Circuit Switching

What does Circuit Switching mean?

Circuit Switching is a fundamental networking technique that establishes a dedicated, temporary connection between two or more devices over a network. It creates a dedicated path, or circuit, between the sender and receiver, ensuring guaranteed bandwidth and a fixed communication channel. Unlike Packet switching, circuit switching does not involve dividing data into packets and routing them independently.

During circuit switching, a physical or logical circuit is established before data transmission begins. The circuit remains active for the duration of the communication, regardless of whether data is being transmitted at all times. The established circuit ensures continuous connectivity and constant bandwidth, making it suitable for applications that require real-time and reliable data transfer, such as voice and video calls.

To initiate circuit switching, a connection request is sent from the originating device to the destination. If the circuit is available, it is established, and a dedicated pathway is created between the two endpoints. Once the circuit is established, data can flow freely and uninterrupted, as the allocated bandwidth is reserved exclusively for the duration of the connection.

Circuit switching offers several benefits, including guaranteed bandwidth, low latency, and high reliability. However, it also has disadvantages, such as wasted bandwidth when the circuit is not fully utilized and potential delays in establishing the connection.

Applications

Circuit switching finds applications in various areas of technology due to its ability to provide guaranteed bandwidth and real-time communication:

• Telecommunications: Circuit switching has been traditionally used in telephony and voice communications to provide reliable and high-quality voice calls.

• Data Communications: In the early days of data communications, circuit switching was used to establish dedicated connections for data transfer. Examples include leased lines and X.25 networks.

• Video Conferencing: Circuit switching has been employed in video conferencing to ensure uninterrupted and high-quality video communication.

• Network Management: Circuit switching is sometimes used for network management and control purposes, where dedicated connections are required for remote access and configuration.

• Satellite Communications: Circuit switching is utilized in satellite communications to provide reliable and secure communication links between earth stations and satellites.

History

Circuit switching dates back to the early days of telephony. In the 1800s, telephone operators manually connected circuits between two subscribers to establish calls. Over time, automatic switching systems were developed, allowing users to dial directly and establish connections without operator intervention.

The concept of circuit switching was later adopted in data communications. In the 1960s, the International Telegraph and Telephone Consultative Committee (CCITT) developed the X.25 protocol for packet-switched data networks. However, X.25 also included a circuit-switching mode, which provided a dedicated connection for data transfer.

Circuit switching remained the dominant networking technique until the late 1980s when packet switching emerged as a more efficient Method for handling data traffic, especially in the emerging internetworking era. Packet switching allowed for more flexible and efficient use of network resources, and it became the preferred approach for internet data communications.

Despite the widespread adoption of packet switching, circuit switching still finds applications in specialized areas where guaranteed bandwidth and real-time communication are critical.