Network Operating Systems1

Every network today has some form of software to manage its resources. This software runs on a special, high-powered computer and is called a network operating system (or NOS, for short). The NOS is one of the most important components of the network.

A networking operating system (NOS) is the software that runs on a server and enables the server to manage data, users, groups, security, applications, and other networking functions.
The most popular network operating systems are:-
* Microsoft Windows Server 2003/ 2008,
* UNIX, Linux,
* Mac OS X, and
* Novell NetWare.

Network Operating Systems are based on a client/server architecture in which a server enables multiple clients to share resources.
Network Operating Systems (NOS) are embedded in a router or hardware firewall that operates the functions in the network layer (layer 3) of the OSI model.
Examples:
Cisco IOS (formerly "Cisco Internetwork Operating System").
MikroTik RouterOS™ (is a router operating system and software which turns a regular Intel PC or MikroTik RouterBOARD™ hardware into a dedicated router.)