The telecommunications infrastructure has been revolutionized by advances in information technology in the past two decades to form an information and communications infrastructure, consisting of the Public Telecommunications Network (PTN), the Internet, and the many millions of computers in home, commercial, academic, and government use. The Internet depends heavily on the PTN. The PTN, in turn, depends on electrical power for operations and on telephone lines and fiber optic cables that often run along transportation routes. The PTN is software driven, and remotely managed and maintained through computer networks.
Taking advantage of the speed, efficiency and effectiveness of computers and digital communications, all the critical infrastructures are increasingly connected to networks, particularly the Internet. Thus, they are connected to one another. Networking enables the electronic transfer of funds, the distribution of electrical power, and the control of gas and oil pipeline systems. Networking is essential to a service economy as well as to competitive manufacturing and efficient delivery of raw materials and finished goods. The information and communications infrastructure is basic to responsive emergency services. It is the backbone of the military command and control system. And it is becoming the core of our educational system.