Service access procedure (SAP) for the transmission control protocol (TCP)

The concept and design of a service access procedure (SAP) are presented for establishing transparent and reliable connections between the top three layer protocols of the ISO Open System Interconnection (OSI) and the corresponding bottom four layer protocols. The transport and network protocols have been selected to be the US Department of Defense standard transmission control protocol (TCP) and internet protocol (IP), respectively. The upper layer protocols are made a part of the host processor's software whereas the TCP/IP and the subsequent lower layer protocols are resident in a physically distinct device such as an interface unit.<>