It 205 Network Topologies

Network topologies are a key consideration when developing a system. A network topology, or layout of the network, connects the computers, printers, scanners, copiers, faxes and other devices on the network. There are three common topologies that will be discussed below, along with a spin-off of two of them.

Bus Topology

The bus topology connects all of the computers and devices with one central cable or backbone. The backbone is the communication medium by which all of the computers and devices interface with one another.

Some of the advantages of the bus topology include that it is less expensive than other topologies, it is easily expandable, and implementation is fairly easy.

The biggest disadvantage of the bus topology is that if the backbone cable fails, all of the computers on the system shut down. Other disadvantages are that due to the limitations on the cable, you are limited to the number of computers the system will serve, and with each computer that is added to the network, the level of performance deteriorates.

Ring Topology

The ring topology connects each node to two other nodes which create a ring, hence the name. Data travels around the ring until it finds its final destination.

Some of the advantages of the ring topology are that it is more reliable because if one node fails, the administrator or specialized network hardware can reroute data around the failed node keeping the other nodes up and running. The ring network topology is also very orderly, it performs better with larger networks, and does not need a server to manage the connectivity between terminals.

Some of the disadvantages of the ring topology are that it is more expensive and difficult to install. It is not as efficient as other systems because data has to travel around the ring until it finds it final destination. Also, adding and removing terminals could cause disruption to the entire network, while isolating problems on the network is difficult. Finally, it is possible that one computer could bring down the entire network.

A spin-off of the ring topology is the dual ring topology. The dual ring topology uses two rings instead of one, which gives the system some redundancy. In the event that one ring fails, the second ring can keep the network up and running.

Star Topology

The star topology connects each computer or device to a hub or server using a dedicated cable for each computer or device. The computer