Those who be able to access the network to use as a test bed would include developers from enterprises, whether they are AT&T customers or not, system-integrators and ISVs, Shepcaro said.

AT&T had previously said it was working to build out this infrastructure, but as it moves closer to becoming a reality, Shepcaro offered more insight into the strategy. Notably, he said the applications being developed on the network would be provided for and charged on a pay-as-you-go basis.

What’s very unique about what we’re building is that you can deliver these applications in a utility network-based environment, he said. So, no longer is the model going to be buying these perpetual software licenses . . . we’re moving more to a utility-based model.

That model envisions an enterprise consuming and paying for IP services in much the same way it would other utilities, such as electricity.

The flavor of applications that AT&T expects to be built on the open network includes IP-based communications that be used across all mobile and fixed devices used in an enterprise, as well as its supply-chain partners, Shepcaro said.

These types of applications will continue to increase enterprise adoption [of VoIP networks], said Shepcaro, who is AT&T’s VP of business strategy and development,

He bills the forthcoming app-development network as unique. I’ve not seen this before . . . partially because many of these [rival] companies are just building their IP today, he said, citing BT as an example. I think we’re very much ahead of our competition.

Shepcaro said AT&T more often is seeing convergence within its enterprise customers, not only voice with data but also the convergence of IT and networking around applications into IP networks.

Unified collaboration and new collaboration tools are driving the adoption of enterprise VoIP, he said. Also, functions that work across these applications, such as mobility, presence and business continuity in the event of a disaster, he added.

But more applications are needed and AT&T is betting is developers’ network will be a trigger. The network would lie on top of AT&T’s global IP, or multi-protocol label-switching (MPLS) network.

This underlying network is AT&T’s key strategic advantage, Shepcaro said, because it has the broadest reach in the industry. Also, security is integrated into the network, which is key, he said.

Security has to be build in at every layer of the network, he said. Security has clearly been a key concern [for enterprise customers] and we think AT&T is much further along in addressing VoIP security.

The company has spent $10bn during the past five years to build the network globally. It enables remote access and services to 127 countries and has network nodes, which gives customers the same features and functionality in multinational locations, in more than 60 countries, Shepcaro said. Candidly, I don’t see anyone clearly approaching us.

AT&T reckons its moves about 4.6 petabytes of data and IP traffic on an average business day.

The company is still spending to expand the network, such as deploying new network codes in fast-growing countries where there is demand from enterprise customers, Shepcaro said.

This year, AT&T plans to expand the reach of its network currently available in China, India, the Middle East and Latin America, Shepcaro said. If our customers need a network in a new region . . . then we will invest there, he said.

To company will push its brand by doubling the number of countries where AT&T-branded DSL service is available and triple the number of countries where it delivers Ethernet services.

Shepcaro also sees AT&T’s 30 Internet data centers globally as the other key differentiator for the vendor, whereby customers host servers, IP PBX and other infrastructure for business continuity and disaster recovery.

Of course, the company also has a slew of SIP-based services, which Shepcaro touted. The company’s strategy is to bundle services in a way that they are squarely aimed at enterprises, he said.

A customer can have three-way calling capability on a utility basis, BlackBerry support, custom directory service and identity verification, for example, through a policy engine and application gateway. This can be built directly onto the MPLS network and accessed through a business portal, Shepcaro said.

AT&T declined to quantify by how much its VoIP business has grown in recent years. But its IP telephony services are part of its IP and Enhanced services unit, which grew 7.3% in the third quarter of 2005 to $630m from last year.