•After the power-up self-test on the router, the following events occur

when the router initializes:

• The generic bootstrap loader executes from ROM 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. The term comes from

the data processing concept of the system “pulling itself up by its

own bootstraps.”

• The operating system source 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.

• The operating system image is loaded into low-addressed

memory. Once loaded and operational, the operating system

determines the hardware and software components and lists the

results on the console terminal.

• 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 no valid configuration file exists in NVRAM, the operating

system executes a question-driven initial configuration routine

referred to as the system configuration dialog. This special mode

is also called the setup dialog.

•Setup is not intended as the mode for entering complex protocol

features in the router. Use setup mode to bring up a minimal

configuration. Instead of setup, network administrators use various

config-mode commands for most router configuration tasks.