Star Topology

Star topology, also known as star network, is a computer network topology. It is a common network setup where the computers and other devices on the network are connected to a central or master computer, also known as the hub. The star topology, which is one of the types of network topologies, got its name because the connections of the computers resemble a star. The hub, along with the leaf nodes and the transmission lines connecting them form the topology of a star. The star network is used mostly in Ethernet and Local Area Networks (LAN). After installation the topology resembles the spokes of a bicycle wheel. The cabling segments of the topology meet at a central connection point which is known as a router or switch. Each host or computer is connected to the central device or hub with the help of cables that transmit data. An extended star topology is a star network that is expanded and an additional networking device is connected to the central or main networking device.

The active star network or topology has an active central node which prevents problems related to echoes created during transmissions. But in a passive central node, the initial or originating central node should be able to bear up the echoes created during the receptions of the transmission. There is also a delay caused due to a two way transmission. The chances of a failure in the network is reduced when all the systems are connected to the central node. This topology can also be applied to a bus network. A bus network or bus topology is a central hub which broadcasts transmissions that is received from a peripheral mode to the rest of the peripheral modes that are connected to the network, including the central node. If there is a failure in the transmission in any peripheral node to the originating node, then that peripheral is isolated without affecting the rest of the system. A node consists of workstations, peripherals and file servers that are connected directly to the network hub. The data on the star network topology is transmitted through the hub before it reaches its destination. The central hub controls all the functions and transmissions of the networks that are connected to it. The configuration of the star network is done with the help of optical fiber cable, twisted pair cable or a coaxial cable.

Advantages of Star Topology

A star network topology has many advantages. Some of the advantages of a properly functioning star topology are listed below;

• The star network is easy to install and wire.
• This topology type gives a better performance than any other network topology as there is no clogging of nodes. In order to communicate between any two devices only 2 links and 3 devices are involved to prevent confusion. The hub also has adequate capacity to handle high utilization by one device, without disrupting the functioning of the other devices.
• The working of the network topology is simple to establish, understand and navigate. Any fault in the devices connected to the central hub can be detected easily as the malfunctioned device or link is isolated, which allows easy probing into the matter.
• The faulty and defective parts of the network can be easily replaced. Till the links are replaced, the other devices continue their normal functions without any disruptions.
• Expansion of the star network is easy as the format is very simple thus aiding the growth of networking.

Disadvantages of Star Topology

One of the main disadvantages of this topology is that if the central hub has some errors, then the communication between the systems fail, as the nodes are highly dependent on the proper functioning of the central hub. There is a limit to the number of networks that can be connected to
the hub and the performance of the entire computer network is monitored by its throughput. The traffic of the network is also disrupted if the node that occupies a major portion in the processing capability of the central node is faulty. This is one of the costliest network topologies and the wiring of the system is a complex process.

The star topology is used mainly in telecommunication systems. In spite of its disadvantages, this network topology is more beneficial than any other topology.