Cisco 3925 User Manual

D-1
Cisco 3900 Series, Cisco 2900 Series, and Cisco 1900 Series Integrated Services Routers Generation 2 Software Configuration Guide
APPENDIX
D
Changing the Configuration Register Settings
The following sections describe the 16-bit configuration register in NVRAM in the Cisco 3900 series,
Cisco 2900 series, and Cisco 1900 series integrated services routers (ISRs):
• About the Configuration Register, page D-1
• Changing the Configuration Register Settings, page D-4
• Displaying the Configuration Register Settings, page D-5
• Configuring the Console Line Speed (Cisco IOS CLI), page D-5
About the Configuration Register
The router has a 16-bit configuration register in NVRAM. Each bit has value 1 (on or set) or value 0 (off
or clear), and each bit setting affects the router behavior upon the next reload power cycle.
You can use the configuration register to
• Force the router to boot into the ROM monitor (bootstrap program)
• Select a boot source and default boot filename
• Enable or disable the Break function
• Control broadcast addresses
• Recover a lost password
• Change the console line speed
Table D-1 describes the configuration register bits.
Table D-1 Configuration Register Bit Descriptions
Bit
Number Hexadecimal Meaning
00–03 0x0000–0x00
0F
Boot field. The boot field setting determines whether the router loads an
operating system and where it obtains the system image.
See Table D-2 for details.
06 0x0040 Causes the system software to ignore the contents of NVRAM.
07 0x0080 OEM
1
bit enabled.

Cisco 3925 Specifications

General

Product Type	Router
Form Factor	Rack-mountable
Data Link Protocol	Ethernet, Fast Ethernet, Gigabit Ethernet
Connectivity Technology	Wired
Power	AC 120/230 V (50/60 Hz)
Redundant Power Supply	Optional
Routing Protocol	OSPF, IS-IS, BGP, EIGRP, PIM
Network/Transport Protocol	IPSec
Remote Management Protocol	SNMP, Telnet, SSH, HTTP
Encryption Algorithm	DES, Triple DES, AES
Flash Memory	256 MB
Weight	11.5 kg
Interfaces	2 x SFP (mini-GBIC)
Power Source	Internal power supply
Authentication Method	RADIUS, TACACS+, LDAP
Compliant Standards	IEEE 802.1Q, IEEE 802.3af
Operating Temperature	0 to 40 °C
Operating Humidity	5% to 85% (non-condensing)
Dimensions (WxDxH)	44.5 x 47.2 x 8.9 cm