Network operating systems enable servers to share resources with clients. They also facilitate other services such as communications, security, and user management. Network operating systems do not fit neatly into one layer of the OSI Model. Some of their functions - those that facilitate communication between computers on a network - belong in the Application layer.

However, many of their functions - those that interact with users - take place above the Application layer. Consequently, the OSI Model does not usefully describe all aspects of network operating systems.