Most Common Network Topologies in 3 Minutes

A topology is the layout of the network. It defines how the devices will connect to the network and between each other. There are 4 main common network topologies and they are bus, mesh, ring, and star. We will dive into each one of them in a little bit of detail.

Bus Topology

In a bus topology, you have a central cable(bus), and all the devices of the network are connected to the bus with dropped cables. When a device sends a message to another device, it sends it to the network in a frame, and all the other devices receive the frame but do not accept it. As an analogy, imagine a teacher asking a question to a certain student in the class. All the other students hear the question. Yet, no one answers except that student.

Although it is easy to install and not expensive, it comes with 3 main disadvantages.

1. When a device sends a message along the bus, no other devices can send or receive messages simultaneously. If multiple devices attempt to communicate at the same time, a data collision occurs.
2. It is also not secure, since any message being sent is received by all other devices, it means that any other device can read any message.
3. The entire network is only the central cable (the bus). If this cable gets damaged, the entire network goes down. This leads to very low fault tolerance.

Ring Topology

The ring topology connects all the devices of the network using each other. When you send a message, it goes through all the devices between the source and destination. It is also easy to install, and slightly prevents the data collision problem since the data goes in one way. Yet, it is difficult to add a device (reconfigure)to it. It also has a low fault tolerance and slow transmission.

Mesh Topology

The mesh topology solves the problems of the bus and the ring topology. It connects every device to all other devices. It simply makes a complete graph. This causes it to have low fault tolerance, high privacy, and high security. Yet, it is so expensive to implement and hard to reconfigure. It is also so complex, and hard to manage or troubleshoot. For example, to connect 10 devices, you need 45 cables for such a small network. The mesh topology is mostly used to connect the routers, not the devices.

Star Topology

Star Topology is the most appropriate and commonly used topology today. It simply connects all the devices to a central device, and this central device is responsible for data transfer.

It is inexpensive and scalable and has a high fault tolerance unless this fault is in the central device. We can solve this problem using a standby device. That’s why it is mostly used.