A bus network is a computer network architecture in which all devices on the network share the same cable connection, which is referred to as a bus. A bus network uses one cable segment on which each computer is connected, and the cable segment used has a termination at each end. Bus networks commonly use 10Base2 and 10Base5 cables. When data travels from a device, also called a node, to the cable segment, it travels to each computer on the network as it goes, checking whether each computer is the destination device.
Unlike a ring network or a star network, a bus network has issues with cable loss. The farther that data must travel down on the bus network, the higher the amount of data loss that can occur, especially if the devices on the bus network are far apart from each other. As a result, devices on a bus network have to be placed at a distance in which data loss should not be a problem and do not allow scattered workstations such as what is possible on a star, ring or mesh network.
Although other network architectures allow multiple devices to send data, bus networks are limited in that only one computer can send data at a time. If two devices try to send data at the same time, a data collision can occur. If this happens, both computers will wait a random amount of time and try to send the data again.
Bus networks also rely much on the single cable segment to keep the network up and running. Any kind of break in the cable will affect all attached systems and take down the entire network, because a single segment is used to connect all of the computers. If one needs to add or remove a computer from the network, there also will be disruption in the network while the computer is being added or removed. If a problem does occur, network technicians might find it difficult to find out exactly what went wrong.
Many companies find bus networks appealing, however, and bus networks are an easy and less expensive way to implement a network. Bus networks require no special equipment, use less cable than other technologies and are useful for smaller networks. On the other hand, companies who plan to use several devices on a network might prefer the expandability offered by a star network, regardless of the additional cable and setup time required.