What Is a Network Topology?
Understanding computer network topologies
“Network topology”, you may wonder what this means. Basically, a network topology means a kind of arrangement of the elements of a communication network. In other words, network topology refers to the geometric shape that a network takes when it is laid physically. When it comes to networks there are many ways a network can be arranged. For example, think of a network as your hometown. Then the topology means the road map of your hometown. We know when it comes to a city there are many ways to maintain a city. Just like that, there are many ways to arrange a network. In this article, I am going to discuss the main types of network topologies.
- Bus Topology
- Star Topology
- Ring Topology
- Mesh Topology
Bus Topology
In the bus topology, all the devices are connected to the main cable which is running in a single direction from one end of the network to the other. The devices are connected to this main cable through drop lines. Sometimes this is also called line topology or backbone topology. There are some advantages of this topology. One advantage is that this one is easy to install and this is a cost-effective choice for smaller networks. All needed to connect devices to this network is just a single coaxial cable or RJ45 cable. Therefore the cables used in this topology are less than the others. But on the other hand, this topology has some disadvantages also. One of the main disadvantages is that since all data is transmitted over the main cable there is somewhat vulnerable. If the main cable face any issue then the whole network goes down. Another disadvantage is that it is difficult to detect the faults in this topology. However, this bus topology is suitable for small networks.
Star Topology
When it comes to Star topology the main feature is that every device in the network is connected to a single place called a hub. So it is easy to manage the network from a single location. Not like in Bus topology if one goes down the others will not be affected by it. Another feature of this topology is that this doesn't allow direct communication between devices. Each device has to communicate through the hub. Apart from that in this topology devices can be added, removed, and modified without taking the entire network offline. So just like the Bus topology this star topology also has some advantages. One thing is that this topology costs less because each device only needs one I/O port and needs to be connected with a hub with one link. Moreover, this topology is much easier to install as fewer cables are required when compared with other network topologies. When it comes to disadvantages the main disadvantage is that if the hub goes down all other devices can not function without the hub. Another thing is that this hub requires more resources and regular maintenance.
Ring Topology
In the ring topology, the devices are connected with the ones on either side. This structure forms a ring pattern. Therefore this is called ring topology. In the ring topology, only one station on the network is permitted to send data and this helps to reduce the risk of packet collisions. Let’s assume that a device wants to send data to another device in the network. In that case, it sends data in one direction. Every device in this topology has a repeater. What this repeater does is when one device sends data to the device which received data check whether it is intended to send to another device. If so the devices forward the data until the correct device receives the data. Just like in the previous topologies even this topology has both advantages and disadvantages. One advantage is that this topology is easy to install. Even managing is much easier because from the topology only two links are required to be changed when adding or removing a device. A disadvantage of this topology is that if any link fails to perform then the entire network will fail because the signals can not be forwarded because of just one failure. Another issue in this topology is the data traffic issue because all the data is circulating in a ring.
Mesh Topology
In the mesh topology, all the devices are interconnected with each other. These devices are connected through a dedicated point-to-point link. These mesh networks can be either full or partial. In these mesh topologies, there are two main methods of data transmission. They are routing and flooding. Let us say we have n number of devices in the network. Then these each device should be connected with n-1 number of devices in the network. We can calculate the number of links within a mesh topology by n(n-1)/2. Even this topology has some advantages as well as disadvantages. One of the advantages of this topology is that there are no data traffic issues because there is a dedicated link between the two devices. Moreover, this topology is reliable and most importantly failure of one link does not affect the other links and the communication between other devices on the network. Not only that it is much easy to detect the faults in this topology. One of the disadvantages of this topology is that amount of wires required to build this network is huge and as each device needs to connect device number of I/O ports required should be also huge.
So I think now you got some basic idea about network topologies from this article. Stay tuned for many more interesting articles.
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