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Cisco ONS 15530 Configuration Guide and Command Reference
78-16019-02, Cisco IOS Release 12.2(18)SV2
Chapter3 Initial Configuration
About CPU Switch Module Redundancy
Redundant Operation Requirements
For fully redundant operation, the following requirements must be met:
•Two CPU switch modules are required.
•The CPU switch modules must haveidentical hardware configurations. This includes variables such
as DRAM size, and so on.
•Both CPU switch modules must have the same functional image.
•Both CPU switch modules must be running compatible system images. System images are
compatible across one major release.
•Both the running and startup configurations are automatically synchronized between the CPU
switch modules.
•Both CPU switch modules must be set to autoboot (a default setting).
If these requirements are met, the Cisco ONS 15530 runs in redundant mode by default. If they are not
met, the system is conditionally redundant.
Note Fordetailed information on updating system images, see the “Updating System Images on Redundant
Processors” section on page 13-14.
Conditions Causing a Switchover from the Active CPU Switch Module
Thefollowing conditions can cause a switchover from the active CPU switch module to the standby CPU
switch module:
•The active CPU switch module is removedor swapped. When the CPU switch module functioning
as the active CPU switch module is removed, the standby CPU switch module takes over. The
Cisco ONS 15530 is nonredundant until a second CPU switch module is inserted.
•The active CPU switch module is rebooted. When a CPU switch module functioning as the active
CPU switch module is rebooted, it relinquishes its activerole if the standby CPU switch module has
reached the hot-standby state.
Table3-2 CPU Switch Module Software States
State Description
Disabled The standby CPU switch module is not yet running the system image or is in
maintenance mode.
Standby cold The standby CPU switch module is running the system image but has not
begun to synchronize data from the active CPU switch module.
Standby hot Thestandby CPU switch modulehas fully synchronized theconfiguration and
other data from the active CPU switch module. It will remain in the
hot-standby state until a switchover occurs.
Active The CPU switch module is in the activehardware state and has completed all
switchoveror initial bootup processing. It is fully ready to control the system.