Cisco Cisco IP Contact Center Release 4.6.2 Design Guide

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Cisco Unified Contact Center Enterprise 7.0, 7.1, and 7.2 SRND
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Chapter 5      Cisco Unified Outbound Option
Call Transfer Timelines
The PortThrottleCount of 10 will allow dialing at a rate of 5 calls per second per Dialer, which should 
give Unified CM sufficient headroom to allow for other incoming traffic and even allow for some shared 
resources. It is a setting that works well for most situations. If your deployment requires a higher call 
rate, ensure that the call rate for all traffic for any one subscriber will not exceed 10 calls per second at 
any time. You need to be vigilant to make sure that traffic is not shared across subscribers.
Currently, a Unified CM subscriber node running on a dual-processor MCS-7845 server has a maximum 
capacity at 10 calls per second. Each Dialer is capable of dialing at a rate of 10 calls per second or 
greater. If the solution is deployed in a way that allows for the Unified CM subscribers to be overloaded, 
then there is a risk of causing dropped customer calls and inefficient dialing.
The throttling mechanism is in each Dialer process, and it is not aware if another Dialer is sharing 
Unified CM resources. Therefore, if two Dialers share the same device pool or trunk, then there is a risk 
of dropped calls and inefficient dialing. This risk especially applies to failover. If the ports belonging to 
one Dialer fail-over to another Unified CM subscriber that is already occupied by another Dialer, again 
there is risk of dropped calls and inefficient dialing.
The Unified CM configuration must be designed and implemented to limit all traffic for a given Dialer 
to a distinct Unified CM subscriber node to prevent two Dialers from overwhelming any shared 
resources. This means that each Dialer requires separate device pools that point to one and only one 
subscriber. Each Dialer also needs its own calling search space, partition, translation pattern, and trunk 
configured on its Unified CM subscriber.
Transferring to Unified CVP using H.323 and MTP Resources
In cases where the customer is reached but no agents are currently available, or in cases where 
unattended campaigns are implemented, calls will be transferred to an IVR. If the solution design uses 
Unified CVP with the H.323 protocol, then media termination point (MTP) resources are required when 
transferring calls to the IVR. To minimize MTP requirements, the trunks configured for calls transferred 
to Unified CVP should be separate from the trunks used for external gateways.
Call Transfer Timelines
The length of time required to complete call transfer of a customer call to an agent is highly dependent 
on the telephony environment. The following factors can add to transfer times:
  •
Improperly configured Cisco Unified Communications infrastructure.—Port speed mismatches 
between servers or inadequate bandwidth.
  •
WAN—WAN unreliable or not configured properly.
  •
IP Communicator—Media termination running on a desk top does not have the same system priority 
as software running on its own hardware platform like a hard phone. This is not recommended for 
Unified Outbound Option usage unless the customer is clearly taking an inexpensive route and is 
OK with a less reliable solution.
  •
Call Progress Analysis—When you enable Call Progress Analysis for the campaign, it takes on an 
order of a half second or so to differentiate between voice and a answering machine, if the voice 
quality is good. When calling cell phones, the voice quality is quite often less than optimal so it 
might take the dialer a bit longer to differentiate.