So far, this book has described all the networking API functions available in Microsoft Windows that allow you to develop applications capable of communicating with other applications over a network. For the most part, our discussions have focused on the application and presentation layers of the seven-layer OSI model. We did not describe the details of a specific network protocol, and most of our discussions centered on using the functions from a protocol-independent standpoint.
The final section of this book describes an important service named Remote Access Service (RAS) that allows users to connect their computer from a remote location to a local computer network. Once connected, you can use the network functions described throughout this book as though your computer were directly connected to a remote network.