Deterministic Lockstep
Deterministic lockstep is a networking architecture used in real-time multiplayer games and simulations to ensure consistent state across all clients by executing the same sequence of deterministic commands in lockstep. It relies on sending only user inputs (e.g., keystrokes) between clients, with each client independently simulating the game logic to produce identical outcomes, eliminating the need for frequent state synchronization. This approach is particularly effective for games where precise, frame-perfect consistency is critical, such as real-time strategy (RTS) or fighting games.
Developers should use deterministic lockstep when building multiplayer games that require high consistency and low bandwidth usage, as it minimizes network traffic by transmitting only inputs rather than full game states. It is ideal for turn-based or real-time games with deterministic physics and logic, such as StarCraft or Age of Empires, where cheating prevention and replay functionality are important. However, it requires careful implementation to handle latency and ensure all clients remain synchronized, often using techniques like input prediction or rollback netcode.