Cisco Systems 78-16019-02 manual Software Configuration Register Settings

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Chapter 3 Initial Configuration

About the Software Configuration Register

•Enable booting from a TFTP server

•Recover a lost password

•Boot the system manually using the boot command at the bootstrap program prompt.

•Force the system to boot automatically from the system bootstrap software (boot image) or from its default system image in onboard Flash memory, using any boot system commands stored in the startup configuration file in NVRAM

Software Configuration Register Settings

Table 3-4describes each of the software configuration register bits.

Caution To avoid confusion and possibly halting the system, remember that valid configuration register settings might be combinations of settings and not just the individual settings listed in Table 3-4. For example, the value of 0x0101 is a combination of settings (bit 8 is 0x0100 and bits 00 through 03 are 0x0001).

Table 3-4 Software Configuration Register Bits

Bit Number

Hexadecimal

Description

 

 

 

00 to 03

0x0000 to 0x000F

Controls the system boot behavior (also known as the boot field)

 

 

 

06

0x0040

Causes system software to ignore NVRAM contents

 

 

 

07

0x0080

Enables the OEM bit

 

 

 

08

0x0100

Disables the break function

 

 

 

09

0x0200

Uses secondary bootstrap during system boot

 

 

 

10

0x0400

Uses an IP broadcast with all zeros

 

 

 

11 to 12

0x0800 to 0x1000

Sets the console line speed (default is 9600 baud)

 

 

 

13

0x2000

Boots the default Flash software if network boot fails

 

 

 

14

0x4000

Uses IP broadcasts without network numbers

 

 

 

15

0x8000

Enables diagnostic messages and ignores the NVRAM contents

 

 

 

Bit 8 controls the console break function. Setting bit 8 (the factory default) causes the system to ignore the console break key. Clearing bit 8 causes the system to use the break key or break signal as a command to force the system into the bootstrap monitor (ROMMON), thereby halting normal operation.

Regardless of the setting of the break enable bit, a break causes a return to the ROMMON during the first few seconds (approximately five seconds) of booting.

Bit 9 controls the secondary bootstrap program function. Setting bit 9 causes the system to use the secondary bootstrap. Clearing bit 9 (the factory default) causes the system to ignore the secondary bootstrap. The secondary bootstrap program is used for system debugging and diagnostics.

Bit 10 controls the host portion of the IP broadcast address. Setting bit 10 causes the system to use all zeros. Clearing bit 10 (the factory default) causes the system to use all ones. Bit 10 interacts with bit 14, which controls the network and subnet portions of the IP broadcast address.

Table 3-5shows the combined effect of bits 14 and 10.

 

Cisco ONS 15530 Configuration Guide and Command Reference

3-26

78-16019-02, Cisco IOS Release 12.2(18)SV2

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Contents Initial Configuration About the CPU Switch ModuleStarting Up the Cisco ONS Using the Console Ports, NME Ports, and Auxiliary PortsYou can now begin configuring the CPU switch module You see the following user Exec promptEnable Secret Password About PasswordsEnable Password Modem SupportConfiguring IP Access on the NME Interface Command PurposeDisplaying the NME Interface Configuration Switch# configure terminal Configuring the Host NameDisplaying the Operating Configurations Switchconfig# hostname name Specifies a system nameAbout NTP Switch# configure terminal Switchconfig# hostname ONS15530ONS15530# copy systemrunning-config nvramstartup-config Command Configuring NTPDisplaying the NTP Configuration Example PurposeConfiguring Authentication Configuring Security FeaturesConfiguring AAA Configuring AuthorizationConfiguring Kerberos Configuring RadiusConfiguring Passwords and Privileges Configuring TACACS+Configuring Traffic Filters and Firewalls About CPU Switch Module Redundancy CPU Switch Module State Transition Diagram State DescriptionRedundant Operation Requirements Redundancy switch-activity force Configuring CPU Switch Module RedundancyForcing a Switchover from Privileged Exec Mode Forcing a Switchover from ROM Monitor Mode SwitchoverSwitchconfig# config-register Configuring AutobootDisplaying the Autoboot Configuration Bootflash filenameFollowing example shows the contents of the boot variable Synchronizing the ConfigurationsSynchronizing Configurations Manually Switchconfig-red# no auto-sync startup-config Filename When SynchronizedSwitchconfig-red# no auto-sync running-config Enabling and Disabling Automatic SynchronizationShow redundancy summary Configuring Maintenance ModeShow redundancy running-config-file Show redundancy capabilitySwitch# show redundancy summary ExamplesFollowing example shows the CPU switch module capabilities Switch# show redundancy capabilitySwitch# redundancy reload peer Reloading the CPU Switch ModulesSby-Switch#show redundancy running-config-file Enable Switchconfig-red# standby privilege-modeEnables access to privileged Exec mode from Standby CPU switch module CLI. The default stateAbout the Software Configuration Register DownBit Number Hexadecimal Description Software Configuration Register Settings4describes each of the software configuration register bits Bit Baud Rate Boot Field ValuesBit Address nethost 7describes the values for the boot field Default System Boot BehaviorBoot Command Boot Field Value DescriptionSwitch# show version Changing the Software Configuration RegisterVerify the Configuration Register Value Displays the current configuration register valueAbout Fan Failure Shutdown Configuring Fan Failure ShutdownSwitchconfig# environment-monitor shutdown fan Displaying the Fan Tray Failure Shutdown Configuration Switch# show environment78-16019-02, Cisco IOS Release 12.218SV2
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