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Cisco ME 3400 Ethernet Access Switch Software Configuration Guide
OL-9639-06
Chapter 3 Assigning the Switch IP Address and Default Gateway Modifying the Startup Configuration
Beginning in privileged EXEC mode, follow these steps to configure the switch to boot a specific image
during the next boot cycle:
To return to the default setting, use the no boot system global configuration command.
Controlling Environment Variables
With a normally operating switch, you enter the boot loader mode only through a switch console
connection configured for 9600 bps. Unplug and then reconnect the switch power cord. After the switch
performs POST, the switch begins the autoboot process. The boot loader prompts the user for a break
key character during the boot-up sequence, as shown in this example:
***** The system will autoboot in 5 seconds *****
Send a break key to prevent autobooting.
The break key character is different for each operating system.
• On a SUN work station running UNIX, Ctrl-C is the break key.
• On a PC running Windows 2000, Ctrl-Break is the break key.
Cisco TAC has tabulated break keys for most common operating systems and provided an alternative
break key sequence for terminal emulators that do not support the break keys. To view this table, see:
http://www.cisco.com/warp/public/701/61.html#how-to
When you enter the break key, the boot loader switch: prompt appears.
The switch boot loader software provides support for nonvolatile environment variables, which can be
used to control how the boot loader, or any other software running on the system, behaves. Boot loader
environment variables are similar to environment variables that can be set on UNIX or DOS systems.
Environment variables that have values are stored in flash memory outside of the flash file system.
Command Purpose
Step 1 configure terminal Enter global configuration mode.
Step 2 boot system filesystem:/file-url Configure the switch to boot a specific image in flash memory during the
next boot cycle.
• For filesystem:, use flash: for the system board flash device.
• For file-url, specify the path (directory) and the name of the bootable
image.
Filenames and directory names are case sensitive.
Step 3 end Return to privileged EXEC mode.
Step 4 show boot Verify your entries.
The boot system global command changes the setting of the BOOT
environment variable.
During the next boot cycle, the switch attempts to automatically boot the
system using information in the BOOT environment variable.
Step 5 copy running-config startup-config (Optional) Save your entries in the configuration file.