functions are done by the equipment at each location. It is a distributed architecture.

A collapsed backbone (also known as inverted backbone or backbone-in-a-box) is a type of backbone network architecture. In the case of a collapsed backbone, each location features a link back to a central location to be connected to the collapsed backbone. The collapsed backbone can be a cluster or a single switch or router. The topology and architecture of a collapsed backbone is a star or a rooted tree.