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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
Refer to the “ConfiguringPasswords and Privileges” part in the Cisco IOS Security Configuration Guide.
About CPU Switch Module Redundancy
The Cisco ONS 15530 supports fault tolerance by allowing the standby CPU switch module to take over
if the active CPU switch module fails. This standby, or redundant, CPU switch module runs in
hot-standby state. In hot-standby state, the standby CPU switch module is partially booted with Cisco
IOS software, but no configuration is loaded.
At the time of a switchover from the active CPU switch module, the standby CPU switch module
becomes active and loads the configuration as follows:
•If the running configuration file on the active and standby CPU switch modules match, the new
active CPU switch module uses the running configuration file.
•If the running configurationfile on the new active CPU switch module is missing or invalid,the new
activeCPU switch module uses the startup configuration file in its NVRAM (not the NVRAM of the
former active CPU switch module).
The former active CPU switch module then reloads and becomes the standby CPU switch module.
Note If the standby CPU switch module is unavailable, the system reports a minor alarm. Use the show
facility-alarm status command to display the redundancy alarm status.
When the Cisco ONS 15530 is powered on, the two CPU switch modules arbitrate to determine which
isthe active CPU switch module and which is the standby CPU switch module. The following rules apply
during arbitration:
•A newly inserted CPU switch module always comes up as the standby CPU switch module, except
in cases where the newly inserted card is the only one present.
•Ifone of the CPU switch modules cannot boot its software image, the redundant CPU switch module
boots as the active CPU switch module, allowing you to correct the situation manually.
•The primary route processor at the time the system is powered off continues as the primary when
the system is powered on.
•If none of the above conditions is true, the CPU switch module in slot 6 becomes the active CPU
switch module.
During normal operation, the active CPU switch module boots completely. The standby CPU switch
module partially boots, stopping short of parsing the configuration. From this point, the active and
standby CPU switch modules communicate periodically to synchronize any system configuration
changes.
Table3-1 describes the five CPU switch module hardware states.