Cisco 3700 series User Manual

C-1
Cisco 3700 Series Routers Hardware Installation Guide
OL-2180-08
APPENDIX C
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:
• 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
Configuration Register Settings
The router has a 16-bit configuration register in NVRAM. You can use the configuration register to
perform the following tasks:
• 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.
Table C-1 describes each of the configuration register bits.
Table C-1 Configuration Bit Meanings
Bit
Number Hexadecimal Meaning
00–03 0x0000–0x000F Boot field. (See Table C-2.)
06 0x0040 Causes the system software to ignore the contents of NVRAM.
07 0x0080 OEM bit enabled.
08 0x0100 Break disabled.
09 0x0200 Causes the system to use the secondary bootstrap. This bit is typically not
used (set to 0).

Cisco 3700 series Specifications

General

Brand	Cisco
Model	3700 series
Category	Network Router
Language	English