Networking mode



Path of Exile and other online games uses various networking modes to make sure that the player and server stays as synchronized as possible even though the distance between the player and server may be large.

Modes
In Path of Exile there are three networking modes, that each use a different way to keep the game client and server synchronized. Players can choose which one to use in the main menu game settings.

Auto
This mode automatically switches between predictive and lockstep mode, depending on the player's latency. The threshold ping is around 150 milliseconds.

Deterministic lockstep
The deterministic lockstep mode perfectly synchronizes the client with the server, and will stop potential unfair deaths caused by desync. Bear in mind that this mode may cause stuttering, depending on the player's latency, like in strategy games such as Starcraft and MOBAs like Dota 2.

When the player performs an action, it is sent to the server for confirmation before it is shown to the player. In this mode everything will stay completely in sync, including all monsters. There is a delay equal to the player's latency to the server. If they suffer from an internet lag spike, everything stops moving until the player receive more data. This mode is recommended for players with low latency to the server.

Client predictive
In predictive mode, actions appear to occur immediately but can get out of sync under some circumstances. While things appear to happen immediately, the actual actions are still delayed by the player's latency behind the scenes. This mode may cause desync, but is probably the best choice for player with more than 100ms of latency to the server.

Desync
Desync is a situation where the game client on a player's computer and the PoE server is out of sync with each other, specifically with the position of players and monsters. This is because information does not travel instantly from the client to the server over the internet. To not allow cheating the server's decisions take precedence over the client. This means a heavily desynced player may actually be standing next to monsters when they appear to be safe from the player's point of view. This is different from network lag (high latency), and desynced clients can still have low ping.

Symptoms
The following are possible symptoms of desync:


 * "Rubberbanding": When the game resyncs players may be "teleported" back to their actual position. Depending on how severely they were desynced, this may be up to several rooms away.
 * A monster standing still, neither attacking nor taking damage. This means the monster is actually in a different position.
 * Area of effect skills may appear to affect monster outside the area of effect. This means the monster is actually inside the area of effect on the server.
 * Items always drop from the actual position of the monster, which may be far from the apparent position.
 * Taking damage from invisible effects. Generally damage is much better synced than positions or visual effects.

Causes

 * Stunning. If your client does not realize you were stunned, following actions, especially movement, may not actually take place on the server.
 * Line of sight. If you use a skill that requires line of sight, you may have line of sight on the client but not on the server. This may cause a skill to fail to execute (e.g. ) since the targeted location is not legal, or even cause your character to move forwards in order to establish line of sight ( being one of the most severe examples).

Mitigation

 * Switching to lockstep mode, granted you have a low enough latency to the server (lower than 100 ms).
 * The chat console command /oos will manually synchronize you with the server. Some players bind this command to a macro using software like autohotkey. Using a macro that sends /oos for you when you press one button (with AHK or some other tool) is legal and not against GGG's rules. /oos has a cooldown of 10 seconds.
 * Attacking from place (default Shift) will prevent you from moving due to desync. This is especially useful for ranged skills.
 * Try not to use movement skills near corners or doorways, as you may not have line of sight on the server.
 * Avoid running through enemy packs or tight openings.
 * The allows you to pass through enemies, which can prevent rubberbanding caused by your path being blocked by enemies on the server.
 * For melee characters, a long weapon range, notably from Master of the Arena, will help ensure that enemies you are trying to attack are actually in range. 's automatic targeting can help ensure you are actually attacking enemies.

Version history

 * Lockstep was introduced to the game.
 * }