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Recommendations for the Technical Utilization of the Root Zone Label Generation Rules Published

LOS ANGELES – 7 October 2019 – The Internet Corporation for Assigned Names and Numbers (lCANN) announced the release of the Recommendations for the Technical Utilization of the Root Zone Label Generation Rules by the Root Zone Label Generation Rules Study Group (RZ-LGR SG). These recommendations are being provided to the ICANN Board for further consideration.

With the availability of the Root Zone Label Generation Rules (RZ-LGR) and its fundamental role envisaged for defining the variant labels of top-level domains (TLDs), the ICANN Board asked the ICANN community (including Supporting Organizations (SOs), Advisory Committees (ACs), and the Internet Architecture Board (IAB)) to study and recommend how to technically apply the RZ-LGR in a harmonized way to generic and country code top top-level domains (gTLDs/ccTLDs).

To address the request from the ICANN Board, the RZ-LGR SG was formed from the nominees of SOs, ACs, IAB, and additional volunteers from the ICANN community following the call for formation in February 2018. The SG first determined the scope of its work, and enriched it with feedback received from the community through the first public comment call in August 2018.  Based on this scope, the SG has developed a set of recommendations, which was released for public comment in May 2019. The RZ-LGR SG has now completed and published its Recommendations for the Technical Utilization of the Root Zone Label Generation Rules, after incorporating the community feedback. Further details of the SG's work are available at the wiki page.


ICANN's mission is to help ensure a stable, secure, and unified global Internet. To reach another person on the Internet, you need to type an address – a name or a number – into your computer or other device. That address must be unique so computers know where to find each other. ICANN helps coordinate and support these unique identifiers across the world. ICANN was formed in 1998 as a not-for-profit public-benefit corporation with a community of participants from all over the world.

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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."