Cisco RSP2 - Route Switch Processor 2 Installation And Configuration Manual page 79

Software Configuration Register Settings
Settings for the 16-bit software configuration register are written into the NVRAM. Following are some
reasons for changing the software configuration register settings:
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•
The Break function (software configuration register bit 8) when enabled allows you to send a Break
Note
signal to the router during a system (re)boot. This stops the boot process and places the router into
ROM monitor mode. You can activate the Break function by using a dedicated Break key function on
the keyboard, or by entering the Ctrl-[ (left square bracket) key combination.
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•
•
•
•
•
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If the router finds no boot system commands, it uses the configuration register value to form a filename
from which to boot a default system image stored on a network server. (See
Table 18
boot field.
To avoid confusion and possibly halting the router, remember that valid configuration register
Caution
settings might be combinations of settings and not just the individual settings listed in
example, the factory default value of 0x0102 is a combination of settings.
Table 18
Bit Number
00 to 0F
06
07
08
09
10
11 to 12
13
OL-4923-01 B0
To select a boot source and default boot filename
To enable or disable the Break function
To control broadcast addresses
To set the console terminal baud rate
To load operating software from the Flash memory card
To enable booting from a Trivial File Transfer Protocol (TFTP) server
To recover a lost password
To allow you to manually boot the system using the b command at the bootstrap program prompt
To force the router to boot automatically from the system bootstrap software (boot image) or from
its default system image in onboard Flash memory, and to read any boot system commands that are
stored in the configuration file in NVRAM
lists the meaning of each of the software configuration memory bits, and
Software Configuration Register Bit Meanings
1
Hexadecimal
0x0000 to 0x000F
0x0040
0x0080
0x0100
0x0200
0x0400
0x0800 to 0x1000
0x2000
Meaning
Boot field (see Table 19)
Causes system software to ignore NVRAM contents
2
OEM bit enabled
Break disabled
Use secondary bootstrap
IP broadcast with all zeros
Console line speed (default is 9600 baud)
Boot default Flash memory software if network boot fails
Table 20.)
Table 19 defines the
Table 18. For
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