Maintenance Manual

Chapter 2 Fault Tolerance
Central Controller
2-6
Cisco ICM Enterprise Edition Administrator Guide Release 6.0(0)
Figure 2-2 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 Admin
Workstations.
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.
Single failures are typically caused by system crashes, operating system failures,
or disk failures. However, LAN outages and IP router failures can also cause
single failures. Figure 2-3 shows five possible Central Controller failure
scenarios.
Database
Manager
Logger
Call Router
Synchronizer
Agent
Central Controller
Side A
Database
Manager
Logger
Call Router
Synchronizer
Agent
Central Controller
Side B
37157