Network Topology

Network topology means the physical layout of a LAN. It includes geometrical arrangement of computer resources, remote devices and communication facilities. Each device or computer in the network is called a node. Following topologies are most common for local area networking

There are several network topolgies which are as discussed below –

1. Star topology – In this topology host computer is the server of the network. This host can be mainframe or a smaller computer. The printer and the database are the parts of this host computer. It is located in center of the network and all other nodes are connected to it. All the messages are routed throughout the host. In case of its failure, the whole network fails.
2. Ring topology – In this arrangement, all the nodes are connected in a circle. The network has no host computer. The message travels along the ring connectivity in one direction or both the directions and reaches a particular computer to which it is addressed. In case of failure of ring connection, the entire network fails.
3. Bus topology – Bus topology does not consist of a host computer instead each node forms an independent part of the network. The mesages are transmitted from one node to another without travelling through any other unaddressed node. In this case, the network does not fail even if more or more computers fail.
4. Tree topology – It consists of several computers linked in a hierarchical manner. The messages are transmitted from the main computer to the terminal computers from where it is transmitted onwards to other nodes. In this case, if main computer fails, the whole network is rendered inoperative. However, it is easier to isolate a defective node or the entire branch from the main computer.
5. Mesh topology – It is that type of topology where all nodes cooperate to distribute data amongst each other. In this topology, each workstation has to send messages frequently to all other workstations. It has a few main sites and a large number of remote offices or sites.
6. Hybrid topology – In this topology, two or more different topologies are connected or combined in the sane network. In hybrid topology, several parts of the network may use different topologies and the design can be changed as per the requirements of network.