Cisco Cisco IP Contact Center Release 4.6.1 Design Guide

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Cisco Unified Contact Center Enterprise 7.0, 7.1, and 7.2 SRND
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Chapter 2      Deployment Models
IPT: Multi-Site with Centralized Call Processing
As with the single-site deployment model, all the same options exist when using traditional Unified CCE 
configurations. For example, multi-site deployments can run the Unified ICM software all on the same 
server or on multiple servers. The Unified ICM software can be installed as redundant or simplex. The 
Unified ICM software can be deployed either with the Unified CCE System PG or the Unified CCE PG. 
The system can be a System Unified CCE deployment. The number of Unified CM and Unified IP IVR 
or Unified CVP servers is not specified by the deployment model, nor are the LAN/WAN infrastructure, 
voice gateways, or PSTN connectivity. For other variations, see 
Best Practices
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VoIP WAN connectivity is required for RTP traffic to agent phones at remote sites.
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RTP traffic to agent phones at remote sites may require compression to reduce VoIP WAN bandwidth 
usage. It may be desirable for calls within a site to be uncompressed, so transcoding might also be 
required depending upon how the Cisco Unified Communications deployment is designed.
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Skinny Client Control Protocol (SCCP) call control traffic from IP phones to the Unified CM cluster 
flows over the WAN.
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CTI data to and from the Unified CCE Agent Desktop flows over the WAN. Adequate bandwidth 
and QoS provisioning are critical for these links.
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Because there are no voice gateways at the remote sites, customers might be required to dial a 
long-distance number to reach what would normally be a local PSTN phone call if voice gateways 
with trunks were present at the remote site. This situation could be mitigated if the business 
requirements are to dial 1-800 numbers at the central site. An alternative is to offer customers a 
toll-free number to dial, and have those calls all routed to the centralized voice gateway location. 
However, this requires the call center to incur toll-free charges that could be avoided if customers 
had a local PSTN number to dial.
  •
The lack of local voice gateways with local PSTN trunks can also impact access to 911 emergency 
services, and this must be managed via the Unified CM dial plan. In most cases, local trunks are 
configured to dial out locally and for 911 emergency calls.
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Unified CM locations-based call admission control failure will result in a routed call being 
disconnected. Therefore, it is important to provision adequate bandwidth to the remote sites. Also, 
an appropriately designed QoS WAN is critical.
IVR: Treatment and Queuing with Unified IP IVR
As in the single-site deployment, all call queuing is done on the Unified IP IVR at a single central site. 
While calls are queuing, no RTP traffic flows over the WAN. If requeuing is required during a transfer 
or reroute on ring-no-answer, the RTP traffic flow during the queue treatment also does not flow over 
the WAN. This reduces the amount of WAN bandwidth required to the remote sites.
IVR: Treatment and Queuing with Unified CVP
In this model, Unified CVP is used in the same way as Unified IP IVR.
Unified CCE: Transfers
Transfers in this scenario are, from the point of view of the contact center, the same as in the single-site 
scenario. Therefore, the same call and message flows will occur as in the single-site model, whether the 
transferring agent is on the same LAN as the target or on a different LAN. The only differences are that