A circuit-switched network is a type of telecommunications network in which two endpoints are connected through a continuous physical circuit. Once the path is established, it remains immutable for the entire duration of the connection.

How it works

Circuit switching works by establishing a dedicated path between the sender and the receiver before communication begins. This path remains reserved and cannot be used by other communications until the connection is terminated. The circuit establishment process involves several steps:

1. Connection request: The sender sends a connection request to the network.
2. Path setup: The network identifies an available physical path and establishes the circuit.
3. Communication: Once the circuit is established, data is transmitted continuously and without interruption along the path.
4. Termination: At the end of the communication, the circuit is disconnected and the resources are released.

Advantages

• Reliability: Once established, the path is dedicated exclusively to the ongoing communication, ensuring interference-free transmission.
• Consistent quality: The quality of service remains constant because the path is reserved and not shared with other communications.
• Low latency: Since the path is physical and dedicated, latency is generally lower compared to other network technologies.

Disadvantages

• Inefficient resource utilization: Resources remain occupied for the entire duration of the connection, even if they are not used continuously, leading to inefficient use of network capacity.
• Limited scalability: Establishing and maintaining dedicated circuits can become complicated and expensive as the number of required connections increases.

Applications

Circuit-switched networks have been widely used in traditional telephone networks (PSTN). In these networks, every phone call establishes a dedicated path between the two parties. Although this technology has been largely replaced by more modern technologies such as packet-switched networks, understanding circuit-switched networks is fundamental to understanding the evolution of telecommunications.

Conclusion

Circuit-switched networks represent one of the fundamental technologies in the history of telecommunications, offering a reliable and consistent method for transmitting data over dedicated paths. Despite their limitations in terms of efficiency and scalability, these networks have played a crucial role in the development of modern communication infrastructures.