Configuring The Boot Field - Cisco 3700 Series Hardware Installation Manual

Configuring the Boot Field

The boot field specifies a number in binary form. If you set the boot field value to 0, you must have
console port access to boot the operating system manually. See the boot command in the
Command Descriptions" section on page
If you set the boot field to a value of 2 to F, and a valid boot system command is stored in the
configuration file, the router software processes each boot command in sequence until the process is
successful or the end of the list is reached. If no boot commands are in the configuration file, the router
attempts to boot the first file in CompactFlash memory.
In the following example, the configuration register is set to boot the router automatically from
CompactFlash memory and to ignore Break at the next reboot of the router:
Router# configure terminal
Enter configuration commands, one per line.
Edit with DELETE, CTRL/W, and CTRL/U; end with CTRL/Z
config-register 0x102
Ctrl-z
Router#
A boot system command in the router configuration in NVRAM overrides booting from CompactFlash
Note
memory.
Bit 8 controls the console Break key. Setting bit 8 (the factory default) causes the processor to ignore the
console Break key. Clearing bit 8 causes the processor to interpret Break as a command to force the
router into the bootstrap monitor, halting normal operation. Break can always be sent in the first
60 seconds while the router is rebooting, regardless of the configuration settings.
Bit 9 controls the system boot. Clearing bit 9 (the factory default) causes the system to boot from
CompactFlash memory. Clearing bit 9 causes the system to use the secondary bootstrap. This bit is
typically not used.
Bit 10 controls the host portion of the IP broadcast address. Setting bit 10 causes the processor to use all
zeros; clearing bit 10 (the factory default) causes the processor to use all ones. Bit 10 interacts with
bit 14, which controls the network and subnet portions of the broadcast address.
combined effect of bits 10 and 14.
Table C-3
Bit 10
Off
On
On
Off
Bit 13 determines how the router responds to a bootload failure. Setting bit 13 causes the router to load
operating software from ROM after six unsuccessful attempts to load a boot file. Clearing bit 13 causes
the router to continue indefinitely to attempt loading a boot file. By factory default, bit 13 is set to 0.
Bits 5, 11, and 12 of the configuration register determine the data rate of the console terminal.
shows the bit settings for the eight available rates. (The default data rate is 9600 bps.)
Cisco 3700 Series Routers Hardware Installation Guide
C-4
Configuration Register Settings for Broadcast Address Destination
Bit 14 Address (<net> <host>)
Off <ones> <ones>
Off <zeros> <zeros>
On <net> <zeros>
On <net> <ones>
B-3.
Appendix C Configuration Register
"ROM Monitor
Table C-3 shows the
Table C-4
OL-2180-08