Internet DRAFT - draft-hoffman-char-lang-media
draft-hoffman-char-lang-media
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.
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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
