This volume explains telephone-switching systems and how the technology is evolving to accommodate voice-over-IP traffic. Unlike data networks, telephone networks are proprietary. They're purchased as complete systems and are hard, if not impossible, to modify. Sulkin explains how to acquire, deploy and maintain a system with all the features needed to support essential new applications, and how to get the optimal performance from the system you have. He describes how to make telephone-switching systems work in harmony with cutting-edge internet technology to support IP telephony, mobile computing, Web portals and instant messaging. A companion website contains the author's feature and function matrices, previously available only to consulting clients. This book should be of interest to: datacom managers who have been given responsibility for telephony; telecom managers; VoIP product vendors; and network professionals on internet-working certification tracks.