Switching involves sending data along routes so that it can be sent from the sender to the receiver. Circuit switching is a switching technique in which data travels along a dedicated communication path between a source and a destination. The resources along the path are reserved for that circuit for the duration of the connection.
The three phases of communication in a circuit-switched network are as follows:
1. Circuit establishment
A dedicated circuit is established between the source and the destination through several intermediate switches.
2. Data transfer
Once the circuit is established, the sender starts to send data to the receiver.
3. Tear down
Upon completion of the data transfer, the established connection is terminated. All the nodes involved in the connection are notified to release the resources that were reserved for the circuit.
The illustration below explains this concept:
The following are some important advantages and disadvantages of circuit switching:
A consistent data transfer rate is guaranteed.
There are no delays at the switches after circuit establishment.
The reserved resources cannot be used to transmit data from some other source even if the circuit is free.
The circuit establishment process is complicated.