VoIP's broadband bottleneck

Broadband Net-phoning services pushing aggressive expansion plans are discovering a harsh reality: Some residential Internet service providers in the United States currently can't guarantee the bandwidth required to handle calls effectively. AT&T Vice President Kathy Martine said she learned that lesson the hard way during recent trials of the company's CallVantage Net-phoning plan, which it hopes to introduce in 100 markets this year. Some customers' broadband connections just weren't good enough to provide "AT&T-like" quality, she said. So the company was forced to help the broadband providers fix their connections.

Now AT&T Labs is "doing a lot of statistical modeling and analysis on that so we can, in fact, prove where the problems are in the future," Martine said recently. "But the reality is, it's only as good as the broadband connection to your home."