< draft-mealling-iana-xmlns-registry   rfc3688.txt 
Network Working Group M. Mealling Network Working Group M. Mealling
Internet-Draft VeriSign, Inc. Request for Comments: 3688 VeriSign, Inc.
Expires: December 16, 2003 June 17, 2003 BCP: 81 January 2004
Category: Best Current Practice
The IETF XML Registry The IETF XML Registry
draft-mealling-iana-xmlns-registry-05.txt
Status of this Memo Status of this Memo
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all provisions of Section 10 of RFC2026. Internet Community, and requests discussion and suggestions for
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Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved. Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract Abstract
This document describes an IANA maintained registry for IETF This document describes an IANA maintained registry for IETF
standards which use Extensivle Markup Language (XML) related items standards which use Extensible Markup Language (XML) related items
such as Namespaces, Document Type Declarations (DTDs), Schemas, and such as Namespaces, Document Type Declarations (DTDs), Schemas, and
Resource Description Framework (RDF) Schemas. Resource Description Framework (RDF) Schemas.
1. Introduction 1. Introduction
Over the past few years the Extensible Markup Language (XML) Over the past few years, the Extensible Markup Language (XML)
[W3C.REC-xml] has become a widely used method for data markup. There [W3C.REC-xml] has become a widely used method for data markup. There
have already been several IETF Working Groups that have produced have already been several IETF Working Groups that have produced
standards that define XML Document Type Definitions (DTDs), XML standards that define XML Document Type Definitions (DTDs), XML
Namespaces [W3C.REC-xml-names] and XML Schemas [W3C.REC-xmlschema-1]. Namespaces [W3C.REC-xml-names], and XML Schemas [W3C.REC-xmlschema-
Each one of these technologies uses Uniform Resource Identifiers 1]. Each one of these technologies uses Uniform Resource Identifiers
(URIs) [RFC2396] and other standardized identifiers to identify (URIs) [RFC2396] and other standardized identifiers to identify
various components. various components.
For example, while it has been the practice within some standards For example, while it has been the practice within some standards
that use Document Type Definitions (DTDs) to forego the use of the that use Document Type Definitions (DTDs) to forego the use of the
PUBLIC identifiers in favor of 'well known' SYSTEM identifiers, it PUBLIC identifiers in favor of 'well known' SYSTEM identifiers, it
has proven to be more trouble than its worth to attempt to has proven to be more trouble than its worth to attempt to
standardize SYSTEM identifiers. The result is that several IETF standardize SYSTEM identifiers. The result is that several IETF
standards that have simply created non-resolvable URIs in order to standards that have simply created non-resolvable URIs in order to
simply identify but not resolve the DTD for some given XML document. simply identify but not resolve the DTD for some given XML document.
This document seeks to standardize and improve these practices by This document seeks to standardize and improve these practices by
creating an IANA maintained registry of XML element identifiers so creating an IANA maintained registry of XML element identifiers so
that document authors and implementors have a well maintained and that document authors and implementors have a well maintained and
authoritative location for their XML elements. As part of this authoritative location for their XML elements. As part of this
standard, the IANA will maintain standard, the IANA will maintain:
o the public representation of the document, o the public representation of the document,
o the URI for the elements if one is provided at the time of o the URI for the elements if one is provided at the time of
registration, registration,
o a registry of Public Identifiers as URIs. o a registry of Public Identifiers as URIs.
In the case where the registrant does not request a particular URI, In the case where the registrant does not request a particular URI,
the IANA will assign it a Uniform Resource Name that follows the IANA will assign it a Uniform Resource Name (URN) that follows
[RFCXXXX]. [RFC3553].
2. Terminology 2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119. document are to be interpreted as described in BCP 14, RFC 2119
[RFC2119].
3. Registerable Documents 3. Registerable Documents
3.1 The Assigned/Registered URI 3.1. The Assigned/Registered URI
All elements (except PUBLIC identifiers) in this registry will All elements (except PUBLIC identifiers) in this registry will
require a URI in order to be registered. If the registrant wishes to require a URI in order to be registered. If the registrant wishes to
have a URI assigned then a URN of the form: have a URI assigned, then a URN of the form
urn:ietf:params:xml:<class>:<id> urn:ietf:params:xml:<class>:<id>
will be assigned where <class> is the type of the document being will be assigned where <class> is the type of the document being
registered (see below). <id> is a unique id generated by the IANA registered (see below). <id> is a unique id generated by the IANA
based on any means the IANA deems necessary to maintain uniqueness based on any means the IANA deems necessary to maintain uniqueness
and persistence. NOTE: in order for a URN of this type to be and persistence. NOTE: in order for a URN of this type to be
assigned, the item being registered MUST have been through the IETF assigned, the item being registered MUST have been through the IETF
concensus process. Practically this means it must be documented in an consensus process. Basically, this means that it must be documented
RFC. The RFC XXXX [RFCXXXX] URN registration template is found in in a RFC. The RFC 3553 [RFC3553] URN registration template is found
Section 6. in Section 6.
The IANA will also maintain a file server available via at least HTTP The IANA will also maintain a file server available via at least HTTP
and FTP that contains all of the registered elements in some publicly and FTP that contains all of the registered elements in some publicly
accessible file space in the same way that all of the IANA's accessible file space in the same way that all of the IANA's
registered elements are available via registered elements are available via
http://www.iana.org/assignments/. While the directory structure of http://www.iana.org/assignments/. While the directory structure of
this server is up to the IANA, it is suggested that the files be this server is up to the IANA, it is suggested that the files be
organized by the <class> and the individual files have the <id> as organized by the <class> and the individual files have the <id> as
their filename. their filename.
Implementors are warned that they should not programatically rely on Implementors are warned that they should not programatically rely on
those resources being available or the directory structure remaining those resources being available or the directory structure remaining
static for any reason. It is explicitly recognized that some software static for any reason. It is explicitly recognized that some
tools attempt to download DTDs, schema, etc 'on the fly' and that software tools attempt to download DTDs, schema, etc., 'on the fly'
developers should understand when this is done and to not reference and that developers should understand when this is done and when to
IANA network resources as a 'schema download repository'. This is the not reference IANA network resources as a 'schema download
reason that the IANA will not register or provide SYSTEM identifiers. repository'. This is the reason that the IANA will not register or
provide SYSTEM identifiers.
3.2 Registerable Classes 3.2. Registerable Classes
The list of types of XML elements that can be registered with the The list of types of XML elements that can be registered with the
IANA are: IANA are:
publicid -- An XML document that contains a DOCTYPE declaration or publicid -- An XML document that contains a DOCTYPE declaration or
any other external reference can identify that reference via both any other external reference can identify that reference via both
a PUBLIC identifier and a SYSTEM identifier. The SYSTEM identifier a PUBLIC identifier and a SYSTEM identifier. The SYSTEM
is system-specific information that enables the entity manager of identifier is system-specific information that enables the entity
an XML system to locate the file, memory location, or pointer manager of an XML system to locate the file, memory location, or
within a file where the entity can be found. It should also be pointer within a file where the entity can be found. It should
noted that a system identifier could be an invocation of a program also be noted that a system identifier could be an invocation of a
that controls access to an entity that is being identified. Thus program that controls access to an entity that is being
they are not registered items. In many cases, SYSTEM identifiers identified. Thus, they are not registered items. In many cases,
are also URIs but in these cases the URI is still only used for SYSTEM identifiers are also URIs. However, in these cases, the
system-specific information. In the case where a PUBLIC Identifier URI is still only used for system-specific information. In the
is also a URI it is possible for the SYSTEM Identifier to contain case where a PUBLIC Identifier is also a URI, it is possible for
the same URI but this behavior is not recommended unless its side the SYSTEM Identifier to contain the same URI but this behavior is
effects are well known and understood to not cause any not recommended unless its side effects are well known and
unacceptable harm. understood to not cause any unacceptable harm.
A PUBLIC identifier is a name that is intended to be meaningful A PUBLIC identifier is a name that is intended to be meaningful
across systems and different user environments. Typically it will across systems and different user environments. Typically, it
be a name that has a registered owner associated with it, so that will be a name that has a registered owner associated with it, so
public identifiers will be guaranteed unique and no two entities that public identifiers will be guaranteed unique and no two
will have the same public identifier. In practice, PUBLIC entities will have the same public identifier. In practice,
identifiers are typically Formal Public Identifers [ISO.8879.1986] PUBLIC identifiers are typically Formal Public Identifiers
but they are not restricted to just that set. As said in [ISO.8879.1986] but they are not restricted to just that set. As
[RFC3151]: said in [RFC3151]:
"Any string which consists only of the public identifier "Any string which consists only of the public identifier
characters (defined by Production 13 of Extensible Markup characters (defined by Production 13 of Extensible Markup
Language (XML) 1.0 Second Edition) is a legal public Language (XML) 1.0 Second Edition) is a legal public
identifier." identifier."
Therefore it is legal for a PUBLIC identifier to be a URN if it Therefore, it is legal for a PUBLIC identifier to be a URN if it
adheres to the character set restrictions. adheres to the character set restrictions.
Thus, the identifier registered along with a DTD is its PUBLIC Thus, the identifier registered along with a DTD is its PUBLIC
identifier. The only restriction being that it must adhere to the identifier. The only restriction being that it must adhere to the
character set restrictions. In the case where the registrant does character set restrictions. In the case where the registrant does
not provide one, the IANA will assign one of the form not provide one, the IANA will assign one of the form
'urn:ietf:params:xml:pi:<id>'. Registrants are encouraged to 'urn:ietf:params:xml:pi:<id>'. Registrants are encouraged to
investigate RFC 3151 [RFC3151] as a recommended method for investigate RFC 3151 [RFC3151] as a recommended method for
minting a URN that can also be represented as an FPI. minting a URN that can also be represented as an FPI.
ns -- XML Namespaces [W3C.REC-xml-names] are named by a URI. They ns -- XML Namespaces [W3C.REC-xml-names] are named by a URI. They
have no real, machine-parseable representation. Thus the have no real, machine-parseable representation. Thus, the
registered document will be either the specification or a registered document will be either the specification or a
reference to it. In the case where a URI is not provided by the reference to it. In the case where a URI is not provided by the
registrant, the IANA will assign a URN of the form registrant, the IANA will assign a URN of the form
'urn:ietf:params:xml:ns:<id> which will be the XML Namespace's 'urn:ietf:params:xml:ns:<id> which will be the XML Namespace's
name. name.
schema -- XML Schemas [W3C.REC-xmlschema-1] are also identified by a schema -- XML Schemas [W3C.REC-xmlschema-1] are also identified by a
URI but their contents are machine parseable. The IANA registered URI but their contents are machine parseable. The IANA registered
document will be the XML Schema file. The URN the IANA assigns can document will be the XML Schema file. The URN the IANA assigns
be used as the URI for the schema and is of the form can be used as the URI for the schema and is of the form
'urn:ietf:params:xml:schema:<id>'. 'urn:ietf:params:xml:schema:<id>'.
rdfschema -- The Resource Description Format (RDF) rdfschema -- The Resource Description Format (RDF)
[W3C.CR-rdf-schema] is an XML serialization of a connected graph [W3C.CR-rdf-schema] is an XML serialization of a connected graph
based data model used for metadata expression. RDF makes use of based data model used for metadata expression. RDF makes use of
schemas for RDF that express grammars about relationships between schemas for RDF that express grammars about relationships between
URIs. These grammars are identified by URIs. The URN assigned by URIs. These grammars are identified by URIs. The URN assigned by
the IANA can be used as the identifying URI and is of the form the IANA can be used as the identifying URI and is of the form
'urn:ietf:params:xml:rdfschema:<id>'. 'urn:ietf:params:xml:rdfschema:<id>'.
4. Registration Procedures 4. Registration Procedures
Until such time as the IANA requests or implements an automated Until the IANA requests or implements an automated process for the
process for the registration of these elements, any specifications registration of these elements, any specifications must make that
wishing to do so must make that request part of the IANA request part of the IANA considerations section of their respective
considerations section of their respective documents. That request documents. That request must be in the form of the following
must be in the form of the following template: template:
URI URI
The URI or PUBLIC identifier that identifies the XML component. The URI or PUBLIC identifier that identifies the XML component. If
If the registrant is requesting that the IANA assign a URI then the registrant is requesting that the IANA assign a URI then this
this field should be specified as "please assign" field should be specified as "please assign".
Registrant Contact Registrant Contact
The individual/organization that is the registration contact for The individual/organization that is the registration contact for
the component being registered. Ideally this will be the name and the component being registered. Ideally, this will be the name
pertinent physical and network contact information. In the case of and pertinent physical and network contact information. In the
IETF developed standards the Registrant will be the IESG. case of IETF developed standards, the Registrant will be the IESG.
XML XML
The exact XML to be stored in the registry. Unless otherwise The exact XML to be stored in the registry. Unless the beginning
obvious what the beginning and end of the file are, the document and end of the file is obvious, the document should use the text
should use the text "BEGIN" to mark the beginning of the file and "BEGIN" to mark the beginning of the file and "END" to mark the
"END" to mark the end of the file. The IANA will insert any text end of the file. The IANA will insert any text between those two
between those two strings (minus any page breaks and RFC strings (minus any page breaks and RFC formatting inserted by the
formatting inserted by the RFC Editor) into the file kept in the RFC Editor) into the file kept in the repository.
repository.
5. Security Considerations 5. Security Considerations
The information maintained by the IANA will be authoritative and thus The information maintained by the IANA will be authoritative and will
will be a target for attack. In some cases, such as XML Schema and be a target for attack. In some cases, such as XML Schema and DTDs,
DTDs, the content maintained by the IANA may be directly input into the content maintained by the IANA may be directly input into
software. Thus, extra care should be taken by the IANA to maintain software. Thus, extra care should be taken by the IANA to maintain
the security precautions required for an important reference location the security precautions required for an important reference location
for the Internet. for the Internet.
Beyond this concern there are no other security considerations not Beyond this concern, there are no other security considerations not
already found with any other IANA registry. already found with any other IANA registry.
6. IANA Considerations 6. IANA Considerations
This documents seeks to create a rather large registry for which the This document seeks to create a rather large registry for which the
IANA (at the direction of the IESG) will be primarily responsible. IANA (at the direction of the IESG) will be primarily responsible.
The amount of effort required to maintain this registry is not The amount of effort required to maintain this registry is not
insignificant and the policies and procedures surrounding any insignificant and the policies and procedures surrounding any
approval process are non-trivial. The registry is on a First Come approval process are non-trivial. The registry is on a First Come
First Served basis but at this time a Specification is Required. Once First Served basis, but a Specification is Required. Once the IETF
the IETF has some experience with this registry these policies may has some experience with this registry, these policies may change.
change.
RFC XXXX [RFCXXXX] specifies that any new registry that requires a RFC 3553 [RFC3553] specifies that any new registry requiring a name,
name to be assigned below the 'urn:ietf:params' namespace must to be assigned below the 'urn:ietf:params' namespace and must specify
specify the structure of that space in template form. The IANA is the structure of that space in template form. The IANA has created
directed to create and maintain this new sub-namespace: and will maintain this new sub-namespace:
Registry-name: xml Registry-name: xml
Specification: This document contains the registry specification. The Specification: This document contains the registry specification.
namespace is organized with one sub-namespace which is the <id>. The namespace is organized with one sub-namespace which is the
<id>.
Repository: To be assigned according to the guidelines found above. Repository: To be assigned according to the guidelines found above.
Index value: The class name Index value: The class name
Normative References 7. Normative References
[ISO.8879.1986]
International Organization for Standardization,
"Information processing - Text and office systems -
Standard generalized markup language (SGML)", ISO Standard
8879, 1986.
[RFC2396] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform
Resource Identifiers (URI): Generic Syntax", RFC 2396,
August 1998.
[RFC3151] Walsh, N., Cowan, J. and P. Grosso, "A URN Namespace for
Public Identifiers", RFC 3151, August 2001.
[RFCXXXX] Mealling, M., Masinter, L., Hardie, T. and G. Klyne, "An [ISO.8879.1986] International Organization for Standardization,
IETF URN Sub-namespace for Registered Protocol "Information processing - Text and office
Parameters", draft-mealling-iana-urn-02.txt (work in systems - Standard generalized markup language
progress), August 2001. (SGML)", ISO Standard 8879, 1986.
[W3C.CR-rdf-schema] [RFC2119] Bradner, S., "Key words for use in RFCs to
Brickley, D. and R. Guha, "Resource Description Framework Indicate Requirement Levels", BCP 14, RFC 2119,
(RDF) Schema Specification 1.0", W3C CR-rdf-schema, March March 1997.
2000, <http://www.w3.org/TR/2000/CR-rdf-schema-20000327>.
[W3C.REC-xml] [RFC2396] Berners-Lee, T., Fielding, R. and L. Masinter,
Bray, T., Paoli, J., Sperberg-McQueen, C. and E. Maler, "Uniform Resource Identifiers (URI): Generic
"Extensible Markup Language (XML) 1.0 (2nd ed)", W3C Syntax", RFC 2396, August 1998.
REC-xml, October 2000, <http://www.w3.org/TR/REC-xml>.
[W3C.REC-xml-names] [RFC3151] Walsh, N., Cowan, J. and P. Grosso, "A URN
Bray, T., Hollander, D. and A. Layman, "Namespaces in Namespace for Public Identifiers", RFC 3151,
XML", W3C REC-xml-names, January 1999, <http://www.w3.org/ August 2001.
TR/REC-xml-names>.
[W3C.REC-xmlschema-1] [RFC3553] Mealling, M., Masinter, L., Hardie, T. and G.
Thompson, H., Beech, D., Maloney, M. and N. Mendelsohn, Klyne, "An IETF URN Sub-namespace for
"XML Schema Part 1: Structures", W3C REC-xmlschema-1, May Registered Protocol Parameters", BCP 73, RFC
2001, <http://www.w3.org/TR/xmlschema-1/>. 3553, June 2003.
Author's Address [W3C.CR-rdf-schema] Brickley, D. and R. Guha, "Resource Description
Framework (RDF) Schema Specification 1.0", W3C
CR-rdf-schema, March 2000,
<http://www.w3.org/TR/2000/CR-rdf-schema-
20000327>.
Michael Mealling [W3C.REC-xml] Bray, T., Paoli, J., Sperberg-McQueen, C. and
VeriSign, Inc. E. Maler, "Extensible Markup Language (XML) 1.0
(2nd ed)", W3C REC-xml, October 2000,
<http://www.w3.org/TR/REC-xml>.
Mountain View, CA [W3C.REC-xml-names] Bray, T., Hollander, D. and A. Layman,
US "Namespaces in XML", W3C REC-xml-names, January
1999, <http://www.w3.org/TR/REC-xml-names>.
URI: http://www.research.verisignlabs.com [W3C.REC-xmlschema-1] Thompson, H., Beech, D., Maloney, M. and N.
Mendelsohn, "XML Schema Part 1: Structures",
W3C REC-xmlschema-1, May 2001,
<http://www.w3.org/TR/xmlschema-1/>.
Intellectual Property Statement 8. Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and IETF's procedures with respect to rights in standards-track and
standards-related documentation can be found in BCP-11. Copies of standards-related documentation can be found in BCP-11. Copies of
claims of rights made available for publication and any assurances 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 licenses to be made available, or the result of an attempt made to
obtain a general license or permission for the use of such obtain a general license or permission for the use of such
proprietary rights by implementors or users of this specification can proprietary rights by implementors or users of this specification can
be obtained from the IETF Secretariat. be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive this standard. Please address the information to the IETF Executive
Director. Director.
Full Copyright Statement 9. Author's Address
Copyright (C) The Internet Society (2003). All Rights Reserved. Michael Mealling
VeriSign, Inc.
Mountain View, CA
USA
EMail: [email protected]
URI: http://www.research.verisignlabs.com
10. Full Copyright Statement
Copyright (C) The Internet Society (2004). All Rights Reserved.
This document and translations of it may be copied and furnished to This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of Internet organizations, except as needed for the purpose of
developing Internet standards in which case the procedures for developing Internet standards in which case the procedures for
copyrights defined in the Internet Standards process must be copyrights defined in the Internet Standards process must be
followed, or as required to translate it into languages other than followed, or as required to translate it into languages other than
English. English.
The limited permissions granted above are perpetual and will not be The limited permissions granted above are perpetual and will not be
revoked by the Internet Society or its successors or assignees. revoked by the Internet Society or its successors or assignees.
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