Path Control: The Transport Network of SNA

A primary virtue of a communications system is transparency of the transport network to the person using the system. The layered structure of SNA provides for the separation of the transport network, called path control, from higher level functions involving the end users of the network. This paper describes the structure of the path control layer of SNA, focusing on connectivity, routing, and flow control. The end user´s view of these architectural concepts is presented, as well as a discussion of the underlying formats and protocols.