Booting Process OF a Router.

        It is often asked in interview " Tell the  booting process OF A router ." So following are the steps we should follow .
When you turn the router on, it runs through the following boot process.
1. The Power-On Self Test (POST) checks the router's hardware. When the POST completessuccessfully, the System OK LED indicator comes on.
2. The router checks the configuration register to identify where to load the IOS image from.
A setting of 0x2102 means that the router will use information in the startup-config file to locate the IOS image. If the startup-config file is missing or does not specify a location, it will check the following locations for the IOS image:
    1. Flash (the default location)
    2. TFTP server
    3. ROM (used if no other source is found)
3. The router loads the configuration file into RAM (which configures the router). The router can load a configuration file from:
    1. NVRAM (startup-configuration file)
    2. TFTP server
    3. If a configuration file is not found, the router starts in setup mode.

Anyone can find the  answers of the following questions from the above process

1.     If the router can't find an IOS image in flash, where will it look next?
2.     What happens if the router can't find a configuration file at startup?
3.     What is the role of the configuration register?
4.     What configuration register value tells the router to skip the startup-config file?

Enjoy the questions