Network operating system

network operating system (NOS): Software that (a) controls a network and its message (e.g. , packet) traffic, and queues, (b) controls access by multiple users to network resources such as files, and (c) provides for certain administrative functions, including security.

Note 1: A network operating system is most frequently used with local area networks and wide area networks, but could also have application to larger network systems.

Note 2: The upper 5 layers of the OSI--Reference Model provide the foundation upon which many network operating systems are based.

Source: from Federal Standard 1037C