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Registration of Charset and Languages Media Features Tags
draft-hoffman-char-lang-media-04

The information below is for an old version of the document that is already published as an RFC.
Document Type
This is an older version of an Internet-Draft that was ultimately published as RFC 2987.
Author Paul E. Hoffman
Last updated 2013-03-02 (Latest revision 2000-07-07)
RFC stream Legacy
Intended RFC status Proposed Standard
Formats
Stream Legacy state (None)
Consensus boilerplate Unknown
RFC Editor Note (None)
IESG IESG state Became RFC 2987 (Proposed Standard)
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Responsible AD (None)
Send notices to (None)
draft-hoffman-char-lang-media-04
Internet Draft                                 Paul Hoffman
draft-hoffman-char-lang-media-04.txt           Internet Mail Consortium
July 3, 2000
Expires in six months

     Registration of Charset and Languages Media Features Tags

Status of this memo

This document is an Internet-Draft and is in full conformance with all
provisions of Section 10 of RFC2026.

Internet-Drafts are working documents of the Internet Engineering Task
Force (IETF), its areas, and its working groups.  Note that other
groups may also distribute working documents as Internet-Drafts.

Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time.  It is inappropriate to use Internet-Drafts as reference material
or to cite them other than as "work in progress."

The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt

The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.

Abstract

This document contains the registration for two media feature tags:
"charset" and "language". These media features allow specification of
character sets and human languages that can be understood by devices
and the devices' users. The templates in this document are derived from
[TAG-REG].
                                   
1. Registration for charset

To: media-feature-tags@apps.ietf.org (Media feature tags mailing list)
Subject: Registration of media feature tag charset

Media feature tag name:
    charset

ASN.1 identifier associated with feature tag:
    New assignment by IANA

Summary of the media feature indicated by this feature tag:
    Ability to display particular charsets as defined in [CHARSET]. For
        most devices, this media feature is usually a capability; that is,
        most devices cannot intelligently process text in a charset that
        is unknown to the device.

Values appropriate for use with this feature tag:
    The values are tokens as defined in [CHARSET]. The values can only
        be compared for equality. Comparison is not case sensitive.

The feature tag is intended primarily for use in the following
applications, protocols, services, or negotiation mechanisms:
    Any protocol that uses media tags

Examples of typical use:
    (| (charset=utf-8);q=1.0 (charset=iso-8859-1);q=0.9
       (charset=utf-16);q=0.5 )

Related standards or documents:
    "IANA Charset Registration Procedures", RFC 2278

Considerations particular to use in individual applications,
protocols, services, or negotiation mechanisms:
    None

Interoperability considerations: Aliases for charsets should not be
        used in media feature expressions because feature expression
        manipulation tools may convert aliases to the the principal name
        for the charset. Even though charset names are not case-sensitive,
        values should be expressed as all lowercase letters to increase the
        likelihood of interoperability. The "charset" capability should
        always be indicated in conjunction with any capability to handle
        textual data.

Security considerations:
    If it is known that there is a security bug in the display
    of a particular charset in a particular environment, knowing
    that a device can accept that charset may slightly help an
    attacker.

Additional information:
    None

Name(s) & email address(es) of person(s) to contact for
further information:
    Paul Hoffman <phoffman@imc.org>

Intended usage:
    COMMON

Author/Change controller:
    IETF

Requested IANA publication delay:
    None

Other information:
    None

2. Registration for language

To: media-feature-tags@apps.ietf.org (Media feature tags mailing list)
Subject: Registration of media feature tag language

Media feature tag name:
    language

ASN.1 identifier associated with feature tag:
    New assignment by IANA

Summary of the media feature indicated by this feature tag:
    Ability to display particular human languages as defined in [LANG].
    Note that "display" in this case will most often mean speech
    by a computer. For most devices, this media feature is a preference,
    not a requirement.

Values appropriate for use with this feature tag:
    The values are tokens, with allowable values defined by
        registration as defined in [LANG]. The values can only be compared
        for equality. As described in [LANG], language tags are always
        handled as a single token, and "subtags" are not used for
        comparison. Comparison is not case sensitive.

The feature tag is intended primarily for use in the following
applications, protocols, services, or negotiation mechanisms:
    Any protocol that uses media tags

Examples of typical use:
    (| (language=no-nynorsk);q=1.0 (language=no-bokmaal);q=0.9
       (language=i-sami-no);q=0.5 )

Related standards or documents:
    "Tags for the Identification of Languages", RFC 1766

Considerations particular to use in individual applications,
protocols, services, or negotiation mechanisms:
    None

Interoperability considerations:
    Even though langage tags are not case-sensitive, values should be
        expressed as all lowercase letters to increase the likelihood of
        interoperability.

Security considerations:
    If it is known that there is a security bug in the display
    of a particular language in a particular environment, knowing
    that a device can accept that language may slightly help an
    attacker.

Additional information:
    None

Name(s) & email address(es) of person(s) to contact for
further information:
    Paul Hoffman <phoffman@imc.org>

Intended usage:
    COMMON

Author/Change controller:
    IETF

Requested IANA publication delay:
    None

Other information:
    None

3. Security Considerations

The security considerations are listed in the two registrations above.

4. IANA Considerations

The bulk of this document is IANA registrations.

5. References

[CHARSET] "IANA Charset Registration Procedures", RFC 2278

[LANG] "Tags for the Identification of Languages", RFC 1766

[TAG-REG] "Media Feature Tag Registration Procedure", RFC 2506

6. Author Contact Information

Paul Hoffman
Internet Mail Consortium
127 Segre Place
Santa Cruz, CA  95060 USA
phoffman@imc.org