For the most part, the DirectX Application Programming Interfaces (APIs) have included components that cover just about every aspect of game development. Naturally, graphics is a big part of that, but as you've seen in earlier chapters, it includes other types of things, such as sound and user input. Networking is included as well.
Beginning with the Summer 2004 release of the Managed DirectX assemblies, the DirectPlay assemblies are no longer being updated.
In the world of networking, you can follow two major types of designs: peer-to-peer and client/server. You should take a moment to understand the differences ...