Cisco 3000 Series - Page 84

Virtual
Configuration Register Settings
Step
At the
privileged
level
system prompt
router
enter the command
configure
terminal
You will be
prompted
as
shown in the
following example
router
configure
term
Enter
configuration commands one
per
line
Edit with
DELETE CTRL/W
and
CTRL/tJ
end
with CTRL/Z
Step
To set the contents of the
configuration register
enter
the
configregister
value
configuration
command where value is hexadecimal number
preceded by
Ox
See
Table
B-3
as
in the
following
config-register
Oxvalue
The
virtual
configuration register
is
stored in nonvolatile
memory
Step
Exit the
configuration
mode
by entering
Ctrl-Z The new value
settings
will
be
saved to
memory
however
the new
settings
do not take effect until the
system
software is reloaded
by rebooting
the
router
Step
To
display
the
configuration register
value
currently
in effect and the value that will be used
at the next
reload
enter the show version EXEC
command
and the value will be
displayed
on the last line of the screen
display as
in the
example
following
Configuration register
is 0x142
will
be 0x102 at next
reload
Step
Reboot the router The
new
value takes effect
Configuration
register changes
take effect
only
when the
server
restarts such
as
when
you
switch the
power
off and
on
or
when
you
issue reload command from the console
The lowest four bits of the
processor configuration register
bits
and form the boot
field
See
Table
B-2
The boot field
specifies
number in
binary
If
you
set
the boot field value
to
you
must
boot the
operating system manually by entering
the command
at
the
bootstrap prompt
as
follows
ttftp
flash filename
Definitions of the various command
options
follow
bBoots the default
system
software from
ROM
flashBoots the first file in Flash
memory
bfilenanie using
TFTP
flash
the
file
filename
from
Flash
memory
For more information about the flash
filename command
see the Router Products
Configuration
and
Reference publication
If
you
set the boot field value to value of
through
and there is valid
system
boot command
stored in the
configuration file
then the router boots the
system
software
as
directed
by
that value
See
Table
B-3
If
you
set the boot field to
any
other bit
pattern
the router
uses
the
resulting
number
to form default boot filename for
netbooting
In the
following example
the virtual
configuration register
is set to boot the router
automatically
from Flash
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
Virtual
Configuration Register
B-3