The most commonly used methods for connecting various communicating devices with each other are Circuit switching and Packet switching. Circuit switching contrasts with Packet switching, which divides the data to be transmitted into packets and then transmits through the network independently. In packet switching, instead of being dedicated to one communication session at a time, network links are shared by packets from multiple competing communication sessions, resulting in the loss of the quality of service guarantees that are provided by circuit switching.
Initially, Circuit Switching was specifically designed for voice communication and it was less suitable for data transmission. So, a better solution evolved for data transmission called Packet switching. The major differences between Circuit switching and packet switching are given below.
Circuit Switching Packet Switching Circuit switching is Connection oriented, i.e, a semi-permanent connection is established before any useful data gets transferred, and the stream of data is then delivered in the same order as it was sent. Packet switching is connection-less, which means data transfer takes place directly without the need to establish a connection. In circuit switching, each data unit knows the entire path address that is provided by the source. This method is inflexible as once a path is set all parts of a transmission follows the same path. In Packet switching, each data unit just knows the final destination address and the intermediate path is decided by the routers. This method is flexible because a route is created for each packet to travel to the destination. A message is received in the order in which it is sent from the source. Packets of a message are received out of order and all of them get assembled at the destination. The delay between data units is uniform in case of circuit switching. The delay between data units is not uniform in case of packet switching. The main disadvantage is that if the connection is lost at any place, the entire communication must be restarted. The main advantage of packet switching is if one path is lost only the packets which are on that path will be restarted. But not the entire data packets. More reliable. Less reliable. This is implemented in the Physical layer. This is implemented in the network layer.