CCNA - Config Register Question

Author

Config Register Question

trebor

2001-11-07, 3:00 am

As I understand it there are two places the router tries to get an IOS to execute. One is based on the value of the configuration register. The second method is with the boot system configuration command.

I am looking at the following table from the Cisco Press CCNA Certification Guide

0x1 IOS from ROM is loaded.
0x2-0xF IOS from ROM is loaded.
0x2-0xF First file from Flash is loaded.
0x2-0xF IOS is loaded from Flash.
0x2-0xF IOS is loaded from tftp server

What am I missing? the last four hexadecimal #'s are all the same.

mparry

2001-11-07, 3:08 am

Hello,

I think want they Cisco are trying to say is that if the Hex charcter in the configuration regester is anything from from 2 to F (i.e. 0x2102, 0x2104 or 0x210f)
then the IOS will look for the 'system boot commands'. So whether you have only one boot system command (say boot system tftp) or you have three boot system rom commands (boot syetm tftp, flash, rom) as long as the last four bitsd of the conf register are hex 2 or above - these commands will run.

Marcus

trebor

2001-11-07, 4:15 am

Got it. Thanks.

I just needed that push in the right direction.

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