Network Working Group P. Faltstrom, Ed.
Internet-Draft Cisco
Intended status: Standards Track October 18, 2010
Expires: April 21, 2011
The Unicode code points and IDNA - Unicode 6.0
draft-faltstrom-5892bis-00.txt
Abstract
This document specifies updates Section 2.7 of RFC 5892 so that the
calculation of the rules are backward compatible when Unicode 6.0 is
released.
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This Internet-Draft will expire on April 21, 2011.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. New section 2.7 . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. BackwardCompatible (G) . . . . . . . . . . . . . . . . . . 3
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 3
3.1. IDNA derived property value registry . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 4
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 4
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 4
6.1. Normative References . . . . . . . . . . . . . . . . . . . 4
6.2. Informative References . . . . . . . . . . . . . . . . . . 4
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 4
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1. Introduction
RFC 5892 [RFC5892] specifies an algorithm that based on The Unicode
Standard [Unicode6] defines a derived property value. Unicode 6.0
have one codepoint that has changed GeneralCategory which implies the
codepoint would move from PVALID to DISALLOWED.
This document updates section 2.7 Backward Compatible and adds the
codepoint U+19DA NEW TAI LUE THAM DIGIT ONE to it.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. New section 2.7
Between Unicode 5.2 and 6.0, three codepoints have changed in a non-
compatible way. U+0CF1 and U+0CF2 move from DISALLOWED to PVALID,
and can be treated as codepoints that move from UNASSIGNED to PVALID.
U+19DA moves from PVALID to DISALLOWED due to a change of
GeneralCategory from Nd to No. This new section 2.7 has added U+19DA
for backward compatibility reasons.
2.1. BackwardCompatible (G)
G: cp is in {19DA}
This category includes the code points that property values in
versions of Unicode after 5.2 have changed in such a way that the
derived property value would no longer be PVALID or DISALLOWED. If
changes are made to future versions of Unicode so that code points
might change property value from PVALID or DISALLOWED, then this
table can be updated and keep special exception values so that the
property values for code points stay stable.
PVALID -- Would otherwise have been DISALLOWED
19DA; PVALID # NEW TAI LUE THAM DIGIT ONE
3. IANA Considerations
3.1. IDNA derived property value registry
IANA is to update the algorithm used for derived property value
registry to reflect this change in the algorithm.
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4. Security Considerations
If algorithm presented in RFC 5892 [RFC5892] is applied to Unicode
6.0 without adding the change described in this document, the
codepoint U+19DA will have the wrong derived property value. That in
turn will make the codepoint DISALLOWED instead of PVALID.
5. Acknowledgements
The main contributors are (in alphabetical order) Eric Brunner-
Williams, Vint Cerf, Tina Dam, Mark Davis, Paul Hoffman, John
Klensin, Pete Resnick, Markus Scherer, Andrew Sullivan, Kenneth
Whistler and Nicholas Williams.
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5892] Faltstrom, P., "The Unicode Code Points and
Internationalized Domain Names for Applications (IDNA)",
RFC 5892, August 2010.
[Unicode6]
The Unicode Consortium, "The Unicode Standard, Version
6.0.0", 2010.
6.2. Informative References
Author's Address
Patrik Faltstrom (editor)
Cisco
Email: paf@cisco.com
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