Keeping players consistent.
WHAT MUST BE SYNCHRONISED
Positions and orientations Actions and events Health and resources World state changes
WHAT TO NOT SYNCHRONISE
Anything derivable locally Purely visual effects Anything only one client needs
WHY
Bandwidth is limited, and every byte multiplies by player count.
WHAT SNAPSHOT SYNCHRONISATION IS
Sending the relevant world state periodically.
WHAT DELTA COMPRESSION DOES
Sending only what changed since the last acknowledged state.
WHAT RELEVANCE FILTERING DOES
Sending each client only what affects them.
WHY THAT MATTERS MOST AT SCALE
It bounds bandwidth regardless of total player count.
WHAT IT ALSO PREVENTS
Clients receiving information they could use to cheat.
WHAT UPDATE RATE AFFECTS
Smoothness and bandwidth, in tension.
WHAT TO SEND RELIABLY
Events that must not be lost: deaths, purchases, state changes.
WHAT TO SEND UNRELIABLY
Positions, since a newer one supersedes a lost one.
WHY THAT DISTINCTION MATTERS
Reliable delivery costs retransmission and delay.
WHAT TO MEASURE
Bandwidth per player, at the maximum player count.
