|Microsoft DirectX 9.0|
A lobby is an application whose primary purpose is to enable players to meet and arrange games. It is typically located on a remote computer, and accessed over the Internet. Lobby servers often also perform a variety of other functions, such as hosting chat rooms, posting news and information, and selling merchandise. While lobby servers are convenient and commonly used to arrange multiplayer games, they aren't required. Multiplayer games can also be arranged by direct communication between lobby clients.
There are normally three components that are needed to enable a game to interact with a lobby:
Microsoft?DirectPlay?does not specify how you should implement a lobby server application. Instead, DirectPlay provides support for a lobby client. A lobby client is an application that is implemented by a lobby server vendor, and installed on each user's system. It serves as a link between the user and the lobby. While you could handle such communication directly, you would have to know the specific implementation details of every lobby that might launch your game.
The lobby client application handles the details of communicating with its associated lobby server, using whatever protocols are appropriate. The lobby client communicates with the user and their game applications through a DirectPlay interface. DirectPlay then passes messages to the application. The application can also use a DirectPlay interface to pass messages to the lobby client.
A lobby can launch virtually any application. However, the application must have some specific lobby-aware components to take full advantage of lobby-launching. In particular, a lobbyable application can communicate with the lobby client throughout the course of the session. If an application is registered as lobbyable, the lobby client also automatically receives updates for various changes in game status, such as host migration.