Maintenance Manual

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Cisco ICM Enterprise Edition Administrator Guide Release 6.0(0)
Chapter 2 Fault Tolerance
Central Controller
Central Controller
The Central Controller includes the CallRouter, Logger, and the Database
Manager. The CallRouter and Logger processes are typically on separate
computers. However, in smaller call center configurations the CallRouter and
Logger processes can be on the same computer. The Database Manager works
very closely with the Logger. The Logger and Database Manager processes are
always on the same computer.
A duplexed Central Controller uses the synchronized execution approach to fault
tolerance. The Central Controller processes are duplicated and run as
synchronized process pairs. In synchronized execution, if one component fails its
peer continues running and the system runs without interruption. The Database
Manager is also duplicated, but technically it does not run synchronized. Since all
modifications to the database come through the Logger, the databases
automatically remain synchronized.
Two Sides
All components of the Central Controller, with their duplicates, form one logical
duplexed system. The system can be divided into two sides, each of which
contains one instance of a component. Each side of the Central Controller has a
Database Manager, Logger, CallRouter, Synchronizer, and an Agent. By
convention, the two sides are referred to as Side A and Side B.
All components within a side are collocated; that is, located on the same local area
network (LAN). However, Side A might be geographically separated from Side
B. Figure 2-2 shows the two sides of a duplexed Central Controller.