Appendix; Configuration Register; Configuration Register Settings - Cisco 3700 Series Hardware Installation Manual

Configuration Register

This appendix describes the factory default settings of the configuration register, and procedures for
changing those settings.
This appendix includes the following sections:
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Configuration Register Settings

The router has a 16-bit configuration register in NVRAM. You can use the configuration register to
perform the following tasks:
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Table C-1
Table C-1
Bit
Number
00–03
06
07
08
09
OL-2180-08
Configuration Register Settings, page C-1
Changing Configuration Register Settings, page C-2
Configuring the Boot Field, page C-3
Enabling Booting from CompactFlash Memory, page C-5
Set and display the configuration register value.
Force the router into the ROM monitor (bootstrap program).
Select a boot source and default boot filename.
Enable or disable the Break function.
Control broadcast addresses.
Load operating software from ROM.
describes each of the configuration register bits.
Configuration Bit Meanings
Hexadecimal Meaning
0x0000–0x000F Boot field. (See
0x0040 Causes the system software to ignore the contents of NVRAM.
0x0080 OEM bit enabled.
0x0100 Break disabled.
0x0200 Causes the system to use the secondary bootstrap. This bit is typically not
used (set to 0).
A P P E N D I X
Table C-2.)
Cisco 3700 Series Routers Hardware Installation Guide
C
C-1