Cisco Cisco Customer Response Solution Downloads Designanleitung

All of the metrics in 

 are basic call sizing metrics. Once this information is obtained, the 

number of gateway trunk ports, IVR ports, and agents can be calculated using the IPC Resource 
Calculator available at:

The IPC Resource Calculator uses Erlang C for sizing agents, and Erlang B for sizing IVR ports. The 
output of this sizing process will provide you with the total number of Gateway trunk ports, IVR ports 
and total number of agents to size the Unified CCX system properly.

See 

 for an overview of the IP call center sizing process, and see the section on 

, for detailed sizing information for both IVR 

ports and Unified CCX agents.

If the system being designed is a replacement for an existing ACD or an expansion to an installed Unified 
CCX or Unified IP IVR system, you might be able to use the historical reporting information from the 
existing system to arrive at the above metrics. 

In addition, call sizing design considerations may vary if the call center is more self-service oriented.

Busy Hour Call Attempts 
(BHCA)

Average number of calls received in a busy hour.

Grade of service (% blockage) 
for gateway ports to the PSTN

Percentage of calls that get a busy tone (no gateway trunks 
available) out of the total BHCA.