Internet DRAFT - draft-garshol-applicationxtmxml
draft-garshol-applicationxtmxml
Network Working Group L. Garshol
Internet-Draft Bouvet ASA
Intended status: Informational November 24, 2009
Expires: May 28, 2010
application/xtm+xmlMedia Type Registration
draft-garshol-applicationxtmxml-00
Abstract
This document describes a media type (application/xtm+xml) for
serialization of Topic Maps into Extensible Markup Language (XML).
Topic Maps is a technology for encoding knowledge and connecting this
encoded knowledge to relevant information resources. Topic maps are
organized around topics, which represent subjects of discourse;
associations, representing relationships between the subjects; and
occurrences, which connect the subjects to pertinent information
resources. Topic Maps is an ISO standard (ISO 13250).
Status of this Memo
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Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the
document authors. All rights reserved.
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1. Introduction
Topic Maps is a technology for encoding knowledge and connecting this
encoded knowledge to relevant information resources. Topic Maps has
a common structure defined by [ISO13250-2] that can be used for
interoperable data interchange.
Many formats exist for the interchange of Topic Maps, but ISO has
defined the XTM syntax [ISO13250-3] as the main interchange syntax,
in order to allow topic map to be serialized in an XML format. The
application/xtm+xml media type allows consumers of Topic Maps
information to identify XTM documents so they can be processed
properly.
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 BCP 14, RFC 2119
[RFC2119].
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2. application/xtm+xml Registration
This is a media type registration as defined in RFC 4288, "Media Type
Specifications and Registration Procedures" [RFC4288].
*MIME media type name:* application
*MIME subtype name:* xtm+xml
*Required parameters:* none
*Optional parameters:* charset
Same as charset parameter of application/xml, defined in RFC 3023
[RFC3023].
*Encoding considerations:* Same as encoding considerations of
application/xml, defined in RFC 3023 [RFC3023].
*Security considerations:* See Section 5.
*Interoperability considerations:* It is RECOMMENDED that XTM
documents use the new XTM 2.0 syntax [ISO13250-3] as opposed to the
older XTM 1.0 syntax [XTM1.0]. In general use of features of XML
which XML processors may choose not to support should be avoided.
ISO SC34 is currently developing XTM 2.1, which is backwards
compatible with XTM 2.0. When XTM 2.1 becomes a standard it is
RECOMMENDED to use XTM 2.1 instead of XTM 2.0, despite 2.0 being a
subset, as 2.1 is better suited to the interchange of fragments over
the internet.
*Published specification:* See the Topic Maps Data Model [ISO13250-2]
and the XTM specification [ISO13250-3].
*Applications which use this media type:* Any tool which can process
or produce data according to the Topic Maps Data Model [ISO13250-2].
This has included in the past generic Topic Maps tools, web portals,
product configuration tools, e-learning systems, and a variety of web
services and web service clients.
*Magic number(s):* none
Although no byte sequences can be counted on to consistently identify
XTM, XTM documents will have the sequence
"http://www.topicmaps.org/xtm/" to identify the XTM namespace. This
will usually be near the top of the document.
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*File extensions(s):* .xtm
*Macintosh File Type Code(s):* "xtm "
*Person & email address to contact for further information:For
further information:* Lars Marius Garshol <larsga@garshol.priv.no>
*Intended usage:* COMMON
*Author:* Lars Marius Garshol <larsga@garshol.priv.no>
*Change controller:* The IESG.
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3. Fragment Identifiers
The id attribute can be used to define fragments in an XTM document.
So given an XTM document with the URL someurl the URL reference
someurl#frag is taken to refer to the topic element in the XTM
document whose id attribute value is "frag". Such URLs commonly
occur in XTM documents to refer to topics defined either in the same
XTM document or a different XTM document.
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4. IANA Considerations
This document calls for registration of a new MIME media type,
according to the registration in Section 2.
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5. Security Considerations
XTM is a generic format for exchanging application information, but
application designers must not assume that it provides generic
protection against security threats. RFC 3023 [RFC3023], section 10,
discusses security concerns for generic XML, which are also
applicable to XTM.
XTM documents can be secured for integrity, authenticity and
confidentiality using any of the mechanisms available for MIME and
XML data, including XML signature, XML encryption, S/MIME, OpenPGP or
transport or session level security (e.g., see [RFC3631], especially
sections 3.4, 3.5, 3.10, [RFC2818], [RFC3275], [xmlenc-core]).
XTM is intended to be used to combine information from disparate
sources into a coherent whole, but it is entirely possible for
sources outside the control of the receiver to provide information
that is false, misleading, unclear, or inappropriately structured.
The use of Topic Maps schemas may guard against inappropriate
structure, but as far as the other concerns go, caution and careful
engineering are required.
XTM documents may contain references to other XTM documents via the
mergeMap element, and XTM processors are required to dereference and
process these references. This can be a source of insecurity, by
means either subtle or obvious, such denial of service attacks by
automatically generated never-ending chains of mergeMap references or
infinitely sized documents.
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6. References
[ISO13250-2]
Garshol, L. and G. Moore, "ISO 13250-2:2006 - Topic Maps -
Data Model", August 2006.
The International Organization for Standardization.
Prepared by ISO/SC 34.
<http://www.isotopicmaps.org/sam/sam-model/>
[ISO13250-3]
Garshol, L. and G. Moore, "ISO 13250-3:2007 - Topic Maps -
XML Syntax", March 2007.
The International Organization for Standardization.
Prepared by ISO/SC 34.
<http://www.isotopicmaps.org/sam/sam-xtm/>
[RFC2119] Bradner, R., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.
[RFC3023] Murata, M., St.Laurent, S., and D. Kohn, "XML Media
Types", RFC 3023, January 2001.
[RFC3275] Eastlake, D., Reagle, J., and D. Solo, "(Extensible Markup
Language) XML-Signature Syntax and Processing", RFC 3275,
March 2002.
[RFC3631] Bellovin, S., Schiller, J., and C. Kaufman, "Security
Mechanisms for the Internet", RFC 3631, December 2003.
[RFC4288] Freed, N. and J. Klensin, "Media Type Specifications and
Registration Procedures", BCP 13, RFC 4288, December 2005.
[xmlenc-core]
Eastlake, D. and J. Reagle, "XML Encryption Syntax and
Processing", December 2002.
W3C xmlenc-core
<http://www.w3.org/TR/2002/REC-xmlenc-core-20021210/>
[XTM1.0] Pepper, S. and G. Moore, "XML Topic Maps (XTM) 1.0",
August 2001.
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TopicMaps.org Specification.
<http://www.topicmaps.org/xtm/1.0//>
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Author's Address
Lars Marius Garshol
Bouvet ASA
Email: larsga@garshol.priv.no
URI: http://www.garshol.priv.no
Garshol Expires May 28, 2010 [Page 11]
