Cisco Cisco Customer Voice Portal 8.0(1) Design Guide
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Cisco Unified Customer Voice Portal (CVP) 8.x Solution Reference Network Design (SRND)
OL-15989-06
Chapter 4 Designing Unified CVP for High Availability
Content Services Switch (CSS)
Call Disposition
If the VoiceXML gateway fails, the following conditions apply to the call disposition:
•
Calls in progress are default-routed to an alternate location by survivability on the ingress gateway.
(Survivability does not apply in NIC-routing models.)
(Survivability does not apply in NIC-routing models.)
•
New calls find an alternate VoiceXML gateway.
Hardware Configuration for High Availability on the Voice Gateways
The individual hardware components have the following high-availability options:
•
Redundant power supplies and on-hand spares
•
Separate components for higher availability
•
Dedicated components, which have fewer interaction issues
Example 1: Separate PSTN Gateway and VoiceXML Gateway
A PSTN gateway and a separate VoiceXML gateway provide greater availability than a combine PSTN
and VoiceXML gateway.
and VoiceXML gateway.
Example2: Duplicate Components for Higher Availability
•
Two 8-T1 PSTN gateways provide greater availability than one 16-T1 PSTN gateway.
•
Two 96-port Unified CVP VXML Servers provide greater availability than one 192-port
Unified CVP VXML Server.
Unified CVP VXML Server.
•
Larger designs can use N+1 spares for higher availability.
Example3: Geographic Redundancy for Higher Availability
Geographical redundancy and high availability can be achieved by purchasing duplicate hardware for
Side A and Side B.
Side A and Side B.
Content Services Switch (CSS)
The VoiceXML gateway is the only box in the Unified CVP system that makes requests to the CSS.
When the VoiceXML gateway needs to make a request for media, ASR/TTS, or VoiceXML, it looks in
its configuration to determine to where it should make the request. When a CSS is used, the IP address
that is configured on the VoiceXML gateway is a virtual IP address that points to a service configured
on the CSS. There are three types of services that the VoiceXML gateway client can request from the
CSS:
When the VoiceXML gateway needs to make a request for media, ASR/TTS, or VoiceXML, it looks in
its configuration to determine to where it should make the request. When a CSS is used, the IP address
that is configured on the VoiceXML gateway is a virtual IP address that points to a service configured
on the CSS. There are three types of services that the VoiceXML gateway client can request from the
CSS:
•
Media Server
•
ASR/TTS
•
Unified CVP VXML Server
If the primary CSS that is servicing these requests should fail, the client VoiceXML gateway must still
be able to obtain media and VoiceXML from the servers.
be able to obtain media and VoiceXML from the servers.
Note
Cisco recommends using the CSS to find an available VXML Server via heartbeat and to perform load
balancing. Subsequent requests and responses between the VoiceXML gateway and the VXML Server
should bypass the CSS.
balancing. Subsequent requests and responses between the VoiceXML gateway and the VXML Server
should bypass the CSS.