ITU secretary Yoshio Utsumi last week wrote to the Internet Corp for Assigned Names and Numbers, urging caution before approving Pulver’s .tel proposal, and any other domain that would use telephone numbers.

Pulver, which provides a popular PC-to-PC voice over IP service called Free World Dialup, is proposing that ICANN approve .tel as a means to kickstart adoption of voice over IP services, letting people use regular telephone numbers online.

Utsumi wrote in a letter to ICANN president Paul Twomey: Any application for a new internet top level domain name that envisages interfacing with the global telephony addressing system merits careful consideration.

The ITU is concerned because Pulver’s .tel would use normal telephone numbers, which are administered by the ITU according to a numbering plan known as E.164. This plan ensures no two phone numbers in the world are the same.

There are currently slow moving plans to implement E.164 in the DNS using an IETF standard called ENUM. The RIPE Network Coordination Center in Europe is handling ENUM delegations, giving codes like +44 to countries like the UK.

Pulver previously told ComputerWire that its .tel domain would be fully compatible with the ITU-backed ENUM rollout, and that despite that fact that .tel would look like a top-level domain, it will actually take its cues from RIPE’s root: e164.arpa.

Utsumi wrote that E.164 is a politically significant numbering resource with direct implications of national sovereignty… subject to a multitude of national approaches, regulatory provisions, and, in some cases, multilateral treaty provisions.

He added that the ITU has been instructed by its members, in a 2002 resolution, to take any necessary action to ensure the sovereignty of ITU Member States with regard to country code numbering plans… in whatever application they are used

Pulver had a similar .tel application shot down by ICANN in November 2000, apparently at the behest of the ITU, which at the time had a less fully-formed policy regarding ENUM and the implementation of E.164 in the DNS.

This article is based on material originally published by ComputerWire