Cisco Systems 2600 manual ROM Monitor Command Descriptions, Router Management Commands

Appendix B Using the ROM Monitor

ROM Monitor Command Descriptions

ROM Monitor Command Descriptions

Router Management Commands

This section lists some useful ROM monitor commands. Refer to the Cisco IOS configuration guides and command references for more information on ROM monitor commands.

Boot Commands in the ROM Monitor

Functions of Boot Commands

The router always boots first from a Cisco IOS image in flash memory, because there is no separate, dedicated boothelper image ([rx]boot). The first image in flash memory functions as the boothelper image, but you can override this by setting the BOOTLDR Monitor environment variable to point to another image. If the ROM monitor does not recognize a device ID specified in the boot command (device does not exist, or command entered incorrectly), the router boots from the first image in flash memory.

To boot a router from a Cisco IOS image on a TFTP server (netboot), the installed DRAM must be adequate to hold two uncompressed Cisco IOS images: the image from flash memory and the image downloaded from the TFTP server.

If the router is configured to boot from a TFTP server (boot bits in the configuration register are set from 2 to 15), the router first boots from the image in flash memory. It decompresses that image in DRAM, parses the boot system commands, downloads the Cisco IOS image from the TFTP server, and decompresses it in DRAM. After the Cisco IOS image from the TFTP server is in DRAM, the DRAM memory occupied by the boothelper image is released.

Note Booting from a TFTP server is useful if the router does not have enough flash memory to hold large images. With a small image in flash memory (just large enough to support the necessary interfaces), the router boots from flash memory, and then the larger image is downloaded from the TFTP server.

Entering Boot Commands

The boot command syntax is as follows, where:

•partition is a partition number in the flash memory.

•filename is the Cisco IOS image filename.

•tftpserver is the IP address of the TFTP server.

•-xdirects the router to load the image but not execute the boot process.

•-v(verbose) specifies that progress print setting messages and error information be displayed.

boot [flash: [partition: [filename]] slot0: [partition: [filename]] slot1: [partition: [filename]] filename tftpserver] [-x][-v]

Some examples of boot commands are as follows:

Note In all boot commands, boot can be entered as b.

Cisco 2600 Series Routers Hardware Installation Guide

B-4 OL-2171-06