LAN Topologies & Why many Topologies

                                      LAN Topologies:

Network can be classified by shape. According to which there are three most popular topologies, which are given as follows:

1. Star
2. Ring
3. Bus

Star Topology:

In this topology, all computers are attached to a central point, which is sometimes called the “Hub”. It is important to note that these networks are not physically like stars but they are logically like stars. It means that their shape does not look like a star but their connections are just like a star. The above diagram is idealized.

Ring Topology:

In this topology of network the computers are connected to each other in closed loop. In this network first computer passes data to the second and then second passes data to third and so on. Like star topology the ring network are also logically ring and not physically.

Bus Topology:

In a bus topology all computers are attached to a single long cable and any computer can send data to any other computer. For this purpose, coordination is required to decide which computer has to use the
line at what time.

Why there are many Topologies:

Each topology has advantages and disadvantages, which are discussed below:

In Ring Network:
It is easy to coordinate access to other computers however entire network is disabled if a cable cut occurs.
In Star Network
On the other hand only once computer is affected when a cable cut occurs.
In Bus Network:
The network needs fewer wires than a star, however entire network is disabled when a cable cut occurs.

Except these there are some other topologies which are

• Tree
• Mesh 

These are hybrid topologies. which means they are build by the combination of above listed topologies.

Written By: Asad Hussain