Star Topology

Each computer on a network communicates with a central hub that re-sends the message either to all the computers (in a broadcast star network) or only to the destination computer (in a switched star network). The hub in a broadcast star network can be active or passive.

            An active hub regenerate the electrical signal and sends it to all the computers connected to it. This type of hub is often called a multiport repeater. Active hub and switches require electrical power to run. A passive hub merely acts as a connector point and does not amplify or regenerate the signals. Passive hubs do not require electrical power to run.

            You can use several types of cable to implement a star network. Hybrid hub can accommodate several types of cable in the same star network. You can expand a star network by placing another star hub where a computer might otherwise go, allowing several more computers or hubs to be connected to that hub. This created a hybrid star network.

Advantages of Star Topology

1.      It is much easier to modify or add new computers to a star network without disturbing the rest of the network. You simply run a new line from the computer to the central location and plug it into the hub. When the capacity of the central hub is exceeded, you can replace it with one that has a larger number of posts to plug lines into it.

2.      The center of a star network is a good place to diagnose network faults. Intelligent hub (hub with microprocessors that implement features in addition to repeating network signals) also provide for centralized monitoring and management of the network.

3.      Single computer failures do not necessarily bring down the whole star network. The hub can detect a network fault and isolate the offending computer or network cable and allow the rest of the network to continue its operation.

4.      You can use several cable types in the same network with a hub that can accommodate multiple cable types.

Disadvantages of Star Topology

1.      If the central hub is fails, the whole network fails to operate.

2.      Many star networks require a device at the central point to rebroadcast or switch the network traffic.

3.      It costs more to cable a star network because all networks cables must be pulled to one central point, requiring more cable length than other networking topologies.