Cisco Unified Contact Center Enterprise Solution Reference ...

Chapter 3 Design Considerations for High Availability
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Cisco Unified Customer Voice Portal (Unified CVP) Design Considerations
Unified CVP Call Control Server
The Unified CVP Call Control Server provides call control signaling when calls are switched
between the ingress gateway and another endpoint gateway or a Unified CCE agent. It also provides
the interface to the Unified ICM VRU Peripheral Gateway and translates specific Unified ICM VRU
commands into VoiceXML code that is rendered on the Unified CVP Voice Gateway.
Unified CVP Media Server
The Unified CVP caller treatment is provided either by using ASR/TTS functions via MRCP or with
predefined .wav files stored on media servers. The media servers act as web servers and serve up
the .wav files to the voice browsers as part of their VoiceXML processing. Media servers can be
clustered using the Cisco Content Services Switch (CSS) products, thus allowing multiple media
servers to be pooled behind a single URL for access by all the voice browsers in the network.
Unified CVP Web Server
Unified CVP Release 3.0 provides a VoiceXML service creation environment using an Eclipse
toolkit browser, which is hosted on the Unified CVP Web Server. This server also hosts the
Unified CVP VoiceXML runtime environment where the dynamic VoiceXML scripts are executed
and Java and Web Services calls are processed for external systems and database access.
H.323 Gatekeepers
Gatekeepers are used with Unified CVP to register the voice browsers and associate them with
specific dialed numbers. When calls come into the network, the gateway will query the gatekeeper
to find out where to send the call based upon the dialed number. The gatekeeper is also aware of the
state of the voice browsers and will load-balance calls across them and avoid sending calls to
out-of-service voice browsers or ones that have no available sessions.
Availability of Unified CVP can be increased by the following methods:
Adding redundant Unified CVP systems under control of the Unified ICM Peripheral gateways, thus
allowing the calls to be balanced automatically across multiple Unified CVP Call Control Servers
Adding TCL scripts to the Unified CVP gateway to handle conditions where the gateway cannot
contact the Unified CVP Call Control Server to direct the call correctly
Adding gatekeeper redundancy with HSRP
Adding Cisco Content Server to load-balance .wav file requests across multiple Unified CVP Media
Servers and VoiceXML URL access across multiple servers.
Note Calls in Unified CVP are not dropped if the Unified CVP Call Control Server or Unified CVP PG fails
because they can be redirected to another Unified CVP Call Control Server on another
Unified CVP-controlled gateway as part of the fault-tolerant design using TCL scripts (which are
provided with the Unified CVP images) in the voice gateway.
For more information on these options, review the Unified CVP product documentation at
http://www.cisco.com/univercd/cc/td/doc/product/icm/isn/cvp30/index.htm
Cisco Unified Contact Center Enterprise 7.x SRND
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