and that information, commonly called "metadata", is organized in
machine-readable forms conforming to other standards. These metadata
sets then become resources in their own right. It is important to
give them URN identifiers consistent with the document identification
scheme.

4. Community Considerations

The ISO community is broad in two dimensions. In one dimension, its
documents are developed and used in a large variety of industries and
professions: natural sciences, manufacturing, construction,
transportation, information technology, social sciences, etc. In the
other dimension, it is a community of expert developers, standards

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managers, publishers, professional users, and consumers. And
Internet information technologies are a part of common professional
practice in all of these areas in both dimensions.

ISO standards are cited in business agreements, in professional
publications, in product descriptions, and in standards development
and publication activities. When these citations appear in
electronic form, the references must be unambiguous.

The information technology community is itself very active in the
development and use of standards, and many ISO publications are
developed by and for that community. When an Internet information
exchange uses a form specified in an ISO document, or a terminology
defined in an ISO document, it is often necessary to identify that
ISO specification in the envelope surrounding the exchange. That
identification should use a formal, unambiguous identifier in a form
readily recognized by the receiving software, and possibly by the
ultimate human recipient of the information.

In order to facilitate the use of existing and emerging Internet
technologies for all of these purposes, URNs conforming to [RFC2141]
represent the most useful form of formal, globally unambiguous
identifiers. The use of a managed namespace for such identifiers,
following a consistent scheme for identifying ISO documents and their
derivatives, would be of significant benefit to the entire ISO
community.

It would give professional users in many industries a standard
form for electronic reference to ISO standards in HTML, XML, PDF,
etc., documents.

It would give software developers a standard form for reference to
ISO standard protocols, schemata, languages, data sets, etc.

It would give standards developers a standard form for reference
to other ISO publications in various stages of development. And
it would give them a standard form for creating identifiers for
machine-readable information sets contained in, or derived from,
the specifications.

It would give standards managers and publishers a formal uniform
scheme for reference to specific publications, editions, and
versions of ISO documents.

While the assignment of identifiers under this scheme is managed by
the ISO Central Secretariat, the processes by which the identified
objects arise and acquire such identifiers are the result of
agreements made by the member bodies. Every such project is

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initiated by one member body and reviewed and voted on by the others.
Every accepted project is open to participation by any member body,
and in fact, participation by a certain minimum number (usually 5) of
member bodies is required for acceptance of most projects. In
general, the member bodies are open professional and industrial
organizations reflecting broad expertise and national interest.

It should be noted that ISO documents in draft state are not usually
made available outside the ISO standards development community.
Making them available to professionals outside of the process might
well mislead the recipients into premature adoption of practices that
are not yet completely specified or have not yet achieved consensus,
and therefore may well change.

It should also be noted that ISO documents are not, in general,
freely available over the Internet. Rather, there are complex
agreements between ISO and its member institutes as to the rights to
the publications and the corresponding fees that may be charged for
paper or electronic copies of various editions. Some ISO documents
are freely available, and some are freely available in certain forms.
In general, derivatives of ISO documents (schemata, metadata sets,
etc.) are freely available over the Internet in the appropriate
machine-readable forms. A URL associated with a URN in the requested
namespace may therefore lead directly to a machine-readable copy of
the text of the document or derivative, or it may lead to a site that
can provide that text for a fee, or it may lead to a site that can
only sell a paper copy of the document. Bearing in mind that ISO is
a network of otherwise independent institutes, this behavior is
simply a property of the ISO community.

Finally, it should be noted that, for many purposes, reference to the
ISO standard is what is required, and only the product engineer or
software tool builder actually needs access to the text. This
request is based on the need to standardize the form of reference,
not the means of access.

5. IANA Considerations

IANA has assigned "iso" (29) as a formal NID.

The ISO Central Secretariat will maintain a registry of the
permissible values for the elements comprising the NSS. Information
may be obtained from the following address: [email protected].

6. Security Considerations

The ISO URN Namespace ID shares the security considerations outlined
in [RFC3406], but has no other known security considerations.

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7. References

7.1. Normative References

[ISODIR-1] International Organization for Standardization,
"Procedures for the technical work", ISO/IEC Directives
Part 1, Edition 5, 2004.

[ISODIR-2] International Organization for Standardization, "Rules
for the structure and drafting of International
Standards", ISO/IEC Directives Part 2, Edition 5, 2004.

[ISODIR-S] International Organization for Standardization,
"Procedures specific to ISO", ISO/IEC Directives
Supplement.

[ISOGUIDE69] International Organization for Standardization,
"Harmonized Stage Code system (Edition 2) - Principles
and guidelines for use", ISO Guide 69:1999.

[ISO639-1] International Organization for Standardization, "Codes
for the representation of names of languages - Part 1:
Alpha-2 code", ISO 639-1:2002.

[RFC2141] Moats, R., "URN Syntax", RFC 2141, May 1997.

[RFC3406] Daigle, L., van Gulik, D., Iannella, R., and P.
Faltstrom, "Uniform Resource Names (URN) Namespace
Definition Mechanisms", BCP 66, RFC 3406, October 2002.

[RFC5234] Crocker, D., Ed., and P. Overell, "Augmented BNF for
Syntax Specifications: ABNF", STD 68, RFC 5234, January
2008.

7.2. Informative References

[ISO8879:1986]
International Organization for Standardization,
"Information processing -- Text and office systems --
Standard Generalized Markup Language (SGML)", ISO
8879:1986.

[ISO/IEC9070:1991]
International Organization for Standardization,
"Information technology -- SGML support facilities --
Registration procedures for public text owner
identifiers", ISO/IEC 9070:1991.

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[ISO/IEC8824-1:2002]
International Organization for Standardization,
"Information technology -- Abstract Syntax Notation One
(ASN.1): Specification of basic notation -- Part 1",
ISO/IEC 8824-1:2002.

[ISO/IEC8825:1987]
International Organization for Standardization,
"Information processing systems -- Open Systems
Interconnection -- Specification of Basic Encoding Rules
for Abstract Syntax Notation ONE (ASN.1)", ISO/IEC
8825:1987.

[CCITT] "Specification of Basic Encoding Rules for Abstract
Syntax Notation One (ASN.1)", CCITT Recommendation
X.209, January 1988.

[RFC3061] Mealling, M., "A URN Namespace of Object Identifiers",
RFC 3061, February 2001.

[RFC3151] Walsh, N., Cowan, J., and P. Grosso, "A URN Namespace
for Public Identifiers", RFC 3151, August 2001.

[RFC4646] Phillips, A. and M. Davis, "Tags for Identifying
Languages", BCP 47, RFC 4646, September 2006.

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Appendix A. Alternative Naming Schemes

Before initiating this request, ISO attempted to find an existing or
currently proposed URN NID scheme that might be used instead of a
dedicated scheme. Two existing schemes were carefully considered
because they clearly meet part of the requirements:

o The OID scheme, documented in [RFC3061]

o The PublicId scheme, documented in [RFC3151]

The OID scheme is derived from the joint ISO/ITU-T ASN.1
object-identifier scheme specified in [ISO/IEC8824-1:2002] (original
edition 1984; [RFC3061] cites the 1988 [CCITT] edition of the
encoding rules in [ISO/IEC8825:1987]. This standard assigned the
registry authority for all identifiers in the { iso(1) } namespace to
ISO, and therefore, ISO controls the registry of all identifiers
beginning "oid:1:". And in fact, ISO has developed, and is using, an
identification scheme under ASN.1 that meets most of the above
requirements. ISO could clearly define a use of the OID scheme that
would be adequate to meet all of its technical objectives, although
it would further complicate the current ASN.1 scheme.

The original intent of ISO 8824 was to permit both a human-readable
form for the identifier, to maximize intuitive recognition, and an
encoding that minimized the number of bits needed to communicate an
OID value over a network. Regrettably, the encoding chosen in RFC
3061 is much closer to the minimal bits encoding than to the
human-readable one. The NSS for the OID scheme consists entirely of
digits and punctuation. For example, the ASN.1 identifier { iso(1)
standard(0) 7852 part(2) edition(3) } becomes: urn:oid:1:0:7852:2:3.

This is difficult for a human reader or author to interpret. It is
also easy to mistype, and the scheme contains no "check-digits",
which makes it difficult to validate, leading to the propagation of
URNS that are invalid or valid but erroneous. Finally, the
all-numeric form conveys no hint of the name of the responsible
organization, and therefore no hint of any URL that might aid a human
reader in interpreting the reference. The OID scheme makes all of
the required identifiers technically possible and technically useable
by software, but for all practical purposes, the OID URNs are useful
only to software.

The PublicId scheme is derived from Standard Generalized Markup
Language (SGML) [ISO8879:1986] and [ISO/IEC9070:1991] bibliographic
catalogue forms. Narrowed to ISO publications, it is adequate for
the unique global persistent identification of published documents,
in both paper and machine-processable form.

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Importantly, the PublicId scheme does not have a "conceptual
document" notion -- it identifies specific publications and editions.
"Weak identification" could be used to implement the conceptual
document concept, but the PublicId scheme does not document that
interpretation. In any case, the PublicId scheme does not extend to
draft documents, which are often referenced in pilot implementations,
to separate forms of a document, or to resources extracted from
documents. It supports only those metadata elements that are defined
in SGML. The scheme could be extended to do most of these, but the
ISO-specific extensions would not in general extend to the much
broader base of documents identified by PublicIds. (Version and
edition management practices vary significantly across publishers,
depending on their milieu.) Further, the ISO Central Secretariat
could not and should not control the registry of such URNs.

ISO therefore concluded that the alternative schemes are not adequate
to meet the requirements of the ISO community.

Whilst requesting a new namespace for ISO documents and their
derivatives, ISO does not wish to discourage the use of these other
identifiers for ISO publications. The PublicId form, in particular,
is useful for referring to ISO publications in a larger bibliographic
information space.

Appendix B. ABNF Definition of Namespace ID = "iso" (Informative)

NSS = std-nss

std-nss = "std:" docidentifier *supplement *docelement
[addition]

docidentifier = originator [":" type] ":" docnumber [":" partnumber]
[[":" status] ":" edition]
[":" docversion] [":" language]

originator = "iso" / "iso-iec" / "iso-cie" / "iso-astm" /
"iso-ieee" / "iec"

; iso = International Organization for
; Standardization

; iec = International Electrotechnical
; Commission (IEC), or Commission
; Electrotechnique Internationale

; iso-iec = jointly developed by ISO and IEC

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; iso-cie = jointly developed by ISO and the
; Commission Internationale d'Eclairage
; (CIE)

; iso-astm = jointly developed by ISO and the
; American Society for Testing and
; Materials (ASTM) International

; iso-ieee = jointly developed by ISO and the
; Institute for Electrical and
; Electronics Engineers (IEEE)

type = "data" / "guide" / "isp" / "iwa" /
"pas" / "r" / "tr" / "ts" / "tta"

; data = Data (document type no longer published)

; guide = Guide

; isp = International Standardized Profile

; iwa = International Workshop Agreement

; pas = Publicly Available Specification

; r = Recommendation (document type no longer
; published)

; tr = Technical Report

; ts = Technical Specification

; tta = Technology Trends Assessment

docnumber = DIGITS

partnumber = "-" 1*( DIGIT / ALPHA / "-" )

status = ( "draft" / "cancelled" ) / stage

; draft = document that has not yet been
; accepted for publication by
; international ballot

; cancelled = document that has been deleted or
; withdrawn

stage = "stage-" stagecode ["." iteration]

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stagecode = DIGIT DIGIT "." DIGIT DIGIT

iteration = "v" DIGITS

edition = "ed-" DIGITS

docversion = "v" (simpleversion / isoversion)

simpleversion = DIGITS

; 1 = first version published

; 2 = corrected version published

isoversion = baseversion *includedsuppl

baseversion = DIGITS

includedsuppl = "-" suppltype supplnumber [ "." supplversion ]

language = monolingual / bilingual / trilingual

monolingual = "en" / "fr" / "ru" / "es" / "ar"

bilingual = "en,fr" / "en,ru" / "fr,ru"

trilingual = "en,fr,ru"

supplement = ":" suppltype ":" supplnumber
[":" supplversion ] [":" language ]

suppltype = "amd" / "cor" / "add"

; amd = Amendment

; cor = Technical Corrigendum

; add = Addendum

supplnumber = DIGITS

supplversion = "v" DIGITS

docelement = ":" ( "clause" / "figure" / "table" / "term" ) ":"
elementnumber / elementrange
*( "," elementnumber / elementrange )

elementnumber = ( ALPHA / DIGITS ) *( "." DIGITS )

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elementrange = elementnumber "-" elementnumber

addition = techdefined / isodefined

techdefined = ":tech" *techelement

techelement = <unspecified>

isodefined = <unspecified>

DIGITS = DIGIT *DIGIT

DIGIT = %x30-39 ; 0-9

ALPHA = %x41-5A / %x61-7A ; A-Z / a-z

Authors' Addresses

Joanna Goodwin
International Organization for Standardization
Case Postal 56
Geneva 20 1211
Switzerland

EMail: [email protected]
URI: http://www.iso.org

Holger Apel
International Organization for Standardization
Case Postal 56
Geneva 20 1211
Switzerland

EMail: [email protected]
URI: http://www.iso.org

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Full Copyright Statement

Copyright (C) The IETF Trust (2008).

This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.

This document and the information contained herein are provided on an
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OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
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