Many variables in the Unified CCE configuration and deployment options can affect the server requirements and capacities. This section describes the major sizing variables and how they affect the capacity of the various Unified CCE components.
Busy Hour Call
The number of
calls attempted during a busy hour is an important metric. As BHCA increases,
there is an increase in the load on all Unified CCE components, most notably on
Unified CM, Unified IP IVR, and the Unified CM PG. The capacity
numbers for agents assume up to 30 calls per hour per agent. If a deployment
requires more than 30 calls per hour per agent, it decreases the maximum number
of supported agents for the agent PG. Handle such occurrences on a case-by-case
The number of
agents is another important metric that impacts the performance of most Unified
CCE server components, including Unified CM clusters.
Groups or Precision Queues Per Agent
The number of
skill groups or precision queues per agent (which is independent of the total
number of skills per system) significantly affects the following:
CTI OS servers
Limit the number of skill groups and precision queues per agent to 5
or fewer, when possible. Periodically remove unused skill groups or precision
queues so that they do not affect the system's performance. You can also manage
the effects on the CTI OS Server by increasing the value for the frequency of
The Finesse server does not display
statistics for unused skill groups. Therefore, the number of skill groups that are
assigned to agents affects the performance of the Finesse server more than the total
number of skill groups configured.
group) statistics are updated on the Finesse Desktop at 10-second intervals.
The Finesse Desktop also supports a fixed number of queue statistics fields.
These fields cannot be changed.
The first table
shows examples of the number of skill groups or precision queues (PQ) per agent
affecting the capacity of the Unified CCE system. The table shows the capacity
for each CTI OS instance. The Finesse server supports the same number of agents
and skill groups as CTI OS.
supports a maximum of 50 unique skill groups across all agents on a
supervisor’s team, including the supervisor’s own skill groups. If this number
is exceeded, all skill groups monitored by the supervisor still appear on the
supervisor desktop. However, exceeding this number can cause performance issues
and is not supported.
queue that you configure creates a skill group per Agent PG and counts toward
the supported number of skill groups per PG.
in this table are subject to specific hardware and software requirements.
Table 2 Sizing
Effects of Skill Groups or Precision Queues for Each Agent (12,000
|Avg Configured PQ or SG
for each Agent
||Generic PG Limits
Concurrent Agent for each System
Concurrent Agent for each PG
Configured PQ or SG for each PG
Configured VRU Ports for each PG
Configured VRU PIMs for each PG
CTI OS monitor
mode applications are supported only at 20 or lower skill groups per agent.
The number of
supervisors and team members can also be a factor impacting the CTI OS Server
performance. Distribute your agents and supervisors across multiple teams and
have each supervisor monitor only a few agents.
can monitor only agents within their own team, and all of the agents must be
configured on the same peripheral.
A Unified CCE
system can support a maximum of 50 agents per supervisor with the assumptions
below. If a particular environment requires more than 50 agents per supervisor,
then use the following formula to ensure that there is no impact to the CTI OS
Server and Supervisor desktop. The most important factor in this calculation is
the number of updates per second.
You can add a
maximum of 50 agents per team. You can add a maximum of ten supervisors per
X = (Y * (N + 1) / R) + ((Z * N * A) / 3600), rounded up to the next integer
X = Number of updates per second received by the CTI OS Supervisor desktop.
Y = Weighted Average of Number of Skill Groups or Precision Queues per Agents. For example, if total of 10 agents have the following skill group distribution: 9 have 1 skill group and 1 agent has 12 Skill Groups. The number of skills per agent ('Y') is, Y = 90% * 1 + 10% * 12 = 2.1.
(The number of configured statistics in the CTI OS server is 17.)
Z = Calls per hour per agent.
A = Number of agent states. (Varies based on call flow; average = 10.)
N = Number of agents per supervisor.
R = The skill group or precision queue refresh rate configured on the CTI OS Server. (Default = 10 seconds.)
(Y * (N + 1) / R) = Number of updates per second, based on skill groups.
(Z * N * A) / 3600 = Number of updates per second, based on calls.
The CTI OS Supervisor desktop is not impacted as long as there are fewer than 31 updates per second. This threshold value is derived by using the above formula to calculate the update rate for 50 agents per supervisor (N = 50), as follows:
X = (5 * (50 + 1) / 10) + ((30 * 50 * 10) / 3600) = 25.5 + 5 = 31 updates per second
The maximum number of agents per supervisor must not exceed 200 for any given configuration, still holding updates per second to a maximum of 31 with the above formula.
Monitor Mode Applications
A CTI OS Monitor
Mode application can affect the performance of the CTI OS Server. CTI OS
supports only two such applications per server pair. Depending on the filter
specified, the impact on the CPU utilization might degrade the performance of
the Agent PG.
monitored call adds more processing for the PG and Unified CM. Each silently
monitored call is equivalent to two unmonitored calls to an agent. Make sure
that the percentage of the monitored calls is within the capabilities of PG
CTI OS Skill
Group Statistics Refresh Rate
The skill group
statistics refresh rate can also affect the performance of CTI OS Server. Cisco
requires that you do not lower the refresh rate below the default value of 10
The call type is also an important metric that affects the performance of most Unified CCE server components. An increase in the number of transfers and conferences increase the load on the system which decreases the total capacity.
The Unified IP IVR and Unified Customer Voice Portal (CVP)
place calls in a queue and play announcements until an agent answers the call.
For sizing purposes, it is important to know whether:
The VRU will handle all calls initially (call treatment), and
direct the callers to agents after a short queuing period.
The agents will handle calls immediately, and the VRU queues only
unanswered calls when all agents are busy.
The answer to this question determines very different
VRU sizing requirements and affects the performance of the Call Router/Logger
and Voice Response Unit (VRU) PG.
translation route pool depends on the expected call arrival rate. Use the
following formula to size the translation route pool:
Translation route pool = 20 * (Calls per second)
is specific to Unified CCE. For more general Unified ICM deployments, consult
your Cisco Account Team or Partner.
complexity and/or number of Unified CCE scripts increase, the processor and
memory overhead on the Call Router and VRU PG increases significantly. The
delay time between replaying Run VRU scripts also has an impact.
reporting can have a significant effect on Logger and Rogger processing due to
database access. A separate VM is required for an Administration & Data
Server to off-load reporting overhead from the Logger and Rogger.
As VRU script
complexity increases with features such as database queries, the load placed on
the IP IVR Server and the Router also increases. There is no good rule or
benchmark to characterize the Unified IP IVR performance when used
for complex scripting, complex database queries, or transaction-based usage.
Test complex VRU configurations in a lab or pilot deployment to determine the
response time of database queries under various BHCA and how they affect the
processor and memory for the VRU server, PG, and Router.
IVR Self-Service Applications
where the Unified IP IVR is also used for self-service applications,
the self-service applications are in addition to the Unified CCE load. Factor
self-service applications into the sizing requirements as stated in the sizing
Database and Cisco Resource Manager Connectivity
examine connectivity of any Unified CCE solution component to an external
device and/or software to determine the overall effect on the solution. Cisco
Unified CCE solutions are flexible and customizable, but they can also be
complex. Contact centers are often mission-critical, revenue-generating, and
customer-facing operations. Therefore, engage a Cisco Partner (or Cisco
Advanced Services) with the appropriate experience and certifications to help
you design your Unified CCE solution.
Call Context (ECC)
The ECC usage
impacts PG, Router, Logger, and network bandwidth. There are many ways that ECC
can be configured and used. The capacity impact varies based on ECC
configuration, handled on a case-by-case basis.