Cisco Internetwork Operating System (IOS) is a family of network operating systems used on many Cisco Systems routers and current Cisco network switches.

Is Cisco an operating system?

Cisco IOS (Internetwork Operating System) is a proprietary operating system that runs on Cisco Systems routers and switches. The core function of Cisco IOS is to enable data communications between network nodes.

What OS is Cisco IOS based on?

Cisco IOS is a monolithic operating system running directly on the hardware while IOS XE is a combination of a linux kernel and a (monolithic) application (IOSd) that runs on top of this kernel.