5 ms·

If a normal game sends 2mbps, then 20mbps would be 10 times as many objects.

frollogaston 3mo ago
That's what I'm asking, seems like this isn't a normal game, but what specifically about it makes the bandwidth requirement so high? I know RTSes send inputs instead of state, but that has its own drawbacks.
- gafferongames 3mo ago
  The space game has 1000 players. Most FPS games today have a maximum of 100 players. Let's assume these FPS games send 1mbps - 2mbps per-client (many send less, some send more) but it's a good range to start with. Now increase the player count from 100 to 1000. The number of objects that needs to be sent from server to client also 10Xs, because you need to send state for each player visible to each client, so that client can actually see the other players moving around. The end result is bandwidth is now approximately 10X what it was before, or 10-20mbps. To address your question around RTS and inputs. Game developers usually end up using state synchronization methods (sending the positions, rotations etc per-object) instead of relying on input based deterministic methods whatever player counts are high. My personal threshold is around 4 players. This is the reason FPS games and other higher player count games usually send state instead of just inputs. Because if they were to rely on a deterministic simulation synchronized only by inputs like an RTS, the server would have to wait for input from the the most lagged player before it could step the server simulation forward, and with regular internet jitter, packet loss and so on, as the player count increases it becomes more and more likely that the game will hitch and stutter waiting for these inputs. So the answer is, bandwidth sent per-client scales with the number of players in the game, and games with higher player counts tend to send state instead of just inputs for the reasons above. cheers
  - Hikikomori 3mo ago
    I don't think anyone disagrees that linearly scaling of traffic scales linearly. What they're getting at, why would you still use that rather implementing something more efficient? Like Battlefield games (bf4?) did, using different update rates for nearby and distant players. Would also argue that RTS inputs are different from fps as in general you give commands to units, like go here in move/attack mode, and they do it for you. In fps your inputs control a character directly. So they can use different methods of conveying progress of state. And an fps game can use both methods, like doing deterministic physics for objects. Also don't need to wait for inputs just because its deterministic simulation?
    - gafferongames 3mo ago
      > I don't think anyone disagrees that linearly scaling of traffic scales linearly. What they're getting at, why would you still use that rather implementing something more efficient? Like Battlefield games (bf4?) did, using different update rates for nearby and distant players. I guess my confusion/frustration comes from this sort of default, "wow, that's a lot of bandwidth, umm I guess somewhere he must be doing something really inefficient" train of thought that I see so many commenters are going through in this thread. What if it wasn't inefficient. What if what I'm describing is actually using the 10-20mbps and packing in an appropriate amount of game that justifies that amount of bandwidth on top of already doing all the smart compression techniques? Think of it like this, what if you did all the compression and bandwidth optimization techniques available, and instead of targeting 1-2mbps, you just used the additional bandwidth to fit in more game? More players. Greater object density. A bigger world. More networked objects. Higher tick rate. There are any number of dimensions you can expand along. Nobody is suggesting "LOL, bandwidth is free now, make the same game, but be lazy and have it take up 10-20mbps! hahah". The industry doesn't take kindly to the same things over and over, players want novelty. So give it to them!
      - Hikikomori 3mo ago
        Then its fine, but its not what was described, and I guess that is what people had issues with as just scaling player numbers without optimization wouldn't work great right? Good luck with your game though, great if it works, but seems like many large player count games cut corners to simplify things.
thunderfork 3mo ago
If you're using stream compression, 20mbps would likely be a lot more than 10 times as many objects (and you shouldn't be serializing the whole state every update, and... yadda yadda) You can fit a lot of game in 2mbit/s with a little bit of work.
- gafferongames 3mo ago
  > You can fit a lot of game in 2mbit/s with a little bit of work. And you can fit exactly 10X the game in 20mbps with the same amount of work, plus some AF_XDP magic.
mvdtnz 3mo ago
Even 2mbps would be on the extremely high side. I doubt many mainstream games, if any, use this kind of bandwidth. Excluding games that stream video of course. A 6v6 game of Forged Alliance (12 players each moving hundreds of units around, many with simulated projectile weapons) uses 0.3mbps.
- bluefirebrand 3mo ago
  I was going to say this too. Games don't need to send much data to sync game state across clients
- gafferongames 3mo ago
  > A 6v6 game of Forged Alliance (12 players each moving hundreds of units around, many with simulated projectile weapons) uses 0.3mbps. Yes, because it's networked via deterministic lockstep and it sends only inputs. Other games genres like FPS use a different network model and send object state. This means their bandwidth is proportional to how many objects there are in the world (or how many objects are relevant to each player).
axus 3mo ago
At the absolute worst, a room full of 32-players in Quake 3: Arena would be sending 120 kilobits per second to each player. Fortnite peaks at ~400 kbps during the initial 100-player drop and goes down from there. I understand that those are big budget games, but there is a lot of room for improvement in 10000 kbps.
- gafferongames 3mo ago
  > At the absolute worst, a room full of 32-players in Quake 3: Arena would be sending 120 kilobits per second to each player. OK I'll bite. Quake 3: Arena supports 32 players. What if it supported 1000 players? 1000/32 = 31.25 theoretical quake 3 but with 1000 players (all visible) would be: 31.25 x 120 kilobits per-second = 3,750 kilobits per-second = 3.75 mbps sent per-client. now make quake 3 more interesting by putting in 1000 NPCs in to interact with, so 2000 total objects -> double the bandwidth to 7.5 mbps per-client. fill the rest of the bandwidth with weapon data (one shots), sounds, fx and other random events -> 10mbps is pretty easy to hit, maybe even go over, especially if a lot of stuff is going on in the level. > Fortnite peaks at ~400 kbps during the initial 100-player drop and goes down from there. Fortnite has 100 players. Theoretically, if it supported 1000 players, then you would multiply bandwidth by 10 if all other players were visible, or if you had the 1000 players in the same size world, so on average you would see 10X more players than before with relevancy / culling by distance or LoS. 400 kbps x 10 -> 4000 kbps -> 4 mbps sent per-client. Now make it more fun and add 1000 NPC characters to the level, 2000 characters per-level total. 8 mbps per-client for theoretical, 1000 player Fortnite w. 1000 NPC characters in the level. > I understand that those are big budget games, but there is a lot of room for improvement in 10000 kbps. This is simply not true. It would be really great if you guys would do some light math before making statements like this.
  - axus 3mo ago
    Why are all 1000 players visible to each other at once? The numbers I quoted were worst case, not a baseline. Streaming sounds and FX every single time and never caching is a choice that will lead to 10Mbps, but completely unnecessary. All you "really need" is initial state, the timestamps / inputs of the other players, and reproducible physics.

That's what I'm asking, seems like this isn't a normal game, but what specifically about it makes the bandwidth requirement so high? I know RTSes send inputs instead of state, but that has its own drawbacks.

gafferongames 3mo ago
The space game has 1000 players. Most FPS games today have a maximum of 100 players. Let's assume these FPS games send 1mbps - 2mbps per-client (many send less, some send more) but it's a good range to start with. Now increase the player count from 100 to 1000. The number of objects that needs to be sent from server to client also 10Xs, because you need to send state for each player visible to each client, so that client can actually see the other players moving around. The end result is bandwidth is now approximately 10X what it was before, or 10-20mbps. To address your question around RTS and inputs. Game developers usually end up using state synchronization methods (sending the positions, rotations etc per-object) instead of relying on input based deterministic methods whatever player counts are high. My personal threshold is around 4 players. This is the reason FPS games and other higher player count games usually send state instead of just inputs. Because if they were to rely on a deterministic simulation synchronized only by inputs like an RTS, the server would have to wait for input from the the most lagged player before it could step the server simulation forward, and with regular internet jitter, packet loss and so on, as the player count increases it becomes more and more likely that the game will hitch and stutter waiting for these inputs. So the answer is, bandwidth sent per-client scales with the number of players in the game, and games with higher player counts tend to send state instead of just inputs for the reasons above. cheers
- Hikikomori 3mo ago
  I don't think anyone disagrees that linearly scaling of traffic scales linearly. What they're getting at, why would you still use that rather implementing something more efficient? Like Battlefield games (bf4?) did, using different update rates for nearby and distant players. Would also argue that RTS inputs are different from fps as in general you give commands to units, like go here in move/attack mode, and they do it for you. In fps your inputs control a character directly. So they can use different methods of conveying progress of state. And an fps game can use both methods, like doing deterministic physics for objects. Also don't need to wait for inputs just because its deterministic simulation?
  - gafferongames 3mo ago
    > I don't think anyone disagrees that linearly scaling of traffic scales linearly. What they're getting at, why would you still use that rather implementing something more efficient? Like Battlefield games (bf4?) did, using different update rates for nearby and distant players. I guess my confusion/frustration comes from this sort of default, "wow, that's a lot of bandwidth, umm I guess somewhere he must be doing something really inefficient" train of thought that I see so many commenters are going through in this thread. What if it wasn't inefficient. What if what I'm describing is actually using the 10-20mbps and packing in an appropriate amount of game that justifies that amount of bandwidth on top of already doing all the smart compression techniques? Think of it like this, what if you did all the compression and bandwidth optimization techniques available, and instead of targeting 1-2mbps, you just used the additional bandwidth to fit in more game? More players. Greater object density. A bigger world. More networked objects. Higher tick rate. There are any number of dimensions you can expand along. Nobody is suggesting "LOL, bandwidth is free now, make the same game, but be lazy and have it take up 10-20mbps! hahah". The industry doesn't take kindly to the same things over and over, players want novelty. So give it to them!
    - Hikikomori 3mo ago
      Then its fine, but its not what was described, and I guess that is what people had issues with as just scaling player numbers without optimization wouldn't work great right? Good luck with your game though, great if it works, but seems like many large player count games cut corners to simplify things.

thunderfork 3mo ago

If you're using stream compression, 20mbps would likely be a lot more than 10 times as many objects (and you shouldn't be serializing the whole state every update, and... yadda yadda) You can fit a lot of game in 2mbit/s with a little bit of work.

gafferongames 3mo ago
> You can fit a lot of game in 2mbit/s with a little bit of work. And you can fit exactly 10X the game in 20mbps with the same amount of work, plus some AF_XDP magic.

mvdtnz 3mo ago

Even 2mbps would be on the extremely high side. I doubt many mainstream games, if any, use this kind of bandwidth. Excluding games that stream video of course. A 6v6 game of Forged Alliance (12 players each moving hundreds of units around, many with simulated projectile weapons) uses 0.3mbps.

bluefirebrand 3mo ago
I was going to say this too. Games don't need to send much data to sync game state across clients
gafferongames 3mo ago
> A 6v6 game of Forged Alliance (12 players each moving hundreds of units around, many with simulated projectile weapons) uses 0.3mbps. Yes, because it's networked via deterministic lockstep and it sends only inputs. Other games genres like FPS use a different network model and send object state. This means their bandwidth is proportional to how many objects there are in the world (or how many objects are relevant to each player).

axus 3mo ago

At the absolute worst, a room full of 32-players in Quake 3: Arena would be sending 120 kilobits per second to each player. Fortnite peaks at ~400 kbps during the initial 100-player drop and goes down from there. I understand that those are big budget games, but there is a lot of room for improvement in 10000 kbps.

gafferongames 3mo ago
> At the absolute worst, a room full of 32-players in Quake 3: Arena would be sending 120 kilobits per second to each player. OK I'll bite. Quake 3: Arena supports 32 players. What if it supported 1000 players? 1000/32 = 31.25 theoretical quake 3 but with 1000 players (all visible) would be: 31.25 x 120 kilobits per-second = 3,750 kilobits per-second = 3.75 mbps sent per-client. now make quake 3 more interesting by putting in 1000 NPCs in to interact with, so 2000 total objects -> double the bandwidth to 7.5 mbps per-client. fill the rest of the bandwidth with weapon data (one shots), sounds, fx and other random events -> 10mbps is pretty easy to hit, maybe even go over, especially if a lot of stuff is going on in the level. > Fortnite peaks at ~400 kbps during the initial 100-player drop and goes down from there. Fortnite has 100 players. Theoretically, if it supported 1000 players, then you would multiply bandwidth by 10 if all other players were visible, or if you had the 1000 players in the same size world, so on average you would see 10X more players than before with relevancy / culling by distance or LoS. 400 kbps x 10 -> 4000 kbps -> 4 mbps sent per-client. Now make it more fun and add 1000 NPC characters to the level, 2000 characters per-level total. 8 mbps per-client for theoretical, 1000 player Fortnite w. 1000 NPC characters in the level. > I understand that those are big budget games, but there is a lot of room for improvement in 10000 kbps. This is simply not true. It would be really great if you guys would do some light math before making statements like this.
- axus 3mo ago
  Why are all 1000 players visible to each other at once? The numbers I quoted were worst case, not a baseline. Streaming sounds and FX every single time and never caching is a choice that will lead to 10Mbps, but completely unnecessary. All you "really need" is initial state, the timestamps / inputs of the other players, and reproducible physics.