The metropolitan area is a large population center consisting of one large metropolis and the surrounding area, or several neighboring central cities and the surrounding area. One or more big cities can act as a hub, and metropolitan areas are usually named according to the biggest or most important central city in them. An example is the Jabodetabek Metropolitan Area, where Jakarta is the core city and "Bodetabek" as the surrounding buffer zones have interdependent relations. Metropolitan is an urban system which means a collection of cities interacting and working together to achieve certain goals in a complex environment.