In a packet-switched network, a mode of transmission in which there is a complete information transfer transaction for each packet or group of packets, i.e., the information transfer phase is preceded by an access phase and followed by a disengagement phase. Note 1: During the information transfer phase of connection-oriented mode transmission, more than one packet may be transmitted. The header of each information packet contains a sequence number and an identifier field that associates the packet with the connection that was established during the access phase before the information transfer phase begins. Note 2: Connection-oriented mode transmission usually enables detection of lost, erroneous, duplicated, or out-of-sequence packets because a connection is established from end to end before transmission begins. Note 3: The ITU-T X. 25 protocols are widely used to implement connection-oriented mode transmission on packet-switched public data networks. The protocols are implemented at Layers 1, 2, and 3 of the Open Systems Interconnection--Reference Model. 2. The transfer of data between two or more peer entities which involves three distinct phases: connection establishment, data transfer, and connection release.