Asynchronous Transfer Mode (ATM) networking is an outgrowth of efforts during the 1970s and 1980s to develop a broadband Integrated Service Digital Network (ISDN) capability. ATM provides a transport mechanism that allows digital data to be efficiently transmitted over high-speed links. Currently, most of the high-speed backbone networks throughout the world use ATM technology. It is also used to some extent as a local area networking technology, although the availability of low-cost 100 megabyte and gigabyte Ethernet equipment reduces its appeal for this application.

ATM technology was developed to support a blending of circuit-switching and packet-switching technologies. It is intended to support traffic that requires a fairly constant rate of data delivery, such as voice and video, as well as variable data rate traffic, such as most computer data. ATM is a connection-oriented technology. This means that a fixed path through the network must be...