(TCP) The most COMmon transport layerprotocol used on Ethernet and the Internet. It was developed by DARPA. TCP is the connection-oriented protocol built on top of Internet Protocol (IP) and is nearly always seen in the COMbination TCP/IP (TCP over IP). It adds {reliable COMmunication} and {flow-control} and provides {full-duplex}, process-to-process connections. TCP is defined in STD 7 and RFC 793. User Datagram Protocol is the other, connectionless, protocol that runs on top of IP. (2001-06-14)