Cisco Cisco Packet Data Gateway (PDG)
Software Management Operations
▀ Upgrading the Operating System Software
▄ ASR 5000 System Administration Guide, StarOS Release 18
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Important:
Configuration files created and saved in StarOS release 12.2 and higher cannot be shared across
multiple chassis due to a change in the encryption algorithm for passwords and secrets. These release 12.2 + changes
modify encrypted data in the configuration file so that it cannot be recognized by software builds prior to 12.2. If it is
necessary to revert to a previous build, the chassis must be booted with the copy of the original configuration file. If this
copy is not available, then the chassis must be loaded as if it is a new chassis.
modify encrypted data in the configuration file so that it cannot be recognized by software builds prior to 12.2. If it is
necessary to revert to a previous build, the chassis must be booted with the copy of the original configuration file. If this
copy is not available, then the chassis must be loaded as if it is a new chassis.
Preparing for a Software Downgrade
Downgrading from Release 12.2 to 12.0
If a software upgrade to release 12.2+ fails, you may need to downgrade to a previous software release, such as 12.0.
Since the encryption algorithm for passwords and secrets is difference from 12.0 to 12.2+, you must save the 12.0
configuration file using the obsolete-encryption keyword to preserve passwords and secrets that used the earlier
algorithm.
Since the encryption algorithm for passwords and secrets is difference from 12.0 to 12.2+, you must save the 12.0
configuration file using the obsolete-encryption keyword to preserve passwords and secrets that used the earlier
algorithm.
Important:
You must save the configuration prior to upgrading to release 12.2+.
The general sequence for a software downgrade in this scenario is as follows:
Develop a downgrade plan with the assistance of Cisco support personnel.
Save the pre-12.2 configuration using the obsolete-encryption keyword in conjunction with the Exec mode save
configuration command as shown in the example.
[local]host_name# save configuration /flash/v120_system.cfg obsolete-
encryption
Warning: Use of weaker encryption significantly reduces the security of
the system
Are you sure? [Yes|No]: Yes
encryption
Warning: Use of weaker encryption significantly reduces the security of
the system
Are you sure? [Yes|No]: Yes
To reboot the system using the old configuration, change the boot configuration via the Global Configuration
mode to use the old boot image and its previously saved configuration. See the example below.
[local]host_name(config)# boot system priority 1 image
/flash/v120_asr5000.bin config /flash/v120_system.cfg
/flash/v120_asr5000.bin config /flash/v120_system.cfg
Reload the system using the pre-12.2 image and configuration.
Once the system has reloaded, verify that the configuration is correct.
Save the current configuration as a backup once the configuration has been validated.
Downgrading from Release 15.0 to 14.0
Release 14 and Release 15 chassis IDs use different encryption formats. Release 15 will recognize a Release 14 chassis
ID and consider it as valid. Upgrading from 14.x to 15.0 will not require changing the chassis ID or configuration file.
ID and consider it as valid. Upgrading from 14.x to 15.0 will not require changing the chassis ID or configuration file.
However, if the chassis key is reset in Release 15 through the setup wizard or chassis-key CLI command, a new chassis
ID will be generated in Release 15 format (44 instead of 16 characters). Release14 builds will not recognize the 44-
character chassis ID. If the chassis is subsequently downgraded to Release 14, a new 16-character chassis ID will be
generated. To accommodate the old key format, you must save the configuration file in pre-v12.2 format before the
ID will be generated in Release 15 format (44 instead of 16 characters). Release14 builds will not recognize the 44-
character chassis ID. If the chassis is subsequently downgraded to Release 14, a new 16-character chassis ID will be
generated. To accommodate the old key format, you must save the configuration file in pre-v12.2 format before the