The ROM Monitor environment variables define the location of the Cisco IOS XE software and describe how
to load it. After ROM Monitor 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 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, the nonmanagement interfaces are not accessible. Basically, all Cisco IOS XE software resources
are unavailable.
Network Management Access and ROM Monitor Mode
ROM Monitor mode is a router mode, not a mode within the Cisco IOS XE software. 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 is running one of these programs, but it never runs both at the same time.
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 router users get comfortable with
configuring the Management Ethernet interface in the Cisco IOS XE software. When the router is in ROM
Monitor mode, however, the router is not running 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.
Entering ROM Monitor Mode
The following sections describe how to enter the ROMMON mode, and contains the following sections:
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.
Router# show rom-monitor r0
System Bootstrap, Version 12.2[16.6(1r)RC3], DEVELOPMENT SOFTWARE
Copyright (c) 1994-2017 by cisco Systems, Inc.
Compiled at Fri Jul 28 13:07:32 2017 by user5
Router# show platform
Chassis type: C1111-8PLTELAWN
Slot
Type
State
Insert time (ago)
--------- ------------------- --------------------- -----------------
0
C1111-8PLTELAWN
ok
00:04:56
0/0
C1111-2x1GE
ok
00:02:41
0/1
C1111-ES-8
ok
00:02:40
Hardware Installation Guide for the Cisco 1100 Series Integrated Services Router
42
ROM Monitor Overview and Basic Procedures
Entering ROM Monitor Mode
