A basic game like World of Warcraft that you run off of your PC is called a massive multiplayer online role-playing game (MMORPG). To simplify how the data transfers from your PC to allow you to play with individuals all around the world, you could basically say that you need two things, a client and a server. This would I believe over-simplify how the game transmits data but it’s basically what happens. You install the game on your PC, which becomes the client. You then connect to the server, or servers, (last known was that Blizzard had over 9000 servers for WOW), when you’re ready to play the game. Your PC, or client is a combination of the playing board and the window used to view the game world. Nearly everything about the world, including maps, landscapes and even what different mobs look like exists in files and databases on your computer. Your computer uses algorithms, or sets of rules, to translate these files into a representation of the game world and what's in it. But on Blizzards side as well they have more than just one server to handle the game and all that goes with it. You also need.
•A login server allows players to log in to the game and access the game world. Some games route players from multiple realms through one login server.
•A chat server relays all the text players use to communicate with one another. A VoIP or voice server does the same for voice traffic.
•A Web server allows players to access their account information. Some games display characters' statistics and gear on a Web page -- in these cases, the game's databases have to have access to the Web server. But from your house, you’re going to need the following hardware to play the game on line. It doesn’t matter if you’re playing WOW or Call of Duty, you need a client to run the game with. This would be either a PC, a, Xbox or PS3/4. You will also need internet access to be