Cisco Cisco IPCC Web Option Leaflet

The Cisco Unified Communications Sizing Tool (Unified CST) can help you quickly and accurately size 
large and complex Unified Communications Systems. This tool supports sizing of many Unified 
Communications components, such as Unified CM, Unified CCE, Unified IP IVR, Unified CVP, 
gateways, and Expert Advisor.

The Cisco Unified Communications Sizing Tool is available to Cisco employees and Cisco partners. 
Refer to the documentation for this tool for more details and instructions.

The following guidelines apply to all Unified CM clusters with Unified CCE.

A cluster may contain a mix of server platforms, but is strongly discouraged except in migration/upgrade 
scenarios. All primary and failover backup server pairs must be of the same type. All servers in the 
cluster must run the same Unified CM software release and service pack.

Within a cluster, you may enable a maximum of 8 servers with the Cisco CallManager Service, 
including backup servers. Additional servers may be used for more dedicated functions such as 
TFTP, publisher, music on hold, and so forth.

You can configure a maximum of 2,500 CTI monitored devices (for example, logged-in agent 
phones, agent phones not logged in, CTI Route Points, CTI ports, agent phones monitored by a 
recording application via JTAPI, and soft clients in a desk phone mode using CTI third-party call 
control) per Cisco MCS-7845 server. This means a maximum of 10,000 CTI monitored devices per 
cluster. Beginning with Cisco Unified CM 7.1(2), the CTI capacity limits have been increased and 
the Cisco MCS-7845-H2/I2 supports 3,375 CTI devices per server or 13,500 devices per cluster. 
These capacities can vary, depending on your specific deployment. All deployments must be sized 
by using the Cisco Unified CM Capacity Tool or the Cisco Unified Communications Sizing Tool. 
The BHCA of the CTI monitored or controlled devices entered in the Unified CM Capacity Tool or 
the Unified Communications Sizing Tool should also reflect a consistent call arrival rate, with only 
small variations or peaks (no more than 20%) around the average calls per second.

In a deployment with IP IVR, each Unified CM cluster (four primary and four backup subscriber 
servers) can support up to approximately 2,000 Unified CCE agents. This limit assumes that the 
BHCA call load and all configured devices are spread equally among the eight call processing 
servers with 1:1 redundancy. (See 

, for redundancy schemes.) 

Each of the eight Unified CM servers (MCS-7845 High Performance Servers) would support a 
maximum of 250 agents. In a failover scenario, the primary server would support a maximum of 500 
agents. These capacities can vary, depending on your specific deployment. All deployments must be 
sized by using the Cisco Unified CM Capacity Tool or the Unified Communications Sizing Tool. 
Some deployments with more than 500 agents per pair of subscriber nodes or 2000 agents per cluster 
might be supported, depending upon the output of the Unified CM Capacity Tool or the Unified 
Communications Sizing Tool.

In a deployment with Unified CM 7.0 and Unified CVP (no IP IVR), each Unified CM cluster (four 
primary and four backup subscriber servers) can support up to about 4,000 Unified CCE agents. This 
limit assumes that the BHCA call load and all configured devices are spread equally among the eight 
call processing servers with 1:1 redundancy. (See 

, for 

redundancy schemes.) Each of the eight Unified CM servers (MCS-7845-H2/I2 or later High 
Performance Servers) would support a maximum of 500 agents. In a failover scenario, the primary