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.
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.
This mode automatically switches between predictive and lockstep mode, depending on the player's latency. The threshold ping is around 150 milliseconds.
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.
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 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.
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.
- 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. Leap SlamLeap SlamAttack, AoE, Movement, Melee
Mana Cost: 15
Cast Time: 1.40 secRequires Level 10Jump into the air, damaging enemies (and knocking back some) with your main hand where you land. Enemies you would land on are pushed out of the way. Requires an axe, mace, sword or staff. Cannot be supported by Multistrike.Per 1% Quality:
0.5% chance to Knock Enemies Back on hitDeals (100-122.8)% of Base Damage
20% chance to Knock Enemies Back on hitPlace into an item socket of the right colour to gain this skill. Right click to remove from a socket.) since the targeted location is not legal, or even cause your character to move forwards in order to establish line of sight (BarrageBarrageAttack, Bow
Mana Cost: (7 to 11)
Cast Time: 1.00 sec
Damage Effectiveness: (50% to 61%)Requires Level 12After a short preparation time, you attack repeatedly with a ranged weapon. These attacks have a small randomised spread. Only works with Bows and Wands.Per 1% Quality:
0.5% increased Projectile DamageDeals (50-61.4)% of Base Damage
3 additional ProjectilesPlace into an item socket of the right colour to gain this skill. Right click to remove from a socket. being one of the most severe examples).
- 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 Quartz FlaskQuartz FlaskLasts 4.00 Seconds
Consumes 30 of 60 Charges on use
10% chance to Dodge Attacks
10% chance to Dodge Spell DamageRequires Level 27Right click to drink. Can only hold charges while in belt. Refills as you kill monsters. 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. Multistrike SupportMultistrike SupportAttack, Melee, Support
Mana Multiplier: 180%Requires Level 38Supports melee attack skills, making them repeat twice when used, targeting a random enemy each time. Cannot support Vaal skills, totem skills, channelling skills, or triggered skills.Per 1% Quality:
Supported Skills deal 0.5% increased Melee Physical DamageSupported Skills Repeat 2 additional times
Supported Skills have (75-94)% more Melee Attack Speed
Supported Skills deal 30% less Attack DamageThis is a Support Gem. It does not grant a bonus to your character, but to skills in sockets connected to it. Place into an item socket connected to a socket containing the Active Skill Gem you wish to augment. Right click to remove from a socket.'s automatic targeting can help ensure you are actually attacking enemies.
- Negativefrags (April 10, 2015). "Re-write of netcode with A4 to reduce dsync?!". Reddit. Retrieved July 5, 2017.
- Chris_GGG (Apr 15, 2014). "Client-server Action Synchronisation". Path of Exile Forums. Retrieved July 5, 2017.
- Jess_GGG (Jul 24, 2013). "Autohotkey". Path of Exile Forums. Retrieved July 5, 2017.