Cisco Cisco IP Contact Center Release 4.6.2 Installation Guide

Stopping the side B Central Controller puts side A (from a Central 
Controller prospective) into a simplex condition when the services are 
started. 

Short term default routing

Once all Central Controller services are stopped on side B, start the side A 
Central Controller services.

When the side B Central Controller is stopped and the side A Central 
Controller services are coming on line, the Service Provider’s default network 
routing plan is invoked.

The side A CallRouter requires successful connectivity with 50% of the 
configured PGs for that instance.

Before proceeding with the upgrade of the B side central controller, testing 
should be completed with side A in a simplex condition. Only upon 
successful completion of testing should a “Go” decision be made to continue 
with upgrading the B side central controller.

To stop the upgrade at this point, stop the ICM software on the upgraded 
machines and start ICM on the non-upgraded machines. Once the 
non-upgraded machines are back on line the upgraded machines can be 
brought back to their original state using the stored image. 

If any component is not functioning properly, capture the appropriate 
log for troubleshooting purposes before the old image is restored.

If no issues are identified, or if a problem is assessed as “non-critical” to the 
business, the upgrade continues.

Only upon successful completion of side A simplex testing should a “Go” 
decision be made to continue with upgrade of the side B Central Controller. 

Once the Central Controller has been successfully upgraded and 
synchronized, testing should be completed in duplex mode.