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IDN Variant TLD Program -- Draft Final Report Examining the User Experience Implications of Active Variant TLDs

Comment/Reply Periods (*) Important Information Links
Comment Open: 18 January 2013
Comment Close: 8 February 2013
Close Time (UTC): 23:59 UTC Public Comment Announcement
Reply Open: 9 February 2013 To Submit Your Comments (Forum Closed)
Reply Close: 1 March 2013 View Comments Submitted
Close Time (UTC): 23:59 UTC Report of Public Comments
Brief Overview
Originating Organization: ICANN
  • Top-Level Domains
  • Internationalized Domain Names
Purpose (Brief): To receive community feedback on the latest draft of the report "Examining the User Experience Implications of Active Variant TLDs" [PDF, 507 KB].
Current Status: ICANN is opening a 21-day public comment on the latest draft report "Examining the User Experience Implications of Active Variant TLDs."
Next Steps: Based on the input received in this public forum, ICANN will produce a final report that incorporates the community feedback. The final report will be published within 30 days after the closure of public comment.
Staff Contact: Steve Sheng Email:
Detailed Information
Section I: Description, Explanation, and Purpose

The IDN Variant TLD Program has been exploring the issues associated with the potential inclusion of IDN variant TLDs in the DNS root zone at the request of the ICANN Board and the community.

Should ICANN activate variant TLDs in the root, many parts of the Internet ecosystem will be affected, with corresponding impacts on the user experience. Examples of user roles that have been identified previously include registrants, registrars, registry operators, system administrators, network operators, application developers, and end users. As the coordination body for the DNS, ICANN has a responsibility to investigate possible impacts of new developments, and to proactively identify and publicize potential issues.

To better understand and address these challenges, the report: 1) summarizes and compares, from a user experience and registry management perspective, variant practices in several ccTLD registries; 2) proposes a set of guiding principles to define an acceptable user experience; and 3) identifies how various users communities (e.g., end users, system/network administrators, application developers, registrants, registrars and registries) will be impacted by active variant top-level domains, and based on 1, 2, and 3, proposes a set of recommendations to ensure the security, stability and acceptable user experience for active variant top-level internationalized domains.

The latest draft report improves the following way from the interim report [PDF, 558 KB]:

  1. Incorporated community feedback (through public comment), technical expert feedback, and additional input provided by Arabic registries, Devanagari registries, and Chinese registries.
  2. Included a recommendation section that proposes a set of recommendations and guidelines for the introduction of IDN variant TLDs

The proposed guiding principles, the list of identified challenges, as well as recommendations are neither considered comprehensive nor final. By publishing this draft final report, we seek to establish a dialog with the community to refine these principles, impacts and recommendations.

Based on the input received in this public forum, ICANN will produce a final report, to be published within thirty (30) days after the closure of the public comment forum.

Section II: Background

On 20 April 2011, ICANN announced the IDN Variant Issues Project to explore the issues associated with the potential inclusion of IDN variant TLDs in the DNS root zone. This project was initiated in response to a 2010 ICANN Board of Directors resolution. The project completed with the publication of the final Integrated Issues Report on 17 February 2012.

The IDN Variant TLD Program follows on from that work. The Program consists of several projects, and continues as a multi-phase multi-year program. The Program Plan was announced – after substantial public input and comment - on 23 August 2012.

This project considers the user experience implications when two or more IDN variant TLDs are activated (i.e., have resource records in the DNS). The study findings are expected to inform the formulation of rules and guidelines for active variant TLDs.

Section III: Document and Resource Links
Examining the User Experience Implications of Active Variant TLDs [PDF, 507 KB]
Section IV: Additional Information

(*) Comments submitted after the posted Close Date/Time are not guaranteed to be considered in any final summary, analysis, reporting, or decision-making that takes place once this period lapses.

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"""" is not an IDN."