In Networking there are so many topics are there. And here we will discuss about Network Topology. The Physical / Geometric structure of a network and clarifies how the device are connected each other.


Computer Network:-It is a practice of connecting multiple computing device in order to share resources, Exchange files and allow electronic Communication.


Network Topology:-

It refers to the virtual layout or arrangement of device in a network. or It is the Physical structure of a network and clarifies how the devices are connected each other through communication links.

There are 6 Main Types of Topology

  • Bus Topology
  • Ring Topology
  • Star Topology
  • Tree Topology
  • Mesh Topology
  • Hybrid Topology

1.Bus Topology

  • This Topology utilizes a common backbone in general a single cable will be used to connect all the devices on a network.
  • It is a Multipoint Topology(More than two specific device share a single link).
  • Dropline is a connection running between device and main cable.
  • If N Devices are connected to each other in a bus topology, then the number of cables required to connect them is 1.(which is known as Backbone cable) and N drop lines required.
  • It transmit the data from one end to another in a single direction.
  • No bi-directional feature is in bus topology.
  • At Each end of the bus there is a terminator(It absorb any signal. and It removes the signal from the bus also.)

Advantage:-

  • In Bus Topology installation is easy.
  • It works very efficient when there is a small network.
  • The Bus Topology uses less cabling than Mesh or Star Topology.
  • it is very cost effective as compared to other network topology i.e Mesh and star.
  • It is easy to connect or remove devices in this network without affecting any other device.

Disadvantage:-

  • If the common cable fails or break. Then the whole system will crash down. It stops all transmission.
  • In Bus Topology Security is Very Low.
  • It is a non-robust topology
  • If the network traffic is heavy, it increases collisions in the network.
  • Damage area reflects signal back in the direction of origin creating noise in both directions.

2.Ring Topology

  • In this Topology Each device will have two neighbors for communication.
  • In Ring Topology transmission is unidirectional.
  • But it can be made bidirectional by having 2 connection between each Network Node. It is called Dual Ring Topology.
  • All data travels in a ring and a failure of that ring will bring the whole network down.
  • Each Device has a dedicated point to point configuration only with two devices on either side.
  • A number of repeaters are used for ring topology with a large number of nodes. Because if someone wants to send data to last node in ring topology then the data have to pass through each and every node to reach the last node so to prevent data loss repeaters are used in the network.
Advantage:-
  • Ring Topology is cheap to install and expand.
  • The possibility of collision is minimum in Ring Topology.
  • A network server is not needed to control network connectivity between each workstation.
Disadvantage:-
  • Addition of station in between or removal of station can disturb the whole topology.
  • It is Less Secure.
  • In this Topology Troubleshooting is difficult.

3.Star Topology

  • In star Topology, all stations are directly attached to a common central device(hub) or node through a cable.
  • This hub is the central node and all other nodes are connected to the central node.
  • Hub may refer to a repeater, bridge, switch, router, or any combination of these.
  • In star Topology Each station need only one link & one I/O points to connect it to any number of stations.
  • Star Topology does not allow direct traffic between devices. The Central controller acts as an Exchange.
  • If N devices are connected to each other in a star topology, then number of cables required to connect them is N.

Advantage:-

  • It is easy to set up.
  • Star Topology is Robust in nature.
  • Robust means if one link fails that link is only affected but all other links remain active.
  • It is high-performing as no data collision can occur.
  • A star topology is less expensive than a mesh Topology.
  • In Star Topology Fault identification and Fault isolation is Easy.

Disadvantage:-

  • The cost of installation is high.
  • Performance is based on the single concentrator i.e. hub.
  • If Hub goes down, then entire system will collapsed.
  • This type of network uses most cables and extra hardware( hubs or switches) which adds to cost.

4.Tree Topology

  • It combines characteristics of linear bus and Star topologies.
  • It consist of group of star-configured workstations connected to a linear bus backbone cable.
  • It is a multi-point connection and a non-robust Topology.
  • In this, the various secondary hubs are connected to the central hub which contains the repeater.
  • In this Topology data flow from top to bottom or bottom to top.
  • Top to Bottom:-From the central hub to secondary and then to the devices
  • Bottom to top:-From Devices to the secondary hub and then to the central hub.

Advantages:-

  • It provides easy maintenance and fault identification.
  • Other nodes in a network are not affected, if one of their nodes get damaged.
  • It allows the network to get isolate and also prioritize from different computers.
  • It provides high scalability, as leaf nodes can add more nodes in the hierarchical chain.
  • In tree topology transmission from any station propagates through the medium and can be received by all other stations.

Disadvantage:-

  • If the central hub gets fails the entire system fails.
  • Due to the presence of large number of nodes, the network performance of Tree Topology becomes a bit slowly.
  • This network is very difficult  to configure as compared to the other network topologies.
  • Reconnection and fault isolation is difficult.
  • Length of a segment is limited & the limit of the segment depends on the type of cabling used.

5.Mesh Topology

  • In Mesh Topology, Each device in the network are interconnected to other device via the particular channel.
  • Every Node not only sends its own signal but also relays data from other nodes.
  • The channels by which every device are connected with each other these channels are known as links.
  • In Mesh Topology N numbers of devices are connected with each other in a mesh topology, the total number of ports that are required by each device is N-1. Let us take an Example if there are 5 devices connected to each other, hence the total number of ports required by each device is 4.
  • Formula for Total Number of ports required=N*(N-1).
  • If N numbers of devices are connected with each other in a mesh topology, then a total number of dedicated links required to connect them is N(N-1)/2.

Advantage:-

  • It is Robust. It means a failure of one device does not cause a break in the network or transmission of data.
  • It Provides Security and Privacy.
  • In Mesh Topology adding additional devices does not disrupt data transmission between other devices.
  • Uses of dedicated Link in Mesh Topology guarantees that each connection can carry its own data.
  • When Link must be shared by multiple devices we can eliminate the traffic problem.
  • In Mesh Topology Fault identification and Fault isolation is Easy.

Disadvantage:-

  • In Mesh Topology Every Device Must be connected to every other device  So Installation and Configuration are difficult.
  • Cost of Maintenance is high.
  • The chance of redundant connections is high, which adds to the high costs and potentials for reduced efficiency.

6.Hybrid Topology

  • Hybrid Topology Uses the combination of two or more different network Topologies.
  • It may be a star at its backbone and bus at its branches.(The exact configuration of network depends on the need and overall organizational Structure.) 

Advantage:-

  • It can be Modified as per requirement.
  • It is extremely flexible.
  • It is very Reliable
  • This type of Topology combines the benefits of different types of topologies in one topology.

Disadvantage:-

  • Design of a hybrid network is very complex.
  • We need to change hardware in order to connect topology with another topology.
  • Usually hybrid architectures are usually larger in scales so they requires a lot of cables in installation process.

If you loved this post and found something informative Do share with your friends.

Thanks For reading....😃