This Supplement provides background, tutorial and guidance information on a broad range of operational and administrative issues associated with the inclusion of E.164 numbers corresponding to non-geographic country codes into the DNS (i.e., the inclusion of ENUM domain names based on E.164 numbers). It contains considerations of and potential consequences arising from such issues.

Non-geographic country code numbers have been allocated as codes that apply worldwide and are not technically restricted in their use to specific geographic locations. Therefore, an important factor to consider when addressing the applicability of the association of ENUM DNS with these numbers is the ENUM registrant's ability to access the specific applications and services associated with these non-geographic numbers to and from all locations worldwide.

NOTE The insertion of E.164 numbers in the TLD (Top Level Domain) (e.g., in .e164.tld) and the designation of an ENUM Tier 0 Registry (presently RIPE-NCC) remain an open issue at this stage. However for consistency, reference to this TLD and this registry at the ENUM Root Level are made throughout this Supplement. This will be reviewed before this Supplement is finalized and, if necessary, amended to align with the situation at that time.

Important note on the status of ITU-T Supplements

Supplements are only informative and are, therefore, not considered to be an integral part of any Recommendation(s). They do not imply any agreement on the part of the ITU-T (see 2.4/A.13). For further information, please consult the referenced Recommendation: Organization of the work of the ITU-T: ITU-T Rec. A.13, "Supplements to ITU-T Recommendations" (October 2000).