A network topology defines the way that multiple computers in a network are connected together. Some topologies are protocol specific while others are protocol-agnostic. There are three main types of network topologies.

Bus Topology

   The bus topology is one of the oldest forms of network topologies in existence. Each computer is connected in a single line with a backbone cable. Usually the line is terminated at the end. This network suffers reliability problems because if the backbone cable fails at only one point, the network is split in pieces.

Ring Topology

    The ring topology used to be used in many types of networks such as token-ring and ARCnet networks. These networks have fallen behind as a leader in network design in recent times. Each computer is hooked to the next computer in the ring. These networks cannot be expanded to too large a size because each packet must go through a majority of the network to get where it needs to go. If the backbone cable connecting even ONE of the computers in the ring is broken, the network is broken.

Star Topology

    A star topology is used for Ethernet connections mostly. A star topology consists of having hubs or switches that send data to all the computers connected to them. These hubs are connected to each other to foster inter-hub communication.

Combining Topologies

    These topologies can be mixed together. For example, if you had hubs that connected computers of a bus topology, you would have created a star-bus topology. Mixing topologies is a rare occurrence but possible.