Types of network topology in computer system

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Introduction

How devices are connected in a computer network is determined by the topology of the network.They set up the network's configuration,determining how data flows between devices and how they communicate with one another.Building,implementing, and managing reliable and efficient networks requires an understanding of different network topologies.

We will look at several network topologies,their characteristics,advantages,disadvantages and common uses in this comprehensive guide.

Various Network Topologies used in computer system

The term topology refers to the way a network is laid out, either physically or logically. A topology can be considered as the network’s shape. It is the geometric representation of the relationship of all the links. There are five basic topologies: Bus, Ring, Star, Tree, and Mesh.

1.Bus Topology

  • Bus topology uses a common bus or backbone (a single cable) to connect all devices with terminators at both ends.The backbone acts as a shared communication medium and each node (file server,workstations, and peripherals) is attached to it with an interface connector.
  • Whenever a message is to be transmitted on the network, it is passed back and forth along the cable, past the stations (computers) and between the two terminators, from one end of the network to the other. As the message passes each station, the station checks the message’s destination address.
  • If the address in the message matches the station’s address, the station receives the message. If the addresses do not match, the bus carries the message to the next station, and so on. Figure 1 illustrates how devices such as file servers, workstations, and printers are connected to the linear cable or the backbone.
Figure 1

Advantages of Bus Topology

  1. Connecting a computer or peripheral to a linear bus is easy.
  2. This topology requires least amount of cabling to connect the computers and, therefore,less expensive than other cabling arrangement.

Disadvantages of Bus Topology

  1. Entire network shuts down if there is a failure in the backbone.
  2. Heavy traffic can slow down a bus because computers on such networks do not coordinate with each other to reserve time to transmit.

2.Ring Topology

  • In ring topology computers are placed on a circle of cable without any terminated ends since there are no unconnected ends.Every node has exactly two Neighbours for communication purposes.All messages travel through a ring in the same direction (clockwise or counterclockwise) until it reaches its destination.
  • Each node in the ring incorporates a repeater. When a node receives a signal intended for another device, its repeater regenerates the bits and passes them along the wire.
Figure 2

 Advantages of Ring Topology

  1. Ring topology is easy to install and reconfigure.
  2. Every computer is given equal access to the ring.Hence no single computer can monopolize the network.

Disadvantages of Ring Topology

  1. Failure in any cable or node breaks the loop and can take down the entire network.
  2. Maximum ring length and number of nodes are limited.

3.Star Topology

  • In star topology, devices are not directly linked to each other, but they are connected via a centralized network component known as hub or concentrator.The hub acts as a central controller and if a node wants to send data to another node, it boosts up the message and sends the message to the intended node.This topology commonly uses twisted pair cable; however, coaxial cable or fiber optic cable can also be used.
Figure 3

Advantages of Star Topology

  1. Star topology is easy to install and wire.
  2. The network is not disrupted even if a node fails or is removed from the network.
  3. Fault detection and removal of faulty parts is easier in star topology.

Disadvantages of Star Topology

  1. It requires a longer length of cable.
  2. If the hub fails, nodes attached to it are disabled.
  3. The cost of the hub makes the network expensive as compared to bus and ring topology.

4.Tree Topology

  • A tree topology combines characteristics of linear bus and star topologies.It consists of groups of star configured workstations connected to a bus backbone cable. Not every node plugs directly to the central hub. The majority of nodes connect to a secondary hub that, in turn, is connected to the central hub. Each secondary hub in this topology functions as the originating point of a branch to which other nodes connect.
Figure 4

Advantages of Tree Topology

  1. The distance to which a signal can travel increases as the signal passes through a chain of hubs.
  2. Tree topology allows isolating and prioritizing communications from different nodes.
  3. Tree topology allows for easy expansion of an existing network,which enables organizations to configure a network to meet their needs.

Disadvantages of Tree Topology

  1. If the backbone line breaks, the entire segment goes down.
  2. It is more difficult to configure and wire than other topologies.

5.Mesh Topology

  • In a mesh topology, every node has a dedicated point-to-point link to every other node. Messages sent on a mesh network can take any of several possible paths from source to destination.
  • A fully connected mesh network has n(n-1)/2 physical links to link n devices. For example, if an organization has 5 nodes and wants to implement a mesh topology, 5(5-1)/2, that is, 10 links are required.
  • In addition, to accommodate that many links, every device on the network must have n-1 communication (input/output) ports.
Figure 5

Advantages of Mesh Topology

  1. The use of large number of links eliminates network congestion.
  2. If one link becomes unusable, it does not disable the entire system.

Disadvantages of Mesh Topology

  1. The amount of required cabling is very large.
  2. As every node is connected to the other, installation and reconfiguration is very difficult.
  3. The amount of hardware required in this type of topology can make it expensive to implement.

Conclusion

With a thorough examination of these variables and an understanding of the distinct characteristics of various network structures, you can confidently design and implement network systems that meet your company's needs and objectives. Each topology has pros and cons of its own, and the optimal choice will change according on your network's specific requirements and constraints.

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