Call load testing captures the results of busy hour call attempts (BHCA) tests. BHCA tests measure the volume of calls generated and handled, regardless of whether the calls are answered. The BHCA data is used in capacity calculations. Review Call Load Testing 
for an overview of the call loads that were tested with these site models:
•
Very Large Campus with Clustering over the WAN
•Multisite Centralized, Clustering over the WAN with Unified SRST
•Large SIP Site
•Cisco Unified Communications Manager 4.2(3) Interoperability Site
•Small Campus SIP Unified Communications Manager Express Site
•Small Campus H.323 Unified Communications Manager Express Site
•Medium Business with Remote Locations
See also Develop Traffic Engineering Specifications on the Design tab for more information on capacity calculations.