Skip to main content

Guidelines for Designing Script-Specific Label Generation Rules (LGR) for the Root Zone

ICANN is releasing a set of documents that present an overview of the tasks of a Generation Panel as well as additional orientation and guidance. They include:

  • Guidelines [PDF, 359 KB] and Considerations [PDF, 187 KB] for designing script-specific Label Generation Rules (LGR) for integration into the Root Zone,
  • A summary of the Requirements [PDF, 624 KB] on format and contents for submitting an LGR proposal.

The overview and guidelines are based on the prescription in the Procedure to Develop and Maintain Label Generation Rules (LGR) for the Root Zone With Respect to IDN Labels [PDF, 772 KB] (the Procedure); they do not supersede the Procedure as the authoritative definition of the process for developing and maintaining a label generation ruleset for the Root Zone. Instead, they intend to give practical guidance as well as a focused overview of the tasks involved in creating a single-script LGR for integration into the Root Zone LGR.

As the first Generations Panels have been formed and begun to take up their work under the Procedure, a number of issues have been raised that demanded further clarification as well as suggested the need for explanation of some of the provisions of the Procedure. To this end, the overview and guideline documents intend to provide a succinct summary of the tasks of a Generation Panel together with practical guidelines on how best to accomplish them. They are intended as adjunct to, and as help in, reading of the Procedure, which otherwise remains the authoritative description of the process.

The output of the work of a Generation Panel is a set of Label Generation Rules (LGR) for a given script (or multiple LGRs in case a panel works on more than one script). These are to be released for public comments and finally submitted to the Integration Panel for review and integration into the Root Zone LGR. In order to facilitate the review, the Integration Panel has released a document describing the expected format and organization of an LGR proposal and Generation Panels are expected to submit LGR proposals that adhere to these Requirements [PDF, 624 KB]. These include, in particular, further details on how to create a formal specification of an LGR using the XML Format for Representing Label Generation Rules.

Finally, the Guidelines [PDF, 359 KB] collect in one place a set of references to various technical documents that Generation Panels might need to consult in doing their work.

The guidelines and associated documents are:


More Announcements
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."