Requirements and Constraints

FPS and battle royale players feel 50 ms; turn-based tolerates seconds. Pick transport and authority model accordingly.

Games are distributed systems with humans in the loop. Fairness means everyone sees a consistent world; responsiveness means hiding network delay with prediction and reconciliation.

In practice

Riot Games deploys regional shards (NA, EUW) with dedicated UDP servers. Among Us uses simpler authoritative state with lower tick demands. Protocol choice follows latency budget.

Key Takeaways

Sub-100 ms RTT often requires regional servers and UDP-based protocols.
Authoritative server prevents most cheating; client prediction hides latency.
Tick rate (20–128 Hz) trades CPU for smoothness.
Matchmaking groups similar skill and low ping — data problem + queue system.
Disconnect/reconnect must restore state from server snapshot.
Anti-cheat inspects impossible state transitions server-side.

latencyUDPauthoritative servermatchmakingtick rate

Back-of-the-Envelope Estimation →