Configuration Register: A router has to know which software to load and which configuration file to utilize when it first powers up.. (0×2) and 1-1-1-1 (0xF). In the absence of boot system commands in the startup configuration file, the router first tries to load a valid image from the default Flash device, and if that fails, it tries to.. The lowest four bits of the configuration register (bits 3, 2, 1, and 0) form the boot. field. The boot field determines if the router boots manually, from ROM, or from Flash or. the network. About the values: · If you set the configuration register boot field value to 0x0, you must boot the. operating system manually with the boot command.
If you set the configuration register boot field to any value from 0x2 to 0xF, the router uses the boot field value to form a default boot filename for booting from a network server. For more information about the configuration register bit settings and default filenames, see the appropriate router hardware installation guide.. The configuration register (confreg) is a bitmap. If you convert the number to binary, you will see a series of "switches" that are either enabled or disabled.. Bin 1111 = Hex 0xf (15 in decimal) So now, the trick is to find out which bits correspond to which options, then set the register value accordingly. Often, the bits are numbered.
