Virtual circuit

Virtual Circuit

A virtual circuit is a communication protocol used in computer networks to establish a logical connection between two endpoints. It provides a reliable and efficient way to transmit data by emulating the behavior of a dedicated physical circuit, even though the actual transmission may occur over shared network infrastructure.

Overview

In a virtual circuit, data is transmitted in a sequential manner, similar to how it would be transmitted over a physical circuit. However, instead of reserving a dedicated path for the entire duration of the communication, virtual circuits dynamically allocate resources as needed.

The virtual circuit protocol operates in two phases: the connection establishment phase and the data transfer phase. During the connection establishment phase, a logical path is established between the sender and receiver. This involves negotiating parameters such as bandwidth, quality of service, and error control mechanisms.

Once the virtual circuit is established, data can be transmitted in a connection-oriented manner. Each packet is assigned a virtual circuit identifier (VCI) that allows the network to route the packet along the established path. This ensures that packets are delivered in the correct order and without errors.

Advantages

Virtual circuits offer several advantages over other communication protocols:

1. **Reliability**: Virtual circuits provide reliable data transmission by using error control mechanisms, such as error detection and retransmission, to ensure data integrity.

2. **Efficiency**: By reserving resources only when needed, virtual circuits optimize network utilization and minimize congestion. This allows for efficient use of available bandwidth.

3. **Quality of Service**: Virtual circuits can prioritize certain types of traffic, ensuring that critical data, such as real-time audio or video streams, receive higher priority and are delivered with minimal delay.

4. **Connection-oriented**: The connection-oriented nature of virtual circuits allows for predictable and deterministic communication, making them suitable for applications that require guaranteed delivery and low latency.

Implementation

Virtual circuits are implemented using various protocols, such as Frame Relay and Asynchronous Transfer Mode (ATM). These protocols define the format of the virtual circuit headers, the procedures for connection establishment, and the mechanisms for data transfer.

In computer networks, virtual circuits are often used in wide area networks (WANs) to establish connections between geographically dispersed locations. They are also utilized in virtual private networks (VPNs) to create secure and private communication channels over public networks.

Conclusion

Virtual circuits provide a reliable and efficient means of transmitting data in computer networks. By emulating the behavior of dedicated physical circuits, they offer advantages such as reliability, efficiency, quality of service, and connection-oriented communication. With their widespread implementation in various protocols and applications, virtual circuits play a crucial role in modern network infrastructure.

See Also

• Computer Network
• Frame Relay
• Asynchronous Transfer Mode
• Wide Area Network
• Virtual Private Network