Understanding Multiplayer / Netcode and Requirements

[Dangerzone]

I was just wondering if someone can please enlighten me as to how multiplayer or the netcode of things works (in a basic overview). 

 

Some questions:

 

1) Does the hosting server have to do the entire calculations for all the units plus AI, or does it only do the AI and each client does the calculations for it's own flight model?

 

2) If each client does the calculations for it's own flight model - does it send limited data (ie, speed, position, orientation and vector plus a few extra things such as aileron position) to the server and the server just passes this out to other clients and it just renders on the client accodingly?

 

3) If the main server handles all the AI calculations - just wondering why my CPU seems to 'go through the roof' when the server appears to have a lot of AI movement. 

 

4) Will hosting a server create a lot of outbound traffic, or is there a calculator or some formula to get an average idea of what to expect for bandwidth requirements (both quota and speed) depending on client count?

 

 

[QuiGon]

AFAIK:

 

1) The latter. All the AI is being processed on the server, while the clients calculate their own flight model.

 

2) Yes, that's how it works.

 

3) Because your CPU will still have to deal with all the network traffic and the extrapolation (calculating the movement of a network objects inbetween network updates).

 

4) Yes, hosting a server does create a lot of outbound traffic. I'm not aware of any such calculator or formula though.

Edited March 5, 2021 by QuiGon

[Dangerzone]

Sweet, thanks QuiGon. 

 

There's no indication of what sort of bandwidth requirements are needed for x player servers? How do server operators know how much bandwidth they need, or is it trial by fire for each server that's out there?

[QuiGon]

55 minutes ago, Dangerzone said:

Or is it trial by fire for each server that's out there?

 

Pretty much. The most potent servers manage about 50-60 players at most, but that also depends on the complexity of the mission and the number of AI units.

Edited March 6, 2021 by QuiGon

[Hobel]

On 3/6/2021 at 1:49 AM, QuiGon said:

 

Pretty much. The most potent servers manage about 50-60 players at most, but that also depends on the complexity of the mission and the number of AI units.

 

With a certain number of players, it goes in the direction of unplayable From 40+ it seems to start slowly and the laggs get stronger and stronger, especially fast objects are hit less and less (missiles fizzle out) Already observed on several servers, is that because of the servers or simply because of DCS itself?

[QuiGon]

24 minutes ago, Hobel said:

With a certain number of players, it goes in the direction of unplayable From 40+ it seems to start slowly and the laggs get stronger and stronger, especially fast objects are hit less and less (missiles fizzle out) Already observed on several servers, is that because of the servers or simply because of DCS itself?

 

Both. With 50+ players the DCS netcode requires so much CPU power, that pretty much any server struggles with it unless its a NASA super computer.