Packet SwitchingPacket switching is a communications paradigm in which packets of data are routed individually between hosts, with no previously established communication path. Packet switching is used in TCP/IP (Transmission Control Protocol/Internetworking Protocol), the common language of the Internet.
On connectionless networks such as the Internet, computers along the way examine the destination address in the header and pass the packet along to another router, chosen by route-finding algorithms. The packets are then reassembled by the destination computer.
Since routes are dynamically updated, it is possible for packets from a single session to take different routes to the destination. Packets from many different sources can share a line, thereby increasing the efficiency of the fixed-capacity lines. With current technology, packets are generally accepted onto the network on a first-come, first-served basis. If the network becomes overloaded, packets are delayed or dropped.
Other packet-switching networks are connection oriented: A connection is set up before transmission begins, as in a circuit-switched network. A fixed route is defined, and the information necessary to match packets to their session and defined route is stored in memory tables in the routers, which eliminating the need to recalculate a route for each packet.