Star Topology

Star Topology

In the star topology, computers are connected by cable segments to centralized component, called a hub or switch. Signals are transmitted from the sending computer through the hub or switch to all computers on the network. This topology originated in the early days of computing with computers connected to a centralized mainframe computer. It is now a common topology in microcomputer networking. Each device has a dedicated point-to-point link only to a central controller, usually called a hub. The devices are not directly linked to one another. Unlike a mesh topology, a star topology does not allow direct traffic between devices. The controller acts as an exchange: If one device wants to send data to another, it sends the data to the controller, which then relays the data to the other connected device.
The star network offers centralized resources and management. However, because each computer is connected to a central point, this topology requires a great deal of cable in a large network installation. Also, if the central point fails, the entire network goes down.

Star Topology

Advantages of Star Topology

1. As compared to Bus topology it gives far much better performance, signals don’t necessarily get transmitted to all the workstations. A sent signal reaches the intended destination after passing through no more than 3-4 devices and 2-3 links. Performance of the network is dependent on the capacity of central hub.
2. Easy to connect new nodes or devices. In star topology new nodes can be added easily without affecting rest of the network. Similarly components can also be removed easily.
3. Centralized management. It helps in monitoring the network.
4. Failure of one node or link doesn’t affect the rest of network. At the same time it is easy to detect the failure and troubleshoot it.

Disadvantages of Star Topology

1. Too much dependency on central device has its own drawbacks. If it fails whole network goes down.
2. The use of hub, a router or a switch as central device increases the overall cost of the network.
3. Performance and as well number of nodes which can be added in such topology is depended on capacity of central device.