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RSSAC Statement on ICANN's Proposed Next Steps for IDN Deployment in the Root Zone

The statement is published on the RSSAC website at http://www.icann.org/committees/dns-root/ :

The DNS Root Server System Advisory Committee (RSSAC) has been asked for a statement on ICANN's proposed next steps for IDN deployment in the root zone. Policy discussions are continuing and are clearly out of scope for RSSAC. RSSAC takes no position on what the contents of the strings used to instantiate IDNs in the root should be, or how many there should be within a factor of 2-5 times the current size of the root zone, or what the duration of the test should be, as long as DNS protocol is followed regarding length of labels, permitted characters, and so on.

With regards to technical and operational issues, RSSAC's consensus as discussed 18 March in the Praha meeting includes:

  • There's no issue with adding standard delegations (NS records) to the root zone to instantiate IDN at the root.
  • RSSAC urges ICANN to consult DNS experts on constraints such as appropriate TTL values for test IDNs. RSSAC itself represents a significant reserve of such expertise and its members would be happy to try to provide guidance on this subject. However, these details are immaterial to the job of serving a root zone that includes IDNs; the impact is on resolvers and applications.
  • ICANN will be coordinating the test, collating test results, and making further decisions about how to go forward to production deployment. ICANN, particularly IANA as the party responsible for the root zone, are asked to provide notice to RSSAC as the test begins and ends and the findings that result from it.
  • It's our understanding that several of ICANN's policy bodies are examining aliasing of domain names as one possible component of an IDN solution. Aliasing can be accomplished in a variety of ways. If aliasing of existing domain names is needed as part of the deployment of IDN, RSSAC would provide technical and operational input on how to accomplish it effectively. IANA would have to provide notification of changes to software, hardware, or procedures the root server operators would need to implement in advance of major changes in the capabilities required to serve root zone data; the best way to make sure this happens is to keep RSSAC advised as decisions are made regarding further tests and eventual production deployment so expectations are clear.
  • ICANN may find that it will be useful to have specific data or measurements from the root server operators, as part of testing or production deployment of IDN, regarding any changes in traffic or other operational parameters IDN labels might cause. ICANN is encouraged to outline any specific measurements in which they are interested relating to the effects of the test deployment.

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Domain Name System
Internationalized Domain Name ,IDN,"IDNs are domain names that include characters used in the local representation of languages that are not written with the twenty-six letters of the basic Latin alphabet ""a-z"". An IDN can contain Latin letters with diacritical marks, as required by many European languages, or may consist of characters from non-Latin scripts such as Arabic or Chinese. Many languages also use other types of digits than the European ""0-9"". The basic Latin alphabet together with the European-Arabic digits are, for the purpose of domain names, termed ""ASCII characters"" (ASCII = American Standard Code for Information Interchange). These are also included in the broader range of ""Unicode characters"" that provides the basis for IDNs. The ""hostname rule"" requires that all domain names of the type under consideration here are stored in the DNS using only the ASCII characters listed above, with the one further addition of the hyphen ""-"". The Unicode form of an IDN therefore requires special encoding before it is entered into the DNS. The following terminology is used when distinguishing between these forms: A domain name consists of a series of ""labels"" (separated by ""dots""). The ASCII form of an IDN label is termed an ""A-label"". All operations defined in the DNS protocol use A-labels exclusively. The Unicode form, which a user expects to be displayed, is termed a ""U-label"". The difference may be illustrated with the Hindi word for ""test"" — परीका — appearing here as a U-label would (in the Devanagari script). A special form of ""ASCII compatible encoding"" (abbreviated ACE) is applied to this to produce the corresponding A-label: xn--11b5bs1di. A domain name that only includes ASCII letters, digits, and hyphens is termed an ""LDH label"". Although the definitions of A-labels and LDH-labels overlap, a name consisting exclusively of LDH labels, such as""icann.org"" is not an IDN."