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This appendix describes the DistributedDirector 4700-M virtual configuration register, the factory-default settings, and the procedures for changing those settings.
The Director has a 16-bit virtual register, which is written into the nonvolatile random access memory (NVRAM). Use the processor configuration register information contained in this appendix to do the following:
Table D-1 lists the meaning of each of the virtual configuration memory bits.
| Bit No. | Hex | Meaning |
|---|---|---|
| 00-03 | 0x0000-0x000F | Boot field (see Table D-2) |
| 06 | 0x0040 | Causes system software to ignore nonvolatile memory contents |
| 07 | 0x0080 | OEM bit enabled |
| 08 | 0x0100 | Break disabled |
| 10 | 0x0400 | IP broadcast with all zeros |
| 11-12 | 0x0800-0x1000 | Console line speed |
| 13 | 0x2000 | Boots default ROM software if network boot fails |
| 14 | 0x4000 | IP broadcasts do not have net numbers |
| 15 | 0x8000 | Enables diagnostic messages and ignores NVRAM contents |
Some common reasons to modify the value of the virtual configuration register follow:
Take the following steps to change the configuration register while running the Cisco IOS software:
Step 1 Enter the enable command and your password to enter the privileged level, as follows:
enable
Password:
Step 2 At the privileged-level system prompt (DD#), enter the command configure terminal. You will be prompted as shown in the following example:
configure terminal
Step 3 To set the contents of the configuration register, enter the config-register value configuration command where value is a hexadecimal number preceded by 0x
(see Table D-3), as in the following:
config-register 0xvalue
(The virtual configuration register is stored in nonvolatile memory.)
Step 4 Press Ctrl-Z to exit the configuration mode. 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 Director.
Step 5 Enter the show version EXEC command to display the configuration register value currently in effect and the value that will be used at the next reload. The value will be displayed on the last line of the screen display as in the following example:
Step 6 Reboot the Director. The new value takes effect. Configuration register changes take effect only when the server restarts, for example, when you turn the power OFF and ON or when you issue a reload command from the console.
The lowest four bits of the processor configuration register (bits 3, 2, 1, and 0) form the boot field. (See Table D-2.)
| Boot Field | Meaning |
|---|---|
| 00 | Stays at the system bootstrap prompt (ROM monitor) on a reload or power cycle |
| 01 | Boots the boot helper image as a system image |
| 02-F | Specifies a default netboot filename
Enables default booting from system Flash memory Enables boot system commands that override the default netboot filename1 |
The boot field specifies a number in binary. If you set the boot field value to 0, you must have console port access to boot the operating system manually. Boot the operating system manually by entering the b command at the bootstrap prompt as follows:
> b [tftp] flash filename
Definitions of the various command options follow:
b--Boots the default system software from ROM
b flash--Boots the first file in Flash memory
b filename [host]--Boots over the network using TFTP
b flash [filename]--Boots the file filename from Flash memory
For more information about the b [tftp] flash filename command, see the appropriate Cisco IOS software publications.
If you set the boot field value to a value of 2 through F, and there is a valid system boot command stored in the configuration file, the Director boots the system software as directed by that value. (See Table D-3.) If you set the boot field to any other bit pattern, the Director uses the resulting number to form a default boot filename for booting from a network (TFTP) server.
If there are no boot commands in the configuration file, the Director attempts to boot the first file in system Flash memory. If no file is found in system Flash memory, the Director attempts to netboot a default file whose name is derived from the value of the boot field (for example, cisco2-4500). If the attempt to boot from a network (TFTP) server fails, the boot helper image in boot Flash will boot up.
If boot commands are in the configuration file, the Director software processes each boot command in sequence until the process is successful or the end of the list is reached. If the end of the list is reached without a file being successfully booted, the Director will retry the netboot commands up to six times unless the boot default ROM software "if netboot fails" bit (bit 13 of the virtual configuration register) is set. If bit 13 is set, the system boots the boot helper image found in boot Flash memory without any retries.
In the following example, the virtual configuration register is set to boot the Director automatically from Flash memory and to ignore Break at the next reboot of the Director:
DD#configure terminalEnter configuration commands, one per line. Edit with DELETE, CTRL/W, and CTRL/U; end with CTRL/Zconfig-register 0x102Ctrl-ZDD#
The server creates a default boot filename as part of the automatic configuration processes. To form the boot filename, the server starts with cisco and links the octal equivalent of the boot field number, a dash, and the processor-type name. Table D-3 lists the default boot filenames or actions for the processor.
| Action/File Name | Bit 3 | Bit 2 | Bit 1 | Bit 0 |
|---|---|---|---|---|
| bootstrap mode | 0 | 0 | 0 | 0 |
| ROM software | 0 | 0 | 0 | 1 |
| cisco2-4000 or cisco2-4500 | 0 | 0 | 1 | 0 |
| cisco3-4000 or cisco3-4500 | 0 | 0 | 1 | 1 |
| cisco4-4000 or cisco4-4500 | 0 | 1 | 0 | 0 |
| cisco5-4000 or cisco5-4500 | 0 | 1 | 0 | 1 |
| cisco6-4000 or cisco6-4500 | 0 | 1 | 1 | 0 |
| cisco7-4000 or cisco7-4500 | 0 | 1 | 1 | 1 |
| cisco10-4000 or cisco10-4500 | 1 | 0 | 0 | 0 |
| cisco11-4000 or cisco11-4500 | 1 | 0 | 0 | 1 |
| cisco12-4000 or cisco12-4500 | 1 | 0 | 1 | 0 |
| cisco13-4000 or cisco13-4500 | 1 | 0 | 1 | 1 |
| cisco14-4000 or cisco14-4500 | 1 | 1 | 0 | 0 |
| cisco15-4000 or cisco15-4500 | 1 | 1 | 0 | 1 |
| cisco16-4000 or cisco16-4500 | 1 | 1 | 1 | 0 |
| cisco17-4000 or cisco17-4500 | 1 | 1 | 1 | 1 |
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 system into the bootstrap monitor, halting normal operation. A Break can be sent in the first 60 seconds while the system reboots, regardless of the configuration settings.
Bit 10 controls the host portion of the Internet 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. Table D-4 shows the combined effect of bits 10 and 14.
| Bit 14 | Bit 10 | Address (<net> <host>) |
|---|---|---|
| Off | Off | <ones> <ones> |
| Off | On | <zeros> <zeros> |
| On | On | <net> <zeros> |
| On | Off | <net> <ones> |
Bit 13 determines the server response to a bootload failure. Setting bit 13 causes the server to load operating software from ROM after five unsuccessful attempts to load a boot file from the network. Clearing bit 13 causes the server to continue indefinitely to attempt loading a boot file from the network. By factory default, bit 13 is cleared to 0.
Bits 11 and 12 in the configuration register determine the baud rate of the console terminal. Table D-5 shows the bit settings for the four available baud rates. (The factory-default baud rate is 9600.)
| Baud | Bit 12 | Bit 11 |
|---|---|---|
| 9600 | 0 | 0 |
| 4800 | 0 | 1 |
| 1200 | 1 | 0 |
| 2400 | 1 | 1 |
To enable booting from Flash memory, set bits 3, 2, 1, and 0 to a value between 2 through 15. To specify a filename to boot, enter the system software configuration boot system flash filename command in the configuration file.
To enter the configuration mode while in the system software image, enter the configure command at the enable prompt as follows:
Gateway#configureConfiguring from terminal, memory, or network [terminal]?termEnter configuration commands, one per line. Edit with DELETE, CTRL/W, and CTRL/U; end with CTRL/Zboot system flash filename
To disable Break and enable the boot system flash command, enter the config-register command with a value as follows:
config-reg 0x102CTRL/Z
If you set the configuration register value to 0x102, as in the example, it is not necessary to enter the boot system flash command unless there is more than one image in Flash memory.
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