Cisco 7000 Hardware Installation And Maintenance page 178

Installing and Configuring Processor Modules
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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Table 5-4 lists the meaning of each of the software configuration memory bits, and Table 5-5 defines
the boot field.
Caution
register settings might be combinations of settings and not just the individual settings listed in
Table 5-4. For example, the factory default value of 0x0101 is a combination of settings.
Table 5-4
Bit No.
00 to 03
06
07
08
09
10
11 to 12
13
14
15
1. The factory default value for the configuration register is 0x0101. This value is a combination of the
following: bit 8 = 0x0100 and bits 00 through 03 = 0x0001 (see Table 5-5).
2. OEM = Original equipment manufacturer.
5-174 Cisco 7000 Hardware Installation and Maintenance
Set and display the configuration register value
Force the system into the bootstrap program
Select a boot source and default boot filename
Enable or disable the Break function
Control broadcast addresses
Set the console terminal baud rate
Load operating software from ROM
Enable booting from a Trivial File Transfer Protocol (TFTP) server
To avoid confusion and possibly halting the router, remember that valid configuration
Software Configuration Register Bit Meanings
1
Hexadecimal
0x0000 to 0x000F
0x0040
0x0080
0x0100
0x0200
0x0400
0x0800 to 0x1000
0x2000
0x4000
0x8000
Meaning
Boot field (see Table 5-5)
Causes system software to ignore NVRAM contents
2
OEM bit enabled
Break disabled
Use secondary bootstrap
Internet Protocol (IP) broadcast with all zeros
Console line speed (default is 9,600 baud)
Boot default ROM software if network boot fails
IP broadcasts do not have network numbers
Enable diagnostic messages and ignore NVRAM contents