Asynchronous Transfer Mode (ATM) is
|“||[a] transfer mode in which the information is organized into cells; it is asynchronous in the sense that the recurrence of cells depends on the required or instantaneous bit rate.||”|
ATM is a high-bandwidth, low-delay switching and multiplexing technology. It is a method of delivering multiple multimedia programs over a single communications channel at speeds of 1.5 Mbps (T1 line) to 612 Mbps (OC12). The data is broken into small packets (called cells) that are 53 bytes each and routed in order to their destination via high-speed cables.