Setting the Bootstrap Behavior

A Cisco router's bootstrap behavior is set using what is known as the configuration register (conf-reg). On the early Cisco routers (such as AGS), the conf-reg was set with jumpers on the router's system board. On the later Cisco models (Cisco 1000 and up), the conf-reg can be set in global configuration mode using the config-register command:

Router# configure terminal
Router(config)#config-register 0x2102

Alternatively, if access to global configuration mode is unavailable, the ROM Monitor (rommon), which is similar in function to a PC's BIOS mode, can be used. To access rommon, you need to be attached to the console port and you need to issue a terminal break sequence through ...

Get Understanding the Network: A Practical Guide to Internetworking now with the O’Reilly learning platform.

O’Reilly members experience live online training, plus books, videos, and digital content from nearly 200 publishers.