Router Modes

Accessing a router can be done through a console port, a modem connection, or through one of the operational interfaces. Once accessed, a router can be placed in one of five primary modes:

• User

• Privileged

• Setup

• Rxboot

• Global configuration

There are more than five operational modes. However, additional modes are used for very specific functions and are invariably lumped together in a category called "other." The CCNA exam will only cover the five primary modes.

Each of these modes provides access to specific memory areas and functions, as described in the following sections.

User Mode

User mode provides a display-only environment. You can view limited information about the router but you cannot change the configuration of the router.

Privileged Mode

Privileged mode enables you to perform an extensive review of the router. This mode supports testing commands, debugging commands, and commands to manage the router configuration files.

Setup Mode

Setup mode is triggered on router startup when no configuration file resides in nonvolatile random access memory (NVRAM). This mode executes an interactive prompted dialog box to assist in creating an initial router configuration.

RXBOOT Mode

A router's maintenance mode is called RXBOOT mode or ROM monitor mode . This mode facilitates recovery functions when the router password is lost or the IOS file stored in Flash memory has been erased or is corrupt. Pressing the Break key (from a console terminal directly connected to the router) within the first 60 seconds of startup also allows you to place the router in this mode.

Global Configuration Mode

You perform simple configuration tasks that permeate all aspects of the router in global configuration mode. For example, router names , router passwords, and router banners are all configured in this mode.