In this article, we will discuss what is switching?, types of switching techniques: Circuit Switching, Message Switching, Packet Switching, and also discuss the difference between circuit, message, and packet switching.
What is Switching?
Switching is the mechanism in computer networks that helps in deciding the best route for data transmission if there are multiple paths in a larger network. Larger networks may have multiple routes to link the sender and receiver. So whenever we send any information between the sender and receiver then the information switches through multiple routes.
It is the process of transferring data packets from a source device to a destination device through a series of connected networks.
Whenever we send information from one device to another, that information does not directly reach that device, there are many intermediate nodes in the middle, and the information switches through these nodes.
You should also read: How Switch Works, How Router Works.
Types of Switching Techniques
- Circuit Switching
- Message Switching
- Packet Switching
In-Circuit Switching, a dedicated channel is established for a single connection where the sender and receiver can communicate during the communication session.
In-Circuit Switching, whenever a device communicates with another device, a dedicated communication path (circuit) is established in them over the network.
It is a switching technique that creates a pre-specific route between the sender and receiver and this route is reserved for both these devices as long as the connection is active. Both devices are connected through this specific route and data transfer can also be done only through this specific route. Other devices cannot use this specific route for data transmission because this specific route is reserved.
This type of network switching was designed and used in the early analog telephone network. We used circuit switching to physically connect devices in the telephone network.
Communication that takes place through circuit switching has 3 phases:
- Establish a circuit: In the first phase, a circuit is established means a dedicated link is established between the sender and the receiver through a number of switching centers or nodes.
- Transfer the data: Once the circuit is established, means the connection is established between the sender and receiver, they can communicate with each other.
- Disconnect the circuit: Once the communication is completed between the sender and receiver, the circuit disconnects. The circuit disconnection is done by one of the users i.e. the sender or the receiver.
Simple Example of Telephone Network: First we call the other user, once he receives the call, the connection is established and both can communicate with each other, after if one of the users disconnects the phone, the circuit disconnects.
Advantages of Circuit Switching
- A dedicated link is established between both devices which provides a guaranteed data transmission.
- Once the connection is established between the sender and receiver, data can be transmitted without any delay because they are directly connected so no waiting time at each switch.
- A dedicated continuous data transmission path is established between the sender and receiver so this switching method is suitable only for long continuous transmission.
Disadvantages of Circuit Switching
- The main disadvantage of this switching method is that once a dedicated path is established then this path becomes reserved and other devices cannot use this path.
- This method does not properly utilize system resources, as resources are allocated for the entire duration, these are not available to other connections.
- A dedicated continuous data transmission channel requires more bandwidth.
- Before actual data transfer, a dedicated path has to be established, it takes a long time to establish the path.
There is no dedicated path established between the sender and receiver in message switching, as in circuit switching.
For sending the message, there are many intermediary messages switching nodes that are responsible for transferring the message, and the message is transmitted as a whole from the source node-to-destination node.
In Message Switching, when the source node sends a message, the destination address is appended to the message. So in message switching, there is no need to establish a dedicated path between two communication nodes.
When a sender sends a message, the message sends as a whole to the next message switching node, store it in its entirety on the disk, and then transmits the whole message to the next switching node and so on, until the message reaches the destination.
If the next message-switching node does not have enough space to store the message, the previous switching node has to wait. When the next node has enough space to store the message, then the previous forwards the message to the next node. That’s why this type of network is also called a store-and-forward network.
This technique is not recommended for real-time applications like video and voice, etc.
Advantages of Message Switching
Message switching has several advantages over other forms of communication:
- Robustness: Message switching is a highly robust method of communication because it does not rely on a continuous connection between nodes. Messages can be stored and forwarded, so the communication can continue even if some of the nodes in the network are unavailable.
- Reliability: In message switching, each message is sent individually, and each switch confirms receipt of the message before forwarding it to the next switch. This ensures that messages are delivered reliably, with no loss or corruption of data.
- Prioritization: Because messages are stored in switches, they can be prioritized based on their importance or urgency. This means that critical messages can be given priority over less important messages, ensuring that they are delivered quickly.
- Security: Message switching is inherently more secure than other types of communication because messages are not sent in a continuous stream. This makes it more difficult for an attacker to intercept or interfere with the communication.
- Cost-effectiveness: Message switching can be more cost-effective than other types of communication because it does not require a continuous connection between nodes. This means that it can be used in situations where other forms of communication may be too expensive or impractical.
You should also read: How Switch Works, How Router Works.
In packet switching, when we send a message, then the whole message is divided into smaller pieces called packets. These pieces or packets travel across the network and take the shortest path possible.
Every packet has a sequence number to identify its order at the receiving end.
Each packet contains some information including a source address, a destination address, intermediate node address information, sequence number, etc. so that individual packets can be routed through the internetwork independently. This method allows for more efficient use of network resources and enables multiple transmissions to occur simultaneously.
Advantages of Packet Switching
- Efficiency: Packet switching is a very efficient method of transmitting data because it allows multiple packets to be transmitted simultaneously over the same network. This can significantly increase the speed of data transmission.
- Flexibility: Packet switching allows different types of data, such as text, voice, and video, to be sent over the same network. This makes it a versatile communication method that can handle a wide variety of applications.
- Robustness: Packet switching is highly robust because it allows packets to be sent along different routes to their destination. If one route is unavailable or congested, packets can be automatically rerouted to another path.
- Scalability: Packet switching is highly scalable because it can handle a large number of users and devices. As the number of users and devices in a network grows, the network can be expanded by adding more switches and routers.
- Cost-effectiveness: Packet switching is a cost-effective method of communication because it allows multiple packets to be sent across the network simultaneously, making better use of network resources. It also requires less bandwidth than other communication methods, which reduces costs.
Difference between Circuit Switching, Message Switching and Packet Switching
|Circuit Switching||Message Switching||Packet Switching|
|There is physical connection b/w transmitter and receiver||No physical path is set in advance b/w transmitter and receiver||No physical path is established b/w transmitter and receiver|
|All the packet uses same path||Packet are stored and forward||Packet travels independently|
|Need an end to end path before the data transmission||No need of end to end path before data transmission||No need of end to end path before data transmission|
|Reserves the entire bandwidth in advance||Does not reserve the bandwidth in advance||Does not reserve the bandwidth in advance|
|Waste of bandwidth is possible||No waste of bandwidth||No waste of bandwidth|
|It cannot support store and forward transmission||It support store and forward transmission||It support store and forward transmission|
|Not suitable for handling interactive traffic||Suitable for handling interactive traffic||Suitable for handling interactive traffic|
Video Explanation of Switching Techniques
Some of the articles you should read:
Switching Techniques Multiple Choice Questions (MCQ)