Network Topologies

A network topology is referring to the way the computers of a network are connected. Topologies are designed for specific tasks. The type of topology used is based on how many and what type of equipment is to be used. The type of applications that will be used and the rate of the transfer of data will need to be known as well. Response time requirements and the cost are also considerations when the choice of the topology is being decided. There are three general network topologies that this paper is going to describe, they are: bus, ring, and star.

The bus topology is basically a cable that carries the transmitted message. Each workstation (computer, printer, or server) that is connected by the bus topology cable has an address. When a message is sent, it is sent with a destination workstation address. The message stops at each workstation and checks the workstation’s address, if the address is not the one it is looking for it will move to the next workstation until it finds the workstation with the correct address. This is the reason it is called “bus”. The bus topology is like a bus route and the message is the bus following the bus route, the message will travel through the entire route to the last workstation to find which workstation it needs to go to. The bus topology is normally a point to point wiring and workstations are connected to the same cable. The advantages of the bus topology are the low cost and the ease in which to add new devices. A disadvantage of the bus topology is that one computer could bring the entire network down.

The ring topology uses multi access units (MAU). A token, a short message, is passed from one workstation or device to another. When a device wants to send or transmit it attaches the data packet to the token, the token continues around to each device until it reaches the receiving device. The receiving device takes the data packet from the token and replaces it with an acknowledgement receipt. The token takes the receipt back to the device that originally sent the message, which receives the receipt from the token. The token continues on to the next device waiting for another data packet.