Network Working Group                                           N. Freed
Request for Comments: 2048                                      Innosoft
BCP: 13                                                       J. Klensin
Obsoletes: 1521, 1522, 1590                                          MCI
Category: Best Current Practice                                J. Postel
                                                                     ISI
                                                           November 1996


                 Multipurpose Internet Mail Extensions
                           (MIME) Part Four:
                        Registration Procedures

Status of this Memo

   This document specifies an Internet Best Current Practices for the
   Internet Community, and requests discussion and suggestions for
   improvements.  Distribution of this memo is unlimited.

Abstract

   STD 11, RFC 822, defines a message representation protocol specifying
   considerable detail about US-ASCII message headers, and leaves the
   message content, or message body, as flat US-ASCII text.  This set of
   documents, collectively called the Multipurpose Internet Mail
   Extensions, or MIME, redefines the format of messages to allow for

    (1)   textual message bodies in character sets other than
          US-ASCII,

    (2)   an extensible set of different formats for non-textual
          message bodies,

    (3)   multi-part message bodies, and

    (4)   textual header information in character sets other than
          US-ASCII.

   These documents are based on earlier work documented in RFC 934, STD
   11, and RFC 1049, but extends and revises them.  Because RFC 822 said
   so little about message bodies, these documents are largely
   orthogonal to (rather than a revision of) RFC 822.










 
RFC 2048              MIME Registration Procedures         November 1996


   This fourth document, RFC 2048, specifies various IANA registration
   procedures for the following MIME facilities:

    (1)   media types,

    (2)   external body access types,

    (3)   content-transfer-encodings.

   Registration of character sets for use in MIME is covered elsewhere
   and is no longer addressed by this document.

   These documents are revisions of RFCs 1521 and 1522, which themselves
   were revisions of RFCs 1341 and 1342.  An appendix in RFC 2049
   describes differences and changes from previous versions.

Table of Contents

   1. Introduction .........................................    3
   2. Media Type Registration ..............................    4
   2.1 Registration Trees and Subtype Names ................    4
   2.1.1 IETF Tree .........................................    4
   2.1.2 Vendor Tree .......................................    4
   2.1.3 Personal or Vanity Tree ...........................    5
   2.1.4 Special `x.' Tree .................................    5
   2.1.5 Additional Registration Trees .....................    6
   2.2 Registration Requirements ...........................    6
   2.2.1 Functionality Requirement .........................    6
   2.2.2 Naming Requirements ...............................    6
   2.2.3 Parameter Requirements ............................    7
   2.2.4 Canonicalization and Format Requirements ..........    7
   2.2.5 Interchange Recommendations .......................    8
   2.2.6 Security Requirements .............................    8
   2.2.7 Usage and Implementation Non-requirements .........    9
   2.2.8 Publication Requirements ..........................   10
   2.2.9 Additional Information ............................   10
   2.3 Registration Procedure ..............................   11
   2.3.1 Present the Media Type to the Community for  Review   11