Cisco Systems 15530 Redundant Operation Requirements, Conditions Causing a Switchover from the Active CPU Switch Module

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Cisco ONS 15530 Configuration Guide and Command Reference
78-14227-01, Cisco IOS Release 12.1(10)EV2
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 have identical 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 For detailed information on updating system images, see the “Updating System Images on Redundant
Processors” section on page 10-14.
Conditions Causing a Switchover from the Active CPU Switch Module
The following conditions can cause a switchover from the active CPU switch module to th e standby CPU
switch module:
•The active CPU switch module is removed or swapped. When the CPU switch module functioning
as the active CPU switch module is removed, the standby CPU switch module takes over. The
Cisco ONS15530 is nonredundant until a second CPU sw itch m odule i s insert ed.
•The active CPU switch module is rebooted. When a CPU switch module functioning as the active
CPU switch module is rebooted, it relinquishes its active role if the standby CPU switch module has
reached the hot-standby state.
•The active CPU switch module fails. The standby CPU sw itc h m odu le takes over as the active CPU
switch module, using the last synchronized running configuration file (or the last saved startup
configuration file if the running configuration file synchronization was disabled or failed).
•A switchover is manually forced with the redundancy switch-activity command.