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In astar topology all nodes indirectly connect to each other through one or more switches or hubs. A hub broadcasts a message across the whole network, whereas a switch sends the message to the intended recipient only. The switch or hub acts as a central point through which all communications are passed. Star topologies are used in many networks, large and small.

Large networks using a star topology are usually controlled by one or more servers. Hence, the client-server model usually uses a star topology. However, peer-to-peer networks can also have a star topology. Even though no single computer controls the network, all communications still pass through the central switch.

Advantages and disadvantages of using a star topology

The advantages of a star topology are:

• Each node is separately connected. Therefore, the failure of one node or its link, also known as transmission media, does not affect any other nodes.
• New nodes can be added to the network simply by connecting them to the switch.
• Star networks tend to have higher performance, since a message is passed on only to its intended recipient.

The disadvantages of a star topology are:

• the whole network fails if the switch fails, since no node can communicate
• a wired star topology requires a lot of cable - in a large network this can be expensive

Star topologies in use

Star topologies tend to be found in large organisations, such as educational establishments and businesses, where high performance is a must.

They are also found in home networks, especially those that are wireless. In this case, a router with a wireless access point (WAP) provides the central connection for all nodes.