Cisco Cisco Unified Contact Center Enterprise 10.0(1) Design Guide

The skill group statistics refresh rate can also have an effect on the performance of CTI OS Server. Cisco 
requires that you do not lower the refresh rate below the default value of 10 seconds.

The call type is also an important metric that will impact performance of most Unified CCE server 
components. An increase in the number of transfers and conferences will increase the load on the system 
and, thus, decrease the total capacity.

The Unified IP IVR places calls in a queue and plays announcements until an agent answers the call. For 
sizing purposes, it is important to know whether the IVR will handle all calls initially (call treatment) 
and direct the callers to agents after a short queuing period, or whether the agents will handle calls 
immediately and the IVR will queue only unanswered calls when all agents are busy. The answer to this 
question determines very different IVR sizing requirements and affects the performance of the Unified 
ICM Router/Logger and Voice Response Unit (VRU) PG. Required VRU ports can be determined using 
the Cisco Unified CCE Resource Calculator. (See 

, 

for more information.)

Sizing the translation route pool depends on the expected call arrival rate. Use the following formula to 
size the translation route pool:

Translation route pool = 1.5 

 BHCA/60

As the complexity and/or number of Unified ICM scripts increase, the processor and memory overhead 
on the Unified ICM Router and VRU PG will increase significantly. The delay time between replaying 
Run VRU scripts also has an impact.

Real-time reporting can have a significant effect on Logger, Progger, and Rogger processing due to 
database access. A separate server is required for an Administrative Workstation (AW) and/or Historical 
Data Server (HDS) to off-load reporting overhead from the Logger, Progger, and Rogger.

As IVR script complexity increases with features such as database queries, the load placed upon the IVR 
server and the Router also increases. There is no good rule of thumb or benchmark to characterize the 
Unified IP IVR performance when used for complex scripting, complex database queries, or 
transaction-based usage. Cisco recommends that you test complex IVR configurations in a lab or pilot 
deployment to determine the response time of database queries under various BHCA and how they affect 
the processor and memory for the IVR server, PG, and Router.

In deployments where the Unified IP IVR is also used for self-service applications, the self-service 
applications are in addition to the Unified CCE load and must be factored into the sizing requirements 
as stated in 

.