Cisco Cisco IP Contact Center Release 4.6.1 Leaflet
9-7
Cisco Unified Contact Center Enterprise 7.5 SRND
Chapter 9 Sizing Call Center Resources
Cisco Unified CCE Resource Calculators
Before discussing the Cisco Unified CCE Resource Calculator, the next two sections present a brief
description of the generic Erlang models and the input/output of such tools (available on the internet) to
help the reader who does not have access to the Cisco Unified CCE Resource Calculator or who chooses
to use other non-Cisco Erlang tools.
description of the generic Erlang models and the input/output of such tools (available on the internet) to
help the reader who does not have access to the Cisco Unified CCE Resource Calculator or who chooses
to use other non-Cisco Erlang tools.
Erlang-C
The Erlang-C model is used to size agents in call centers that queue calls before presenting them to
agents. This model assumes:
agents. This model assumes:
•
Call arrival is random.
•
If all agents are busy, new calls will be queued and not blocked.
The input parameters required for this model are:
•
The number of calls in the busy hour (BHCA) to be answered by agents
•
The average talk time and wrap-up time
•
The delay or service level desired, expressed as the percentage of calls answered within a specified
number of seconds
number of seconds
The output of the Erlang-C model lists the number of agents required, the percentage of calls delayed or
queued when no agents are available, and the average queue time for these calls.
queued when no agents are available, and the average queue time for these calls.
Erlang-B
The Erlang-B model is used to size PSTN trunks, gateway ports, or Unified IP IVR ports. It assumes the
following:
following:
•
Call arrival is random.
•
If all trunks/ports are occupied, new calls are lost or blocked (receive busy tone) and not queued.
The input and output for the Erlang B model consists of the following three factors. You need to know
any two of these factors, and the model will calculate the third:
any two of these factors, and the model will calculate the third:
•
Busy Hour Traffic (BHT), or the number of hours of call traffic (in Erlangs) during the busiest hour
of operation. BHT is the product of the number of calls in the busy hour (BHCA) and the average
handle time (AHT).
of operation. BHT is the product of the number of calls in the busy hour (BHCA) and the average
handle time (AHT).
•
Grade of Service, or the percentage of calls that are blocked because not enough ports are available
•
Ports (lines), or the number of Unified IP IVR or gateway ports
Cisco Unified CCE Resource Calculators
Cisco is continually enhancing the Cisco Unified Communications Resource Calculators, which
currently include the following calculators:
currently include the following calculators:
•
Standard Unified CCE Resource Calculator — Designed to provide outputs for a single call center
with a single trunk group. It allows the user to vary the number of agents.
with a single trunk group. It allows the user to vary the number of agents.
•
Advanced Unified CCE Resource Calculator — Includes all the calculations of the Standard
calculator and adds the ability to allocate traffic between multiple trunk groups to include calls
going to a self-service IVR. It also has inputs for confidence and growth factors.
calculator and adds the ability to allocate traffic between multiple trunk groups to include calls
going to a self-service IVR. It also has inputs for confidence and growth factors.