A transmission mode in which a network establishes a logical relationship, and often a predetermined path, for all frames or packets associated with an originating and destination address pair to travel.The path can be permanent or can exist for a single session.The public switched telephone network (PSTN) is connection-oriented.Transmission Control Protocol (TCP) is a connection-oriented protocol, where Internet Protocol (IP) is a connectionless datagram service. See also connectionless, frame, IP, packet, protocol, PSTN, session, and TCP.