Showing papers on "Fast packet switching published in 1971"

Extensions of packet communication technology to a hand held personal terminal

Abstract: Electronic communications technology has developed historically almost completely within what might be called the circuit switching domain. Not until the last decade has the other basic mode of communication, packet switching, become competitive. Thus, as a technology, packet communication has only begun to be explored. Circuit switching can be defined in the broad sense as the technique of establishing a complete path between two parties for as long as they wish to communicate, whereas packet switching is where the communication is broken up into small messages or packets, attaching to each packet of information its source and destination and sending each of these packets off independently and asynchronously to find its way to the destination. In circuit switching all conflicts and allocations of resources must be made before the circuit can be established thereby permitting the traffic to flow with no conflicts. In packet switching there is no dedication of resources and conflict resolution occurs during the actual flow perhaps resulting in somewhat uneven delays being encountered by the traffic. Clearly, without the speed and capability of modern computers, circuit switching represented a cheaper and more effective way to handle communications. For radio frequency assignment and telephone exchanges the resource allocation decisions could be made infrequently enough that manual techniques were originally sufficient. Also, since voice was the main information being communicated, the traffic statistics were sufficiently compatible with this approach to make it quite economic for the period. Packet switching of a kind, the telegram, persisted throughout this period but due to the high cost of switching and the limited demand for fast message traffic never attracted much attention.