Access Rom Monitor Mode; Checking The Current Rommon Version; C H A P T E R 5 Rom Monitor Overview And Basic Procedures - Cisco 4451 ISR Hardware Installation Manual

Access ROM Monitor Mode

The configuration register is a software setting that controls how a card starts up. One of the primary
uses of the configuration register is to control whether the router starts in ROM Monitor mode or
Administration EXEC mode. The configuration register is set in either ROM Monitor mode or
Administration EXEC mode as needed. Typically, you set the configuration register using the
Cisco IOS XE software prompt when you need to use ROM Monitor mode. When the maintenance in
ROM Monitor mode is complete, you change the configuration register so the router reboots with the
Cisco IOS XE software.
Accessing ROM Monitor Mode with a Terminal Connection
When the router is in ROM Monitor mode, you can access the ROM Monitor software only from a
terminal connected directly to the console port of the card. Because the Cisco IOS XE software (EXEC
mode) is not operating, nonmanagement interfaces are not accessible. Basically, all
Cisco IOS XE software resources are unavailable. The hardware is available, but no configuration exists
to make use of the hardware.
Network Management Access and ROM Monitor Mode
It is important to remember that ROM Monitor mode is a router mode, not a mode within the
Cisco IOS XE software. It is best to remember that ROM Monitor software and the
Cisco IOS XE software are two separate programs that run on the same router. At any given time, the
router runs only one of these programs, .
One area that can be confusing when using ROM Monitor and the Cisco IOS XE software is the area that
defines the IP configuration for the Management Ethernet interface. Most users are comfortable with
configuring the Management Ethernet interface in the Cisco IOS XE software. When the router is in
ROM Monitor mode, however, the router does not run the Cisco IOS XE software, so that Management
Ethernet interface configuration is not available.
When you want to access other devices, such as a TFTP server, while in ROM Monitor mode on the
router, you must configure the ROM Monitor variables with IP access information.
Access ROM Monitor Mode
The following sections describe how to enter the ROMMON mode, and contains the following sections:
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Checking the Current ROMmon Version

To display the version of ROMmon running on a router, use the show rom-monitor command or the
show platform command.
Hardware Installation Guide for the Cisco 4000 Series Integrated Services Router
5-2
Checking the Current ROMmon Version, page 5-2
Commonly Used ROM Monitor Commands, page 5-4
Changing the ROM Monitor Prompt, page 5-5
Chapter 5 ROM Monitor Overview and Basic Procedures
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