The suboptimal decentralized control scheme is presented for continuous and discrete-time dynamical large-scale systems. The requirements on performance quality are specified with respect to physical properties of the controlled process. The decentralized control scheme is proposed for two boundary structures of the subsystems interconnections. In the first case the interactions among subsystems can be disconnected and reconnected arbitrarily. In the second case subsystems cannot be disconnected and reconnected due to the physical nature of the controlled process.