Network Operating System (NOS) is an operating system that includes special functions for connecting computers and devices into a local-area network (LAN) or Inter-networking. Some popular NOS's for DOS and Windows systems include Novell Netware, Windows NT and 2000, Sun Solaris and IBM OS/2. The Cisco IOS (Internet Operating System) is also a Network Operating System with an focus on the Internetworking capabilities of network devices. It is installed in almost all Cisco network devices such as Cisco routers and switches.

Some of the features of Network Operating System are:

• Provide basic operating system features such as support for processors, protocols, automatic hardware detection and support multi-processing of applications
• Security features such as authentication, authorization, logon restrictions and access control
• Provide name and directory services
• Provide file, print, web services, back-up and replication services
• Support Internetworking such as routing and WAN ports
• User management and support for logon and logoff, remote access; system management, administration and auditing tools with graphic interfaces
• Clustering capabilities; fault tolerant and high availability systems

Related Terms: Operating System, Cisco IOS, Novell Netware, IBM OS/2, Sun Solaris