When a network is initially designed, a topology is selected and the task of developing the parts of the network begins. There are two parts of every network and they are backbones and segments.
Each part of a network is used to achieve communications. The difference between the parts of a network lies in the network clients they serve.
Backbones act as the spine or the main communication highway for the network. In a typical network installation, there is one backbone. Because the backbone is the main communication highway for the network, the bandwidth provided is typically higher than what is found on the network segments. The backbone supports multiple segments and network devices. The network devices you should connect to the backbone include routers, servers, hubs, and MAUs. You want to connect devices directly to the backbone, so network devices on a segment do not have to cross multiple segments to communicate.
Network segments connect devices in a common location to the backbone. Segments can be thought of as islands while the backbone is the bridge to the network mainland. Typically, network segments contain network devices such as workstations, printers and other local peripherals.