30
22 Feb 2001 IWS2001 2
What is MDN?
• Multilingual Domain Name.– Current domain name is represented with ASCI
I 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) W
G is doing the work.– Some confusion by using the word ‘Internation
alized’.
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
• 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.– 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)
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-Mdraft-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 日本語 .JP Unicode
Normaliza-tion
日本語 .jp
(65e5 672c 8a9e.jp)
Unicode
Compress 1101100001…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 s
tring in meaning or displaying.– Character case (upper, lower), compatible charact
ers (Fullwidth, Halfwidth)– Composed characters
• Umlaut in German, accent in French, voiced sound in Japanese, etc.
22 Feb 2001 IWS2001 15
NAMEPREP
• Processes in NAMEPREP1. map
• Case folding of upper/lower characters (UTR#21)
2. normalize• Normalize representation of string (UTR#15)
3. prohibit• Check out inappropriate character as domain name.
4. 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 Resolver
s 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
User
UI
InternalRepresentation
Application servers
End system
Application
Local
Int’l
Resolver
DNS servers
Resolver
DNS servers
API
22 Feb 2001 IWS2001 19
IDNA
User
InternalRepresentation
UI
API
Application servers
End system
Application
Local
Int’l
Resolver
DNS servers
NAMEPREPTo/From Unicode
To/From ACE
NAMEPREP
To/From ACE
To/From Unicode
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– 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
libmdnmdnconv dnsproxy
named namedzone file
zone fileLegacy client
Encoding on DNS Protocol (ACE)
Local Encoding (SJIS, EUC…)
UNIX client Windows client
mDN wrapperMultilingualized
resolver / runmdn
22 Feb 2001 IWS2001 23
Position of mDNkit
User
UI
InternalRepresentation
Application servers
End system
Application
Local
Int’l
Resolver
DNS servers
Resolver
DNS servers
mDNkit API
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 ofNew features in mDNkit
User
InternalRepresentation
UI
API
Application servers
End system
Application
Local
Int’l
Resolver
DNS servers
Resolver
DNS servers
NAMEPREPLocal Mapping
To/From ACE
mDNkit
mDNkit
High-level APIs
Local Mapping
To/From ACE
NAMEPREP
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
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
ACE
ACE
LocalUTF-8
APIs
APIs
Local map
ACE
LocalUTF-8
ACE
Code Converter (Local UTF-8)
Delimiter map
Code Converter (UTF-8 ACE)
Service Servers
NAMEPREPMap
Normalize
Prohibit
UI
22 Feb 2001 IWS2001 30
References
• IETF IDN WG Web page– http://www.i-d-n.net/
• JPNIC IDN Web page– http://www.nic.ad.jp/en/research/idn/
• Unicode Consortium– http://www.unicode.org/
