Circuit switching (Line Switching) is a method of transmitting information (voice, video or other streamed data) between endpoints within telecommunications systems. Each individual subscriber is allocated a dedicated channel of constant bandwidth, which must be maintained open for the duration of their call, even if no actual conversation is taking place and no data being transferred.
Circuit switched systems were used in the old fixed landline telephone networks, for point-to-point connections routed directly between terminals. However, circuit switching may still be the best option when uninterrupted large file transfers need to be sent, or for long voice calls and videoconferencing, but it seems to be mainly suitable for voice traffic. Circuit switching can be considered as the opposite approach to packet switching, which does not require a dedicated channel, and makes more efficient use of the network's resources.