What Is Rommon Mode
Perform these steps to configure the router to boot up in ROM monitor mode the next time it is.u upgrade ROMMON, System will reboot after upgrade.
This chapterprovides an overview of ROM Monitor concepts and operations.
This chapterincludes the following main topics:
ROM Monitor Overview
The ROM Monitor is a bootstrap program that initializes the hardware and boots theCisco IOS XE software when you power on or reload a router. Whenyou connect a terminal to the router that is in ROM Monitor mode,the ROM Monitor command-line interface (CLI) prompt isdisplayed.
During normaloperation, users do not use ROM Monitor mode. ROM Monitor mode isused only in special circumstances, such as reinstalling the entiresoftware set, resetting the router password, or specifying aconfiguration file to use at startup.
The ROM Monitor software is known by many names. It is sometimes called ROMMON because of the CLI prompt in ROM Monitor mode. The ROM Monitorsoftware is also called the boot software, boot image, or boot helper. Although it is distributed with routers that use the Cisco IOS XEsoftware, ROM Monitor is a separate program from the Cisco IOS XEsoftware. During normal startup, the ROM Monitor initializes therouter, and then control passes to the Cisco IOS XE software. Afterthe Cisco IOS XE software takes over, the ROM Monitor is no longerin use.
EnvironmentalVariables and the Configuration Register
Two primaryconnections exist between ROM Monitor and the Cisco IOS XEsoftware: the ROM Monitor environment variables and theconfiguration register.
The ROM Monitorenvironment variables define thelocation of the Cisco IOS XE software and describe how to load it.After the ROM Monitor has initialized the router, it uses theenvironment variables to locate and load the Cisco IOS XEsoftware.
The configuration register is a software setting that controls how a card starts up. One ofthe primary uses of the configuration register is to controlwhether the router starts in ROM Monitor mode or AdministrationEXEC mode. The configuration register is set in either ROM Monitormode or Administration EXEC mode as needed. Typically, you set theconfiguration register using the Cisco IOS XE software prompt whenyou need to use ROM Monitor mode. When the maintenance in ROMMonitor mode is complete, you change the configuration register sothe router reboots with the Cisco IOS XE software.
Accessing ROMMonitor Mode with a Terminal Connection
When the router isin ROM Monitor mode, you can access the ROM Monitor software onlyfrom 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 CiscoIOS XE software resources are unavailable. The hardware isavailable, but no configuration exists to make use of thehardware.
NetworkManagement Access and ROM Monitor Mode
It is important toremember that ROM Monitor mode is a router mode, not a mode withinthe Cisco IOS XE software. It is best to remember that ROM Monitorsoftware and the Cisco IOS XE software are two separate programsthat run on the same router. At any given time, the router runsonly one of these programs, .
One area that canbe confusing when using ROM Monitor and the Cisco IOS XE softwareis the area that defines the IP configuration for the ManagementEthernet interface. Most users are comfortable with configuring theManagement Ethernet interface in the Cisco IOS XE software. Whenthe router is in ROM Monitor mode, however, the router does not runthe Cisco IOS XE software, so that Management Ethernet interfaceconfiguration is not available.
When you want toaccess other devices, such as a TFTP server, while in ROM Monitormode on the router, you must configure the ROM Monitor variableswith IP access information.
Access ROM Monitor Mode
The followingsections describe how to enter the ROMMON mode, and contains thefollowing sections:
Checking the Current ROMmon Version
To display theversion of ROMmon running on a router, use the show rom-monitor command or the show platform command.
Copyright (c) 1994-2014 by cisco Systems, Inc.
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Commonly Used ROM Monitor Commands
Table 5-1 summarizes the commands commonly used in ROM Monitor. Forspecific instructions on using these commands, refer to therelevant procedure in this document.
Table 5-1 Commonly Used ROM Monitor Commands
Description | |
|---|---|
boot image | Manually boots aCisco IOS XE software image. |
boot image –oconfig-file-path | Manually boots theCisco IOS XE software with a temporary alternative administrationconfiguration file. |
confreg | Changes theconfig-register setting. |
dev | Displays theavailable local storage devices. |
dir | Displays the fileson a storage device. |
reset | Resets thenode. |
set | Displays thecurrently set ROM Monitor environmental settings. |
sync | Saves the new ROMMonitor environmental settings. |
unset | Removes anenvironmental variable setting. |
Table 5-2 describes the available help commands for ROM Monitor mode.
Table 5-2 Help Commands in ROMMON
Description | |
|---|---|
help or ? | Displays a summaryof all available ROM Monitor commands. |
-? | Displaysinformation about command syntax. |
Note Commands are case-sensitive. You can halt any command by pressingCtrl-C.
Examples
The followingexample shows what appears when you enter the ? command on a router:
Changing the ROM Monitor Prompt
You can change theprompt in ROM Monitor mode by using the PS1= command as shown in the following example:
Changing theprompt is useful if you are working with multiple routers in ROMMonitor at the same time. This example specifies that the promptshould be “ISR4400 rommon ”, followed by the line number, and thenfollowed by “ > “ by the line number.
Displaying the Configuration Register Setting
To display thecurrent configuration register setting, enter the confreg command without parameters asfollows:
The configurationregister setting is labeled Virtual Configuration Register. Enter the no command to avoid changing the configuration register setting.
Environment Variable Settings
The ROM Monitorenvironment variables define theattributes of the ROM Monitor. Environmental variables are enteredlike commands and are always followed by the equal sign (=).Environment variable settings are entered in capital letters,followed by a definition. For example:
Under normaloperating conditions, you do not need to modify these variables.They are cleared or set only when you need to make changes to theway ROM Monitor operates.
This sectionincludes the following topics:
Frequently Used Environmental Variables
Table 5-3 showsthe main ROM Monitor environmental variables. For instructions onhow to use these variables, see the relevant instructions in thisdocument.
Table 5-3 Frequently Used ROM Monitor EnvironmentalVariables
Description | |
|---|---|
IP_ADDRESS=ip_address | Sets the IPaddress for the Management Ethernet interface. |
IP_SUBNET_MASK=ip_address | Sets the subnetmask for the Management Ethernet interface. |
DEFAULT_GATEWAY=ip_address | Sets the defaultgateway that serves. |
TFTP_SERVER=ip_address | Sets the IPaddress of the TFTP server where a bootable software image islocated. |
TFTP_FILE=path/file | Sets the directoryand filename of a bootable software image. |
BOOT=path/file | Identifies theboot software for a node. This variable is usually setautomatically when the router boots. |
Displaying EnvironmentVariable Settings
To display thecurrent environment variable settings, enter the set command :
Entering EnvironmentVariable Settings
Environmentvariable settings are entered in capital letters, followed by adefinition. Pro evolution soccer download. The following example shows the environmental variablesused to configure the control Ethernet port on a router:
Saving EnvironmentVariable Settings
To save thecurrent environment variable settings, enter the sync command:
Note Environmental values that are not saved with the sync command are discarded whenever the system isreset or booted.
Exiting ROM Monitor Mode
To exit ROMMonitor mode, you must change the configuration register and resetthe router.
SUMMARYSTEPS
1. confreg
2. Respond to each prompt as instructed.
3. reset
DETAILEDSTEPS
Command orAction | ||
|---|---|---|
Step1 | confreg Example: rommon1> confreg | Initiates theconfiguration register configuration prompts. |
Step 2 | Respond to eachprompt as instructed. | See the example thatfollows this procedure for more |
Step 3 | reset Example: rommon2> reset | Resets andinitializes the router. |
ConfigurationExample
Upgrading the ROMmon for aRouter
Use this procedureto upgrade the ROMmon on a router:
Step 1 (Optional) Run the show platform command or theshow rom-monitorslot command on the router to see the current release numbers of ROMmonon the hardware. See the “Checking the Current ROMmon Version” section for informationabout interpreting the output of the command that you run.
Step 2 Ifthe ROMmon image has not been copied onto the router, copy the PKGfile that is made available as part of this ROMmon release onto thebootflash: or usb[0-1]: file system using the copy source-locationdestination-location command. For example, if you are upgrading toRelease 15.2(1r)S, copy the isr4400-rommon-154-3r.S.pkg file.
Step 3 Runthe dirfile-system command to verify that the ROMmon file is copied into thespecified directory.
Step 4 Runthe upgrade rom-monitor filenamelocationall command to begin the ROMmon image upgrade, where location is the path to the ROMmon file.
Step 5 Messages pertaining to the upgrade are displayed on the console.After the display of these messages stops and the router prompt isavailable, run the reload command to reload the router.
Step 6 Ifautoboot has not been enabled by using the config-register 0x2102 command, run the bootfilesystem:/file-location command at the ROMmon prompt to boot the Cisco IOS XE image, wherefilesystem:/file-location is the path to the consolidated package file. The ROMmon upgradeis not permanent for any piece of hardware until the Cisco IOS XEimage is booted.
Step 7 Runthe enable command at the user prompt to enter the privileged EXEC mode afterthe boot is complete.
Step 8 Runthe show platform command or the show rom-monitor slot command to verify whether the ROMmon has been upgraded.