The concept of Massively Multiplayer Games (MMG) recently has spread into all classical genres of real-time computer games. This paper summarizes our work on a novel proxy server-network topology which provides the required scalability to enable massive multiplayer gaming in the genres of First Person Shooter (FPS) and Real-Time Strategy (RTS) games. Besides scalability, i.e., the ability to maintain the game service with an increasing number of participating players, our topology provides a high degree of responsiveness which is necessary to support the fast-paced game play of contemporary game designs. This paper compares our proxy servernetwork to network topologies commonly used in FPS and RTS games. We present the results of an analytical scalability model which allows to forecast maximum player numbers for a given game and discuss experimental results.