Unified CVP VXML Server Design Implications
This chapter cover the following topics:
between the Cisco Unified CVP VXML Server and the Voice Browser is based on
request-response cycles using VoiceXML over HTTP. VoiceXML documents are linked
together by using the Uniform Resource Identifiers (URI), a standardized
technology to reference resources within a network. User input is carried out
by web forms similar to HTML. Therefore, forms contain input fields that are
edited by the user and sent back to a server.
the Voice Browser are located on the Unified CVP VXML Server. These resources
are VoiceXML files, digital audio, instructions for speech recognition
(Grammars) and scripts. Every Communication process between the VoiceXML
browser and Voice Application has to be initiated by the VoiceXML browser as a
request to the Unified CVP VXML Server. For this purpose, VoiceXML files
contain Grammars which specify expected words and phrases. A Link contains the
URL that refers to the Voice application. The browser connects to that URL as
soon as it recovers a match between spoken input and one of the Grammars.
From CVP 9.0
onwards the CVP installer would install CVP Call Server, CVP VXML Server and
Media Server together. On this installation you can configure only the Call
Server, y the VXML server, the Media Server or any other combination as
Unified CVP VXML Server performance, consider the following key aspects:
QoS and network
bandwidth between the Web application server and the voice gateway.
Network Infrastructure Considerations, for more details.
Performance on the
Unified CVP VXML Server.
System Software Specification for Cisco Unified CVP (formerly called the
Materials), available at
specifies the supported hardware for a Unified CVP VXML Server.
Use of prerecorded
audio versus Text-to-Speech (TTS)
user-interface applications tend to use prerecorded audio files wherever
possible. Recorded audio sounds much better than TTS. Prerecorded audio file
quality must be designed so that it does not impact download time and browser
interpretation. Make recordings in 8-bit mu-law 8 kHz format.
Audio file caching
Make sure the
voice gateway is set to cache audio content to prevent delays from having to
download files from the media source. For more details about prompt management
on supported gateways, see
Cisco IOS Caching and Streaming Configuration.
Use of grammars
application, like any user-centric application, is prone to certain problems
that might be discovered only through formal usability testing or observation
of the application in use. Poor speech recognition accuracy is one type of
problem common to voice applications, and a problem most often caused by poor
grammar implementation. When users mispronounce words or say things that the
grammar designer does not expect, the recognizer cannot match their input
against the grammar. Poorly designed grammars containing many
difficult-to-distinguish entries also results in many mis-recognized inputs,
leading to decreased performance on the Unified CVP VXML Server. Grammar tuning
is the process of improving recognition accuracy by modifying a grammar based
on an analysis of its performance.
The Cisco IOS Voice Browser or the Media Resource Control Protocol (MRCP) specification does not impose restrictions on support for multiple languages. However, there might be restrictions on the automatic speech recognition (ASR) or TTS server. Check with your preferred ASR or TTS vendor about their support for your languages before preparing a multilingual application.
You can dynamically change the ASR server value by using the command cisco property com.cisco.asr-server in the VoiceVXML script. This property overrides any previous value set by the VoiceXML script.
Cisco Unified Call Studio Installation
Cisco Unified Call Studio is an Integrated Development Environment (IDE). As in the case of any IDE, the Unified Call Studio needs to be installed in a setup that is conducive for development, such as workstations that are used for other software development or business analysis purposes. Because the Unified Call Studio is Eclipse-based, many other development activities (such as writing Java programs or building object models) can be migrated to this tool so that developers and analysts have one common utility for most of their development needs.
Because the Unified Call Studio has not been tested with Microsoft Windows 2008 R2 server, Cisco does not support co-locating the Cisco Unified Call Studio with the Unified CVP VXML Server.