Cisco 3000 Series - Page 83

Virtual
Configuration
Register Settings
Table B-i Virtual
Configuration Bit
Meanings
Bit
Hex
Meaning
No
0003 Ox0000Ox000F
Boot field
see
Table
B-2
06 0x0040
Causes
system software to
ignore
nonvolatile
memoiy
contents
07 0x0080
OEM bit enabled
08 OxOlOO
Break disabled
10
0x0400 IP broadcast with
all zeros
1112
0x0800Oxl000 Console line
speed
13 0x2000
Boot default ROM
software if network boot
fails
14
0x4000 IP broadcasts do
not have net numbers
15
0x8000 Enable
diagnostic
messages
and
ignore
NVM contents
Table B-2
Explanation
of Boot Field
Configuration
Register
Bits
0003
Boot Field
Meaning
00
Stays
at the
system bootstrap prompt
01
Boots
system image on
EPROM
02-F
Specifies
default
netboot filename
Enables boot
system
commands that override
default netboot
filename1
Values of the boot field
are 215 in the form
ciscon-processor
nrnne
where 15
Changng
Configuraton Register
Settigs
Some
common
reasons to
modify
the value of the
virtual
configuration register
follow
Recover lost
password
Change
the
console baud rate
Enable
or
disable
Break
Allow
you
to
manually
boot the
operating system
using
the
command at the
bootstrap program
ROM
monitor prompt
Force the
router to boot
automatically
from
the
system bootstrap
software
boot
ROM
image
its
system image
in Flash
memory
or read
any
boot
system
commands that
are
stored in its
configuration
file in NVRAM
If the
router finds no boot
system
commands
it
uses
the
configuration register
value
to
form
filename
from which to netboot
default
system image
stored on network
server
See
Table
B-3
To
change
the
configuration
register
while
running
the
system software
follow these
steps
Step
Enter the enable command
and
your password
to enter the
privileged
level as follows
router enable
Password
router
B-2 Cisco 3000
Hardware Installation and Maintenance