Pulver.com last week applied to ICANN for the right to offer .tel domain names to IP communications service providers using ENUM, a standard for mapping telephone numbers into the internet domains name system.

Pulver.com is an early leader in the PC-to-PC VoIP communications space, and has been heavily involved in the VoIP regulatory debate in the US. ENUM is expected to be the de facto standard for addressing voice calls over the internet.

We’re trying to provide legs for ENUM, said Pulver.com CEO Jeff Pulver. The ENUM standard has been around for a few years, and while there are many test-beds underway, mostly in Europe, there are no widespread commercial services based on it.

Pulver said that a .tel domain and the associated brand will be a great way to accelerate adoption of ENUM and VoIP. But regulatory concerns could be Pulver.com’s biggest obstacle in having its .tel application accepted.

The firm submitted a similar application to ICANN in 2000, but was denied largely due to objections from the ITU, which told ICANN that phone number-based TLDs would be premature and could interfere with the ITU’s own work.

Regular phone numbers are administered by the ITU under a plan known as E.164, which provides each geography with a dialing code, like +1 for North America and +44 for the UK, and delegates responsibility for numbers beneath each code to entities like NeuStar Inc and Oftel.

In late 2000, it was decided that to turn a E.164 phone number into a DNS-enabled ENUM, you reverse the order of the digits, put dots between them, and add .e164.arpa to the end. So +1 415 543 5496 becomes 6.9.4.5.3.4.5.5.1.4.1.e164.arpa.

The domain e164.arpa domain is the Tier 0 root of the ENUM hierarchy, hosted by the RIPE Network Coordination Center in Europe. The idea is that each country will allocate one of more Tier 1 registries to manage their respective domain.

We had .tel opposed in 2000 because it could possibly have got in the way of e164.arpa, Pulver said. E164.arpa was not around at the time of the original application, he said, and the new .tel would be fully compatible with this root, he said.

While all current TLDs act as the authoritative sources of translating their domains into IP numbers, .tel would defer to e164.arpa when necessary. In practice, .tel would look like a third-level domain under e164.arpa.

This is all about marketing and promoting ENUM, Pulver told ComputerWire yesterday. We need to market and promote it as a TLD, but internally it works like a secondary domain between .tel and e164.arpa.

He said that .tel would be compatible with any global E.164 telephone number. IP communications providers would register .tel domains on behalf of their users, and would have to legally certify that they have control over the numbers they register.

Currently there are a little over 20 countries that have allocated an organization to manage their respective ENUM domains. The UK’s Department of Trade and Industry, for example, claimed its .4.4.e164.arpa domain in May 2002.

Because ENUM is a disruptive technology, it is being handled very carefully by the regulatory agencies that are being assigned the domains. North America has yet to select who will operate .1.e164.arpa, but the US government favors multiple providers.

Pulver.com thinks this works in its favor. If ENUM happens in a big way, if the US government puts it forward or NeuStar puts it forward, then that’s still great. Alternate ENUM implementations would be compatible, he said.

Before any of this becomes a reality, Pulver will have to convince ICANN and its stakeholders that .tel is technologically sound and that it fits into the category of a sponsored TLD that ICANN is looking for.

There is also a political angle to this. The ITU, it is whispered, wants to eventually take over management of the DNS from ICANN. If the ITU were to object to .tel again, ICANN could find itself in a difficult situation.

There is also another .tel application, filed by Telname Ltd of London. This application does not envisage an ENUM implementation. In fact, it would prevent any numbers being registered for fear of interfering with existing numbering plans.

This article is based on material originally published by ComputerWire