What is Topology?

 A Topology provides a different layout to create a network. While connecting computers and other networking devices together to form a network, the user needs to consider the structure, layout and cabling requirements.

Topology is a network pattern that describes the way in which networking devices are connected.

There are mainly two types of topologies:

Physical: Refers to the actual, physical structure of the network.

Logical: Defines the passage of data through the network across devices and how signals perform on the network media.

Topologies are further classified based on their structure and functions as follows:

Bus Topologies

In the language of networking, a 'Bus' is the central cable or a single coaxial cable -- that connects all devices on a Local-Area Network (LAN). It is also called the backbone. This is often used to describe the main network connections constituting the Internet. Bus networks are fairly inexpensive and are easy to install therefore ideally suitable for small networks. Ethernet systems utilize a Bus Topology.

Advantages:

This method makes it easy to connect a computer or device to the central cable, and typically requires less cable than the Star Topology option.

Disadvantages: 

1) The entire network shuts down if there is a break in the main cable. 
2) It is difficult to identify the cause for the problem if the network shuts down.