User Guide

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Cisco 7600 Optical Services Router Quick Software Configuration Guide
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Chapter 2 Basic MSFC Software Configuration
Performing Other Configuration Tasks
Configuring Boot Field Settings and Using the Boot Command
The four low-order bits of the software configuration register (bits 3, 2, 1, and 0)
form a boot field that defines the source of a Cisco IOS software image for booting
the Cisco 7600 OSR.
You can set or change the contents of the boot field by entering the config-register
command at the global configuration mode prompt [Router(config)#].
The factory default setting for the software configuration register is 0x0102.
When the boot field is set to either 0 or 1 (0-0-0-0 or 0-0-0-1), the system ignores
any boot instructions in the system configuration file and one of the following
occurs, depending on the boot field setting:
• When the boot field is set to 0, you must boot the system manually by entering
the boot command at the ROM monitor prompt (rommon>). You can enter the
boot command with or without arguments.
If you enter the boot command without an argument (that is, without
specifying a file or any other boot instructions), the system automatically
boots using the default image in the Flash memory SIMM.
If you enter the boot command with arguments (that is, by instructing the
system to boot from a specific source), these options are available to you:
– You can instruct the system to boot from a specific Flash SIMM image
(by entering the boot system flash filename command), or you can
instruct the system to boot from a specific image stored on a PCMCIA
Flash memory card.
– You can instruct the system to boot from a network TFTP server either
by sending broadcast TFTP requests (by entering a boot system filename
command), or by sending a direct request to a specific network TFTP
server (by issuing a boot system filename ip-address command).
• When the boot field is set to 1, the system automatically boots using the first
image found in the onboard Flash SIMM.
If you set the boot field to any bit pattern other than 0 or 1, the router uses the
software configuration register settings to create a filename from which to boot a
default system image stored on a network TFTP server.