Internet Client-Server Play

Authority sits in one place. Clients send inputs rather than outcomes, the server simulates and returns state, and each client meanwhile predicts the result of its own input so movement feels immediate; when the server disagrees, the client is corrected, which is the rubber-banding players recognise. Interpolation smooths other players' movement, and lag compensation rewinds the world briefly to judge whether a shot connected.

id Software released Quake in 1996, and the network model that made internet play workable arrived through an updated client later that year, written after the original struggled over dial-up connections. Client-side prediction was the crucial addition. Constraints were physical: latency across the public internet cannot be removed, so the engineering problem was never speed but disguising delay convincingly enough to keep matches fair.

Everything social in the medium since rests on this architecture, from persistent worlds to matchmaking to competitive leagues, and an authoritative server remains the main defence against cheating. Costs are ongoing rather than one-off, because servers must be paid for, which turned multiplayer into a service with a lifespan. Games whose servers close become unplayable in a way that cartridges never were.