7 ms·

What's kind of sad and funny is that these assumptions changed again and no one seemed to have noticed. We're not on PPP or SLIP connections anymore and yet gam

What's kind of sad and funny is that these assumptions changed again and no one seemed to have noticed. We're not on PPP or SLIP connections anymore and yet game devs are still writing netcode as though we are. Client side prediction should have been a temporary hack until low latency connections were mainstream not a permanent aspect of all gaming netcode, and yet it is. Maybe Carmack will wake everyone up again and tell them to stop copying his ancient hack two decades later.

Alupis 7y ago
Maybe you could elaborate on this? CSP is still relevant as far as I can tell. Yes, connections in a lot of countries are now on average lower latency, and yes on average CSP might not be required. However, it's not uncommon to have a couple of high latency connections on a game server (player in another country, roommate is running bit torrent, or just a poor connection). You can't always guarantee low latency, and sometimes connections are interrupted temporarily and packets get lost (assuming UDP). Short of full sync more often, CSP helps make these unpredictabilities a little more tolerable and transparent for the player.
- staunch 7y ago
  Sure, this is why you have a < 60ms ping restriction or whatver. You simply don't let players play on a server with high latency because then it's a bad experience for everyone else. This is how competitive Quake Live servers worked.
  - Alupis 7y ago
    That's not really a great solution, particularly for less popular games where there may not be many local servers, or servers that are not full, or servers that have at least some other players.
keerthiko 7y ago
I think gaming netcode engineers would love to ditch CSP, but the problem is even though low-latency connections are mainstream, stable latency connections are not. It's always possible to have lag spikes or temporary slowdowns in your routing or connection. Second, it's also possible to end up through matchmaking lobbies on a server halfway around the world from one or more of the players in a given match. At some level the limitations of physics still result in noticeable latency and CSP is still mandatory for any fast-paced real-time online multiplayer game.
- staunch 7y ago
  Within a US city or state it's very rare to have much packet loss at all. It's very easy to spot using the builtin netgraph in Quake Live and other games. Players that are separated by thousands of miles should not be playing competitive FPS games together. It's physically impossible to make it a consistently good experience.
boomlinde 7y ago
You must be living under a very pleasant rock if you think that low latency, to the degree that client side prediction is useless, is mainstream. Not accounting for routing, drops and mux/demuxing, and assuming that the signal travels at the speed of light as the crow flies, from west coast USA to where I'm at, the latency is 29ms or roughly two frames. This would be debilitating in an online game without CSP where even the latency introduced by screen buffering and vertical sync may make or break yor game, and in reality the latency is of course much higher, usually around 100ms or higher. Check your assumptions: https://wondernetwork.com/pings https://wondernetwork.com/pings
- pedrocr 7y ago
  By your numbers then the OP is right. Carmack says: the bottom line is that I was working with the wrong basic assumptions for doing a good internet game. My original design was targeted at <200ms connection latencies. People that have a digital connection to the internet through a good provider get a pretty good game experience. Unfortunately, 99% of the world gets on with a slip or ppp connection over a modem, often through a crappy overcrowded ISP. This gives 300+ ms latencies, minimum. So he designed for 200ms and then the real world was 300+ so it didn't work. Your 100ms would then work fine in that context. Maybe games have gotten more complex or our expectations higher so prediction is still worth it even on <50ms connections. But OPs point that the assumptions underlying Carmack's redesign have once again shifted seems correct, at least for that specific design.
  - boomlinde 7y ago
    > By your numbers then the OP is right. By my numbers (though as you can clearly see from the link I posted, >200ms latencies are not uncommon), and Carmack's assumptions in 1996 about what latencies would be acceptable. > So he designed for 200ms and then the real world was 300+ so it didn't work. Your 100ms would then work fine in that context. He designed for <200ms which by the frame of reference he cites (T1 connection) probably was a lot lower than 200ms on average. > Maybe games have gotten more complex or our expectations higher so prediction is still worth it even on <50ms connections. Quake was not a very complex world, but more important (to latency) is that it's a fast paced game by today's standards (IME). It seems more likely to me that perception on what an acceptable hand to eye latency is has changed, just like the perception on acceptable frame rates. To me, joining an online shooter with >100ms latency (even with prevalent client side prediction) feels debilitating, especially if other players have lower latencies. > But OPs point that the assumptions underlying Carmack's redesign have once again shifted seems correct, at least for that specific design. Yes, I agree that PPP and SLIP are not common any more. High latency unfortunately is, and client side prediction is still an effective mitigation strategy that makes a huge difference to online play. The specific design used in Quake has of course been superseded.
taneq 7y ago
Latency is better than it was so prediction times are shorter, but there's still latency so prediction is still important.
uasm 7y ago
> "We're not on PPP or SLIP connections anymore and yet game devs are still writing netcode as though we are." Your average multiplayer today is significantly more complex than Quake. More data needs to pass through, at higher rates. The network is still very much a bottleneck.
- staunch 7y ago
  Fair point but bandwidth has also increased from 56 kbit/s 100,000 kbit/s. CPUs have had similarly massive increases in speed as well. A lot of the extra bandwidth usage is also probably in large part due to sloppiness. John Carmack did some impressively smart things in Quake Live to reduce bandwidth usage. I doubt most modern games like PUBG are anywhere near as optimized.
instantwhat 7y ago
Go listen to actual competitive FPS players, and hear them complain about having 60 ms latency. Listen to them complain about living on one U.S. coast and playing on servers on the opposite one and having 80-100 ms latency. Listen to players in EU who play on NA servers because they don't like players' behavior on EU servers, and they're willing to suffer 150 ms latency. Then visit Australia and listen to players who suffer 300 ms latency to play with people who aren't in the relatively small Australian population for whatever game they're playing. Then take out CSP from their games and watch what happens. CSP will always be necessary for any Internet-based game. Only LANs have low enough latency to not need it.
- staunch 7y ago
  This is why you ping restrict servers. There's no way to make a game competitive when one player has 10ms ping and another has 100ms (10x higher!) ping. It's just bad for everyone. Which is exactly what competitive Quake Live players do and I suspect CS players probably do. Every player has 15-40ms ping and it's amazing.
  - keerthiko 7y ago
    I don't get it, many people want to play a game and there just aren't enough players in their city, games want as many players as possible to be playing them. Your requirement that games ping-restrict servers is an absolute non starter: unless the game is already guaranteed to have hundreds of players active and available near any given player at any given time of day, and evenly distributed redundant always-up servers that scale for demand near every player cluster across the planet. I think CSP is a far more realistic solution to giving a good player experience than magicking player base activity and distribution
    - staunch 7y ago
      For major games like PUBG and Fortnite this shouldn't be a problem at all. It might mean that it takes 60 seconds of matchmaking to join a new game instead of 6 seconds. What you get in exchange is a stable and predictable competitive game. I, and many others, experienced endless frustration in PUBG due to players warping around corners and shots that were clear hits missing due to CSP. And I'm not one to complain about this kind of thing unnecessarily. It really sucked. The PUBG people didn't even geolock their servers at all last time I played, so you could be playing with people with 300ms+ ping which is just miserable. For less successful games maybe you have to increase the maximum ping from 40-60ms to 80-100ms or something but it should be kept as low as possible. The more players per city, the lower you can make the maximum ping. I realize that this might make it more difficult for people in Australia (or whereever) to find a game but it seems even more wrong to make the experience bad for everyone all the time. And at least when they do find a game it will be a great experience instead of terrible.

Alupis 7y ago

Maybe you could elaborate on this? CSP is still relevant as far as I can tell. Yes, connections in a lot of countries are now on average lower latency, and yes on average CSP might not be required. However, it's not uncommon to have a couple of high latency connections on a game server (player in another country, roommate is running bit torrent, or just a poor connection). You can't always guarantee low latency, and sometimes connections are interrupted temporarily and packets get lost (assuming UDP). Short of full sync more often, CSP helps make these unpredictabilities a little more tolerable and transparent for the player.

staunch 7y ago
Sure, this is why you have a < 60ms ping restriction or whatver. You simply don't let players play on a server with high latency because then it's a bad experience for everyone else. This is how competitive Quake Live servers worked.
- Alupis 7y ago
  That's not really a great solution, particularly for less popular games where there may not be many local servers, or servers that are not full, or servers that have at least some other players.

keerthiko 7y ago

I think gaming netcode engineers would love to ditch CSP, but the problem is even though low-latency connections are mainstream, stable latency connections are not. It's always possible to have lag spikes or temporary slowdowns in your routing or connection. Second, it's also possible to end up through matchmaking lobbies on a server halfway around the world from one or more of the players in a given match. At some level the limitations of physics still result in noticeable latency and CSP is still mandatory for any fast-paced real-time online multiplayer game.

staunch 7y ago
Within a US city or state it's very rare to have much packet loss at all. It's very easy to spot using the builtin netgraph in Quake Live and other games. Players that are separated by thousands of miles should not be playing competitive FPS games together. It's physically impossible to make it a consistently good experience.

boomlinde 7y ago

You must be living under a very pleasant rock if you think that low latency, to the degree that client side prediction is useless, is mainstream. Not accounting for routing, drops and mux/demuxing, and assuming that the signal travels at the speed of light as the crow flies, from west coast USA to where I'm at, the latency is 29ms or roughly two frames. This would be debilitating in an online game without CSP where even the latency introduced by screen buffering and vertical sync may make or break yor game, and in reality the latency is of course much higher, usually around 100ms or higher. Check your assumptions: https://wondernetwork.com/pings https://wondernetwork.com/pings

pedrocr 7y ago
By your numbers then the OP is right. Carmack says: the bottom line is that I was working with the wrong basic assumptions for doing a good internet game. My original design was targeted at <200ms connection latencies. People that have a digital connection to the internet through a good provider get a pretty good game experience. Unfortunately, 99% of the world gets on with a slip or ppp connection over a modem, often through a crappy overcrowded ISP. This gives 300+ ms latencies, minimum. So he designed for 200ms and then the real world was 300+ so it didn't work. Your 100ms would then work fine in that context. Maybe games have gotten more complex or our expectations higher so prediction is still worth it even on <50ms connections. But OPs point that the assumptions underlying Carmack's redesign have once again shifted seems correct, at least for that specific design.
- boomlinde 7y ago
  > By your numbers then the OP is right. By my numbers (though as you can clearly see from the link I posted, >200ms latencies are not uncommon), and Carmack's assumptions in 1996 about what latencies would be acceptable. > So he designed for 200ms and then the real world was 300+ so it didn't work. Your 100ms would then work fine in that context. He designed for <200ms which by the frame of reference he cites (T1 connection) probably was a lot lower than 200ms on average. > Maybe games have gotten more complex or our expectations higher so prediction is still worth it even on <50ms connections. Quake was not a very complex world, but more important (to latency) is that it's a fast paced game by today's standards (IME). It seems more likely to me that perception on what an acceptable hand to eye latency is has changed, just like the perception on acceptable frame rates. To me, joining an online shooter with >100ms latency (even with prevalent client side prediction) feels debilitating, especially if other players have lower latencies. > But OPs point that the assumptions underlying Carmack's redesign have once again shifted seems correct, at least for that specific design. Yes, I agree that PPP and SLIP are not common any more. High latency unfortunately is, and client side prediction is still an effective mitigation strategy that makes a huge difference to online play. The specific design used in Quake has of course been superseded.

taneq 7y ago

Latency is better than it was so prediction times are shorter, but there's still latency so prediction is still important.

uasm 7y ago

> "We're not on PPP or SLIP connections anymore and yet game devs are still writing netcode as though we are." Your average multiplayer today is significantly more complex than Quake. More data needs to pass through, at higher rates. The network is still very much a bottleneck.

staunch 7y ago
Fair point but bandwidth has also increased from 56 kbit/s 100,000 kbit/s. CPUs have had similarly massive increases in speed as well. A lot of the extra bandwidth usage is also probably in large part due to sloppiness. John Carmack did some impressively smart things in Quake Live to reduce bandwidth usage. I doubt most modern games like PUBG are anywhere near as optimized.

instantwhat 7y ago

Go listen to actual competitive FPS players, and hear them complain about having 60 ms latency. Listen to them complain about living on one U.S. coast and playing on servers on the opposite one and having 80-100 ms latency. Listen to players in EU who play on NA servers because they don't like players' behavior on EU servers, and they're willing to suffer 150 ms latency. Then visit Australia and listen to players who suffer 300 ms latency to play with people who aren't in the relatively small Australian population for whatever game they're playing. Then take out CSP from their games and watch what happens. CSP will always be necessary for any Internet-based game. Only LANs have low enough latency to not need it.

staunch 7y ago
This is why you ping restrict servers. There's no way to make a game competitive when one player has 10ms ping and another has 100ms (10x higher!) ping. It's just bad for everyone. Which is exactly what competitive Quake Live players do and I suspect CS players probably do. Every player has 15-40ms ping and it's amazing.
- keerthiko 7y ago
  I don't get it, many people want to play a game and there just aren't enough players in their city, games want as many players as possible to be playing them. Your requirement that games ping-restrict servers is an absolute non starter: unless the game is already guaranteed to have hundreds of players active and available near any given player at any given time of day, and evenly distributed redundant always-up servers that scale for demand near every player cluster across the planet. I think CSP is a far more realistic solution to giving a good player experience than magicking player base activity and distribution
  - staunch 7y ago
    For major games like PUBG and Fortnite this shouldn't be a problem at all. It might mean that it takes 60 seconds of matchmaking to join a new game instead of 6 seconds. What you get in exchange is a stable and predictable competitive game. I, and many others, experienced endless frustration in PUBG due to players warping around corners and shots that were clear hits missing due to CSP. And I'm not one to complain about this kind of thing unnecessarily. It really sucked. The PUBG people didn't even geolock their servers at all last time I played, so you could be playing with people with 300ms+ ping which is just miserable. For less successful games maybe you have to increase the maximum ping from 40-60ms to 80-100ms or something but it should be kept as low as possible. The more players per city, the lower you can make the maximum ping. I realize that this might make it more difficult for people in Australia (or whereever) to find a game but it seems even more wrong to make the experience bad for everyone all the time. And at least when they do find a game it will be a great experience instead of terrible.