powerful and it empowers, with far-reaching con- sequences. It has demonstrated the potential to transform society and business, and the revolution has only just begun. With the invention of the telephone, human communications and commerce were forever changed: Time and distance began to melt away as barriers to doing business, keeping in touch with loved ones, and immediately responding to major world events. Through the use of com- puters and telecommunications networks, humans have been able to extend their powers of thinking, influence, and productivity, just as those in the Industrial Age were able to extend the power of their muscles, or physical self, through the use of heavy machinery. Today, new inventions and developments are again poising tele- communications as a force to be reckoned with, changing human communications and commerce, and introducing machines as members of the networked society. This is an exciting era, and we face a host of new telecommunications technologies and applications that bring breathtaking new opportunities, particularly in the industries of entertainment, education, health care, government, advertising, life- style, and, sadly, warfare. Although the information and communications technologies (ICT) industry has suffered greatly in recent years, exciting developments continue unabated in many areas that are key to the ongoing evolution of broadband devices, applica- tions, and network infrastructures. These remarkable developments are propel- ling the broadband evolution, creating good reasons to pursue next-generation networks. Introduction Measurements of the Digital World There are three main measurements of the digital world: Processing power, measured in the number of transistors and operations per second Storage, measured in the number of bytes Bandwidth, or digital data transmission, measured in bits per second The following sections discuss these three measures. Processing Power Moore's Law says that the number of gates on a chip-hence the power of the microprocessor-