Every online game has to solve the same problem — the players are not in the same place, and information takes time to travel. How each solves it produces most of what players experience as good or bad connection.
The fundamental constraint
A signal takes time to cross a network, and that time cannot be reduced below what the physical distance permits.
Which means every player is acting on information that is already out of date, and the game must present a coherent experience anyway.
Everything else in this field is a technique for concealing that.
Client-side prediction
The first technique and the reason your own movement feels immediate.
When you press forward, the client moves your character immediately rather than waiting for the server to confirm.
It also sends the input to the server, which runs the same simulation and returns the authoritative result.
If they agree, nothing happens. If they disagree, the client corrects, which is the rubber-banding players notice on poor connections.
Entity interpolation
How other players are displayed.
Position updates arrive at intervals, and rendering them directly would produce jerky motion.
So the client holds updates briefly and interpolates between them, producing smooth movement at the cost of showing other players slightly in the past.
Which means you are always seeing opponents where they were, not where they are, and the delay is a deliberate buffer.
Lag compensation
The mechanism that produces the most argument.
When you shoot, the server rewinds the world to the state your client displayed, and evaluates the shot against that.
Which means your shot registers against where you saw the opponent, not where they are on the server.
The consequence is that the opponent, on their machine, may have already reached cover and still takes damage.
That experience is unavoidable given the design. Favouring the shooter or favouring the target are the two options, and both produce complaints from one side.
Tick rate
How frequently the server updates the world state.
Higher tick rates reduce the granularity of the simulation and increase server cost, which is why they vary between games and sometimes between game modes within a title.
Low tick rates produce the effect where actions appear to register inconsistently, since the server samples the world less often than events occur.
Tick rate is a frequent subject of player campaigns, and studios generally cite cost, which is a real constraint at scale.
Rollback
An approach used heavily in fighting games and increasingly elsewhere.
The client predicts what the opponent will do, continues simulating, and rolls back to correct when the actual input arrives.
Which allows play to feel immediate across distance in a genre where frame-level timing matters.
The visible artefact is characters snapping to corrected positions, which players broadly prefer to input delay.
Its adoption in fighting games transformed online play in the genre, and the transition took far longer than the technique's availability would suggest.
Peer-to-peer against dedicated servers
Peer-to-peer avoids server costs and makes one player's connection the reference, which produces host advantage and allows manipulation.
Dedicated servers cost money and provide consistent conditions and authoritative simulation.
Which is why competitive games use dedicated servers and why casual titles frequently do not, and it is a cost decision rather than a technical one.
What a player can control
A wired connection, which removes wireless variability that matters more than raw speed.
Selecting the nearest server region where the option exists.
And understanding that bandwidth is largely irrelevant here — games use very little, and latency and consistency are what matter.
Interest management
Deciding what information each client actually receives.
Sending every entity's state to every client is wasteful and, in competitive games, dangerous, since the data can be read.
Which is why servers calculate what each client can plausibly perceive and transmit only that, a technique variously called relevancy or area of interest filtering.
Done well it reduces bandwidth substantially and removes a whole category of cheat, and done poorly it produces enemies appearing abruptly as they enter the transmission radius.
Delta compression
Sending only what changed since the last acknowledged update rather than full state.
Which reduces bandwidth enormously and requires tracking what each client has received, since a lost packet means the baseline is wrong.
Systems handle this by acknowledging receipt and re-baselining, which is why a burst of packet loss produces a brief freeze followed by a jump rather than a gradual degradation.
Packet loss against latency
Two distinct problems producing different symptoms.
High latency produces consistent delay, which players adapt to.
Packet loss produces intermittent freezing and correction, which is considerably harder to play through because it is unpredictable.
Jitter — variation in latency — has similar effects, which is why a consistent higher-latency connection frequently plays better than an inconsistent lower-latency one.