Cisco has a whole bunch of different operating systems for a variety of products:
- IOS runs on most Cisco routers and switches.
- IOS XE is a more modern, modular version of IOS.
- IOS XR runs on high-end routers.
- NX-OS runs on the Nexus line of datacenter switches.
- ASA OS runs on Cisco ASA devices.
- AireOS runs on Access Points.