Network Working Group Y. YONEYA
Internet-Draft JPRS
Intended status: BCP X. LEE
Expires: September 3, 2009 CNNIC
YJ. Suh
NIDA
E. Chen
TWNIC
March 2, 2009
CJK local mapping in IDNA2008
draft-jet-idnabis-cjk-localmapping-00
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Abstract
Development of IDNA2008 is now in final stage. It will cause
incompatibilities for Chinese, Japanese and Korean (CJK) scripts and
languages. To avoid incompatibilities with IDNA2008 and current IDNA
(IDNA2003), definition of specific local mapping (pre process of IDNA
to be performed to IDN candidate string) for CJK is recommended.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1. Positioning of this document . . . . . . . . . . . . . . . 4
1.2. Why CJK? . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. List of incompatibilities of CJK between IDNA2008 and
IDNA2003 . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Label separators . . . . . . . . . . . . . . . . . . . . . 5
3.2. Compatibility characters . . . . . . . . . . . . . . . . . 6
3.3. Exceptions . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Solutions for incompatibilities . . . . . . . . . . . . . . . . 7
4.1. Label saparators . . . . . . . . . . . . . . . . . . . . . 7
4.2. Compatibility characters . . . . . . . . . . . . . . . . . 7
4.3. Exceptions . . . . . . . . . . . . . . . . . . . . . . . . 7
5. Guideline to keep compatibility in registration protocol . . . 7
6. Guideline to keep compatibility in domain name lookup
protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
8. Security Considerations . . . . . . . . . . . . . . . . . . . . 8
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8
10.1. Normative References . . . . . . . . . . . . . . . . . . . 8
10.2. Informative References . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9
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1. Introduction
1.1. Positioning of this document
IDNA protocol is going to be revised by IDNA2008
([I-D.ietf-idnabis-rationale] [I-D.ietf-idnabis-defs]
[I-D.ietf-idnabis-protocol] [I-D.ietf-idnabis-tables]
[I-D.ietf-idnabis-bidi]) which is in the final stage includes
incompatibilities with IDNA2003 ([RFC3490] [RFC3491] [RFC3492]) in
some cases. Due to those incompatibilities, name resolution of
existing registered IDNs are possible to fail. To avoid such
incompatibilities, IDNA2008 recommends to perform local mapping
before registration and domain name lookup of IDNA processing, but it
does not mention any specific method. This document defines local
mapping for IDNA2008 regarding CJK to avoid incompatibilites between
IDNA2008 and IDNA2003.
1.2. Why CJK?
CJK shares some scripts such as Han and punctations. Therefore, it
is useful to have common local mapping definition in areas and / or
languages that share scripts. Furthermore, ccTLDs in CJK area are
initiative of IDN because they have been actively working for IDN
development and deployment since IDNA2003 start up, had published JET
Guideline together, and accumulated and shared their experiences and
knowledge of IDN registration and operation. Definition developed by
such ccTLDs depending on their experiences is useful for community.
2. Terminology
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].
CJK
The term "CJK" stands for "Chinese, Japanese and Korean".
CJK IDN
The term "CJK IDN" stands for "Chinese IDN" or "Japanese IDN" or
"Korean IDN".
CJK scripts
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+---------------------------------------+---------------+-+-+-+
| Script Name | Code(Range) |C|J|K|
+---------------------------------------+---------------+-+-+-+
|CJK Symbols and Punctuation | U+3000-U+3007 |Y|Y| |
|Hiragana | U+3040-U+309F | |Y| |
|Katakana | U+30A0-U+30FF | |Y| |
|CJK Unified Ideographs Extension A | U+3400-U+4DFF |Y| | |
|CJK Unified Ideographs | U+4E00-U+9FFF |Y|Y| |
|Hangul Syllables | U+AC00-U+D7A3 | | |Y|
|CJK Compatibility Ideographs | U+F900-U+FAFF |Y| | |
|Halfwidth and Fullwidth Forms | U+FF00-U+FFEF |Y|Y| |
|CJK Unified Ideographs Extension A |U+20000-U+2A6D6|Y| | |
|CJK Compatibility Ideographs Supplement|U+2F800-U+2FA1F|Y| | |
+---------------------------------------+---------------+-+-+-+
Chinese IDN
The term "Chinese IDN" stands for "IDN consists from CJK scripts
marked with 'Y' in 'C' column and LDH". Permitted characters in
Chinese IDN are listed in [IANA-IDN-Language-zh-CN] and
[IANA-IDN-Language-zh-TW].
Japanese IDN
The term "Japanese IDN" stands for "IDN consists from CJK scripts
marked with 'Y' in 'J' column and LDH". Permitted characters in
Japanese IDN are listed in [IANA-IDN-Language-ja-JP].
Korean IDN
The term "Korean IDN" stands for "IDN consists from CJK scripts
marked with 'Y' in 'K' column and LDH". Permitted characters in
Korean IDN are listed in [IANA-IDN-Language-ko-KR].
Other terms defined in [I-D.ietf-idnabis-defs] are used.
3. List of incompatibilities of CJK between IDNA2008 and IDNA2003
3.1. Label separators
Following characters are defined as label separator in IDNA2003, but
not defined in IDNA2008.
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+---------------------------------------+---------------+-+-+-+
| Script Name | Code |C|J|K|
+---------------------------------------+---------------+-+-+-+
|IDEOGRAPHIC FULL STOP | U+3002 |Y|Y| |
|HALFWIDTH IDEOGRAPHIC FULL STOP | U+FF61 |Y|Y| |
|FULLWIDTH FULL STOP | U+FF0E |Y|Y| |
+---------------------------------------+---------------+-+-+-+
CJK IDN which includes those characters are valid in IDNA2003 but
invalid in IDNA2008.
3.2. Compatibility characters
Compatibility characters that are mapped to canonical (valid)
characters by Unicode Normalization Form KC (NFKC) [Unicode] [UAX15]
in IDNA2003 are invalid in IDNA2008.
+---------------------------------------+---------------+-+-+-+
| Script Name | Code(Range) |C|J|K|
+---------------------------------------+---------------+-+-+-+
|FULLWIDTH DIGITS | U+FF10-U+FF19 |Y|Y| |
|FULLWIDTH LATIN CAPITAL LETTERS | U+FF21-U+FF3A |Y|Y| |
|FULLWIDTH LATIN SMALL LETTERS | U+FF41-U+FF5A |Y|Y| |
|HALFWIDTH KATAKANA LETTERS | U+FF65-U+FF9F | |Y| |
+---------------------------------------+---------------+-+-+-+
CJK IDN which includes those characters are valid in IDNA2003 but
invalid in IDNA2008.
3.3. Exceptions
Some of mark characters of quasi-Han or quasi-Kana are exceptions in
IDNA2008 that have position and / or adjacent character property
limitations are valid in IDNA2003.
+---------------------------------------+---------------+-+-+-+
| Script Name | Code |C|J|K|
+---------------------------------------+---------------+-+-+-+
|IDEOGRAPHIC ITERATION MARK | U+3006 | |Y| |
|KATAKANA MIDDLEDOT | U+30FB | |Y| |
+---------------------------------------+---------------+-+-+-+
CJK IDN which includes those characters are valid in IDNA2003 but
happen to be invalid in IDNA2008.
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4. Solutions for incompatibilities
4.1. Label saparators
If characters listed in section Section 3.1 is included in CJK IDN
candidate string, those characters were mapped to FULL STOP (U+002E)
in local mapping processing.
4.2. Compatibility characters
If characters listed in section Section 3.2 is included in CJK IDN
candidate string, those characters were mapped to canonical
characters by NFKC in local mapping processing.
4.3. Exceptions
If characters listed in section Section 3.3 is included in CJK IDN
candidate string, those characters were treated as PROTOCOL VALID
instead of CONTEXTO. [NOTE: this is not local mapping, but requires
property change of those characters]
5. Guideline to keep compatibility in registration protocol
Registries who treat CJK IDN must implement solutions described in
section Section 4.
6. Guideline to keep compatibility in domain name lookup protocol
Application softwares which treat CJK IDN must implement solutions
described in section Section 4. Local mappings or corresponding pre-
processing must be performed on user interface (input/output)
processing, such as:
- User typing or pasting in input area
- String extraction from free context in contents area
- Displaing on dialogue and / or address bar
Note that those strings are used for domain name lookup.
7. IANA Considerations
None.
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8. Security Considerations
None.
9. Acknowledgements
Many suggestions and advices were given from JET members, especially
Yao Jiankang, ...
10. References
10.1. Normative References
[I-D.ietf-idnabis-bidi]
Alvestrand, H. and C. Karp, "An updated IDNA criterion for
right-to-left scripts", draft-ietf-idnabis-bidi-03 (work
in progress), November 2008.
[I-D.ietf-idnabis-defs]
Klensin, J., "Internationalized Domain Names for
Applications (IDNA): Definitions and Document Framework",
draft-ietf-idnabis-defs-06 (work in progress),
February 2009.
[I-D.ietf-idnabis-protocol]
Klensin, J., "Internationalized Domain Names in
Applications (IDNA): Protocol",
draft-ietf-idnabis-protocol-09 (work in progress),
February 2009.
[I-D.ietf-idnabis-rationale]
Klensin, J., "Internationalized Domain Names for
Applications (IDNA): Background, Explanation, and
Rationale", draft-ietf-idnabis-rationale-06 (work in
progress), December 2008.
[I-D.ietf-idnabis-tables]
Faltstrom, P., "The Unicode code points and IDNA",
draft-ietf-idnabis-tables-05 (work in progress),
December 2008.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3490] Faltstrom, P., Hoffman, P., and A. Costello,
"Internationalizing Domain Names in Applications (IDNA)",
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RFC 3490, March 2003.
[RFC3491] Hoffman, P. and M. Blanchet, "Nameprep: A Stringprep
Profile for Internationalized Domain Names (IDN)",
RFC 3491, March 2003.
[RFC3492] Costello, A., "Punycode: A Bootstring encoding of Unicode
for Internationalized Domain Names in Applications
(IDNA)", RFC 3492, March 2003.
[UAX15] The Unicode Consortium, "Unicode Normalization Forms",
Unicode Standard Annex
#15, http://www.unicode.org/reports/tr15/, 2008.
[Unicode] The Unicode Consortium, "The Unicode Standard, Version
5.0", Boston, MA, USA: Addiso-Wesley. ISBN 0-321-48091-0,
2007.
10.2. Informative References
[IANA-IDN-Language-ja-JP]
JPRS, ".JP Japanese", IANA IDN language tables, http://
www.iana.org/domains/idn-tables/tables/jp_ja-jp_1.2.html,
August 2005.
[IANA-IDN-Language-ko-KR]
KRNIC, ".KR Korean", IANA IDN language tables, http://
www.iana.org/domains/idn-tables/tables/kr_ko-kr_1.0.html,
March 2004.
[IANA-IDN-Language-zh-CN]
CNNIC, ".CN Chinese", IANA IDN language tables, http://
www.iana.org/domains/idn-tables/tables/cn_zh-cn_4.0.html,
March 2005.
[IANA-IDN-Language-zh-TW]
TWNIC, ".TW Chinese", IANA IDN language tables, http://
www.iana.org/domains/idn-tables/tables/tw_zh-tw_4.0.html,
March 2005.
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Authors' Addresses
Yoshiro YONEYA
JPRS
Chiyoda First Bldg. East 13F
3-8-1 Nishi-Kanda
Chiyoda-ku, Tokyo 101-0065
Japan
Phone: +81 3 5215 8451
Email: yone@jprs.co.jp
Xiaodong LEE
CNNIC
No.4 South 4th Street, Zhongguancun
Beijing 100080
Peoples Republic of China
Phone: +86 10 58813020
Email: lee@cnnic.cn
YungJin Suh
NIDA
11F, 398, Seocho-no
Deocho-gu, Seoul 137-857
South Korea
Phone: +82 2 2186 4562
Email: yjsuh@nida.or.kr
Erin Chen
TWNIC
4F-2, No.9 Sec. 2, Roosevelt Rd.
Taipei 100
Taiwan
Phone: +886 2 23411313#502
Email: erin@twnic.net.tw
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