Understanding Router Basics
The user interface: user and privileged modes Context-sensitive help and the history command Router modes Router components: RAM, NVRAM, Flash, EPROM, ROM, and network
Router Overview The Cisco IOS is the most important part of your router. Hardware is just metal without the software. The IOS is the program code that deﬁnes how the router functions. Without it, the router cannot route packets. The IOS is feature-rich and pretty much standard across the various Cisco platforms. So once you become familiar with IOS commands on one router, you do not have to learn new commands to work on a new router.