Purpose:  To facilitate and improve consistency of testing and stability of registry operations of new gTLDs, ICANN has developed reference Internationalized Domain Name (IDN) tables in machine readable format, called Label Generation Rulesets (LGRs) for the second level, for use in Pre-Delegation Testing (PDT) and the Registry Service Evaluation Process (RSEP).

Current Status:Reference LGRs for 29 languages have been developed and are being released for public comment. In addition, a process is also being proposed for Evaluation of Deviation from the Reference Second Level LGRs [PDF, 255 KB] for feedback from the community.

Next Steps: Based on the community input, the reference LGRs for these 29 languages will be finalized and will be used for PDT and RSEP as per the process described in the Evaluation of Deviation from the Reference Second Level LGRs.

The reference LGRs are developed in the context of either a language or a script. Current reference LGRs include a core set of code points, variant rules, and WLE rules that must be supported and also include an (optional) extended set serving special needs based on geographical or other variations.

The LGRs are developed for the languages prioritized on the basis of complexity and demand. These include Arabic, Belarusian, Bosnian-Cyrillic, Bosnian-Latin, Bulgarian, Chinese, Danish, English, French, German, Hebrew, Hungarian, Icelandic, Italian, Japanese, Korean, Latvian, Lithuanian, Macedonian, Montenegrin, Norwegian, Polish, Portuguese, Russian, Serbian, Spanish, Swedish and Ukrainian. Additional languages and scripts will be added later, as needed.

A registry would choose the set of code points and associated rules which best serves the needs of its end users. Remaining within the reference (core plus appropriate subset of extended code points along with corresponding variants and WLE rules) will be pre-approved. Any LGR is considered as deviating from the reference LGR if it is smaller than the core or beyond the extended LGR or a combination thereof. The deviations are motivated by the fact that registries would like to remain competitive by offering innovative solutions to address various end user needs. These deviations will be possible based on the provisions documented in Evaluation of Deviation from the Reference Second Level LGRs.

The registries are generally encouraged to collaborate in defining common language-based or script-based IDN tables to allow for consistency for end users. There are multiple formats to submit IDN tables. The IDN tables used by each gTLD and some ccTLDs are posted at the IANA Repository for IDN Practices. During the New gTLD Program’s Pre-Delegation Testing (PDT), ICANN has noted a large number of IDN table submissions. The process to develop these reference LGRs, as detailed in the Guidelines [PDF, 207 KB], ensures both linguistic and technical expert input with finalization based on community review through a formal public comment process. This work builds on the baseline IDN tables already being used in PDT.

• The IANA Repository for IDN Practices: https://www.iana.org/domains/idn-tables
• The machine readable format for Label Generation Rulesets: https://tools.ietf.org/html/draft-ietf-lager-specification-13
• IDN tables and associated information made available by IIS: https://github.com/dotse/IDN-ref-tables
• Public comment on the Guidelines developed: https://www.icann.org/public-comments/comments-lgr-second-level-2015-11-05-en
• Public comments on the process being used to develop these tables: https://www.icann.org/public-comments/lgr-second-level-2015-03-10-en