A bus network is set up by connecting all of the nodes to a single line, and the nodes connect only to the bus. However, most bus networks later began to use a specialized central node called a "hub" to make the practice of attaching nodes easier. The major disadvantage is that any break in the cable will cause all nodes on the cable to loose connection to the network.
The easiest way to add more computers into a network is by connecting each computer in series to the next. If a message is intended for a computer is passed, each system bounces it along in sequence until it reaches the destination. By connecting the computers at each end, a ring topology can be formed.
An advantage of the ring is that the number of transmitters and receivers can be cut in half, since a message will eventually loop all of the way around. This potentially results in a doubling of travel time for data, but since it is traveling at a significant fraction of the speed of light, the loss is usually negligible. The major disadvantage is that a single workstation going down can break the entire ring in this topology.
In a mesh topology, there are at least two nodes with two or more paths between them. This is similar in some ways to a grid network, where a linear or ring topology is used to connect systems in multiple directions. In a true mesh topology (also known as full mesh) every node has a connection to every other node in the network. However, since a full mesh is expensive to implement, partial mesh is more commonly found. The main advantage of mesh topology is that alternate connections or routes exist between nodes incase one does down.
