Type of data transfer where a channel is opened between the origination and destination of the data, be it voice or data. The alternative is packet switching, where data is divided into packets which take multiple routes and are reassembled at their destination.

Circuit switching is a great waster of resources, as the channel is kept open wether or not data is being transmitted, but it is currently the method of choice for telecomms as it gives the best quality of service

Examples of circuit switched protocols: ISDN, SS7

Example of packet switched protocols: TCP, UDP, ATM, Frame Relay, X.25