egin a session, so there are no busy signals and no need to tie up their telephone line. Also, with prices ranging from $40 and $60 per month, which includes cable modem rental and unlimited Internet access, cable modem Internet service is extremely cost effective when compared to other high-speed data systems. Unfortunately for the cable companies, it is not just a simple matter of attaching cable modems to their subscribers PCs and letting them surf away at light speed. To get into the high-speed Internet Service Provider (ISP) business, a CATV company must build an expensive and complex IP networking infrastructure. This network has to be able to support thousands of subscribers. Building cable data network involves addressing such items as Internet backbone connectivity, routers, servers, network management tools, as well as security and billing systems (Salent, 1999). Furthermore, CATV data systems are comprised of many different technologies, so standards governing cable modems had to be developed which would allow products from different vendors to be interoperable. But, the biggest hurdle facing the cable companies is that cable television systems were designed for one-way traffic, and must be upgraded into modern two-way networks in order to support advanced communications services (Medin, 1999). This is an expensive and technically complex undertaking. CATV systems were originally designed to deliver broadcast television signals to subscribers' homes. In the cable industry, this is known as downstream traffic. The Head-end is the central distribution point for a CATV system. Video signals are received at the Head-end from satellites or other sources, frequency modulated to the appropriate channels, and then transmitted downstream through the cable medium into the subscribers homes. The subscriber's television tuner, or set-top cable converter box, demodulates the signal back to a video image. To insure that consu...
