semblages of hardware and software, as you will see in the chapter on telephony. Functionally, however, they are straight- forward: Customer traffic goes into the network on the Gozinta; the traf- Gozinta Figure 1-5 The network cloud Gozouta Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. First Things First First Things First fic then emerges, unchanged, on the Gozouta. How it happens is unim- portant to the customer; all he or she cares about-or wants to care about -is that the network receives, interprets, transports, and delivers his or her voice/video/images/data/music to the destination in a correct, timely, and cost-effective fashion. Later in the book we will discuss the various technologies that live within the network, but for now suffice it to say that its responsibilities fall into two categories: access and transport, as illustrated in Figure 1-6. Network Access As the illustration shows, network access is exactly that: the collection of technologies that support connectivity between the customer and the transport resources of the network. At its most common level, access is the local loop-the (typically) two-wire circuit that connects a customer's telephone to the local switch, which provides telephony service to that customer. As the network has become more data-aware, other solutions have emerged that provide greater bandwidth as well as multiservice capability. ISDN, which uses the two-wire local loop, provides greater bandwidth than the traditional analog local loop through digitization and time-division multiplexing (both explained shortly). Digital sub- scriber line (DSL) is also a local loop-based service, but offers even more diverse service than ISDN in the areas where it is available. Cable Transport Figure 1-6 Access VS. transport regions of the network Access Access Downloaded from Digital Engineering Library @ McGra