Conceptual Issues for ATM

Abstract

The Asynchronous Transfer Mode (ATM) has been strongly promoted, as the transport structure for future broadband telecommunication networks, within standards bodies CCITT Study Group XVIII (inter-nationally) and T1S1 (North America) [1] [2]. ATM is a transport technique based on fast packet switching, where the information is packed into fixed-size cells of relatively short length, 32–120 octets, perhaps. (Although standards clearly do not exist at this time, there is a strong trend, particularly in Europe, towards very short cells.) These cells are identified and switched throughout the network by means of a label in the header—hence, the term “label multiplexing” is often used. This label contains the virtual connection identification and whatever other addressing is required, as well as perhaps priority and other control data. In OSI terminology, ATM has Layer 1 functionality but only some Layer 2 functions. © 1989 IEEE