Sem 2v2 Chapter 4 Router Startup and Setup

1. Sem 2v2 Chapter 4 Router Startup and Setup

2. A router initializes by loading the bootstrap, the operating system, and a configuration file. If the router cannot find a configuration file, then it enters setup mode. The router stores, in NVRAM, a backup copy of the new configuration from setup mode

3. The router must deliver reliable performance in its job of connecting the user networks it was configured to serve. • Make sure that the router comes up with all its hardware tested. • Find and load the Cisco IOS software that the router uses for its operating system. • Find and apply the configuration statements about the router, including protocol functions and interface addresses. When a Cisco router powers up, it performs a power-up self test. During this self test, the router executes diagnostics from ROM on all hardware modules. These diagnostics verify the basic operation of the CPU, memory, and network interface ports. After verifying the hardware functions, the router proceeds with software initialization.

4. Step 1 - The generic bootstrap loader, in ROM, executes on the CPU card. A bootstrap is a simple, preset operation to load instructions that in turn cause other instructions to be loaded into memory, or cause entry into other configuration modes. • Step 2 - The operating system (Cisco IOS) can be found in one of several places. The location is disclosed in 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. • Step 3 - The operating system image is loaded. Then, when it is loaded and operational, the operating system locates the hardware and software components and lists the results on the console terminal. • Step 4 - The configuration file saved 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. • Step 5 - If no valid configuration file exists in NVRAM, the operating system executes a question-driven initial configuration routine referred to as the system configuration dialog, also called the setup dialog.

5. Setup is not intended as the mode for entering complex protocol features in the router. You should use setup to bring up a minimal configuration, then use various configuration-mode commands, rather than setup, for most router configuration tasks

6. The top command in the graphic - show startup-config - displays the backup configuration files that are located in NVRAM. The second command in the graphic - show running-config - displays the active configuration files that are located in RAM. The erase startup-config command deletes the backup configuration file in NVRAM. The reload (reboot) command reloads the router, causing it to run through the entire startup process. The last command, setup, is used to enter setup mode from the privileged EXEC prompt.

7. One of the routines for initial configuration is the setup mode. The main purpose of the setup mode is to bring up, quickly, a minimal configuration for any router that cannot find its configuration from some other source. For many of the prompts in the system configuration dialog of the setup command facility, default answers appear in square brackets [] following the question. Press the Return key to use these defaults. If the system has been previously configured, the defaults that will appear will be the currently configured values. If you are configuring the system for the first time, the factory defaults will be provided. If there is no factory default, as in the case of passwords, nothing is displayed after the question mark [?]. During the setup process you can press Control+C at any time to terminate the process and start over.

8. The first global parameter allows you to set the router host name. This host name will be part of the Cisco IOS prompts for all configuration modes. Use the next global parameters shown in the graphic to set the various passwords used on the router. You must enter an enable password. When you enter a string of password characters for the prompt, “Enter enable secret”, the characters are processed by Cisco proprietary encryption this is done in Privileged EXEC mode. This enhances the security of the password string. Whenever anyone lists the contents of the router configuration file, this enable password appears as a meaningless string of characters.

9. When the console prompt requests global parameters, use the configuration values that you have selected for your router. Whenever you answer yes to a prompt, additional questions may appear regarding the protocol.

10. At the prompts, you must enter parameters for each installed interface. To do this, you can use the configuration values that you have already selected for your interfaces

11. After you have answered yes in the Setup mode to the last question, your system will be ready to use. If you want to modify the configuration you have just established, you must do the configuration manually. The script tells you to use configuration mode to change any commands after setup has been used. The script file generated by setup is additive; you can turn features on with setup, but you cannot turn them off. Also, setup does not support many of the advanced features of the router, or features that require a more complex configuration.