Types of Network Topology

 

In this article we will cover the types of networks topology  , how network equipment/computers get connected, bus, star, hub, hybrid, mesh, tree topologies and network physical design. In Computer Networking the term “topology” means the layout or design/setup of the connected devices. Network Topologies can be physical or logical. We will talk about the different types of the topologies in more details.

 

 Physical Topology means the physical design of a network including the devices, location and cable installation.

Logical Topology are actually how data transfers in a network as opposed to its design and setup

Topology can be treated as a virtual diagram or structure of a network. This shape actually does not correspond to the real physical design of the devices on the network. The computers on the home network can be arranged in a circle shape but this does not necessarily mean that it presents a ring

Network topologies can be classified in the following categories.

• Bus

• Star

• Ring

• Mesh

• Tree.

Hybrid networks are the complicated networks, which can be built of two or more above mentioned topologies.

Bus Topology

Bus topology depends on a common backbone connecting all the network devices in a network in a linear and straight shape. A single cable connection acts as the shared communication medium for all the network equipment attached with this cable with an interface connector. The device, which needs to communicate send the broadcast message to all the devices attached with the shared cable but only the intended recipient actually accepts and process the message.

Ethernet bus topologies are easy to build and don’t need much cabling/connections and only a main shared cable is used for network communication. 10Base-2 and 10BaseT are two common types of the Ethernet cables being used in the Bus topology. Also, Bus network function with very limited devices. Performance problems are expected to occur in the Bus topology if more than 12-15 computers are added in a Bus Network. In addition to that, if the Backbone cable fails then all network becomes useless and no communication work among all the computers. Unlike in the Star topology in which if one computer is disconnected from a network then there is not effect on the other computers in the network.

Ring Topology

It is one of the Types of network topology, In ring Network, each computer or network devices has two adjacent neighbors for communication. In a ring network, all the communication messages pass in the same direction whether clockwise or anti clockwise. Any failure of the 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 are used to implement and build Ring Technology. Ring topologies can be found in offices, schools or small buildings.

Star Topology

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

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

On the other hand if the central connecting devices such as switch or router fails due to any reason, then ultimately all the network can come down or collapse.

Tree Topology

Tree topologies are composed of the multiple star topologies on a bus. Tree topologies integrate multiple star topologies together onto a bus. Only the hub devices able to 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 expansion of the computer networks, much better than a bus or star.

Mesh Topology

Mesh topology depends on the concept of routes. In Mesh topology, message when sent to the destination can take any possible shortest, easiest route to reach its destination. In the mentioned topologies star and bus, messages are usually broadcasted and reached to every computer, especially in bus topology. Similar as the Ring topology, message can travel in only one direction i.e clockwise or anticlockwise. Internet depends on the Mesh topology and the message finds its route for its destination. Router works in to find the routes for the messages and in reaching them to their destinations depending on the learned routes through the routing protocols. The topology in which every network device is connected to every other device directly is called a full Mesh topology unlike in the partial mesh in which every device is indirectly connected to the other devices.

 Below some advantages and disadvantages for each type:

Summary

Topologies are the important aspect of the network design theory and architecture. A better network design in terms of redundancy and fast convergence can be built if you have the deep knowledge of these types of network topologies and if you know the difference between each topology. Similarly you should have the knowledge and functionality of each network device so that you can properly use them according to your network needs. A misconfigured network can result in a waste of time and efforts as well as a lots of troubleshooting methods to solve the issue. So the basic understanding of the network topologies and network devices is required to build a good network.