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Versions: 00 01                                                         
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

Status of this Memo

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Copyright Notice



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   Copyright (c) 2009 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents in effect on the date of
   publication of this document (http://trustee.ietf.org/license-info).
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.

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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