Requirements for IDN and its Implementations from Japan

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Requirements for IDN and its Implementations from
Japan

• Yoshiro YONEYA ltyone_at_nic.ad.jpgt
• JPNIC IDN-TF / NTT Software Co.

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Contents

• Scope
• Requirements for IDN
• Requirements for IDN Implementations
• Two experimental implementations of JPNIC
• Reference

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Scope

• Clarify our Requirements for IDN
• Discuss about Implementations of IDN

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Requirements for IDN

• IDN should be naturally readable and/or writable
  in its language context
• IDN should not require users to specify ZLD
• Current ASCII-only Domain Name should be usable
  in any language context
• But, IDN should not depend on natural language
  structure
• Word order, word separator, writing direction,
  etc.

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Requirements for IDN (Cont.)

• IDN should be a common framework to make
  localization easy
• Distinguish or unify of differences between
  characters should be a local (language depend)
  issue
• Examples in Japanese
• ? (UFF71)??? (U30A2) (half-width vs.
  full-width)
• A (U0041)??A (UFF21) (half-width vs.
  full-width)
• ? (U30A2)??? (U3042) (katakana vs. hiragana)
• Guidelines for each language to deal with such
  issues should be documented in an RFC
• Set of characters usable as IDN label,
  canonicalization/normalization rule, etc.

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Requirements for IDN (Cont.)

• IDN should have enough length to store long
  labels
• JPNIC in Japanese is ?????????????????????????
• Each IDN should have a corresponding ASCII-only
  domain name
• CNAME / DNAME like aliasing should be used to
  define IDN
• Reverse mapping should produce 1 or more
  ASCII-only name
• IDN character encoding should be stateless
• UTF-8 is desirable

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Requirements for Implementations

• Internationalization rules should be solved in
  DNS servers, localization rules should be solved
  in clients (resolvers)
• IDN capable DNS servers should not have regional
  dependence
• Maintenance supporting tools for IDN capable DNS
  servers may have regional dependence
• Conversion of charset and canonicalization and/or
  normalization should be done on the client side
  before query
• Proxy servers near clients may do them

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Requirements for Implementations (Cont.)

• IDN capable DNS servers should be fully upper
  compatible with current DNS
• Difference should be whether it can hold IDN
• New RRs such as to hold language selector should
  be examined
• Protocol extensions may be needed to distinguish
  languages strictly

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Requirements for Implementations (Cont.)

• Applications and resolvers should be 8bit through
• DNS protocol RFC1035 is already 8bit through
• Prepare for migration/transition tools and/or
  proxy servers to prevent initial confusion
• URL character code converter, DNS proxy, etc.
• We should discuss about migration/transition
  strategy like IPv6

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Two experimental implementations of JPNIC

• IDNX/idnx-jp
• Proxy DNS server
• Accepts Japanese local charsets and converts them
  into UTF-5
• Uses ZLD
• Worked well near clients side
• GDNS
• 8bit through based on BIND
• Uses CNAME for multilingual labels
• Not uses ZLD
• Worked well even in reverse mapping

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Reference

• JPNIC IDN-TF WebPage
• http//www.nic.ad.jp/en/research/idn/index.html

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Questions?