In large networks, there may be more than one paths for transmitting data from sender to receiver. Selecting a path that data must take out of the available options is called switching. There are two popular switching techniques – circuit switching and packet switching.
When a dedicated path is established for data transmission between sender and receiver, it is called circuit switching. When any network node wants to send data, be it audio, video, text or any other type of information, a call request signal is sent to the receiver and acknowledged back to ensure availability of dedicated path. This dedicated path is then used to send data. ARPANET used circuit switching for communication over the network.
Circuit switching provides these advantages over other switching techniques −
Circuit switching has its disadvantages too −
Long set up time is required
A request token must travel to the receiver and then acknowledged before any transmission can happen
Line may be held up for a long time
As we discussed, the major problem with circuit switching is that it needs a dedicated line for transmission. In packet switching, data is broken down into small packets with each packet having source and destination addresses, travelling from one router to the next router.