Ethernet bus topologies are easy to install and don’t require much cabling and only a main shared cable is used for network communications. 10Base-2 and 10BaseT are two popular types of Ethernet cables used in the Bus topology. Also, Bus network works with very limited devices. Performance issues are likely to occur in the Bus topology if more than 12-15 computers are added in a Bus Network. Additionally, if the Backbone cable fails, then the entire network becomes useless and communication fails among all the computers. Unlike in the Star topology, if one computer is detached from a network there is no effect on the other computers in the network.

Ring Topology

In a ring Network, every computer or devices has two adjacent neighbors for communication. In a ring network, all the communication messages travel in the same directory whether clockwise or anti clockwise. Any damage of the cable of any cable or device can result in the breakdown of the whole network. Ring topology now has become almost obsolete.
FDDI, SONET or Token Ring Technology can be used to implement Ring Technology. Ring topologies can be found in offices, schools or small buildings.

Star Topology

In the computer networking world the most commonly used topology in LAN is the star topology. Star topologies can be implemented in home, offices or even in a building. All the computers in the star topologies are connected to central devices like hub's, switch's or router's. The functionality of all these devices is different. Computers in a network are usually connected with the hub, switch or router with the Unshielded Twisted Pair (UTP) or Shielded Twisted Pair Cables.

As compared to the bus topology, a star network requires more devices & cables to complete a network. The failure of a node or cable in a star network, won’t take down the entire network as compared to the Bus topology.

However, if the central connecting devices such as the hub, switch or router fails due to any reason, then ultimately the entire network can come down or collapse.

Tree Topology

Tree topologies are comprised of multiple star topologies on a bus. Tree topologies integrate multiple star topologies together onto a bus. Only the hub devices can connect directly with the tree bus and each Hub functions as a root of a tree of the network devices. This bus/star/hybrid combination supports future expandability of the computer networks, much better than a bus or star.

Mesh Topology

Mesh topology works on the concept of routes. In Mesh topology, messages sent to the destination can take any possible shortest, easiest route to reach its destination. In the previous topologies star and bus, messages are usually broadcast to every computer, especially in bus topologies. Similarly in the Ring topology, messages can travel in only one direction i.e. clockwise or counter clockwise. Internet employs the Mesh topology and the message finds its route for its destination. The Router works to find the routes for the messages and in getting them to their destinations.The topology in which every device connects to every other device is called a full Mesh topology. With partial mesh, every device is indirectly connected to the other devices.

Summary

Topologies are the important part of the network design theory. A better network can be built if you have the knowledge of these topologies and if you know the difference between each topology. Similarly, you should have knowledge of each network device so that you can properly use them according to your network needs. A mis-configured network can result in a waste of time and energy as well as lots of troubleshooting to resolve any issues that may occur. Basic understanding of the network topologies and network devices is a must - to build a good reliable network.