In general, parameters in the content-type header field are used to convey supplemental information for various content types, and their use is defined when the content-type and subtype are defined. New parameters should not be defined as a way to introduce new functionality.
In order to simplify and standardize the registration process, this appendix gives templates for the registration of new values with IANA. Each of these is given in the form of an email message template, to be filled in by the registering party.
To: IANA@isi.edu Subject: Registration of new MIME content-type/subtype MIME type name: (If the above is not an existing top-level MIME type, please explain why an existing type cannot be used.) MIME subtype name: Required parameters: Optional parameters: Encoding considerations: Security considerations: Published specification: (The published specification must be an Internet RFC or RFC-to-be if a new top-level type is being defined, and must be a publicly available specification in any case.) Person & email address to contact for further information:
To: IANA@isi.edu Subject: Registration of new MIME Access-type for Message/external-body content-type MIME access-type name: Required parameters: Optional parameters: Published specification: (The published specification must be an Internet RFC or RFC-to-be.) Person & email address to contact for further information: