Media Type Registration Procedure
RFC 1590

Document Type RFC - Informational (March 1994; No errata)
Updates RFC 1521
Author Jon Postel 
Last updated 2013-03-02
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Network Working Group                                          J. Postel
Request for Comments: 1590                                           ISI
Updates: 1521                                                 March 1994
Category: Informational

                   Media Type Registration Procedure

Status of this Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.


   Several protocols allow the use of data representing different
   "media" such as text, images, audio, and video, and within such media
   different encoding styles, such as (in video) jpeg, gif, ief, and
   tiff.  The Multimedia Internet Message Extensions (MIME) protocol [1]
   defined several initial types of multimedia data objects, and a
   procedure for registering additional types with the Internet Assigned
   Numbers Authority (IANA).  Several questions have been raised about
   the requirements and administrative procedure for registering MIME
   content-type and subtypes, and the use of these Media Types for other
   applications.  This document addresses these issues and specifies a
   procedure for the registration of new Media Types (content-
   type/subtypes).  It also generalizes the scope of use of these Media
   Types to make it appropriate to use the same registrations and
   specifications with other applications.

1. Introduction

   RFC 1521 [1] defines a procedure for the registration of new data
   types for use with the Multimedia Internet Message Extensions (MIME).
   This registration mechanism was designed to make the identifiers for
   a given data type available for use and to prevent naming conflicts.
   With the growth of new multi-media protocols and access mechanisms,
   this process has the promise of forming a unified general
   registration service for Internet Protocols.  These types, previously
   called "MIME Types", are now called "Media Types".

   The registration process for Media Types (content-type/subtypes) was
   initially defined in the context of the asynchronous mail
   environments.  In this mail environment, there is a need to limit the
   number of possible Media Types to increase the likelihood of
   interoperability when the capabilities of the remote mail system are
   not known.  As Media Types are used in new environments, where the

IANA                                                            [Page 1]
RFC 1590           Media Type Registration Procedure          March 1994

   proliferation of Media Types is not a hindrance to interoperability,
   the original procedure is excessively restrictive and needs to be

   This document addresses the specific questions raised and provides an
   administrative procedure for the registration of Media Types.  This
   procedure also address the registration requirements needed for the
   mapping of Object Identifiers (OIDs) for X.400 MHS use to Media

2. Media Type Registration Procedure

   The following procedure has been implemented by the IANA for review
   and approval of new Media Types.  This is not a formal standards
   process, but rather an administrative procedure intended to allow
   community comment and sanity checking without excessive time delay.

2.1 Present the Request for Registration to the Community

   Send a proposed Media Type (content-type/subtype) to the "ietf-" mailing list.  This mailing list has been
   established for the sole purpose of reviewing proposed Media Types.
   Proposed content-types are not formally registered and must use the
   "x-" notation for the subtype name.

   The intent of the public posting is to solicit comments and feedback
   on the choice of content-type/subtype name, the unambiguity of the
   references with respect to versions and external profiling
   information, the choice of which OIDs to use, and a review of the
   security considerations section.  It should be noted that the
   proposed Media Type does not need to make sense for every possible
   application.  If the Media Type is intended for a limited or specific
   use, this should be noted in the submission.

2.2 Submit the Content Type to the IANA for Registration

   After two weeks, submit the proposed Media Type to the IANA for
   registration.  The request and supporting documentation should be
   sent to "".  Provided a reasonable review period has
   elapsed, the IANA will register the Media Type, assign an OID under
   the IANA branch, and make the Media Type registration available to
   the community.

IANA                                                            [Page 2]
RFC 1590           Media Type Registration Procedure          March 1994

   The Media Type registrations will be posted in the anonymous FTP
   directory "" and the Media Type will
   be listed in the periodically issued "Assigned Numbers" RFC [2].  The
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