Boot Field Settings And The Boot Command - Cisco GSR12/60 - 12012 Router -AnyLAN, SONET/SDH Installation And Configuration Manual

Implementing Other Configuration Tasks

Boot Field Settings and the boot Command

Bits 0 through 3 of the software configuration register form the boot field, specified as a
binary number.
Note
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 the following occurs:
•
When the boot field is set to 0, you must boot the operating system manually by issuing
the boot command to the system bootstrap program or rom monitor.
•
When the boot field is set to 1, the system boots the first image in the onboard bootflash
single in-line memory module (SIMM).
You can enter the boot command only, or include additional boot instructions with the
command such as the name of a file stored in Flash memory or a file that you specify for
booting from a network server. If you use the boot command without specifying a file or
any other boot instructions, the system boots from the default Flash image (the first image
in onboard Flash memory). Otherwise, you can instruct the system to boot from a specific
Flash image (using the boot system flash filename command), or boot from a network
server by sending broadcast TFTP requests (using the boot system filename command), or
send a direct TFTP request to a specific server (using the boot system filename ip-address
command).
You can also use the boot command to boot images stored in the Personal Computer
Memory Card International Association (PCMCIA) Flash memory cards located in
PCMCIA slot 0 or slot 1 on the RP. If you set the boot field to any bit pattern other than 0
or 1, the system uses the resulting number to form a filename for booting over the network.
To form this filename, the system starts with cisco and links the octal equivalent of the boot
field value and the processor type in the following format:
cisco<bootfieldvalue>-<processorname>; for example, cisco2-grp. The system uses this
filename to invoke the system image by booting over the net. However, if the configuration
file contains any boot instructions, the system uses those boot instructions instead of the
filename it computed from the configuration register settings.
4-26 Cisco 12012 Gigabit Switch Router Installation and Configuration Guide
The factory default configuration register setting for systems and RP spares is