IANA Charset Registration Procedures

Versions: 00 01 02 03 rfc2278                                           
Network Working Group                      Ned Freed, Innosoft
Internet Draft                                John Postel, ISI

                      IANA Character Set
                   Registration Procedures

                          April 1996

                     Status of this Memo

This document is an Internet-Draft.  Internet-Drafts are
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1.  Abstract

various other modern Internet protocols are capable of using
many different character sets. This in turn means that the
ability to label different character sets is essential.  This
registration procedure exists solely to associate a specific
name or names with a given character set and to give an
indication of whether or not a given character set can be used
in MIME text objects. In particular, the general applicability
and appropriateness of a given registered character set is a
protocol issue, not a registration issue, and is not dealt
with by this registration procedure.

Internet Draft    Character Set Registration        April 1996

2.  Definition of a Character Set

The term "character set" is used here to refer to a method of
converting a sequence of octets into a sequence of characters.
Note that unconditional and unambiguous conversion in the
other direction is not required, in that not all characters
may be representable by a given character set and a character
set may provide more than one sequence of octets to represent
a particular sequence of characters.

This definition is intended to allow various kinds of
character encodings, from simple single-table mappings such as
US-ASCII to complex table switching methods such as those that
use ISO 2022's techniques, to be used as character sets.
However, the definition associated with a character set name
must fully specify the mapping to be performed.  In
particular, use of external profiling information to determine
the exact mapping is not permitted.

NOTE: The term "character set" was originally to describe such
straightforward schemes as US-ASCII and ISO-8859-1 which have
a simple one-to-one mapping from single octets to single
characters. Multi-octet coded character sets and switching
techniques make the situation more complex. For example, some
communities use the term "character encoding" for what this
document calls a "character set", while using the phrase
"coded character set" to denote an abstract mapping from
integers (not octets) to characters.

3.  Registration Requirements

Registered character sets are expected to conform to a number
of requirements as described below.

3.1.  Required Characteristics

Registered character sets must conform to the definition of a
"character set" given above. In addition, character sets
intended for use in MIME content types under the "text" top-
level type must conform to the restrictions on that type
described in RFC MIME-IMB. All registered character sets must
note whether or not they are suitable for such usage.

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All registered character sets must be specified in an openly
available specification.

3.2.  New Character Sets

This registration mechanism is not intended to be a vehicle
for the definition of entirely new character sets. This is due
to the fact that the registration process does NOT contain
adequate review mechanisims for such undertakings.

As such, only character sets defined by other processes and
standards bodies, or specific profiles of such character sets,
are eligible for registration.

3.3.  Naming Requirements

One or more names must be assigned to all registered character
sets. Multiple names for the same character set are permitted,
but if multiple names are assigned a single primary name for
the character set must be identified. All other names are
considered to be aliases for the primary name and use of the
primary name is preferred over use of any of the aliases.

Each assigned name must uniquely identify a single character
set. All character set names must be suitable for use as the
value of a MIME content type charset parameter and hence must
conform to MIME parameter value syntax. This applies even if
the specific character set being registered is not suitable
for use with "text".

3.4.  Usage and Implementation Requirements

Use of a large number of character sets in a given protocol
may hamper interoperability. However, the use of a large
number of undocumented and/or unlabelled character sets
hampers interoperability even more.

A character set should therefore be registered ONLY if it adds
significant functionality that is valuable to a large
community, OR if it documents existing practice in a large
community. Note that character sets registered for the second
reason should be explicitly marked as being of limited or

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specialized use and should only be used in Internet messages
with prior bilateral agreement.

3.5.  Publication Requirements

Character set registrations can be published in RFCs, however,
RFC publication is not required to register a new character

The registration of a character set does not imply
endorsement, approval, or recommendation by the IANA, IESG, or
IETF, or even certification that the specification is
adequate. It is expected that applicability statements for
particular applications will be published from time to time
that recommend implementation of, and support for, character
sets that have proven particularly useful in those contexts.

4.  Registration Procedure

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

4.1.  Present the Character Set to the Community

Send the proposed character set registration to the "ietf-
charsets@innosoft.com" mailing list.  This mailing list has
been established for the sole purpose of reviewing proposed
character set registrations. Proposed character sets are not
formally registered and must not be used; the "x-" prefix
specified in RFC MIME-IMB can be used until registration is

The intent of the public posting is to solicit comments and
feedback on the definition of the character set and the name
chosen for it over a two week period.

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4.2.  Character Set Reviewer

When the two week period has passed and the registration
proposer is convinced that consensus has been achieved, the
registration application should be submitted to IANA and the
Character Set Reviewer. The character set reviewer, who is
appointed by the IETF Applications Area Director(s), either
approves the request for registration or rejects it.
Rejection may occur because of significant objections raised
on the list or objections raised externally.  If the character
set reviewer considers the registration sufficiently important
and controversial, a last call for comments may be issued to
the full IETF. The character set reviewer may also recommend
standards track processing (before or after registration) when
that appears appropriate and the level of specification of the
character set is adequate.

Decisions made by the reviewer must be posted to the ietf-
charsets mailing list within 14 days. Decisions made by the
reviewer may be appealed to the IESG.

4.3.  IANA Registration

Provided that the character set registration has either passed
review or has been successfully appealed to the IESG, the IANA
will register the character set and make its registration
available to the community.

5.  Location of Registered Character Set List

Character set registrations will be posted in the anonymous
FTP file "ftp://ftp.isi.edu/in-
notes/iana/assignment/character-sets/" and all registered
character sets will be listed in the periodically issued
"Assigned Numbers" RFC [currently RFC-1700].  The description
of the character set may also be published as an Informational
RFC by sending it to "rfc-editor@isi.edu" (please follow the
instructions to RFC authors [RFC-1543]).

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6.  Registration Template

  To: ietf-charsets@innosoft.com
  Subject: Registration of new character set

  Character set name(s):

  (All names must be suitable for use as the value of a
  MIME content-type parameter.)

  Published specification(s):

  (A specification for the character set must be
  openly available that accurately describes what
  is being registered.)

  Person & email address to contact for further information:

7.  Security Considerations

This registration procedure is not known to raise any sort of
security considerations that are appreciably different from
those already existing in the protocols that employ registered
character sets.

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8.  References

     Borenstein, N. and Freed, N., "MIME (Multipurpose
     Internet Mail Extensions): Mechanisms for Specifying and
     Describing the Format of Internet Message Bodies", RFC
     1521, Bellcore, Innosoft, September, 1993.

     Moore, K., "Representation of Non-ASCII Text in Internet
     Message Headers", RFC 1522, University of Tennessee,
     September 1993.

     Postel, J., "Media Type Registration Procedure", RFC
     1590, USC/Information Sciences Institute, March 1994.

     Reynolds, J. and J. Postel, "Assigned Numbers", STD 2,
     RFC 1700, USC/Information Sciences Institute, October

     Borenstein, N. and Freed, N., "Multipurpose Internet Mail
     Extensions (MIME) Part One: Format of Internet Message
     Bodies", RFC MIME-IMB, Bellcore, Innosoft, March 1996.

     Borenstein, N. and Freed, N., "Multipurpose Internet Mail
     Extensions (MIME) Part Two: Media Types", RFC MIME-IMT,
     Bellcore, Innosoft, March 1996.

     Moore, K., "Multipurpose Internet Mail Extensions (MIME)
     Part Three: Representation of Non-Ascii Text in Internet
     Message Headers", RFC MIME-HEADERS, University of
     Tennessee, ?.

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     Coded Character Set -- 7-Bit American Standard Code for
     Information Interchange, ANSI X3.4-1986.

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9.  Author Address

Ned Freed
Innosoft International, Inc.
1050 East Garvey Avenue South
West Covina, CA 91790
 tel: +1 818 919 3600           fax: +1 818 919 3614
 email: ned@innosoft.com

Jon Postel
USC/Information Sciences Institute
4676 Admiralty Way
Marina del Rey, CA  90292
 tel: +1 310 822 1511           fax: +1 310 823 6714
 email: Postel@ISI.EDU

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         Appendix A -- IANA and RFC Editor To-Do List

VERY IMPORTANT NOTE:  This appendix is intended to communicate
various editorial and procedural tasks the IANA and the RFC
Editor should undertake prior to publication of this document
as an RFC.  This appendix should NOT appear in the actual RFC
version of this document!

This document refers to the media types mailing list ietf-
charsets@innosoft.com.  There is no guarantee that
innosoft.com will continue to be able to accomodate this list
throughout the lifetime of this document. As such, this
reference should be replaced by an address of the general form
ietf-charsets@iana.org. The actual list can then either be
moved to this location or forwarders can be installed to
redirect traffic to the host that currently maintains the

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