It is vital to not only understand how to create a network, but how to manage it, how it works, and how to handle different situations.

To make an MMORPG, you must code both a client program and a server program, and you must also have access to a server computer. Luckily, Game Maker can be used to create both of the programs required, and you can use your own PC as a local test server until you're ready to go public with your MMORPG.

The concept behind networking may take a while to wrap your head around.

It is important to understand that nothing happens automatically. The server needs to be the one to tell each player what the others are doing.

Networking is all about connecting clients/players/users to each other, but they don't connect to each other. Your server must act as a message relay, while also handling all aspects of the game. Once each player is connected to the server, they are effectively connected to each other -- they are networked.

Networked player interactions are easiest to describe with an example:

Let's say CLIENT A wants to move. The process to notify CLIENT B and CLIENT C would look something like this:

• CLIENT A presses a direction key and starts moving on his own screen.
  
• CLIENT A instantly sends a MOVEMENT message to the server.
• The SERVER receives this message.
• The SERVER relays the MOVEMENT message to CLIENT B and CLIENT C.
• CLIENT B and CLIENT C both receive the MOVEMENT message originally sent by CLIENT A.
• CLIENT A's character starts moving on CLIENT B and CLIENT C's screen.
  

In this example, the clients have interacted without ever having to send data to each other. This is important, because the server can "moderate" any data to make sure it is accurate, and non-malicious, while also updating its own version of the game world.

It is extremely important to understand the above example before continuing.

Now that you have a grasp on the concept of networking, we'll introduce you to some basic glossary terms which will appear frequently throughout the rest of this tutorial and the site in general.