A networking methodology in which the backbone and switching components are combined into a single device. In a traditional network, local area networks (LANs) are multipoint connections connected using a backbone cable. For example, in a building, a fiber-optic backbone might run from floor to floor and connect with a hub in a wiring closet on each floor. In contrast, collapsed backbones make use of centralized switches, which provide virtual point-to-point connections for LAN connections; these switches are located in one place.
Centralizing the routing in one place, maintenance and troubleshooting is reduced.
Therefore, instead of having a hub for each floor located in that floor’s wiring closet, a set of stackable Ethernet switches would be located in the wiring closet of a single floor, with individual cables running from this closet to stations in work areas on every floor.
The advantages of using a collapsed backbone are that they eliminate the costs of backbone cabling installation, they require fewer devices, their equipment administration is more centralized, and they offer higher available bandwidth for each station.
The disadvantages are that collapsed backbones generally are not feasible for use in more than one building, they require more cabling, they use more expensive devices, and they have a more limited distance capability.