Glossary definition of Packet Switching

Packet Switching is a method of transmitting information (voice, video or other streamed data) over a communications system, without dedicating an exclusive channel to the subscriber.

The information is broken down into small blocks or packets, no more than a few kilobytes in size, which are each identified by a unique address code. The packets are then sent and routed individually over the network, via whatever channels are free at the time, and when the packets arrive at their destination they are then re-assembled in the original sequence as was transmitted.

This method of transmission makes better use of the network's dormant channels, as the network resources are only being used for the handling of each actual packet. Packet switching is therefore a more efficient system than the alternative method of circuit switching (also called line switching), and it enables the network's capacity to be more evenly distributed, so that it can handle more calls than a circuit switched system.

Packet switched communications can give an "always online" appearance, since connections are only being made when packets are being sent or received-this means that the subscriber can be charged according to the volume of data sent, rather than the length of time connected.

The method used by packet switching should ensure more reliable transmission, because the data can be routed via several channels, and any problems on one channel should not cause a break in the connection.