Cisco Cisco IPCC Web Option Leaflet

Number of voicemail ports and the BHCA rate to those VoIP endpoints

Signaling protocol(s) used by the VoIP endpoints

Percent of agent call transfers and conferences

Dial plan size and complexity, including the number of dialed numbers, lines, partitions, calling 
search spaces, locations, regions, route patterns, translations, route groups, hunt groups, pickup 
groups, route lists, and so forth

Amount of media resources needed for functions such as transcoding, conferences, encryption, and 
so forth

Co-resident applications and services such Auto Attendant, CTI Manager, E-911, and Music On 
Hold

Unified CM release (sizing will vary per release)

Desired hardware server model (sizing will vary per hardware server model)

Other factors can affect cluster sizing, but the above list shows the most significant factors in terms of 
resource consumption.

The general process to sizing a Unified CM cluster is to estimate the resource consumption (CPU, 
memory, and I/O) for each of these factors and then to choose hardware that will satisfy the resource 
requirements.

It is important to gather information with regards to the factors listed above before attempting to size a 
cluster with any accuracy. To assist in calculating these numbers that relate to Unified CCE, Cisco 
recommends using the Unified CCE Resource Calculators, discussed in the chapter on 

The next section describes the tools for sizing Cisco Unified CM deployments.

Capacity planning tools for a Cisco Unified Communications deployment include the Cisco Unified 
Communications Sizing Tool and the Cisco Unified Communications Manager Capacity Tool. These 
tools are available at:

Proper login authentication is require. Sizing tools are available for Cisco internal employees and Cisco 
partners.

The Cisco Unified Communications Manager Capacity Tool requires various pieces of information to 
provide a calculation of the minimum size and type of servers required for a Unified CM cluster. The 
focus in this section is on the inputs to the capacity tool that are specific to Cisco Unified CCE.   Details 
on other capacity tool inputs for deployments that are not exclusively for Cisco Unified CCE can be 
found in the Cisco Unified Communications SRND.

The Cisco Unified CM Capacity Tool is available to all Cisco employees and partners at:

http://www.cisco.com/cgi-bin/CT/PGWCT/ct.cgi