Service Access Procedure (SAP) in Support of the WIS Architecture

In the distributed WWMCCS Information System (WIS) network architecture, the top three layers of the ISO Open System Interconnect (OSI) protocols for network communications are resident in each host and workstation; the bottom four layers are contained in the physically distinct interface unit (IU). Of these four layers, the transport and network protocols have been selected to be DoD standard Transmission Control Protocol (TCP) and Internet Protocol (IP), respectively. To establish smooth, transparent and reliable connections between the Upper Layer Protocols (ULP) in the hosts/workstations and the transport and network layer protocols, especially TCP, in the attached IUs, a WIS Service Access Procedure (SAP) has been developed. The rationale for residency of TCP/IP in the IUs, the concept and design of the WIS SAP, and the reasons for selection of lower layer protocols that consititute the host front-end protocol set are presented in this paper.