Video games, multiplayer and servers

In order to get a picture of how hard or easy it is to support a server for a video game, one needs to understand how online multiplayer works. This chapter shows examples how a multiplayer game can work, and that it possible for a community of players to support a game once a publisher ends official support.

Video games are, at their core, programs that a player runs on his computer. They run their code on the machine, output graphics and sound and react to player input. A simplest example would be a single player chess program: it draws the chessboard on the screen, it reacts to the player inputting moves, and it calculates and makes the move of a computer opponent.

_images/chess_example_1.png

Pychess, a free chess program

A video game that wants to support playing with other people over the Internet needs to be able to connect to and talk to other games running on other players’ computers. From a programmer’s point of view, the Internet is just another input and output: the game sends messages out and reacts to messages coming in. For example, two chess programs can talk over the Internet, exchanging moves done by each player, each updating the state of the game independently. This style of online multiplayer is called “peer-to-peer”. It is used for example by the original first person shooter game “Doom”.

_images/chess_example_2.png

Simple “peer-to-peer” multiplayer

Peer-to-peer is not the only way one can implement online multiplayer. In more complex games and with many players, it is easier to have a sort of “referee” or a “game master”: a separate program which keeps track of the game’s state and which all other games talk to. Such a program is called a “server”, while the games ran by the players that talk to this program are called “clients”.

_images/chess_example_3.png

Game of risk. Three players are using a server to play.

A server is a program ran on a computer, just like the video game. In simplest cases the server program is just the game, just stripped of all the player-facing components like graphics and player input. Because a server is still just a program, it can run on any computer. It can, for example, run on a player’s own computer, or on one rented from a hosting company.

Today’s AAA multiplayer video games often rely on multiple dedicated servers that are much more complicated to setup that a single server program described above. These can take different forms and be responsible for different things, such as:

  • Databases which hold, update and serve player data,

  • Payment processing servers which talk to third-party payment services,

  • Game servers that manage game state, with their number dynamically scaled using orchestration,

  • Servers used for Digital Rights Management,

  • Lobby and matchmaking servers,

  • Voice chat,

  • Game forums,

  • And more.

However, the fundamentals of these complex sets of servers are the same: it is a collection of programs that game clients send messages to and receive message from. There’s nothing inherent about servers that requires the publisher specifically to operate them. And so, some games for which the official servers were shut down have been restored to a reasonably playable state by fan communities.

Community servers

Some multiplayer games that require complex server infrastructure were preserved by fan communities after the publisher ended support for multiplayer components. Not all of these games became non-functional after support ended; examples listed here serve as proof that such games can still be preserved and maintained by fans.

Supreme Commander: Forged Alliance

Supreme Commander: Forged Alliance is a real time strategy game released in 2007. The game supports peer-to-peer online multiplayer. Its developer, Gas Powered Games, also operated a multiplayer service “GPGNet” which provided matchmaking, downloading player-made maps and mods, chat, archive of past multiplayer games and so on. GPGNet was shutdown in 2012. [1] Matchmaking continued to be available through Steam, leaving the game in a playable state.

“FAForever” [2] is a fan project which works as a replacement for GPGNet. It provides matchmaking, player-made maps and mods, chat, past game archive, as well as new services like improved peer-to-peer connectivity and proxy servers. The server code is maintained by volunteers and runs on rented computers paid for by community donations.

City of Heroes

City of Heroes is a multiplayer role playing game (MMORPG) released in 2004. It operated until 2012 when the official servers were shut down. MMORPG servers are especially difficult to recreate because they maintain a persistent game word for hundreds of players, with much of game logic only calculated server-side.

A fan implementation of the game’s server called “SCoRE” was developed in secret since shutdown of the official servers, until its existence was leaked in 2019. [3] There are multiple private servers operated using this fan implementation, with the largest called “Homecoming” having over 100,000 total players. [4] In 2024, developers of the “Homecoming” server were granted by the publisher NCsoft an official license to host the game. [5]

The “Homecoming” server developers operate multiple types of services, including 7 map hosts, 4 high-availability database servers, spare servers to handle failures, development infrastructure, forum, website, content delivery network (CDN), as well as rented third party services such as an email service and an SMS service. The infrastructure is supported by donations from the community. [6]

Battleforge

Battleforge is an online-only real time strategy game released by Electronic Arts in 2009. Official servers have been shut down in 2013, making the game inoperable. [7]

A fan server implementation “Skylords Reborn” started development in 2015 and was released in 2020. [8] Today Skylords Reborn has over 100,000 registered player accounts. [TODO: describe server infrastructure here. I asked about it on Skylords Reborn discord.]