XML related protocols survey

Prepared by:
Graham Klyne
Date:
2002-10-21

Survey of features and characteristics of a selection of protocols and data formats related to XML.


Unicode

Specification type: Generic encoding framework
Used by: XML
Data in the form of a sequence of Unicode characters. May be presented in a range of transfer encoding formats, including 32-bit character codes (UCS-4), UTF-16 or UTF-8.

XML

Specification type: Generic encoding framework
Specification(s): http://www.w3.org/TR/REC-xml
Uses: Unicode
Can contain or carry: Unicode
Cannot contain or carry: MIME
DIME
A textual framework for encoding various kinds of data structure.

MIME

Specification type: Generic transfer protocol, Generic encapsulation format, Data labelling framework
Specification(s): http://www.ietf.org/rfc/rfc2045.txt
http://www.ietf.org/rfc/rfc2046.txt
http://www.ietf.org/rfc/rfc2047.txt
http://www.ietf.org/rfc/rfc2048.txt
http://www.ietf.org/rfc/rfc2049.txt
Can contain or carry: XML
ASCII-based data encapsulation and metadata attachment format. Originally designed for conveying extended-content in mail messages, but subsequently used as a generic "tagging and bagging" format.

Has very little to do with XML, other than that it can be used to encapsulate XML data. Also, the metadata expression capabilities of MIME are fairly limited, and may be better served by attaching XML-formatted content.

DIME

Specification type: Generic encapsulation format
Specification(s): http://www.ietf.org/internet-drafts/draft-nielsen-dime-02.txt
Can contain or carry: XML
A general purpose binary content encapsulation format.

Has very little to do with XML, other than that it allows XML namespace URIs to be used as document payload type identifiers.

Performs a small subset of the functions of MIME. There is a clearer division of functional capability between DIME and XML than between MIME and XML.