pxp.sap

provides a communication service, such as a serial line, an Ethernet controller, or a Unix pipe. SAP stands for Service Access Point. It is assumed that the SAP provides, at least, a Transport level service (TSAP). This could be, for instance, TLI or TCP/IP, but some provisions are made to allow some SAPs to work on a Network layer, like X.25-3. Each host defined on the local system has an output access point associated with it, so that the PXP subsystem can determine how to get the message on the network for a given host.