In a star backbone, sometimes called a collapsed or switched backbone, the topology of the backbone is a star. In this configuration, the backbone is just one switch that connects the LANs.
The following figure shows a star backbone. In this configuration, the switch does the job of the backbone and at the same time connects the LANs.
Star backbones are mostly used as a distribution backbone inside a building. In a multi floor building, we usually find one LAN that serves each particular floor. A star backbone connects these LANs. The backbone network, which is just a switch, can be installed in the basement or the first floor, and separate cables can run from the switch to each LAN. If the individual LANs have a physical star topology, either the hubs (or switches) can be installed in a closet on the corresponding floor, or all can be installed close to the switch.
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