Cable-based IP telephony holds the promise of simplified and consolidated communication services provided by a single carrier at a lower total cost than consumers currently pay to separate Internet, television, and telephony service providers. Cable operators have already worked through the technical challenges of providing Internet service and are optimizing the existing bandwidth in their cable plants to deliver high-speed Internet access. Now, cable operators have turned their efforts to the delivery of integrated Internet and voice service using that same cable spectrum.

Cable-based IP telephony falls under the broad umbrella of voice over packet (VoP), meaning that many of the challenges facing cable operators are the same challenges that telecom carriers face as they work to deliver voice over ATM (VoATM) and frame-relay networks. However, ATM and frame-relay services are targeted primarily at the enterprise, a decision driven by economics and the need for service providers to recoup their initial investments in a reasonable amount of time. Cable, on the other hand, is targeted primarily at the home. Unlike most businesses, the overwhelming majority of homes in the United States are passed by cable, reducing the required up-front infrastructure investment significantly.

While cable isn't without competition in the consumer market (digital subscriber line [xDSL] has emerged as the leading alternative to broadband cable), cable operators are positioned well to capitalize on the convergence trend if they are able to overcome the remaining technical hurdles and deliver telephony service that is comparable to the public switched telephone system.