Cisco 2911 Configuration Guide

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 2911 Specifications

General

Ethernet LAN	Yes
Cabling technology	10/100/1000Base-T(X)
Networking standards	IEEE 802.1Q, IEEE 802.1ag, IEEE 802.3, IEEE 802.3ab, IEEE 802.3af, IEEE 802.3ah, IEEE 802.3u
Ethernet LAN data rates	10, 100, 1000 Mbit/s
Ethernet interface type	Gigabit Ethernet
DHCP client	-
Routing protocols	BGP, EIGRP, OSPF
Supported protocols	IPv4, IPv6, IS-IS, IGMPv3, PIM SM, SSM, DVMRP, IPSec, GRE, BVD, MPLS, L2TPv3, PPP, MLPPP, MLFR, HDLC, RS-232, RS-449, X.21, V.35, EIA-530, PPPoE, ATM
USB version	2.0
RS-232 ports	1
Expansion slots	4 x EHWIC 2 x DSP 1 x ISM
USB ports quantity	2
Ethernet LAN (RJ-45) ports	3
Firewall security	Cisco IOS
Input current	2.2 A
AC input voltage	100 - 240 V
Power source type	AC
AC input frequency	47 - 63 Hz
Power consumption (typical)	50 W
Product color	Black
Rack capacity	2U
Operating altitude	0 - 4000 m
Non-operating altitude	0 - 4570 m
Storage temperature (T-T)	-40 - 80 °C
Operating temperature (T-T)	0 - 40 °C
Storage relative humidity (H-H)	5 - 95 %
Operating relative humidity (H-H)	5 - 85 %
Safety	UL 60950-1, CAN/CSA C22.2 No. 60950-1, EN 60950-1, AS/NZS 60950-1, IEC 60950-1
Electromagnetic compatibility	47 CFR, ICES-003, EN55022, CISPR22, AS/NZS 3548, VCCI V-3, EN 300-386, EN 61000, EN 55024, CISPR 24EN50082-1

Weight and Dimensions

Depth	304.8 mm
Width	438.2 mm
Height	88.9 mm
Weight	8200 g