Cisco Cisco IP Contact Center Release 4.6.1 Maintenance Manual
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.
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 side 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.
system. The system can be divided into two sides, each of which contains one side 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, processes, and configuration objects 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. The following figure shows the two sides of a duplexed Central Controller.
on the same local area network (LAN). However, Side A might be geographically separated
from Side B. The following figure shows the two sides of a duplexed Central Controller.
Figure 2: Duplexed Central Controller
During normal operation, the two sides run in parallel. For example, information about each
incoming call is processed by both CallRouters. Both CallRouters, using the same call routing
scripts and identical information about the call centers, determine the same destination for the
call. Both sides of the Central Controller receive the same information from the Peripheral
Gateways and Administration & Data Servers or Administration Clients.
incoming call is processed by both CallRouters. Both CallRouters, using the same call routing
scripts and identical information about the call centers, determine the same destination for the
call. Both sides of the Central Controller receive the same information from the Peripheral
Gateways and Administration & Data Servers or Administration Clients.
A duplexed Central Controller can tolerate a single device or system failure (for example, the
loss of one CallRouter) without losing functions. A double failure, while extremely rare, typically
results in some loss of functions. An example of a double failure would be if both CallRouters
in a duplexed system were to go off-line.
loss of one CallRouter) without losing functions. A double failure, while extremely rare, typically
results in some loss of functions. An example of a double failure would be if both CallRouters
in a duplexed system were to go off-line.
Administration Guide for Cisco Unified ICM/Contact Center Enterprise & Hosted Release 8.x
19
Chapter 2: Fault Tolerance
Central Controller