Cisco Catalyst 4500 Series - Page 457

11-5
Software Configuration Guide—Release IOS XE 3.6.0E and IOS 15.2(2)E
OL_28731-01
Chapter 11 Configuring Supervisor Engine Redundancy Using RPR and SSO on Supervisor Engine 7-E, Supervisor
About Supervisor Engine Redundancy Synchronization
About Supervisor Engine Redundancy Synchronization
During normal operation, the persistent configuration (RPR and SSO) and the running configuration
(SSO only) are synchronized by default between the two supervisor engines. In a switchover, the new
active supervisor engine uses the current configuration.
Note You cannot enter CLI commands on the standby supervisor engine console.
These sections describe supervisor engine redundancy synchronization:
• RPR Supervisor Engine Configuration Synchronization, page 11-5
• SSO Supervisor Engine Configuration Synchronization, page 11-5
RPR Supervisor Engine Configuration Synchronization
Because the standby supervisor engine is only partially initialized in RPR mode, it interacts with the
active supervisor engine only to receive configuration changes at startup and upon saving the
configuration changes.
When a standby supervisor engine is running in RPR mode, the following events trigger synchronization
of the configuration information:
• When the standby supervisor engine boots, the auto-sync command synchronizes the persistent
configuration. This command is enabled by default. For details, refer to “Synchronizing the
Supervisor Engine Configurations” section on page 11-10.
• When the active supervisor engine detects the standby supervisor engine, the configuration
information is synchronized from the active supervisor engine to the standby supervisor engine. This
synchronization overwrites any existing startup configuration file on the standby supervisor engine.
• When you make changes to the configuration, you must use the write command to save and
synchronize the startup configuration to the standby supervisor engine.
SSO Supervisor Engine Configuration Synchronization
When a standby supervisor engine runs in SSO mode, the following events trigger synchronization of
the configuration information:
• When the active supervisor detects the standby supervisor engine, synchronization of the persistent
and running configuration takes place, allowing the standby supervisor engine to arrive at a
fully-initiated state.
• When real-time changes occur, the active supervisor engine synchronizes the running-config and
(or) the persistent configuration (if necessary) with the standby supervisor engine.
• When you change the configuration, you must use the write command to allow the active supervisor
engine to save and synchronize the startup configuration to the standby supervisor engine.
Supervisor Engine Redundancy Guidelines and Restrictions
The following guidelines and restrictions apply to supervisor engine redundancy: