Appendix C Configuration Register
Configuring the Boot Field
The boot field specifies a number in binary form. If you set the boot field value to 0, you must have console port access to boot the operating system manually. Refer to the boot command in the “ROM Monitor Command Descriptions” section on page B-4.
If you set the boot field to a value of 2 to F, and there is a valid boot system command stored in the configuration file, the router software processes each boot command in sequence until the process is successful or the end of the list is reached. If there are no boot commands in the configuration file, the router attempts to boot the first file in flash memory.
In the following example, the configuration register is set to boot the router automatically from flash memory and to ignore Break at the next reboot of the router:
Router# configure terminal
Enter configuration commands, one per line.
Edit with DELETE, CTRL/W, and CTRL/U; end with CTRL/Z config-register 0x102
Ctrl-z
Note A boot system command in the router configuration in NVRAM overrides booting from flash memory.
Bit 8 controls the console Break key. Setting bit 8 (the factory default) causes the processor to ignore the console Break key. Clearing bit 8 causes the processor to interpret Break as a command to force the router into the bootstrap monitor, halting normal operation. Break can always be sent in the first
60 seconds while the router is rebooting, regardless of the configuration settings.
Bit 9 controls the system boot. Clearing bit 9 (the factory default) causes the system to boot from flash memory. Clearing bit 9 causes the system to use the secondary bootstrap (netbooting). This is typically not used.
Bit 10 controls the host portion of the IP broadcast address. Setting bit 10 causes the processor to use all zeros; clearing bit 10 (the factory default) causes the processor to use all ones. Bit 10 interacts with bit 14, which controls the network and subnet portions of the broadcast address. Table C-3shows the combined effect of bit 10 and bit 14.
Table C-3 Configuration Register Settings for Broadcast Address Destination
Bit 10 | Bit 14 | Address (<net> <host>) |
| | |
Off | Off | <ones> <ones> |
| | |
On | Off | <zeros> <zeros> |
| | |
On | On | <net> <zeros> |
| | |
Off | On | <net> <ones> |
| | |
Bit 13 determines the router’s response to a bootload failure. Setting bit 13 causes the router to load operating software from ROM after six unsuccessful attempts to load a boot file. Clearing bit 13 causes the router to continue indefinitely to attempt loading a boot file. By factory default, bit 13 is set to 0.
Bit 5, bit 11, and bit 12 of the configuration register determine the baud rate of the console terminal. Table C-4shows the bit settings for the eight available rates. (The default baud rate is 9600 bps.)
Cisco 2600 Series Routers Hardware Installation Guide
Cisco 2600 Series Routers Hardware Installation Guide
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Cisco 2600 Series Routers Hardware Installation Guide
N T E N T S
Iii
Serial DTE or DCE Devices
Initial Configuration Using the Setup Command Facility
Procedure for the tftpdnld Command Configuration Register
Objectives
Vii
Audience
Organization
Conventions
Chapter Title Description
Safety Warnings
Bewaar Deze Instructies
Warnung Wichtige Sicherheitshinweise
Avvertenza Importanti Istruzioni Sulla Sicurezza
Aviso Instruções Importantes DE Segurança
Guarde Estas Instruções
GEM Disse Anvisninger
Xii
Xiii
Related Documentation
Xiv
Cisco Product Document Title
Cisco 90-Day Limited Hardware Warranty Terms
Duration of Hardware Warranty
Replacement, Repair, or Refund Policy for Hardware
Xvi
Obtaining Documentation
Documentation Feedback
Cisco.com
Ordering Documentation
Submitting a Service Request
Obtaining Technical Assistance
Cisco Technical Support Website
Xviii
Definitions of Service Request Severity
Obtaining Additional Publications and Information
Xix
Preface Obtaining Additional Publications and Information
Hardware Features
Overview of Cisco 2600 Series Routers
Advanced
Cisco
Power
Reading the Front-Panel LEDs
RPS
Activity
PWR
SYS/RPS
Reading the Rear-Panel LEDs
ACT
Cisco 2613-Rear-Panel LEDs
Link
ACT
FDX
Modules, Interface Cards, and Memory
CF1
Interface Numbering
WAN and LAN Interface Numbering
11 Interface Numbering in Chassis with 1-RU Height
System Specifications
Description Specification
Voice Interface Numbering
Regulatory Compliance
Safety Recommendations
Safety with Electricity
Preventing Electrostatic Discharge Damage
Power Supply Considerations
Power Source Input Power Tolerance Limits
General Site Requirements
Site Environment
Installation Checklist
Site Configuration
Equipment Racks
Creating a Site Log
Task Verified by Date
Tools and Equipment for Installation and Maintenance
Inspecting the Router
Console and Auxiliary Port Considerations
Console Port Connections
Preparing to Connect to a Network
Auxiliary Port Connections
Ethernet Connections
Token Ring Connections
Configuring Serial Connections
Serial Connections
Serial DTE or DCE Devices
Signaling Standards Supported
Distance Limitations
Device Type Gender Typical Devices
Isdn BRI Connections
Asynchronous/Synchronous Serial Module Baud Rates
EIA/TIA-232
Distance EIA-530 Distance Rate bps Feet Meters
56-K/Switched-56-kbps DSU/CSU Connections
Low-Capacitance Cable
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Installing the Router
Installing Modules, Interface Cards, and Power Supplies
For network modules
For WICs and VICs
For AIMs
Setting Up the Chassis
Setting the Chassis on a Desktop
For internal power supplies
For external power supplies
Mounting the Chassis in a Rack
Right
To the other side of the chassis. Brackets for 19-inch rack
Brackets for 19-inch rack
To the other side of the chassis
Attaching the Brackets to a Router of 2-RU Height
Use two screws on each side For 19-inch rack Right bracket
Installing the Router in a Rack
V0 EN
Mounting the Chassis on the Wall
Attaching Rubber Feet to the Router
Attaching Wall-Mount Brackets to the Router
Mounting the Router on the Wall
16 Attaching the Wall-Mount Brackets
Installing the Chassis Ground Connection
17 Mounting the Chassis on the Wall
Ring terminal
Power Connections
Connecting Routers to AC Power
Connecting Routers to a DC-Input Power Supply
DC Wiring Requirements
Router DC Input DC Input Wire Size1
15A, 120VAC 10A, 240VAC. Statement
Wiring Procedure for DC Input
Connecting WAN, LAN, and Voice Cables
Connecting Routers to the Cisco Redundant Power System
Ports and Cabling
Port or Connection Port Type, Color Connected To Cable
LAN, WAN, and Voice Connection Procedures
Connecting to a Console Terminal or Modem
Connecting to the Console Port
Connecting to the Auxiliary Port
23 Connecting to a Console Terminal
24 Connecting a Modem to the Auxiliary Port
Identifying a Rollover Cable
Powering Up the Router
Checklist for Power Up
Front Panel Indicators
Routers with 1-RU Chassis Height
Power-Up Procedure
Routers with 2-RU Chassis Height
Configuring the Router
Initial Configuration Using SDM
Initial Configuration Using the Setup Command Facility
Enter a hostname for the router this example uses
Initial Configuration Using the CLI Manual Configuration
Configuration is displayed
To proceed with manual configuration using the CLI, enter no
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Troubleshooting
Isolating Problems
Troubleshooting the Power and Cooling Systems
Environmental Reporting Features
Troubleshooting Modules, Cables, and Connections
Recovering a Lost Password
System Messages
Cisco Technical Assistance Center
Using the ROM Monitor
Entering ROM Monitor Mode
ROM Monitor Commands
Enter ROM Monitor Mode by Using the reload Command
ROM Monitor Command Syntax Conventions
Command abc
ROM Monitor Command Descriptions
Router Management Commands
Boot Commands in the ROM Monitor
Informational Commands in the ROM Monitor
Debugging Commands
Other Useful ROM Monitor Commands
Configuration Register Commands
Modifying the Configuration Register in Menu Mode
Recovering Cisco IOS Software Images
Modifying the Configuration Register by Hexidecimal Entry
Copying an Image from the Console Using the xmodem Command
Description and Options of the xmodem Command
Procedure for the xmodem Command
Console Requirements
Restrictions on the tftpdnld Command
Procedure for the tftpdnld Command
Specify the required variables, for example
DEFAULTGATEWAY=172.16.19.1
Configuration Register Settings
Bit Number Hexadecimal Meaning
Nvram
Changing Configuration Register Settings
Configuring the Boot Field
Boot Field Meaning
Bit Address net host
Enabling Booting from Flash Memory
Baud Bit
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Numerics
IN-1
Dram
IN-2
Isdn BRI
LAN
Link LED
IN-3
Sdram
IN-4
IN-5
IN-6