The transmission subsystem in Systems Network Architecture
P. G. Cullum · IBM Systems Journal · 1976
In the data processing world of the future, communications requirements will become more complex and will involve many new application areas. These new applications will need to jointly use the system's communication resources (CPUs , teleprocessing facilities, and terminals) while the management of these resources will grow more complex. SNA provides the management of the communication system so that the end user of the system can develop and use applications, ignoring the system's complexity and sharing its resources with the other end users. SNA also provides the system structure that allows both conceptual and physical growth of the network in the future.