Momentum is building for services that let consumers make phone calls over the Internet. In 2005, the consumer market for voice over Internet Protocol, or VoIP, calling grew by more than 250 percent, with over 3 million people subscribing to a VoIP service, according to Yankee Group Research. This figure is expected to jump yet again in 2006, to a projected 8.4 million subscribers. And by 2009, there will be 28.5 million VoIP users in the U.S., according to the Yankee Group.
For the past couple years, VoIP pioneers such as Vonage and Skype have accounted for the majority of consumer subscriptions to Internet telephony services. But now. Time Warner added 270,000 digital phone subscribers in the first quarter of 2006, its biggest gain ever. And Comcast, the largest cable provider in the U.S., added 211,000 new phone customers during the quarter, more than it had signed up during all of 2005.
such as AOL, Google, EarthLink and Yahoo are also getting into the game with services that let PC users make calls not only between PCs but also from their computers to regular phones.
VoIP is attractive to consumers because it's a cheaper alternative to traditional phone services. But as the saying goes, you get what you pay for. Many of these services suffer from intermittent lapses in quality. While some users may tolerate echoes or a dropped call, analysts say improved quality of service is needed to attract more mainstream consumers.
"When you start addressing the mainstream market, people just want to be able to pick up the phone and have it work," said Marc Itzkowitz, director of product management for SupportSoft, a company that makes software that helps VoIP providers improve the quality of their networks. "A lot of early adopters are willing to put up with the reliability issues, but as we start to see people like my mother use VoIP, they may be less willing to accept it."
An expectation of reliability
The traditional telephone network was developed more than 100 years ago and used dedicated circuits to connect callers. While this network ensures top quality, it is inefficient and thus expensive to operate. By contrast, the Internet was designed to maximize efficiency. It allows different applications--voice, e-mail, video, Web surfing, etc.--to share the same network. The Internet also operates on a "best effort" standard to deliver streams of voice and other data, which are sent over the network in formatted packets: The packets are sent out on the network and essentially jockey for resources as they travel toward their destination. Sometimes packets are delayed or dropped if they hit congestion.
For text-based communications like e-mail, packet delays don't affect the experience much. But voice, video or interactive gaming services require packets to show up at their destination in order and in a timely fashion. If packets are lost or delayed, the sound or picture is distorted.
"It helps when there is a quality-of-service layer in the network to help latency-sensitive traffic get through the network faster," said Joe Laszlo, an analyst with Jupiter Research.
But guaranteeing that VoIP packets get priority is difficult when the company providing the service doesn't control the underlying network. This is the case for companies such as Vonage, EarthLink and SunRocket, which offer services that allow consumers to turn their broadband connections into phone lines. It's also an issue for Internet phone companies such as Skype, Google, Yahoo, AOL and EarthLink, which also let people make calls over the Internet using their PCs.
"If you are Vonage or any unaffiliated VoIP service provider, you will always be susceptible to problems on the network," said, a co-founder of Vonage and a VoIP pundit. "Over time it will become very important for traffic to be prioritized, especially as video is added."