Cisco Systems 7600 manual Configuring Boot Field Settings and Using the Boot Command

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-registercommand 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-addresscommand).

•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.

	Cisco 7600 Optical Services Router Quick Software Configuration Guide
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