A star topology has one central node with all of the other nodes connected to it. The central node would typically be a hub or a switch that could transfer data between nodes.

If a hub is in the central node then it will broadcast the data to all nodes connected to it. If a switch is in the central node then it will transfer the data to the required location.

Advantages

Disadvantages

• A damaged link only affects the attached node
• You can easily add new nodes
• It works well under heavy load — especially when using a switch for the central node

• The central node is a single point of failure
• It requires many more cables than bus and ring, which is expensive

With a bus topology, each node is connected to a single cable. When data is sent from one node to another it is sent in both directions. Terminators are placed at the end of the cable to stop the signal being reflected back down the cable. The data is sent to all nodes connected to the bus. It is only accepted by the node that requires it.

Advantages

Disadvantages

• A bus network is cheap because it uses minimal cables
• A bus network is simpler to set up than other arrangements
• It works well for very small networks

• If the main cable fails then the whole network fails
• It isn’t very secure because data is sent to all nodes on the network
• As more nodes are connected, the network performance reduces

In this arrangement, each node is connected in a ring. When data is transferred it moves around the ring in one direction.

The data will continue to move around the ring until it reaches its destination.

Advantages

Disadvantages

• It performs better than the bus topology when under heavy load
• Additional nodes have a minimal impact on the network performance
• There is less chance for data collision because the data moves in one direction, this makes data transmission quite fast

• There is a single point of failure — if there is a break in the loop then data cannot be transferred
• It isn’t very secure because all nodes can potentially see all of the data
• The whole network is as slow as the slowest link between any two nodes
• To add a new node, the whole network needs to be shutdown 

In this arrangement, there are multiple ways for data to transfer from one node to another. Each node is connected to at least one other node. It is more common for them to be connected to more than one node.

In a mesh network the most efficient route is typically calculated before transferring the required data.

Advantages

Disadvantages

• There is no central node, so there is no single point of failure
• The data uses the most direct route, making data transfer faster
• It works well under heavy load
• If a node breaks then a new route can be found for the data
• New nodes can be added without shutting down the network

• The increased cabling required for a wired network makes it expensive
• A wired mesh is far more complicated to manage and maintain than the other topologies