A network technology based on transferring data in cells or packets of a fixed size. The small, constant cell size allows ATM equipment to transmit video, audio, and computer data over the same network, and assure that no single type of data dominates the line. ATM creates a fixed channel, or path, between two points whenever data transfer begins. This differs from TCP/IP , in which messages are divided into packets and each packet can take a different route from source to destination. This difference makes it easier to track and bill data usage across an ATM network, but it makes it less adaptable to sudden surges in network traffic.