ICANN: Label Generation Rules for the Root Zone Version 2

Brief Overview

ICANN logoPurpose: To determine valid top-level Internationalized Domain Name (IDN) labels and their variant labels, the community had finalized the Procedure to Develop and Maintain the Label Generation Rules for the Root Zone in Respect of IDNA Labels [PDF, 1.39 MB]. The Procedure requires community-based Generation Panels (GPs), organized for relevant scripts, to convene and propose specific rules. These rules are evaluated and then integrated into the Root Zone Label Generation Rules (RZ-LGR) by the Integration Panel (IP).

Current Status: The Integration Panel (IP) has successfully evaluated the Root Zone Label Generation Rules (RZ-LGR) Proposals for five additional scripts, Ethiopic, Georgian, Lao, Khmer and Thai, submitted by the respective GPs, following the release of these individual proposals for public comments. The IP has integrated these proposals, along with Arabic script already integrated into the first version of the Root Zone LGR (RZ-LGR-1), to develop the second version of the Root Zone LGR (RZ-LGR-2 [PDF, 891 KB]).

Next Steps: As per the Procedure, RZ-LGR-2 is being released for public comments to gather community feedback for its finalization. Proposals for additional scripts will be integrated in future versions of the RZ-LGR.

Section I: Description and Explanation

The RZ-LGR-2 [PDF, 891 KB] is designed to be the second installment of a RZ-LGR that meets the requirement for a conservative set of label generation rules for stable and secure operation of the Internet’s Root Zone. As per the Procedure [PDF, 1.39 MB], the second version of RZ-LGR is developed with the GPs starting their analysis from the current version of the Maximal Starting Repertoire (MSR-2). RZ-LGR-2 [PDF, 891 KB] contains rules for six scripts, including Arabic, Ethiopic, Georgian, Lao, Khmer and Thai, based on the proposals submitted by the respective GPs. The IP also considered the Armenian proposal, but as it has interactions with the LGRs for several other scripts that are being developed, it was deemed prudent to delay integration of Armenian script.

RZ-LGR is developed following the Procedure to Develop and Maintain the Label Generation Rules for the Root Zone in Respect of IDNA Labels [PDF, 1.39 MB]. RZ-LGR provides a specification to mechanically determine valid IDN Top-Level Domains (TLDs). The RZ-LGR also determines the corresponding set of blocked and allocable variant labels. Additional mechanisms need to be developed to determine which, if any, of the allocable variant labels generated by the RZ-LGR will be allocated to the applicants.

The current version of the RZ-LGR will be followed by future versions that will support additional scripts and writing systems, as proposals from more GPs become available. It is necessary to ensure that these future additions are upwardly compatible. In addition to the panels which have already completed, work is also underway by Chinese, Cyrillic, Greek, Japanese, Korean, Latin and Neo-Brahmi panels. Generation Panels for additional scripts, including Hebrew, Myanmar, Sinhala, Tibetan and Thaana are actively being solicited as per the Call for Generation Panels.

Section II: Background

The Root Zone LGR development procedure requires three steps. Initially, the IP creates the Maximal Starting Repertoire (MSR) for the GPs to initiate their work. Based on the latest version of the MSR, the community based Generation Panels organize and develop proposals for the RZ-LGR for their respective scripts or writing systems. After public comments, these proposals are submitted to the IP for evaluation. Finally, the successfully evaluated proposals are integrated into the next version of RZ-LGR.

The current MSR-2 covers the following 28 scripts: Arabic, Armenian, Bengali, Cyrillic, Devanagari, Ethiopic, Georgian, Greek, Gujarati, Gurmukhi, Han, Hangul, Hebrew, Hiragana, Kannada, Katakana, Khmer, Lao, Latin, Malayalam, Myanmar, Oriya, Sinhala, Tamil, Telugu, Thaana, Tibetan and Thai, and is based on Unicode version 6.3.

Successful development of RZ-LGR depends on having a community based GP for each script or writing system. A GP develops a LGR proposal to be used to generate valid TLD labels and their variant labels for the relevant script or writing system. Each proposal contains the valid code points, their variant code points and Whole Label Evaluation (WLE) rules. In doing so, the GP may need to coordinate efforts with other GPs, whenever their repertoires either overlap or are closely related. Each proposal is reviewed by the community through public comment process before submission to the IP for further consideration.

In the Procedure [PDF, 1.39 MB] it is stated that the IP creates a set of recommended label generation rules that integrates all the approved proposals from the GPs. When the IP has created such a set, it is posted for public comment using the prevailing ICANN procedures. At the end of the public comment period, the IP receives and reviews the public comments to finalize the LGR. The resulting label generation rules become the next versions of the RZ-LGR.

Section III: Relevant Resources

The following Root Zone Label Generation Rules version 2 (RZ LGR-2) files have been published.

Summary Documents:

  1. Overview and Summary: https://www.icann.org/sites/default/files/lgr/lgr-2-overview-01jun17-en.pdf [PDF, 891 KB]
  2. Repertoire Tables, non-CJK: https://www.icann.org/sites/default/files/lgr/lgr-2-non-cjk-01jun17-en.pdf [PDF, 1.59 MB]

XML versions (normative):

  1. Common: https://www.icann.org/sites/default/files/lgr/lgr-2-common-01jun17-en.xml
  2. Arabic: https://www.icann.org/sites/default/files/lgr/lgr-2-arabic-script-01jun17-en.xml
  3. Ethiopic: https://www.icann.org/sites/default/files/lgr/lgr-2-ethiopic-script-01jun17-en.xml
  4. Georgian: https://www.icann.org/sites/default/files/lgr/lgr-2-georgian-script-01jun17-en.xml
  5. Lao: https://www.icann.org/sites/default/files/lgr/lgr-2-lao-script-01jun17-en.xml
  6. Khmer: https://www.icann.org/sites/default/files/lgr/lgr-2-khmer-script-01jun17-en.xml
  7. Thai: https://www.icann.org/sites/default/files/lgr/lgr-2-thai-script-01jun17-en.xml

HTML versions of the XML files:

  1. Common: https://www.icann.org/sites/default/files/lgr/lgr-2-common-01jun17-en.html
  2. Arabic: https://www.icann.org/sites/default/files/lgr/lgr-2-arabic-script-01jun17-en.html
  3. Ethiopic: https://www.icann.org/sites/default/files/lgr/lgr-2-ethiopic-script-01jun17-en.html
  4. Georgian: https://www.icann.org/sites/default/files/lgr/lgr-2-georgian-script-01jun17-en.html
  5. Lao: https://www.icann.org/sites/default/files/lgr/lgr-2-lao-script-01jun17-en.html
  6. Khmer: https://www.icann.org/sites/default/files/lgr/lgr-2-khmer-script-01jun17-en.html
  7. Thai: https://www.icann.org/sites/default/files/lgr/lgr-2-thai-script-01jun17-en.html

Section IV: Additional Information

This ICANN announcement was sourced from: