Fall VON showed off an advanced form of voice over IP.

Voice-over-IP veteran Tom Evslin likes to talk about the three stages of the “VoIP rocket,” the third of which, in his own words, never quite made it off the ground.

The first stage was voice-price arbitrage. The second: the shift toward IP everywhere, including in the public switched network. Both these predictions became reality, Evslin said at last week's Fall VON conference in Boston. The third stage was the introduction of innovative VoIP applications and services, a leap that never occurred — at least until now.

While VON had VoIP termination players and free or close-to-free VoIP schemers, the focus of VoIP and related technologies these days is enabling carriers, partners and even customers to build and use innovative converged services.

The range of companies aiming to fulfill this promise was evident at the show. In many quarters, the VoIP upstart mentality remained strong. For instance, Evslin claimed that the next wave of VoIP is being invented “as if the [public switched network] never existed,” and VON founder Jeff Pulver criticized traditional carrier service development by observing that “nobody ever went into their garage to add new features to the AT&T network.”

Yet many so-called “voice 2.0” services are as much about leveraging existing network resources as bypassing them.

For example, TalkPlus delivers software — including clients for BlackBerrys and Treos announced at VON — that lets users add multiple numbers and advanced call management features to existing cell phones for $9.95 per month. “This isn't about cheap long-distance,” said Jeff Black, CEO of TalkPlus. “We can add new features on the fly into the phone without waiting for carriers to develop them.”

In addition to working with service providers' cellular networks, TalkPlus also is open to working with carriers as a value-added application provider. In fact, the company currently is testing its service with an unnamed cellular provider, Black said.

Incumbent carriers and their vendors also are embracing the new world of converged IP networks and more open service creation.

AT&T, for instance, used the show to detail progress of its U-verse IPTV service. Derided in some circles for its hybrid fiber/copper access approach, AT&T's focus on building “an all-IP network takes some of that bandwidth conversation off the table,” said Jeff Weber, vice president of products and strategies for AT&T. Embarq, meanwhile, touted progress on its IP-based fixed/mobile convergence services. Customers should view their wireless service “like a sleeping bag — you're glad to have it when you are camping in the woods, but when you walk in your house, you look at the big soft comfy king-sized bed” that is the landline, said Dan Hesse, CEO of Embarq.

Indeed, while the VoIP industry loves David-and-Goliath stories, one should be careful about oversimplified either/ors — VoIP vs. public switched networks, or IP multimedia subsystem (IMS) vs. Web 2.0 — said Marc LeClerc, manager of Ericsson's global IMS development centers.

“It's not IMS vs. Web 2.0. It's IMS and Web 2.0,” he said, noting that Web service developers can try to reinvent the presence and related session information provided by carriers via IMS, or they can simply consume that IMS data using development tools they already work with, such as the open-source Eclipse Java IDE.

In the end, the true power of converged IP comes when all the islands of IP networks, features and capabilities work together rather than compete, said Paul Mankiewich, chief technology officer for Alcatel-Lucent North America.

“I believe that the IMS world will talk to the Microsoft IPTV world and the Web 2.0 world, and there will be hooks between [them],” he said.