Topology in Computer Network, Its advantage and disadvantage

Topology means the arrangement of the network in that way, all the constituents are interconnected to each other. In other words, the arrangement of nodes connected in a network by some physical medium such as optical fiber and cable. Network topology permits you to understand the dissimilar components of your network and the network’s connection.  

There are different types of network topologies

1. Bus topology

Bus topology defines as a network topology where each node is connected through a single physical medium like coaxial cable, RJ45, twisted pairs etc. It is also known as linear bus topology as it has two endpoints, also transmitted in one direction only. The bi-directional function is not available in the bus topology network. 

Bus topology

Advantages of bus topology

  • The cost of this topology is cheaper than other topologies
  • This topology is a familiar technology and hardware constituents are simply available.
  • The breakdown in one node will not create any problem on other nodes.
  • Convenient for small networks like LAN.
  • This topology is easy to configure and install and can be extended according to requirements. 

Disadvantages of bus topology

  • The major problem with this topology is that the entire network goes down if the cable breaks down.
  • The cable length is limited and results in a smaller number of stations.
  • Reconstruction is hellacious in case of faults.
  • Performance of network downfall as the number of nodes increases. 

2. Hierarchical topology

It is also known as tree topology. It is divided into levels, and each level is connected with the help of a medium such as coaxial cable, twisted pairs and fiber optics. The top node is referred as a root node, and all bottom nodes are the descendants of the root node. For bit transmission there is only one path lies between two nodes.

Hierarchical topology

Advantages of hierarchical topology

  • It is normally supported by almost all hardware and software.
  • This topology is in a hierarchical format, so it’s easy to add nodes as the size of the organization increases. 
  • In this topology, finding out an error is very easy. 
  • There is a point-to-point connection to efficiently receive data by all the nodes.

Disadvantages of hierarchical topology

  • Systems required for broadband transmission that are very costly. 
  • If we add new systems, it becomes very difficult to configure and install. 
  • If the root node breaks down, the whole network goes down. 
  • If nodes are increased beyond some extent, maintenance becomes difficult. 

3. Ring topology

As the name suggests, this topology is in circular form. In the ring topology, data flows in a clockwise direction and a single loop. When a node wants to connect with another node in this network, it sends data to its neighbour node in the unidirectional which passes the data to its neighbour in the same way data reaches the node for which it actually sends.

Ring topology

Advantages of ring topology

  • Transmission of data in ring topology is very fast.
  • Affordable to configure, install and expand, twisted pair cables are easily available.
  • This topology is good at handling load in comparison to bus topology.
  • Failure devices can be easily removed without bringing any breakdown of network. 

Disadvantages of ring topology

  • Communication delays will be occurred when new devices are added. 
  • It is difficult to troubleshoot the problem in the ring topology.
  • In this network, computers perform communication with each other, all computers need to be turned on.
  • Complete reliance upon the one cable. 

4. Star topology

In star topology, all nodes are connected through a common central device known as a switch. In this network, if a node wants to communicate with another node, it first sent message to the central device i.e., switch then it forwards message to the intended node. There is a point-to-point connection between node. In star topology hubs are used as connection devices. It is the most demanding topology in network implementation. 

Star topology

Advantages of star topology

  • Comparison of bus topology, troubleshooting is quite effective in a star topology.
  • This topology is quite easy to configure, install and modify.
  • Hubs and switches can be upgraded effortlessly.
  • The use of central devices makes it easy to find errors in the network. 

Disadvantages of star topology

  • Nodes will not be able to connect to other nodes when the central switch goes down.
  • There is a limitation towards the addition of nodes because it depends upon the capacities of the hubs. 
  • The use of central switches or hubs increases the cost of the network.
  • The cost of configuration and installation is expensive. 

5. Mesh topology

In mesh topology, each node is connected to each other through point-to-point connection. Every device is communicated to other device via an exceptional channel. Suppose to link ‘n’ devices, mesh topology has n(n-1)/2 physical channels. The mesh topology does not contain the central devices like switches or hubs. 

mesh topology

There are two types of mesh topology

  • Partial mesh topology- In partial mesh topology, most of the nodes are connected with full mesh topology or provide backbone support to full mesh topology but some nodes just like two or three nodes, are connected to nodes in the network.
  • Full mesh topology- It occurs when every node is interconnected. It is expensive to implement and provides benefits like if one of the nodes fails, the load switch to another node. 

In mesh topology, there are two methods through which data can be transmitted are

  • Routing: Routing occurs where nodes use routing logics to find the shortest distance to transmit data to destination.
  • Flooding: flooding does not require routing logic as much of a muchness data is transmitted to every node in the network. 

Advantages of mesh topology

  • In a mesh topology, if any link goes down will not affect the connection between connected devices. 
  • Data transmission in mesh topology is very reliable due to the point-to-point link between the nodes.
  • The benefit of an alternate path is that if one node fails, the entire network works perfectly. 
  • Mesh topology is robust in nature. 

Disadvantages of mesh topology

  • Mesh topology is very expensive due to connecting devices like routers and more transmission media.
  • This topology is very difficult to configure and install.
  • Maintenance of the network is not easy in a mesh topology.
  • Due to unnecessary connection efficiency of the network reduces in a mesh topology.

6. Hybrid topology

It is a combination of two or more various topologies together. Hybrid topology is generally used in numerous organizations which have different departments. These different departments use different topologies according to need. When these topologies from different organizations are combined together, it is referred to as hybrid topology.

Hybrid topology

Advantages of hybrid topology

  • It can be designed according to the demand of the organization because hybrid topology is very flexible. 
  • It is reliable in the sense that error detection and troubleshooting are effortless.
  • Hybrid topology is efficient as it employs multiple technologies.
  • By adding new systems, the size of the network can be easily extended.

Disadvantages of hybrid topology

  • The hybrid topology is expensive due to the composite of different topologies.
  • The installation and configuration process is complex in this topology.
  • Designing the architecture of the hybrid network is very troublesome. 
  • The hubs required for this topology are expensive to obtain and maintain.