Understanding The Boot Environment Variable; Understanding The Config_File Environment Variable - Cisco WS-C2948G-GE-TX Configuration Manual

Chapter 32 Modifying the Switch Boot Configuration
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Understanding the BOOT Environment Variable

The BOOT environment variable specifies a list of image files on various devices from which the switch
can boot at startup.
You can add several images to the BOOT environment variable to provide a fail-safe boot configuration.
If the first file fails to boot the switch, subsequent images that are specified in the BOOT variable are
tried until the switch boots or there are no additional images to attempt to boot. If there is no valid image
to boot, the system enters ROM-monitor mode where you can manually specify an image to boot.
The system stores and executes images in the order in which you added them to the BOOT variable. If
you want to change the order in which images are tried at startup, you can either prepend and clear
images from the BOOT variable to attain the desired order or you can clear the entire BOOT environment
variable and then redefine the list in the desired order.

Understanding the CONFIG_FILE Environment Variable

In software release 5.2 and later releases, you can use the CONFIG_FILE environment variable to
specify a list of configuration files on various devices to use to configure the switch at startup. You can
specify one of the following functions:
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Note You can alter the CONFIG_FILE variable and change its recurrence properties by entering the
commands in the configuration files that are used to configure the switch at startup. For more
information, see the
When the switch boots up, if any of the files that are specified in the CONFIG_FILE environment
variable are valid configuration files, the configuration in NVRAM is erased and the system uses the
specified configuration file to configure the switch. If multiple valid configuration files are specified,
each configuration file is executed in the order in which it appears in the CONFIG_FILE environment
variable.
Catalyst 4500 Series, Catalyst 2948G, Catalyst 2948G-GE-TX, and Catalyst 2980G Switches Software Configuration Guide—Release 8.2GLX
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Bit 7 (0x0080): Enables OEM bit (not used).
Bit 8 (0x0100): Disables break.
Bit 9 (0x0200): Uses secondary bootstrap (not used by the ROM monitor).
Bit 10 (0x0400): Provides IP broadcast with all zeros (not used).
Bits 11/12 (0x0800/0x1000): These bits are always set to 0/0 (9600 baud).
Bit 13 (0x2000): Boots default Flash software if network boot fails (not used).
Bit 14 (0x4000): IP broadcasts do not have network numbers (not used).
Bit 15 (0x8000): Enables diagnostic messages and ignores NVRAM contents (not used).
Nonrecurring—When you add a list of configuration files to the CONFIG_FILE environment
variable, the next time that the switch is restarted, the system erases the configuration in NVRAM
and uses the specified files to configure the switch. The CONFIG_FILE variable is cleared before
the switch is configured. Nonrecurring is the default setting.
Recurring—When you add a list of configuration files to the CONFIG_FILE environment variable,
the list is stored indefinitely in NVRAM. Each time that the switch is restarted, the system erases
the configuration in NVRAM and configures the switch using the configuration files that are
specified. The CONFIG_FILE variable is not cleared.
"Setting CONFIG_FILE Recurrence" section on page
Understanding How the Switch Boot Configuration Works
32-5.
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