6.1 Introduction

The demand for inexpensive and dependable communications services that resolve local loop problems and enable access to bandwidth-intensive multimedia applications contributes to the development of residential broadband access networks. This chapter examines the capabilities of the DSL (Digital Subscriber Line) technology suite and powerline network solutions for enabling geographically separated subscribers to reliably access basic and sophisticated teleservices from dispersed residential and workplace venues.

DSL is also known as xDSL. The letter "x" stands for any one of the various DSL technologies that are grouped under the DSL umbrella. DSL technologies include ADSL (Asymmetric DSL), RADSL (Rate-Adaptive DSL), VDSL (Very High-Speed DSL), and ADSL.Lite (also known as Universal ADSL and G.Lite). In addition, HDSL1 (High Bit-Rate DSL, Phase 1), HDSL2 (High Bit-Rate DSL, Phase 2), SHDSL (Symmetric High-Bit Rate DSL or G.shdsl), SDSL (Symmetric or Single-Line DSL), IDSL (ISDN or Integrated Services Digital Network DSL), and CDSL (Consumer DSL) are also part of the DSL technology suite.

DSL technologies support links to a broad spectrum of Web portals and Internet services and applications such as e-mail exchange, IP telephony, and television programming. In addition, DSL is an enabler of tele-education, teleshopping, E-banking, teletraining, VPNs (Virtual Private Networks), video gaming, teleworking, telementoring, tele-entertainment, and telemedicine.

DSL technologies transform copper twisted pair lines into high-speed links for provisioning connections to basic and advanced communications networks via the local loop. By fostering fast information transmission over the PSTN (Public Switched Telephone Network), DSL eliminates the need for costly optical fiber installations...