Voice Over IP

Chapter 5. Connecting to Service Providers through the Local Loop

This chapter explains how the VoIP user is connected to the Internet or an internet through the telco local loop. The role of the telephone network is explained, and we examine ISP configurations, as well as Network Access Point (NAP). An analysis is provided of where the user's modem analog signal is terminated.

Due to the major problem of the limited capacity of the local loop, the chapter also provides an overview of the Integrated Services Digital Network (ISDN), the emerging xDSL (X Digital Subscriber Line) and the HFC (Hybrid Fiber Coax) technologies, as well as a proprietary high-speed modem from Nortel. All these schemes are designed to give the Internet user more bandwidth ...