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ROM Monitor Overview
ROM Monitor Overview
The ROMMON environment variables define the location of the Cisco IOS XE software and describe how
to load it. After ROMMON has initialized the router, it uses the environment variables to locate and load the
Cisco IOS XE software.
The configuration register is a software setting that controls how a router starts up. One of the primary uses
of the configuration register setting is to control whether the router starts in ROMMON mode or Administration
EXEC mode. The configuration register is set in either ROMMON mode or Administration EXEC mode as
needed. You can set the configuration register using the Cisco IOS XE software prompt when you need to
use ROMMON mode. When maintenance in ROMMODE mode is complete, change the configuration register
back so that the router reboots with the Cisco IOS XE software.
Access ROMMON Mode with a Terminal Connection
When the router is in ROMMODE mode, you can access the ROMMODE software only from a terminal
connected directly to the console port of the card. Because the Cisco IOS XE software (EXEC mode) is in
operatiion, the nonmanagement interfaces are not accessible. Therefore, all Cisco IOS XE software resources
are unavailable.
Network Management Access and ROMMON Mode
ROMMON mode is a router mode, not a mode within the Cisco IOS XE software. The ROMMON software
and the Cisco IOS XE software are two separate programs that run on the same router. At any given time, the
router is running one of these programs, but it never runs both at the same time.
One area that can be confusing when using ROMMON 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 ROMMON mode,
however, the router is not running the Cisco IOS XE software, therefore, Management Ethernet interface
configuration is not available.
When you want to access other devices, such as a TFTP server, while in ROMMON mode on the router, you
must configure the ROMMON variables with IP access information.
For more information on ROMMON and Basic Procedures, refer to the
Upgrading Field-Programmable
Hardware Devices for Cisco 1000 Series ISRs
Hardware Installation Guide for the Cisco 1000 Series Integrated Services Router
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