Cisco Systems 3700 Series manual Configuration Register Settings, A P P E N D I X C

A P P E N D I X 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-1describes 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 Routers Hardware Installation Guide
	OL-2180-08				C-1