session control protocol (SCP)
Session control protocol (SCP) is a method of creating multiple light-duty connections from a single TCP (Transmission Control Protocol) connection.
Several such lightweight connections can be active simultaneously. SCP is a session layer protocol in the Open Systems Interconnection (OSI) model. In the session layer (layer five in the seven-layer telecommunications model), session layer protocols provide services for coordinating communication between local and remote applications, establishing, managing and terminating connections.
SCP runs on TCP, depending on it to provide connections and reliable service. While SCP is a byte-oriented protocol it also supports message boundary markers. TCP is a set of rules used along with the Internet Protocol (IP) to send data in the form of message units between computers over the Internet.
Other protocols that may be used in this layer include AppleTalk, RPC, ITU x.225 and Zone Information Protocol (ZIP).