The fundamental constraint.
WHAT LATENCY IS
The time for a message to travel and return.
WHY IT CANNOT BE ELIMINATED
Distance and the speed of transmission impose a floor.
WHAT IT MEANS FOR GAMEPLAY
The client's view is always behind the server's, and the server's knowledge of the client is behind too.
WHAT THAT CAUSES WITHOUT MITIGATION
Input delay, where actions respond late.
WHAT CLIENT PREDICTION DOES
Applies the player's input locally and immediately, before the server confirms.
WHY THAT IS NECESSARY
Otherwise every action feels delayed by the round trip.
WHAT RECONCILIATION DOES
Corrects the client when the server's result differs.
WHAT THE PLAYER SEES WHEN IT HAPPENS
A correction, felt as a snap or rubber-banding.
WHAT INTERPOLATION DOES
Displays other players slightly in the past, smoothly between known positions.
WHY
It avoids jitter from irregular updates.
WHAT LAG COMPENSATION DOES
Rewinds the server's view to when the client acted, judging hits accordingly.
WHAT IT PRODUCES
Being hit after appearing to reach cover, which is the correct result of two views differing.
WHAT MATTERS LOCALLY
High latency to distant servers, which makes regional hosting significant.
