Hub & Spoke is a topology that refers to the use of a central point to coordinate activities between the participants. Conceptually, the hub & spoke refers to a wheel (like a bicycle wheel) where no two spokes are directly connected to each other, rather they are all connected (centrally) to a single hub.

In an SOA, the hub & spoke refers to the, service topology (not the physical or logical network).

See: Point-to-Point