1. Multilingual Domain Name
22 Feb 2001
YONEYA, Yoshiro
JPNIC IDN-TF

2. What is MDN? Multilingual Domain Name.
Current domain name is represented with ASCII alpha-numeric and hyphen characters.
Multilingualization of Domain Name is,
Technical challenge to represent domain name with not only ASCII but also NON-ASCII characters.
Almost equivalent to Internationalization of domain name.
22 Feb 2001
IWS2001

3. What is IDN? Internationalized Domain Name.
Framework to multilingualize domain name.
Need to be a Global Standard.
IETF IDN (Internationalized Domain Name) WG is doing the work.
Some confusion by using the word ‘Internationalized’.
22 Feb 2001
IWS2001

4. Why MDN?
Increase of the Internet users who are not familiar with English.
Easy to memorize, type in, etc.
Drastic change of usage of domain name.
Domain name is now used as not only host name but also signboard.
Creates new business opportunities.
Many ventures began services.
22 Feb 2001
IWS2001

5. Drawback of MDN Actually, it is localization.
Loses global acceptability.
Hard to type in or display without appropriate I/O devices.
Cause impact to the operation.
Requires software update and / or additional processing.
Deployment issue.
22 Feb 2001
IWS2001

6. Standardization trend of MDN
REQUIREMENTS
ACE
NAMEPREP
IDNA
22 Feb 2001
IWS2001

7. Requirements draft-ietf-idn-requirements-04.txt
Definition of requirements for MDN.
30 items such as
Interoperability / compatibility with current DNS protocol.
ISO-10646/Unicode for Character set.
Normalization of representation.
Easy to add current domain name space.
22 Feb 2001
IWS2001

8. Requirements Respect to IAB statement. RFC2825 RFC2826
Preservation compatibility with current domain name.
RFC2826
Preservation of uniqueness of domain name space.
Not to divide the Internet into islands.
22 Feb 2001
IWS2001

9. ACE ASCII Compatible Encoding.
Represent NON-ASCII characters by ASCII characters.
Easy to apply current DNS.
Minimize impact to current applications.
Decreases maximum characters in each label.
Penalty of using 5bit to represent 8bit data.
Requires some sort of compression algorithm.
22 Feb 2001
IWS2001

10. ACE Requires explicit ACE-identifier. For reverse conversion.
Choice of ACE-ID is political issue.
ACE-ID itself is ASCII string, so that if any proposal for ACE-ID is raised, it will be registered as ASCII domain name.
Actually happened at gTLD.
ZLD – Zero Level Domain – such as ‘.I’ is not realistic.
22 Feb 2001
IWS2001

11. ACE Impact to operation. Application solution.
Configuration file and zone files should be written in ACE.
Therefore, supporting tools such as editor and / or filter are essential.
Application solution.
Local encoding at user interface.
ACE at network interface.
22 Feb 2001
IWS2001

12. ACE Proposed ACEs. RACE (Row-based ACE) BRACE (Bi-mode Row-based ACE)
draft-ietf-idn-race-03.txt
BRACE (Bi-mode Row-based ACE)
draft-ietf-idn-brace-00.txt
LACE (Length-based ACE)
draft-ietf-idn-lace-01.txt
DUDE (Differential Unicode Domain Encoding)
draft-ietf-idn-dude-00.txt
AMC-ACE-M
draft-ietf-idn-amc-ace-m-00.txt
22 Feb 2001
IWS2001

13. Flow of ACE conversion User 日本語.JP Local Application Code conv Unicode
Normaliza-tion
日本語.jp
(65e5 672c 8a9e.jp)
Compress
…00000.jp
Bit stream
BASE32
3bs6kzzmrkpa.jp
ACE
Network
bq--3bs6kzzmrkpa.jp
ACE(ID)
22 Feb 2001
IWS2001

14. NAMEPREP Preparation of Internationalized Host Names
draft-ietf-idn-nameprep-02.txt
Normalization of representation of the same string in meaning or displaying.
Character case (upper, lower), compatible characters (Fullwidth, Halfwidth)
Composed characters
Umlaut in German, accent in French, voiced sound in Japanese, etc.
22 Feb 2001
IWS2001

15. NAMEPREP Processes in NAMEPREP map normalize prohibit unassigned
Case folding of upper/lower characters (UTR#21)
normalize
Normalize representation of string (UTR#15)
prohibit
Check out inappropriate character as domain name.
unassigned
Treatment of unassigned characters
22 Feb 2001
IWS2001

16. IDNA Internationalizing Host Names in Applications.
Applications do following process.
Character set conversion between local and Unicode.
NAMEPREP.
Character encoding conversion between Unicode and ACE.
22 Feb 2001
IWS2001

17. IDNA Requires adaptation of Application programs. Alternatives are,
Adaptation at resolver.
IDNRA – Internationalized Host Names using Resolvers and Applications
May work well at name resolution, but might not work within application protocol such as SMTP and HTTP.
Adaptation at DNS server.
Requires DNS protocol modification.
Hard to deploy due to back bone system replacement.
22 Feb 2001
IWS2001

18. IDNRA Local User UI Application Internal Representation End system
Resolver
Resolver
API
Int’l
DNS servers
DNS servers
Application servers
22 Feb 2001
IWS2001

19. IDNA Local User NAMEPREP To/From ACE To/From Unicode Application UI
Internal
Representation
End system
To/From ACE
Resolver
API
Int’l
DNS servers
Application servers
22 Feb 2001
IWS2001

20. What is mDNkit? Project of JPNIC
Started on Apr 2000
Multilingual Domain Name evaluation kit
mDNkit-1.x release series
Objectives
Evaluation of the MDN technology
Promoting standardization of MDN
Technical contribution to the Internet community
22 Feb 2001
IWS2001

21. Components of mDNkit libmdn mdnconv dnsproxy runmdn / mDN Wrapper
Core library for MDN processing
mdnconv
DNS zone / configuration file code converter
dnsproxy
DNS query / response code converter
runmdn / mDN Wrapper
Dynamic link resolver library for UNIX / Windows
BIND 9 patch
MDN enhancements for BIND 9 resolver library
22 Feb 2001
IWS2001

22. Diagram of components mdnconv dnsproxy libmdn mDN wrapper named named
Local Encoding (SJIS, EUC…)
zone file
Legacy client
UNIX client
Windows client
mdnconv
Multilingualized resolver / runmdn
mDN wrapper
dnsproxy
libmdn
zone file
named
named
Encoding on DNS Protocol (ACE)
22 Feb 2001
IWS2001

23. Position of mDNkit Local User UI Application Internal Representation
End system
Resolver
Resolver
API
mDNkit
Int’l
DNS servers
DNS servers
Application servers
22 Feb 2001
IWS2001

24. New features in mDNkit (work in progress)
Adopting NAMEPREP
Provides local mapping APIs
Provides high-level MDN APIs
Multilingual Domain Name tool kit
mDNkit-2.x release series
Come to be …
22 Feb 2001
IWS2001

25. Diagram of New features in mDNkit
Local
User
mDNkit
High-level APIs
Local Mapping
To/From ACE
NAMEPREP
Application UI
Local Mapping
NAMEPREP
Internal
Representation
End system
To/From ACE
Resolver
Resolver
API
mDNkit
Int’l
DNS servers
DNS servers
Application servers
22 Feb 2001
IWS2001

26. Localization
Support proposals to be involved in NAMEPREP in the future
Should be discussed at IETF IDN WG
Delimiter mapping
To avoid some harmful behavior
Local mapping
To complement NAMEPREP
22 Feb 2001
IWS2001

27. (means JPNIC.JP in Japanese)
Delimiter mapping
Characters that IME converts when ‘.’ is typed in
Looks like a domain name, but a single word
Ex. ジェーピーニック。JP
(means JPNIC.JP in Japanese)
Web Browser sends query to Search Engine
DNS clients sends query to Root Server!
22 Feb 2001
IWS2001

28. Local mapping Practically NFKC is sufficient but some exceptions
Depends on mapping table of Unicode and Local charset
Map such exceptions onto suitable ones for NFKC
Ex.1 ‘゛’, ‘゜’
(Voiced and semi-voiced sound mark in Japanese)
Need to map onto combining character
“シ゛ェーヒ゜ーニック”  “ジェーピーニック”
Ex.2 ‘－’ (Full-width Hyphen)
Need to map onto ASCII hyphen
22 Feb 2001
IWS2001

29. APIs ACE Local ACE Local UI APIs Code Converter (Local  UTF-8) UTF-8
Delimiter map
Local map
NAMEPREP
Map
Normalize
Prohibit
Code Converter (UTF-8  ACE)
ACE
ACE
Service Servers
22 Feb 2001
IWS2001

30. References IETF IDN WG Web page JPNIC IDN Web page Unicode Consortium
JPNIC IDN Web page
Unicode Consortium
22 Feb 2001
IWS2001