What is Circuit Switching? Detail Explained

What is Circuit Switching?

In circuit switching, a dedicated physical connection is established between the two nodes before communication can take place. This connection, or circuit, is then maintained for the duration of the communication session. Once the session is finished, the circuit is dismantled.

Types of Circuit Switching

There are two main types of circuit switching:

Time-Division Multiplexing (TDM): In TDM, each connection is allocated a certain amount of time on the physical link. This time is then divided into time slots. TDM is commonly used in voice communication because it provides guaranteed quality of service.

Frequency-Division Multiplexing (FDM): In FDM, each connection is allocated a certain frequency on the physical link. This frequency is then divided into frequency bands. FDM is commonly used in data communication because it can provide a higher data rate than TDM.

Advantages of Circuit Switching?

Here are the three main advantages of circuit switching:

• Predictable Latency: Since a physical connection is established before communication can take place, the latency (i.e. delay) in circuit switching is very predictable.
• Reliable Connection: Because a physical connection is maintained for the duration of the communication session, circuit switching is a very reliable way to communicate.
• Quality of Service: Circuit switching can provide a guaranteed quality of service (QoS) because it dedicated resources to each individual connection.

Disadvantages of Circuit Switching

There are also three main disadvantages of circuit switching:

• Expensive Infrastructure: In order to establish physical connections between nodes, circuit switching requires a lot of expensive infrastructures.
• Complex Network Management: Managing a circuit-switched network can be quite complex because of all the individual connections that need to be maintained.
• Limited Flexibility: Circuit switching is not very flexible because resources are dedicated to each individual connection. This means that it is not possible to easily add or remove connections from the network.

Phases of Circuit Switching

There are four main phases in circuit switching:

1. Connection Setup: In this phase, the physical connection is established between the two nodes.
2. Data Transfer: In this phase, the data is transferred over the physical connection.
3. Connection Teardown: In this phase, the physical connection is dismantled.
4. Connection Maintenance: In this phase, the physical connection is maintained for the duration of the communication session.

Where do we use Circuit Switching?

Circuit switching is commonly used in voice communication because it provides guaranteed quality of service. It is also used in data communication, but it is not as common because it can be less efficient than other methods, such as packet switching.

How does Circuit switch differ from Packet Switching?

Circuit switching is different from packet switching in several ways:

1. In circuit switching, a physical connection is established before communication can take place. In packet switching, communication can take place without a physical connection.

2. In circuit switching, the resources are dedicated to each individual connection. In packet switching, the resources are shared among all the connections.

3. In circuit switching, the quality of service (QoS) is guaranteed because of the dedicated resources. In packet switching, the QoS is not guaranteed because of the shared resources.

4. In circuit switching, the latency is predictable because of the dedicated resources. In packet switching, the latency is variable because of the shared resources.

5. In circuit switching, the connection is reliable because of the dedicated resources. In packet switching, the connection is not necessarily reliable because of the shared resources.

How does Circuit Switching Work?

Circuit switching works by establishing a physical connection between two nodes before communication can take place. This connection is then maintained for the duration of the communication session.

The resources are dedicated to each individual connection, which means that the quality of service is guaranteed.

However, this also means that the circuit-switched network is not very flexible because it can only support a limited number of connections at any given time. In addition, the infrastructure required for circuit switching is expensive.

Example of a Circuit Switching

One example of a circuit-switched network is the public switched telephone network (PSTN). The PSTN is a voice communication network that uses circuit switching to connect callers. Another example of a circuit-switched network is an integrated services digital network (ISDN). ISDN is a data communication network that uses circuit switching to connect devices.

Are switches and routers used in circuit switching?

Yes, switches and routers are used in circuit switching. Switches are used to establish the physical connection between two nodes. Routers are used to route the data over the physical connection.

Importance of Circuit Switching for WAN

Circuit switching is important for wide area networks (WANs) because it provides guaranteed quality of service. WANs are often used to connect different sites in a company or organization, and they need to be able to support real-time applications, such as voice and video.

Circuit switching is the only technology that can provide guaranteed quality of service for real-time applications. This is because the resources are dedicated to each individual connection, which means that the quality of service is not affected by other traffic on the network.