An important consideration in sizing a contact center is to determine the worst-case contact center profile for the number of calls that are in each state. For instance, if you observe the contact center at its busiest instant in the busiest hour, observe how many calls you find in the following states:
Self-service—Calls that are executing applications using the VXML Server.
Queue and collect—Calls that are in queue for an agent or are executing prompt-and-collect type self-service applications.
Talking—Calls that are connected to agents or to third-party TDM VRU applications.
the number of calls that are in the talking state, count only calls that are
using Unified CVP or gateway resources. To determine whether a call in talking
state is using resources, consider how the call gets transferred to that VRU or
agent. If the call is transferred using VoIP, it continues to use an Ingress
port and it continues to use a Unified CVP resource, because Unified CVP
continues to monitor the call and provides the ability to retrieve it and
redeliver it at a later time. Unified CVP also continues to monitor calls that
are sent to a TDM target, using both an incoming and an outgoing TDM port on
the same gateway or on a different gateway (that is, toll bypass). Calls that
are transferred to VRUs or agents in this manner are counted as talking calls.
the call was transferred through *8 TNT, hookflash, Two B Channel Transfer
(TBCT), or an ICM NIC, neither the gateway nor Unified CVP play any role in the
call. Both components have reclaimed their resources, therefore, such calls are
not counted as talking calls.
Include in the overall call counts those calls that have been transferred back into Unified CVP for queuing or self-service, using either blind or warm methods. For example, if a warm transfer is used and the agent is queued at Unified CVP during the post-route phase, the call will use two ports due to two separate call control sessions at Unified CVP. Because these calls usually do not contribute to more than 5 percent or 10 percent of the overall call volume, you can easily overlook them.
The definitions of these call states differ from the definitions used for port licensing purposes. Similarly, the call state determination does not influence with whether the agents are Unified CCE agents or ACD agents, nor does it matter whether the customer intends to use Unified CVP to retrieve and redeliver the call to another agent or back into self-service.
You should size the solution for the number of ports in use for calls in a talking state to agents. Even though licenses for those ports do not have to be purchased when using Unified CCE agents, TDM agents do require a Call Director license.
to the overall snapshot profile of calls in the contact center, you must also
consider the busiest period call arrival rate in terms of calls per second. You
need this information for the contact center as a whole because it is difficult
to identify the exact maximum arrival rate. You can use statistical means to
arrive at this number, except in very small implementations, which is seldom
the critical factor in determining sizing.
begin sizing each component in the network following the information in the
overview section. The overview section, deals with the number and type of
physical components required to support the Unified CVP system, but it does not
include any discussion of redundancy. For an understanding of how to extend
these numbers to support higher reliability, see
Unified CVP Design for High Availability.
In Unified CVP,
the Call Server, VXML Server, and Media Server are combined as one installation
as CVP Server. Installing the CVP Server installs all three components. In the
earlier versions, Call Server, VXML Server, and Media Server could be installed
on different machines.