Circuit switching is a method of transmitting data that establishes a dedicated physical path between the sender and the receiver before any data is actually transmitted. This dedicated path remains reserved for the duration of the communication, even if no data is being sent. It's a connection-oriented process, meaning a connection must be established before data transfer can begin.
How Circuit Switching Works
Connection Establishment: A request is sent from the sender to the network to establish a circuit. This involves a process of signaling to reserve the necessary resources (bandwidth, switches) along the path.
Dedicated Path: Once the circuit is established, a dedicated physical or logical path is created between the sender and the receiver.
Data Transmission: Data is transmitted continuously along this dedicated path.
Connection Termination: When the communication is finished, the circuit is terminated, and the reserved resources are released.
Advantages of Circuit Switching
Guaranteed Bandwidth: The dedicated path ensures a constant bandwidth is available for the duration of the connection. This is crucial for real-time applications like voice calls.
Consistent Delay: Since the path is dedicated, the delay is relatively constant and predictable.
No Data Fragmentation: Data is transmitted as a continuous stream, avoiding the need for fragmentation and reassembly.
Disadvantages of Circuit Switching
Inefficient Bandwidth Usage: The dedicated path is reserved even when no data is being transmitted, leading to inefficient use of bandwidth.
Setup Delay: The time required to establish the circuit (signaling) can introduce a delay before data transmission can begin.
Less Flexible: It's less flexible than packet switching, as the path is fixed and cannot be easily adjusted.
Diagram
Suggested diagram: A simple circuit switching diagram showing a sender, a switch, and a receiver with a dedicated circuit between them. Label the circuit as 'Dedicated Path'.
Table: Comparison with Packet Switching
Feature
Circuit Switching
Packet Switching
Connection Type
Connection-oriented
Connectionless
Bandwidth
Guaranteed
Shared
Delay
Relatively Constant
Variable
Bandwidth Usage
Inefficient
Efficient
Setup Delay
Significant
Minimal
Flexibility
Less Flexible
More Flexible
Examples of Circuit Switching
The most common example of circuit switching is the traditional telephone network (PSTN - Public Switched Telephone Network). When you make a phone call, a dedicated circuit is established between your phone and the recipient's phone, ensuring a constant connection for the duration of the call.