Packet switching is a network communications protocol by which data is encapsulated into packets that also contain header information. This allows packet switches to forward incoming packets to their destination then immediately make that communications channel available for the transmission of other packets.
Packet switching relies on packet switches to receive incoming packets and forward them to destination network links. Header information is used in packet switching by network switches while the payload (data) is reserved for use in the application layer.
Packet switching was developed in the late 1960s as research funded by the US DoD and ultimately replaced older systems of network communication relying on reserved bandwidth protocols. Packet switching underpins such protocols as Transmission Control Protocol (TCP) and User Datagram Protocol (UDP).