Moves are being made in the U.S. to create an organization that will be in overall charge of a directory that will link phone numbers to URLs, and thus IP addresses.

The so-called Tier 1 North American ENUM (electronic number mapping) directory promises to play a key role in the development of VOIP services -- and hasten the day when users won’t need different phone numbers and email addresses to access services over different networks.

Operating the directory might also turn into a big business, possibly bigger than that of NeuStar Inc., the administrator of the telephony equivalent, and a likely bidder for operating the Tier 1 ENUM directory as well. Neustar has revenues of $92.4 million, according to Dunn & Bradstreet estimates.

The first step towards setting up such a directory is scheduled for June, when a group of North American telecom companies plans to form a limited liability company that will act as the contracting agency for the directory. The winner of the LLC’s contract will route all ENUM traffic for country code 1, which directs phone calls to the U.S., Canada, and 20 Caribbean countries.

The companies forming the LLC include AT&T Corp. (NYSE: T) and MCI Inc. (Nasdaq: WCOEQ, MCWEQ), together with unidentified cable companies, telephone companies, and ISPs. They're all members of the ENUM Forum, an open industry group, but the Forum itself has been kept apart from the LLC, so that it can't be accused of mixing technical and commercial issues.

The group aims to incorporate the as-yet-unnamed contracting agency by June, issue an RFP in the fourth quarter, select a vendor in the first quarter of 2005, and sign a contract by the second quarter of 2005. (The schedule is subject to change.)

According to the group’s current plan, the LLC will be a not-for-profit entity funded by fees from member companies. “As a vision in the back of our heads, we have the local number portability LLC in the U.S. and Canada,” says Karen Mulberry, senior project manager for numbering at MCI, who is heading up formation of the agency.

Like the local-number portability LLC, which appoints the local-number portability administrator for North America, the ENUM LLC will use its funds to draft an RFP, select a vendor, and oversee that vendor. Rather than paying a Tier 1 ENUM directory administrator for its services, the LLC will set guidelines for how the administrator is to charge customers for connections to its directory.

“Nothing has been decided yet, but the vendor would probably charge those registrars who are applying for telephone numbers to be registered within the Domain Name System, similar to what’s done when you register a domain name at .com or .net,” says Steven Lind, standards strategy manager at AT&T and an ENUM Forum member.

The Tier 1 directory for country code 1 will be connected to the root server, or “golden tree,” for ENUM, which links all country codes and is run by RIPE Network Coordination Centre, a not-for-profit regional Internet registry. The Tier 1 directory will route traffic between the root server and a lower tier of directories, which, according to one plan the ENUM Forum is considering, may be specific to each country under country code 1. Each country-specific directory, in turn, may connect to sub-directories for vertical industries or individual companies (see Cable Cadre Talks VOIP).

The ENUM LLC’s contract will have a limited duration (the exact length hasn’t been determined) and will be up for renewal periodically, ensuring competition. Formation of an industry-led contracting agency was first recommended by the National Telecommunications and Information Administration, which in 2003 sent a joint letter with the Federal Communications Commission to the ENUM Forum supporting the creation of an LLC.

Likely candidates for Tier 1 ENUM directory administrator include NeuStar, the North American Numbering Plan administrator and Local Number Portability administrator, and VeriSign Inc. (Nasdaq: VRSN), the exclusive registry of domain names within the .com and .net top-level domains. “In my mind, the true competition is going to be at the Tier 2,” says MCI’s Mulberry. Beneath the Tier 1 directory, multiple country-specific and industry-specific directories will likely vie for traffic.

— Justin Hibbard, Senior Editor, Light Reading