Circuit Switching is a switching technique used in telecommunication networks to establish a dedicated communication path (circuit) between two nodes for the duration of a conversation. Here’s an overview of Circuit Switching:
Concept:
- In Circuit Switching, a dedicated communication path is established between the sender and receiver before any data transmission occurs.
- The communication path consists of a series of interconnected switches or nodes, forming a continuous circuit.
- Once the circuit is established, data transmission occurs in real-time over the circuit until the conversation is completed.
Operation:
- Call Setup:
- Before data transmission can begin, a call setup phase is initiated to establish the circuit between the sender and receiver.
- During call setup, signaling messages are exchanged between network nodes to reserve the necessary resources and configure the circuit path.
- Once the circuit is established, it remains dedicated to the conversation until the call is terminated.
- Data Transmission:
- After the circuit is set up, data transmission occurs over the dedicated circuit.
- Data is transmitted in a continuous stream from the sender to the receiver, without any packetization or segmentation.
- Call Termination:
- Once the conversation is completed, the circuit is released, and the resources allocated for the call are freed up for other users.
- The circuit-switched connection is torn down, and the communication path is no longer dedicated to the conversation.
Characteristics:
- Predictable Delay: Circuit Switching offers predictable end-to-end delay since the communication path is established before data transmission.
- Guaranteed Bandwidth: Each circuit is allocated a fixed bandwidth, ensuring consistent data transmission rates.
- Resource Reservation: Resources, including bandwidth and switch ports, are reserved for the duration of the conversation, even if data is not actively transmitted.
- Connection-Oriented: Circuit Switching provides a connection-oriented communication model, where a dedicated circuit is established for each conversation.
Applications:
- Circuit Switching was traditionally used in telephone networks for voice communication.
- It is still used in some telecommunication networks for services such as ISDN (Integrated Services Digital Network) and PSTN (Public Switched Telephone Network).
- Circuit Switching is also used in some specialized applications, such as leased lines for data transmission between two fixed locations.
Advantages and Disadvantages:
- Advantages: Predictable delay, guaranteed bandwidth, and connection-oriented communication.
- Disadvantages: Inefficient use of resources, especially for bursty or intermittent traffic, and high setup time for establishing circuits.
Despite its limitations, Circuit Switching remains a vital component of telecommunications, particularly in scenarios where consistent bandwidth and low-latency communication are critical.