RFC 2913 (rfc2913) - Page 2 of 9
MIME Content Types in Media Feature Expressions
Alternative Format: Original Text Document
RFC 2913 MIME Content in Media Feature Expressions September 2000
1. Introduction
In "A Syntax for Describing Media Feature Sets" [1], an expression
format is presented for describing media feature capabilities as a
combination of simple media feature tags, registered according to
"Media Feature Tag Registration Procedure" [2]. This provides a
format for message handling agents to describe the media feature
content of messages that they can handle.
This memo defines a media feature tag whose value is a MIME content
type. This allows the construction of feature expressions that take
account of the MIME content type of the corresponding data.
Note that a content type feature value may contain parameters, but
this is discouraged. See section 3 and appendix A, "Summary of the
media features indicated" for discussion of this point.
1.1 Terminology and document conventions
This section defines a number of terms and other document
conventions, which are used with specific meaning in this memo.
media feature
information that indicates facilities assumed to be available
for the message content to be properly rendered or otherwise
presented. Media features are not intended to include
information that affects message transmission.
feature set
some set of media features described by a media feature
assertion, as described in "A Syntax for Describing Media
Feature Sets" [1]. (See that memo for a more formal definition
of this term.)
feature set expression
a string that describes some feature set, formulated according
to the rules in "A Syntax for Describing Media Feature Sets"
[1] (and possibly extended by other specifications).
This specification uses syntax notation and conventions described in
RFC 2234, "Augmented BNF for Syntax Specifications: ABNF" [3].
NOTE: Comments like this provide additional nonessential
information about the rationale behind this document. Such
information is not needed for building a conformant
implementation, but may help those who wish to understand the
design in greater depth.
Klyne Standards Track