[Cisco Networking Academy] Del Mar College
ITNW 1392-Beginning Router Configuration
 Instructor:Michael P. Harris
Sem2Les8

Semester 2, Lesson 8 Notes:

Router Starup and Setup Configuration

1. What are the three main things the router accomplishes upon starup?

  1. The router hardware must be checked.
  2. The Cisco IOS software image must be found and loaded.
  3. The router configuration information must be found and loaded.

  • System startup routines initiate router software.
  • Fallback routines provide startup alternitives as needed.

2. Briefly describe the router 'startup sequence'.

  1. First, the "Bootstrap" is loaded from ROM into RAM.

  2. Then the "Cisco IOS" is located and loaded, from either Flash , a TFTP server, or ROM into RAM. The location is determined from the boot field of the configuration register. If the boot field indicates a Flash or network load, boot system commands in the configuration file indicate the exact location of the image.

  3. Finally, the "configuration file" is located and loaded from NVRAM, a TFTP server, or the Console into RAM. The saved configuration file in NVRAM is loaded into main memory and executed one line at a time. These configuration commands start routing processes, supply addresses for interfaces, set media characteristics, and so on.

  • If this fails, the router enters "setup mode".

3. What is the main purpose of "setup mode"?
The main purpose of 'setup mode' is to quickly bring up a minimal configuration for any router that cannot find its configuration from some other source.

"Setup mode" is not intended as the mode for entering complex protocol features in the router. Use setup to bring up a minimal configuration. Instead of setup, network administrators use various config-mode commands for most router configuration tasks. You can press'Control-C' to terminate the process and start over at any time.

4. During the "System Configuration Dialog", you will be prompted to setup "global parameters" and to setup "interfaces". Explain:

  • "Global parameters" include 'router name', 'passwords', 'routing protocols', and 'routed protocols'.

  • "Interface parameters" include 'type of port', 'IP addresses', and 'subnet masks'.

Once you've completed the setup command program and your configuration is displayed, you will be asked if you want to use this configuration. If you answer yes, what happens?

The configuration you have just created is executed and saved to NVRAM; your system is ready to use. There is no default for this prompt; you must answer either YES or NO.

The "erase startup-config" (or "write erase" in Cisco IOS Release 10.3 and earlier) command deletes the backup configuration file in NVRAM.

The "reload" command reloads the router, causing it to run through the entire configuration process. This command is used to enter setup mode from the privileged EXEC prompt.

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