Cisco Router Setup Mode and Configuration Backup Quiz

Router Setup and User Interface

• If no TFTP server is found, the setup dialog (setup mode) is initiated.
• Setup mode is not intended to be used to enter complex protocol features in a router, but to permit administrators to install a basic configuration for routers.
• Default answers appear in square brackets [ ] following the question in setup mode.
• Pressing the Enter key uses these defaults.
• Ctrl-C can be pressed at any time to terminate the setup process, which administratively shuts down all interfaces.

Router User Interface Modes

• User EXEC mode: typical tasks include commands that check the status of a router.
• Privileged EXEC mode: typical tasks include commands that change the router configuration.
• Type "enable" to enter privileged mode.
• Type "disable" to exit privileged mode.
• Type "exit" or "end" or press Ctrl-Z to return to privileged mode from configuration mode.

Router CLI

• The CLI (Command Line Interface) environment can be accessed several ways:
  • Through a console session.
  • Through an AUX port with a modem.
  • To Telnet to the router.
• Ways 1 and 2 do not require the router to have any IP services configured.
• Way 3 requires at least one interface to be configured with an IP address.

Cisco IOS Software

• The Cisco IOS is the embedded software architecture in all of the Cisco routers and is also the OS of the Catalyst switches.
• One of the main considerations when selecting a new IOS image is compatibility with the router flash and RAM memory.
• The newer the release and the more features it provides, the more flash and RAM memory it requires.
• Use "show version" to check the current image and available flash.

Operation of Cisco IOS Software

• The Cisco IOS devices have three distinct operating environments or modes:
  • ROM Monitor mode: performs the bootstrap process and provides low-level functionality and diagnostics.
  • Boot ROM mode: only a limited subset of the Cisco IOS feature set is available, and it allows write operations to flash memory.
  • Cisco IOS mode: the normal operation of most Cisco routers requires a copy of the IOS to be loaded into RAM and executed from RAM.

Router Internal Components

• RAM: stores routing tables, holds ARP cache, and provides temporary memory for the configuration file.
• NVRAM (Non-Volatile RAM): provides storage for the startup configuration file and retains content when a router is powered down or restarted.
• Flash: holds the IOS image and retains content when a router is powered down or restarted.
• ROM: maintains instructions for power-on self-test (POST) diagnostics and stores the bootstrap program and basic operating system software.

Router Connections

• Console port: provides physical access for initial configuration.
• Management port: connects to a computer for configuration.
• WAN connections: connects routers to a WAN for packet entry and exit.
• LAN connections: connects routers to a LAN for packet entry and exit.

Power-On Self-Test (POST)

• When a Cisco router powers up, it performs a power-on self-test (POST) to verify the basic operation of the CPU, memory, and network interface ports.
• After the POST, the generic bootstrap loader in ROM executes.
• A bootstrap is a simple set of instructions that tests hardware and initializes the IOS for operation.

Boot Process

• The IOS can be found in several places.
• The boot field of the configuration register determines the location that is used to load the IOS.
• When the IOS is loaded and operational, the configuration file saved in NVRAM is loaded into main memory and executed one line at a time.
• If no valid configuration file exists in NVRAM, the operating system searches for an available TFTP server.