Asynchronous Transfer Mode (ATM)

A wide-area network (WAN) technology, asynchronous transfer mode (ATM) is a transfer mode for switching and transmission that efficiently and flexibly organizes information into cells; it is asynchronous in the sense that the recurrence of cells depends on the required or instantaneous bit rate. Thus, empty cells do not go by when data is waiting. ATM’s powerful flexibility lies in its ability to provide a high-capacity, low-latency switching fabric for all types of information, including data, video, image and voice, that is protocol-, speed- and distance-independent. ATM supports fixed-length cells 53 bytes in length and virtual data circuits between 45 megabits per second (Mbps) and 622 Mbps. Using statistical multiplexing, cells from many different sources are multiplexed onto a single physical circuit. The fixed-length fields in the cell, which include routing information used by the network, ensure that faster processing speeds are enabled using simple hardware circuits. The greatest benefit of ATM is its ability to provide support for a wide range of communications services while providing transport independence from those services.