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Table of contents
1.
Introduction
2.
Why is switching required? 
3.
What are switched Networks? 
4.
Different Methods of switching
4.1.
Circuit Switching
4.2.
Message Switching
4.3.
Packet Switching
5.
Advantages and Disadvantages of Switched Networks
5.1.
Advantages of Switched Networks
5.2.
Disadvantages of Switched Networks
6.
Frequently Asked Questions
6.1.
Which way of switching lessens traffic congestion?
6.2.
Give some application of message switching? 
6.3.
What is a frame relay circuit?
6.4.
What is time-division switching, and how does it work?
7.
Conclusion
Last Updated: Mar 27, 2024

Switching in Computer Networks

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Computer Networks

Introduction

What is Switching?

As we all know, a network is primarily a collection of interconnected devices. However, when several devices are connected in a network, there is a connection issue: linking them so that one-to-one communication is feasible. One method is a point-to-point connection between each pair of devices or a point-to-point connection between the central device and every other device. However, in the case of huge networks, this technique cannot be implemented in practice. Switching is a better answer to this situation.

Switching is forwarding packets from one port to another port that leads to the destination. When the port receives the data, it is referred to as ingress, and when data leaves a port, it is referred to as egress. Switches and nodes may be found in a communication system. Switching may be categorized into two categories at a high level: (Also see, Switching Modes)

  • Connectionless: Data is transmitted by forwarding tables in a connectionless manner. There is no need for initial handshakes, and acknowledgments are optional.
  • Connection-Oriented: Before switching, data can be transmitted to a destination; a circuit must be established between the two endpoints. On such a circuit, data is then transmitted. Circuits may be preserved for future use or shut off immediately after the transfer.

Why is switching required? 

The switching notion was created for the following reasons:

Bandwidth: The maximum transmission rate of a cable is known as bandwidth. It is a highly important and costly resource. As a result, switching strategies are utilized to make the most use of a network's capacity.

Collision: Collision results from numerous devices sending the same message across the same physical media and colliding. To solve this issue, switching technology is used to prevent packets from colliding with one another.

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What are switched Networks? 

A completely switched network is a Computer Network that employs solely network switches rather than Ethernet hubs. Each workstation has its unique connection via the switches. A switch permits many talks to take place at the same time. Before switches, hub-based networks could only transmit data one way at a time, which was known as half-duplex. This limitation is overcome by utilizing a switch; full-duplex communication is preserved, and the collision-free network. This implies that data may now be transferred simultaneously in both ways. Twisted-pair or fiber-optic cabling is used in entirely switched networks, and both utilize distinct conductors for transmitting and receiving data. Because Ethernet nodes are the only possible devices that may access the media, they can bypass the collision detection mechanism and transmit at will. A completely switched network is thus a collision-free environment.

Fully Switched Network

Fully Switched Network

Source: studytonight

A switch's main purpose is to enable each workstation to communicate with the switch rather than with the other. As a result, data may be transferred concurrently from a workstation to a switch and switch to a workstation. The primary function is to decongest network traffic to workstations, allowing connections to share data more efficiently while only receiving signals unique to their network address. When two workstations are exchanging data, the network may be decongested. Data can be sent in both directions simultaneously, thus doubling network speed and capacity. If your network speed is 5 Mbit/s, for example, each workstation may transmit data at 5 Mbit/s simultaneously.

Different Methods of switching

A switching strategy is used to determine the optimal data transmission path. Switching approaches primarily link systems in a manner that facilitates one-to-one communication.

Circuit Switching

Circuit switching divides network resources (bandwidth) into segments and maintains a consistent bit delay across the connection. The dedicated path/circuit created between the sender and recipient provides a guaranteed data rate. Once the circuit is created, data may be sent without delay.

Circuit Switching Diagram

Circuit Switching Diagram

Source: Comparitech 

 

One example of circuit switching is the telephone system network. TDM (Time Division Multiplexing) and FDM (Frequency Division Multiplexing) are two techniques for combining multiple signals onto a single carrier.

FDM(Frequency Division Multiplexing): Splits a signal into multiple bands.

When multiple data signals are combined for simultaneous transmission over a shared communication medium, Frequency Division Multiplexing, or FDM, is used.

It's a method of dividing a total bandwidth into a series of non-overlapping frequency sub-bands, each of which carries a different signal. Multiple separate signals may be shared in the radio spectrum and through an optical fiber.

TDM (time-division multiplexing) is a technique for sending and receiving separate signals across a shared signal route using synchronized switches at both ends of the transmission line. TDM is a long-distance communication connection that can handle a lot of data flow from the end-user.

A digital circuit switch is also known as time-division multiplexing (TDM).

Message Switching

Before packet switching, message switching was created as an alternative to circuit switching. End-users interact through message switching by sending and receiving messages that include all of the material to be transferred. Messages are the smallest unit of communication.

Furthermore, the transmitter and recipient are not linked directly. A number of intermediary nodes transmit data and guarantee that the message reaches its intended recipient. As a result, message switched data networks are called hop-by-hop systems.

Module Switching

Source: Tutorialspoint

 

 

They have two different and crucial features:

Store and Forward: The intermediate nodes are responsible for storing and forwarding the whole message to the next node. As a result, each node must contain storage. If the next-hop and the connection linking it are accessible, a message will be sent; otherwise, it will be held forever. A store-and-forward switch will forward a message if adequate resources are available and the following hop is receiving data. The store-and-forward property is what it's called.

Message delivery entails encapsulating all data in a single message and sending it from the source to the destination node. The message routing information, including the origin and destination, must be included in the header of each message.

Packet Switching

Packet switching was born out of the shortcomings of message switching. The whole communication is divided into smaller pieces known as packets. Each packet's switching information is added to the header and broadcast separately.

Small packets are easy for intermediate networking devices to store, and they do not use many resources on the carrier channel or in the internal memory of switches.

Packet Switching

Packet switching Diagram

Source: Comparitech

Packet switching improves line efficiency by multiplexing packets from several applications across the channel. Packet switching is a technology used on the internet. Packet switching allows users to distinguish data streams depending on their priority. To offer excellent service, packets are kept and sent according to their priority.

Packet switching can further be classified into 2 types: 

Virtual Circuit Switching: It is a network in which a virtual link between the source and the destination is formed. During any call, packets will be transmitted across this network. A dedicated physical circuit arises when a route is constructed between two sites. As a result, it's known as a virtual circuit. It's a packet switching system.

It's a connection-oriented service, meaning that the first packet flows first and the resources for the following packets are reserved.

Datagram Networks: Datagrams are data packets with enough header information to be routed separately to the destination by all intermediate network switching devices. Because datagrams are used to communicate, these networks are referred to as datagram networks. In packet switching networks, they exist.

Advantages and Disadvantages of Switched Networks

Advantages of Switched Networks

  • Switches assist in the creation of a collision domain for each network connection. As a result, the possibilities of a frame collision are reduced.
  • The amount of available bandwidth on the network is increased when switches are used.
  • By using network switches, the strain on each individual PC is decreased.
  • The switch is connected to the workstation through a direct connection.
  • It decreases the amount of work that individual PCs have to do since it only transmits information to the device that has been designated.
  • It improves the network's overall performance by lowering traffic on the network.

Disadvantages of Switched Networks

  • As we are using switches in the switched network, the network becomes expensive because switches are expensive.
  • It is difficult to trace the connectivity issues in the network through a switch.
  • There are chances for the occurrence of trouble in broadcast traffic.
  • In order to handle multicast packets, proper design and configuration are needed.


Also see, Circuit Switching v/s Packet Switching
 

Must Read Subnetting in Computer Networks

Frequently Asked Questions

Which way of switching lessens traffic congestion?

Congestion is a sign of a network that is overburdened. Because packet switching assures that more of the bandwidth of all connections is completely used, it is more efficient than circuit switching. Packet switching is more likely to decrease congestion than circuit switching because it makes better use of resources.

Give some application of message switching? 

Although many large networks and systems are now packet-switched or circuit-switched, message switching may still be used to convey data. The delivery procedure in most electronic mail systems, for example, is based on message switching, despite the fact that the network is either circuit-switched or packet-switched.

What is a frame relay circuit?

A-frame relay is a virtual circuit service that is connection-oriented. It's similar to renting a line between two networks on a temporary basis. A connected public line may carry many talks between various ends over the same connection.

What is time-division switching, and how does it work?

Time-division switching is a technique for allowing several connections to use a single trunk line. It uses time-division multiplexing (TDM), which divides a stream into segments and sends them out on the line at predetermined intervals. The receiving de-multiplexer detects the components of each stream using a synchronized clock.

Conclusion

In this article, we learned we learned about what is switching in computer networks, why switching is required, and what are the different methods of switching in detail. 

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