In order to increase the efficiency and flexibility of the
registration process, different structures of subtype names may be
registered to accommodate the different natural requirements for,
e.g., a subtype that will be recommended for wide support and
implementation by the Internet community, or a subtype that is used
to move files associated with proprietary software. The following
subsections define registration "trees" that are distinguished by the
use of faceted names, e.g., names of the form
"tree.subtree...subtype". Note that some media types defined prior
to this document do not conform to the naming conventions described
below. See Appendix A for a discussion of them.
The standards tree is intended for types of general interest to the
Internet community. Registrations in the standards tree MUST be
approved by the IESG and MUST correspond to a formal publication by a
recognized standards body. In the case of registration for the IETF
itself, the registration proposal MUST be published as an RFC.
Standards-tree registration RFCs can either be standalone
"registration only" RFCs, or they can be incorporated into a more
general specification of some sort.
Media types in the standards tree are normally denoted by names that
are not explicitly faceted, i.e., do not contain period (".", full
stop) characters.
The "owner" of a media type registration in the standards tree is
assumed to be the standards body itself. Modification or alteration
of the specification requires the same level of processing (e.g.,
standards track) required for the initial registration.
The vendor tree is used for media types associated with commercially
available products. "Vendor" or "producer" are construed as
equivalent and very broadly in this context.
A registration may be placed in the vendor tree by anyone who needs
to interchange files associated with the particular product.
However, the registration formally belongs to the vendor or
organization producing the software or file format being registered.
Changes to the specification will be made at their request, as
discussed in subsequent sections.
Registrations in the vendor tree will be distinguished by the leading
facet "vnd.". That may be followed, at the discretion of the
registrant, by either a media subtype name from a well-known producer
(e.g., "vnd.mudpie") or by an IANA-approved designation of the
producer's name that is followed by a media type or product
designation (e.g., vnd.bigcompany.funnypictures).
While public exposure and review of media types to be registered in
the vendor tree is not required, using the ietf-types@iana.org
mailing list for review is strongly encouraged to improve the quality
of those specifications. Registrations in the vendor tree may be
submitted directly to the IANA.
Registrations for media types created experimentally or as part of
products that are not distributed commercially may be registered in
the personal or vanity tree. The registrations are distinguished by
the leading facet "prs.".
The owner of "personal" registrations and associated specifications
is the person or entity making the registration, or one to whom
responsibility has been transferred as described below.
While public exposure and review of media types to be registered in
the personal tree is not required, using the ietf-types list for
review is strongly encouraged to improve the quality of those
specifications. Registrations in the personal tree may be submitted
directly to the IANA.
For convenience and symmetry with this registration scheme, subtype
names with "x." as the first facet may be used for the same purposes
for which names starting in "x-" are used. These types are
unregistered, experimental, and for use only with the active
agreement of the parties exchanging them.
However, with the simplified registration procedures described above
for vendor and personal trees, it should rarely, if ever, be
necessary to use unregistered experimental types. Therefore, use of
both "x-" and "x." forms is discouraged.
Types in this tree MUST NOT be registered.
From time to time and as required by the community, the IANA may, by
and with the advice and consent of the IESG, create new top-level
registration trees. It is explicitly assumed that these trees may be
created for external registration and management by well-known
permanent bodies; for example, scientific societies may register
media types specific to the sciences they cover. In general, the
quality of review of specifications for one of these additional
registration trees is expected to be equivalent to registrations in
the standards tree. Establishment of these new trees will be
announced through RFC publication approved by the IESG.
