Explanation:The Internet, a global network of networks, is a remarkably complex technical system built on the creative contributions of scientists around the world from the 1950s to the present. Throughout its evolution, the Internet and other networks have been promoted by governments, researchers, educators, and individuals as tools for meeting a range of human needs. A combination of high-level policy and grassroots improvisation has produced social benefits including easier and more widespread access to computers and information; increased scientific collaboration; economic growth; the formation of virtual communities and an increased ability to maintain social ties over long distances; the democratization of content creation; and online political and social activism. The Internet’s rapid growth has also spawned technical crises, such as congestion and a scarcity of network addresses, and social dilemmas, including malicious and illegal activities and persistent digital divides based on income, location, age, gender, and education. Such problems continue to demand creative solutions from scientists, policy makers, and citizens.
Several general themes characterize the technical development of the Internet. First, from the 1950s to the present there has been a steady increase in the size of data networks and the variety of services they offer. Rapid growth and diversity have forced network designers to overcome incompatibilities between computer systems and components, manage data traffic to avoid congestion and chaos, and reach international agreement on technical standards. These challenges have led to fundamental advances in research areas such as operating systems and queuing theory. A second trend has been the modeling of network functions as a series of layers, each of which behaves according to a standard protocol, a set of rules for interaction that is implemented in software or hardware. Layering reduces the complexity of the network system and minimizes the amount of standardization necessary, which makes it easier for networks to join the Internet. A third important feature of the Internet’s technical development has been an unusually decentralized and participatory design process. This has opened the system to innovation from a variety of directions and has encouraged informal worldwide collaboration. The following sections describe some of the major milestones in the evolution of the Internet and its predecessors.
