Circuit Switching: Advantages and Disadvantages

This page covers the advantages and disadvantages of circuit switching (CS). It outlines the benefits and drawbacks of circuit switching and provides links differentiating it from packet switching.

What is Circuit Switching?

Introduction: Circuit switching is a network type where a dedicated channel (or circuit) is established between the calling and called users before any conversation begins. This channel remains reserved for these users for the entire duration of their active connection.

A classic example of circuit switching is the traditional telephone system. In this system, dedicated links, wires, or frequencies are made available between the users for the duration of each call.

For half-duplex communication, one channel is allocated. For full-duplex communication, two channels are allocated. Circuit switching networks are primarily used for voice communication, which demands real-time services with minimal delay.

The network requires an initial call setup delay before the conversation can commence. High traffic or network overload can lead to blocked or dropped calls. Circuit switching reserves a fixed bandwidth for the call’s duration.

Benefits or Advantages of Circuit Switching

Here are the benefits of using circuit switching:

• Real-time Voice Services: Due to the minimal delay in establishing a call and during the conversation, circuit switching is widely used for real-time voice services globally. There is almost no waiting time at the voice switches used for the call.
• Realistic Voice Communication: Higher sampling rates result in realistic voice communication, making it easier to identify consecutively speaking persons.
• Guaranteed Reliable Connection: Once a connection is established, it remains available until the end of the conversation. This ensures a reliable connection with a constant data rate and availability of resources such as bandwidth and channels. This makes it suitable for long-distance and long-duration calls without any fatigue.
• No Packet Loss or Out-of-Order Packets: Unlike packet-switched networks, circuit switching is connection-oriented, so there’s no risk of packet loss or out-of-order delivery.
• Low Overhead: Information forwarding is based on time or frequency slot assignments, eliminating the need to examine headers as in packet switching. This absence of header requirements results in low overhead in circuit switching networks.

Drawbacks or Disadvantages of Circuit Switching

Here are the drawbacks of using circuit switching:

• Unsuitable for Data Transmission: As it’s designed primarily for voice traffic, circuit switching isn’t ideal for data transmission.
• Inefficient Resource Utilization: Channels and bandwidth remain dedicated to the connection for its entire duration, even if they aren’t fully utilized. This prevents them from being used for other purposes (e.g., other connections). Consequently, circuit switching is inefficient in terms of resource utilization (channels, bandwidth, etc.). This can lead to dropped calls or failed call establishments if there are more users than available channels.
• Call Setup Delay: Establishing a connection requires a call setup delay and isn’t instantaneous. No communication is possible until the connection is established and resources are available.
• Higher Cost: Compared to other techniques, circuit switching is more expensive due to the dedicated path requirement, resulting in higher call rates.