A communications architecture that requires the establishment of a session between two nodes before transmission can begin. When the communications is completed, the session is ended (torn down). All circuit-switched networks are connection oriented because they require a dedicated channel for the duration of the session. The most ubiquitous circuit-switched network is the PSTN. In addition, packet-switched X.25, frame relay and ATM networks are also connection oriented, because they require receiving nodes to acknowledge their ability to support the transmission before data can be sent.
In an IP network, the TCP transport protocol is connection oriented, requiring a three-way handshake in order to start transmitting data packets. Contrast with connectionless