Introduction to VoiceXML
and Voice Web Architecture
Ken Rehor
© 2007 Ken Rehor. All Rights Reserved.
1
Session Overview
• Voice Web Architecture
– Components of a Voice Web Application
• Voice Standards
– W3C Speech Interface Framework
• VoiceXML
– Language features
– Execution model - Form Interpretation Algorithm (FIA)
• Application Design Techniques
– Static vs. dynamic VoiceXML
– Performance Considerations
• CCXML, VoiceXML and VoIP
• Application Deployment Models
• New Technologies
– Speaker Biometrics, Video, Multimodal, VoiceXML 3.0
© 2007 Ken Rehor. All Rights Reserved.
2
Simplifying Voice Services programming
• Web-based architecture for interactive speech services
– Exploit web technologies to simplify voice service creation and deployment
– Enable consolidation of voice and web services
– Separate service logic from user interaction
• High-level programming languages
– Control speech and telephony resources in uniform manner
– Shield application programmers from implementation details
• No need to know ASR, TTS, telephony APIs
– Create portable applications
• Run on enterprise system or in telephone network
• Run on a variety of platforms, ASR agnostic
© 2007 Ken Rehor. All Rights Reserved.
3
Voice Web Application Architecture
© 2007 Ken Rehor. All Rights Reserved.
4
Key Ideas
• Standard/Common high-level language
– Designed for the task
• Leverage open, known technology
– Web protocols, servers, networks, development tools, expertise
• Phone number mapped to URL
– Phone number associated with URL of voice service
© 2007 Ken Rehor. All Rights Reserved.
5
Voice / Web Application Architecture
<grxml>
.wav
PSTN or
VoIP
<vxml>
Any phone
VoiceXML
browser
HTTP
Internet or
HTTP
HTTP
Intranet
<html>
Web
Browser
• Grammars
• Audio files
• Scripts
• Images
• Audio files
• Scripts
© 2007 Ken Rehor. All Rights Reserved.
Application
(web) server
• Application logic
• Content and data
• Transaction processing
• Database interface
6
Voice Application Architecture and Components
<grxml>
Welcome to
Acme products
…
Customer
service,
please…
.wav
<vxml>
Caller
HTTP
Internet or
intranet
Telephony
middleware
Web
server
OA&M
VoiceXML
interpreter
ASR
TTS
Audio
DTMF
PSTN
VoiceXML
platform
© 2007 Ken Rehor. All Rights Reserved.
7
Application Backend Architecture
<vxml>
• Grammars
• Audio files
• Scripts
Transaction Server
HTTP
Internet or
Intranet
Intranet or
Internet
Application
(web) server
• Application logic
• Content and data
• Transaction processing
• Database interface
Database
(content)
Web
service
© 2007 Ken Rehor. All Rights Reserved.
8
Components of a Voice Solution
• Traditional phone, VoIP phone, mobile phone, or multimodal device
• Telephone network
– Circuit-switched PSTN or packet-switched VoIP
– Connects caller’s telephone with Telephony Server
• Voice User Interface
– Dialog structure / flow
– Prompts – what the application says to the user
– Speech grammars – what the user can say
• Application logic that executes on an application server
– Web "back-end“
– Database, or database interface
• VoiceXML Server that executes dialogs
– Controls resources such as ASR, SIV, TTS, etc
• Data network to connect application server and VoiceXML server
© 2007 Ken Rehor. All Rights Reserved.
9
Inbound or Outbound calls
• VoiceXML application works the same for inbound and
outbound calls
– Additional call progress detection generally required for outbound
• Simple protocol for initiating outbound calls
– No firm standards, but most vendors follow similar techniques
– HTTP, Web Services, etc.
© 2007 Ken Rehor. All Rights Reserved.
10
Standards
© 2007 Ken Rehor. All Rights Reserved.
11
Value of Open Standards
• Non-proprietary interfaces between components
• Allow choice of best components for the task
• User interface languages
– W3C Speech Interface Framework: VoiceXML, SRGS, SSML, SI
– W3C: HTML, XHTML, SMIL, X+V
– OMA: WAP
• Communication protocols
–
–
–
–
–
W3C: CCXML for 3rd-party telephony call control
W3C: HTTP, HTTPS, SOAP, WSDL
IETF: SIP, MRCP, MSCP
3GPP: IMS
ITU: T1, ISDN
© 2007 Ken Rehor. All Rights Reserved.
12
Visual vs. Voice markup
Web app UI
Voice Web app UI
• HTML – Structure
• VoiceXML – Structure
– Layout
– Input declaration
– Transitions
•
•
•
•
•
Images
Audio files / streams
Video
Text
Scripts
– Dialog flow
– Input declaration
– Transitions
•
•
•
•
Audio files
Video, Images
Text (for TTS)
Scripts
© 2007 Ken Rehor. All Rights Reserved.
13
Protocols
Web applications
Voice Web applications
•
•
•
•
•
•
•
•
•
•
•
HTTP, HTTPS
RTP
SOAP
WSDL
…
HTTP, HTTPS
RTP
SOAP
WSDL
SIP
…
© 2007 Ken Rehor. All Rights Reserved.
14
Voice Standards Activities
• Speech Interface Framework
• Network protocols
– SIP, MRCP v2, etc.
• Platform Certification, Developer Certification,
Speaker Biometrics, Architecture, Tools
© 2007 Ken Rehor. All Rights Reserved.
15
Voice Application Standards
CCXML
Call Control
Application
SIP Netann
MSCML
MOML / MSML
MSCP
DMSP
MGCP
etc.
Conference/
Media
Server
Phone
Networ
k
Caller
VoIP
Gateway
T1 / E1
ISDN
SS7
SOAP
Scripts
CCXML
VoiceXML
Application
VXML
HTTP
HTTPS
Media
Control
Interface
SIP
RTP
HTTP
HTTPS
Scripts
Audio
CCXML
Browser
Telephony
Control
Interface
RFC 2833
GRXML
SSML
Dialog
Control
Interface
DTMF
VoiceXML
Browser
Media
Mixer /
Server
VoiceXML 2.0
VoiceXML 2.1
ECMAScript 262
Audio
GRXML
G.711, WAV,
.au, mp3, etc.
MRCP Client
Telephony Control Interface: SIP, etc.
Dialog Control Interface: SIP, MSCP, etc.
MRCP v1
MRCP v2
MRCP
© 2007 Ken Rehor. All Rights Reserved.
Server
Server
Server
TTS
ASR
SIV
SSML
GRXML
** standards in progress16**
W3C Speech Interface Framework
© 2007 Ken Rehor. All Rights Reserved.
17
Voice Application Components
• Dialog – flow control of the inputs, outputs, next steps
• Input grammars
– Control input constraints for DTMF and speech recognition
• Output formatting
– Pronunciation, timing, sequencing
© 2007 Ken Rehor. All Rights Reserved.
18
W3C Speech Interface Framework
•
•
•
•
•
•
VoiceXML
SRGS
SSML
Semantic Interpretation
Pronunciation Lexicon
Call Control
For more information, see:
W3C Voice Browser Working Group
http://www.w3.org/Voice/
© 2007 Ken Rehor. All Rights Reserved.
19
Voice User Interface - Dialog
• W3C VoiceXML 2.0
– W3C Recommendation March 2004
– Widely implemented
• Approximately 4 dozen platforms
• Many service providers worldwide
– VoiceXML Forum certification program
• Nearly two dozen certified platforms, more coming
• W3C VoiceXML 2.1
– Candidate Recommendation Sept 2006
– Test suite under development; Certification Program to follow
– Many platform vendors are implementing
• W3C VoiceXML 3.0
– Early stages of development
– SCXML – state chart markup language designed as a controller for V3 and
CCXML 2.0 ("Working Draft" Jan 2006)
© 2007 Ken Rehor. All Rights Reserved.
20
User Interaction – Input / Output Control
• Input grammars
W3C SRGS 1.0
– W3C Recommendation
– Widely implemented
• Output formatting
W3C SSML 1.0
– W3C Recommendation
– Widely implemented, yet minor real support
(most TTS engines ignore the SSML instructions)
• Semantic Interpretation for Speech Recognition W3C SISR 1.0
– Nearing Candidate Recommendation
– Implementation gaining acceptance
© 2007 Ken Rehor. All Rights Reserved.
21
W3C Speech Interface Framework
Semantic Interpretation
© 2007 Ken Rehor. All Rights Reserved.
22
W3C Speech Recognition Grammar Specification
• Markup language to control input constraints
– Finite-state speech recognition
– DTMF recognition
• Two variations
– XML (GRXML)
– ABNF
• Version 1.0: W3C Recommendation – March 2004
• Implemented and supported by numerous vendors
© 2007 Ken Rehor. All Rights Reserved.
23
GRXML ASR example
• asdf
<grammar type="application/srgs+xml" root="r2" version="1.0">
<rule id="r2" scope="public">
<one-of>
<item>coffee</item>
<item>tea</item>
<item>milk</item>
<item>nothing</item>
</one-of>
</rule>
</grammar>
© 2007 Ken Rehor. All Rights Reserved.
24
GRXML DTMF example
<?xml version="1.0"?>
<grammar mode="dtmf" version="1.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.w3.org/2001/06/grammar
http://www.w3.org/TR/speech-grammar/grammar.xsd"
xmlns="http://www.w3.org/2001/06/grammar">
<rule id="digit">
<one-of>
<item> 0 </item>
<item> 1 </item>
<item> 2 </item>
<item> 3 </item>
<item> 4 </item>
<item> 5 </item>
<item> 6 </item>
<item> 7 </item>
<item> 8 </item>
<item> 9 </item>
</one-of>
</rule>
<rule id="pin" scope="public">
<one-of>
<item>
<item repeat="4"><ruleref uri="#digit"/></item>
#
</item>
</one-of>
</rule>
</grammar>
© 2007 Ken Rehor. All Rights Reserved.
25
W3C Speech Synthesis Markup Language
• Markup language to control spoken and audio output
• Version 1.0: W3C Recommendation – Sept 2004
• Implemented and supported by numerous vendors
• Version 1.1: under development
– Adds support for tonal languages
– First public Working Draft published January 2007
© 2007 Ken Rehor. All Rights Reserved.
26
SSML Functions
• Audio output
– <audio>
• Text-to-Speech output
– Contained within SSML constructs
• Pronunciation controls
– <say-as>
• Interpret-as
• Format
• Detail
– <emphasis>
• Timing
– <break>
© 2007 Ken Rehor. All Rights Reserved.
27
SSML Functions (cont’d)
• Spoken language
– xml:lang
• Prosody and Style – voice control
–
–
–
–
Voice
Gender
Age
Name
• Prosody
– <prosody>
• Pitch
• Contour
• Range
• Rate
• Duration
• Volume
© 2007 Ken Rehor. All Rights Reserved.
28
SSML Functions (cont’d)
• Sentence structure
– <p>
– <s>
• phoneme -- Modify text
– <sub> - substitute text
• Location identification
– <mark>
© 2007 Ken Rehor. All Rights Reserved.
29
VoiceXML 2.x
© 2007 Ken Rehor. All Rights Reserved.
30
VoiceXML Scope
• Human-machine interaction provided by voice response
systems:
– Output
• play audio files
• produce synthesized speech
– Input
• record spoken input
• recognize spoken input
• collect character input
– Control flow
– Telephony
• transfer a user to another destination, such as a live agent
• disconnect a user
© 2007 Ken Rehor. All Rights Reserved.
31
VoiceXML Goals
• Separate user interaction from service logic
– Creates new possible business models
• Service developer can be separate from telephony platform provider
• Enable service portability across implementation platforms
– Assume common set of platform capabilities
– Provide common language for:
• Content providers, Tool providers, Platform providers
• Safely handle shared network-based applications
– deterministic behavior
• Easy to build common types of applications
• Features to build complex types of applications
• Shield application authors from low-level platform-specific details
– Promotes portability, ease of service creation
© 2007 Ken Rehor. All Rights Reserved.
32
VoiceXML 2.0 Basic Functions
• Input
– <field>, <menu>
– <record>
recognition
audio recording
• Output
– <prompt>
– <audio>
container for TTS or prerecorded audio
prerecorded audio
• Control Flow
–
–
–
–
<if>, <else>, <elseif>
<script>
<goto>
<submit>
basic conditional logic
complex scripts using ECMAScript
transition to a new document
submit data to a web application
• Telephony
– <disconnect>
– <transfer>
© 2007 Ken Rehor. All Rights Reserved.
33
VoiceXML Execution Model
• Form Interpretation Algorithm <form>
• Execution is synchronous (mostly)
– Disconnect events are handled (somewhat) asynchronously
• Audio is queued
– Played only when encountering a waiting state
• Processing is always in one of two states:
– Waiting for input in an input item
• such as <field>, <record>, or <transfer>
– Transitioning between input items in response to an input
• Event-driven
– <catch>, <throw> generalized event mechanism
– <nomatch>, <noinput>
short-hand user-input event handling
– <error>
short-hand error event handling
© 2007 Ken Rehor. All Rights Reserved.
34
Key Points
• Architecture leverages all things "internet"
– Languages, protocols, servers, developers, etc.
• Separation of concerns
– Application logic / database vs. telephony / speech resources
– Enables new business models
• Voice ASP
• Prepackaged applications
• URL (application) associated with phone number
– Calling party or Called party
– Share resources among many applications (VoiceASP)
• High-level languages, specific to domain / task
– Simplify development and maintenance
© 2007 Ken Rehor. All Rights Reserved.
35
VoiceXML <form> and <field>
• <form>
– Dialog container
– "Form Interpretation Algorithm" (FIA) specifies default behavior
• <field>
– Collect input from caller
– <grammar> specifies input 'constraints'
• <prompt>
– Container for <audio> and text
© 2007 Ken Rehor. All Rights Reserved.
36
Example
<?xml version="1.0"?>
<vxml version="2.0">
<form>
<field name="main_menu">
<prompt>
<audio src="welcome.wav"> Welcome to Acme.
You can choose sales, repair, or order status.</audio>
</prompt>
<grammar src="main_menu.grxml"/>
</field>
<block>
<submit next="http://acme.com/route... "
</block>
method="get"/>
</form>
</vxml>
main.vxml
Note: Code simplified for demonstration purposes…
© 2007 Ken Rehor. All Rights Reserved.
37
User Input - Grammars
• Grammars can be speech or DTMF (touchtone)
– Both types can be active simultaneously
• Specified by SRGS
– XML grammars are normative (aka GRXML)
– ABNF grammars are more concise but more complex to author
• Grammars may be specified inline or sourced externally
• External grammars are referenced by URI
• Multiple grammars may be active simultaneously.
© 2007 Ken Rehor. All Rights Reserved.
38
Grammars can get very complicated:
There are many ways to say the same thing…
Sales
I'd like to place an order
I need to talk to a salesman
Repair
repair department
service
service department
customer service
Order status
where's my order?
track my order
track my shipment
where the hell is my stuff?
© 2007 Ken Rehor. All Rights Reserved.
39
Basic GRXML grammar example
<grammar …xml:lang="en-US" version="1.0">
<rule id="dept" scope="public">
<one-of>
<item>sales</item>
<item>repair</item>
<item>order status</item>
</one-of>
</rule>
</grammar>
main_menu.grxml
© 2007 Ken Rehor. All Rights Reserved.
40
VoiceXML example – next step
<form>
<field name="sales_menu">
<prompt>
<audio src="sales_menu.wav">
You've reached Acme's sales department.
To place an order, say sales. To speak to
an associate, say I'd like to speak to someone.
</audio>
</prompt>
<grammar src="sales_menu.grxml"/>
</field>
<block>
<submit next="http://acme.com/... "
</block>
method="get"/>
</form>
sales.vxml
© 2007 Ken Rehor. All Rights Reserved.
41
VoiceXML example with error handling
<form>
<field name="main_menu">
<prompt>
<audio src="welcome.wav"> Welcome to Acme.
You can choose sales, repair, or order status.</audio>
</prompt>
<grammar src="main_menu.grxml"/>
</field>
<noinput> You must say something. </noinput>
<block>
<submit next="http://acme.com/route... "
</block>
method="get"/>
</form>
newmain.vxml
© 2007 Ken Rehor. All Rights Reserved.
42
VoiceXML example with error handling
<form>
<field name="main_menu">
<prompt>
<audio src="welcome.wav"> Welcome to Acme.
You can choose sales, repair, or order status.</audio>
</prompt>
<grammar src="main_menu.grxml"/>
</field>
<noinput> You must say something. </noinput>
<nomatch> I didn't understand you. Please try again. </nomatch>
<block>
<submit next="http://acme.com/route... "
</block>
method="get"/>
</form>
newmain.vxml
© 2007 Ken Rehor. All Rights Reserved.
43
VoiceXML example with error handling
<form>
<field name="main_menu">
<prompt>
<audio src="welcome.wav"> Welcome to Acme.
You can choose sales, repair, or order status.</audio>
</prompt>
<grammar src="main_menu.grxml"/>
</field>
<help> You can say sales, repair, or order status. </help>
<noinput> You must say something. </noinput>
<nomatch> I didn't understand you. Please try again. </nomatch>
<block>
<submit next="http://acme.com/route... "
</block>
method="get"/>
</form>
newmain.vxml
© 2007 Ken Rehor. All Rights Reserved.
44
Set platform features via <property>
• Input modes: type of input from a caller
DTMF-only <property name="inputmodes" value="dtmf">
Voice-only <property name="inputmodes" value="voice">
Both <property name="inputmodes" value="dtmf voice">
• Timeouts
<property name="timeout" value="1450ms">
<property name="termtimeout" value="2500ms">
...
© 2007 Ken Rehor. All Rights Reserved.
46
Call processing: <transfer>
• Blind
– Go somewhere but don't return
• Bridge
– Add on another party, resume
execution when done talking
© 2007 Ken Rehor. All Rights Reserved.
47
Call processing: <transfer>
• Blind transfer
<form id="xfer">
<block>
<prompt> Calling Riley. Please wait. </prompt>
</block>
<transfer name="mycall" dest="tel:+1-555-123-4567" >
</transfer>
</form>
© 2007 Ken Rehor. All Rights Reserved.
48
Call processing: <transfer>
• Bridge transfer
<form id="xfer">
<block> <prompt> Calling Riley. Please wait. </prompt> </block>
<transfer name="mycall" dest="tel:+1-555-123-4567" bridge="true" >
</transfer>
</form>
© 2007 Ken Rehor. All Rights Reserved.
49
Call processing: <transfer>
• Bridge transfer with cancel feature
<form id="xfer">
<block> <prompt> Calling Riley. Please wait. </prompt> </block>
<transfer name="mycall" dest="tel:+1-555-123-4567" bridge="true" >
<prompt> Say cancel at any time to disconnect this call.</prompt>
<grammar src="cancel.grxml" type="application/srgs+xml"/>
</transfer>
</form>
© 2007 Ken Rehor. All Rights Reserved.
50
Call processing: <transfer>
<form id="xfer">
<block> <prompt> Calling Riley. Please wait. </prompt> </block>
<transfer name="mycall" dest="tel:+1-555-123-4567" bridge="true" >
<prompt> Say cancel at any time to disconnect this call.</prompt>
<grammar src="cancel.grxml" type="application/srgs+xml"/>
<filled>
<assign name="mydur" expr="mycall$.duration"/>
<if cond="mycall == 'busy'">
<prompt> Riley's line is busy. Try again later. </prompt>
<elseif cond="mycall == 'noanswer'"/>
<prompt> Riley didn't answer the phone.
Please call back another time. </prompt>
</if>
</filled>
</transfer>
</form>
© 2007 Ken Rehor. All Rights Reserved.
51
Call processing: <transfer>
<form id="xfer">
<block> <prompt> Calling Riley. Please wait. </prompt> </block>
<transfer name="mycall" dest="tel:+1-555-123-4567" bridge="true"
transferaudio="music.wav" connecttimeout="60s" >
<prompt> Say cancel at any time to disconnect this call.</prompt>
<grammar src="cancel.grxml" type="application/srgs+xml"/>
<filled>
<assign name="mydur" expr="mycall$.duration"/>
<if cond="mycall == 'busy'">
<prompt> Riley's line is busy. Try back later. </prompt>
<elseif cond="mycall == 'noanswer'"/>
<prompt> Riley didn't answer the phone. Please call
back another time. </prompt>
</if>
</filled>
</transfer>
</form>
© 2007 Ken Rehor. All Rights Reserved.
52
Call processing: <transfer>
© 2007 Ken Rehor. All Rights Reserved.
53
New Features in VoiceXML 2.1
• Dynamically referencing grammars and scripts
– <grammar expr=“…”> <script expr=“…”>
• Detect Barge-in During Prompt Playback: enhance SSML 1.0 <mark>
– Add markexpr attribute
– Add markname and marktime to application.lastresult$ object
• Fetch (XML) data without transition: <data>
– Uses read-only subset of DOM
• Dynamically concatenate prompts: <foreach>
– Interate through ECMAScript array and execute content
• Record user’s utterance while attempting ASR
– recordutterance property
– Add shadow variables: recording, recordingsize, recordingduration
• Send data upon disconnect
– <disconnect namelist=“…” >
• Additional <transfer> types
– <transfer type=“…” …/>
© 2007 Ken Rehor. All Rights Reserved.
54
Dynamic Applications
© 2007 Ken Rehor. All Rights Reserved.
55
VoiceXML Application Structure
• Static
– User experience is the same for everyone
• Information doesn’t change frequently
• No customization per user, time of day, etc.
• Pages are created once and used many times
• Dynamic
– User experience is customized by:
• User: e.g. my.yahoo.com, amazon.com (especially once you log in)
• Situation: e.g. travel specials on expedia.com
– Data driven, e.g. inventory system, airline reservations
– Generated by a program at runtime
• JSP, ASP
• App servers such as BEA, IBM Websphere, Oracle 9iAS
© 2007 Ken Rehor. All Rights Reserved.
56
VoiceXML 2.1 and AJAX
• VoiceXML + ECMAScript + <data> + XML
• <data> element allows retrieval of arbitrary XML data
without document transition
• Static VoiceXML document can fetch user-specific data at
runtime
• Decouple presentation layer from business logic
• Performance improvements due to:
– Cache-able VoiceXML
– No need to generate entirely new pages for each dialog when only the
content is new
– Less network traffic
© 2007 Ken Rehor. All Rights Reserved.
57
Dynamic Application Considerations
Execution of VoiceXML is running a program on your server…
• Must guarantee quality of dynamically-generated VoiceXML
documents and ASR grammars
– Catch parse errors, execution errors
– What does the caller hear if there is an error?
• not “Could not parse VoiceXML document”
• Runtime performance
– Parse and interpretation time of large documents
– Inefficient scripts and speech grammars
• Security implications
– Exploit a bug in a particular implementation? Make free phone calls?
– Could there be a VoiceXML virus? Will all platforms protect against them?
 Careful application design, testing and monitoring is essential
© 2007 Ken Rehor. All Rights Reserved.
58
Dynamic Application Considerations
• A mix of different simultaneous applications means variable
platform load and execution profile
–
–
–
–
Parse time of VoiceXML document
Fetching VoiceXML documents, grammars, audio from remote web servers
Load Balancing
How to protect platform from harmful application? (intentional or otherwise?)
• Max size of document
• Max size of grammar
• Complexity measurement of document or grammar (statically checked before
execution?)
 Platforms, networks, and applications must be carefully engineered
© 2007 Ken Rehor. All Rights Reserved.
59
Performance Considerations
© 2007 Ken Rehor. All Rights Reserved.
60
Load Balancing for Performance and Reliability
• CPU/memory utilization
– Grammar compilation
– ASR load
– TTS load
• Telephony Network
– Channel balancing
– Dead channel
• Incoming/Outgoing channel assignment / mix
© 2007 Ken Rehor. All Rights Reserved.
61
Performance: Caching
•
•
•
•
Fetched documents, grammars, audio files, streams
Local or distributed cache?
Effects of prefetching
Where to cache generated grammars?
– Per system
– In-network
• Use external grammar compilation server?
© 2007 Ken Rehor. All Rights Reserved.
62
Application Management
© 2007 Ken Rehor. All Rights Reserved.
63
Application Monitoring and Maintenance
• Runtime logs
– Web / application server
– Voice server
– Call Detail Reporting
• Utterance recordings and logs
– Useful for grammar and dialog tuning
– Security of recordings may be an issue
– Disk space: full-call recordings may be prohibitively large
 Usage data must be continually monitored to improve user experience
© 2007 Ken Rehor. All Rights Reserved.
64
Operations, Administration, Maintenance,
Provisioning
• System Monitoring
– Interfacing to existing Telco OSSs
– Web-based for ISP environment
• Provisioning
– Application, Customer
• DN-URI mapping
– Telephony
• Call origination/transfer
• Max call timeout
• Max number of concurrent calls
– Platform-specific VoiceXML features
• ECMAScript allowed?
• Telephony control allowed?
• Max grammar size
© 2007 Ken Rehor. All Rights Reserved.
65
Billing
Logging and Charging for usage of resources
• "platform time"
– Usage of server resources
• Toll Free usage
– It's toll free, not free
• Transferred calls
– Inbound minutes
– Outbound minutes
– Network features, e.g. Network Redirect
• Outbound calls
 Accurate billing information is a critical factor in application cost or profitability
© 2007 Ken Rehor. All Rights Reserved.
66
Application Deployment Models
Build-your-own network vs. Outsourcing
© 2007 Ken Rehor. All Rights Reserved.
67
Build vs. Outsource?
Deployment Options Enable a Variety of Business Models
• Completely in-house
– Maintain complete control for security
– Development and deployment systems can be identical
• Outsourced VoiceXML/Telephony
– Large-scale distributed networks without major capital investment
– Grow quickly and incrementally
• Completely outsourced hosting
– All components and systems managed by 3rd party
• Packaged software
– VoiceXML application integrated with existing apps
© 2007 Ken Rehor. All Rights Reserved.
68
Completely In-House
•
•
•
•
•
•
Local control of all systems
Voice server, app server, database can be on local network
Development and deployment systems can be identical
Physical security: in-house team “owns” it
Failover, reliability, scalability must be locally managed
Redundant power, networks, etc. are required
© 2007 Ken Rehor. All Rights Reserved.
69
VoiceXML On-premises Deployment
using TDM or VoIP carrier connection
VoIP
"pipe"
PSTN
TDM:
DS3,
Multiple PRI,
etc.
VoIP
Gateway,
PBX, etc.
VoiceXML
Cisco
Browsers
IPCC
Web
Applications
Web
Applications
ASR
servers
Co-location facility
© 2007 Ken Rehor. All Rights Reserved.
Database
70
Outsourced VoiceXML / Telephony
• Telephony and VoiceXML servers outsourced to "Voice
Service Provider" (VSP)
• Application remains in your data center(s)
– Geographically distributed
– May be dedicated to specific customers
• Many carrier-grade vendors to choose from
© 2007 Ken Rehor. All Rights Reserved.
71
Outsourced VoiceXML / Telephony
• Architecture is identical to in-house deployment
• Secure IP connection used between facilities
Voice Service Provider:
Carrier-grade outsourcing facility
PSTN
VoIP
gateway
VoiceXML
Cisco
Browsers
IPCC
Co-location
facility
Web
Applications
Web
Applications
Interne
t
ASR
servers
Database
© 2007 Ken Rehor. All Rights Reserved.
72
Advantages of Outsourcing to a VSP
• Choice of many vendors: one for all customers, or choose the
best one for each customer
• Add capacity by adding multiple vendors
• No capital investment
• Pay-as-you-go pricing models
• Failover, reliability, scalability simplified
• Physical security of equipment and networks managed by VSP
• VPN or dedicated data connection to your backend systems
© 2007 Ken Rehor. All Rights Reserved.
73
Distribute Load to Multiple VSPs
VoiceXML
Cisco
Browsers
IPCC
PSTN
ASR
servers
VoiceXML
Cisco
Browsers
IPCC
ASR
servers
Internet
Customer
co-location facility
Web
Applications
Web
Applications
Database
VoiceXML
Cisco
Browsers
IPCC
Multiple co-lo facilities
can be deployed for geographic
redundancy and enhanced
capacity.
ASR
servers
VoiceXML
Cisco
Browsers
IPCC
© 2007 Ken Rehor. All Rights Reserved.
74
Completely Outsourced
• Deploy hardware & software systems at customermanaged co-location facilities
• Deploy complete systems at co-location facilities managed
by 3rd party
• Deploy pre-packaged VoiceXML application integrated
with customer's call center (managed by customer)
© 2007 Ken Rehor. All Rights Reserved.
75
Combination of In-house and Outsourced
Several ways to balance resources
• Primary in-house, with overflow or failover to a VSP
– Local control of resources
– Overflow to VSP during peak usage
– Backup for failover / disaster recovery
• In-house development, with primary deployment via VSP
– In-house development and trials
– “Push to the network” when ready to deploy
© 2007 Ken Rehor. All Rights Reserved.
76
CCXML, VoiceXML, and VoIP
3rd-Party Call Control
© 2007 Ken Rehor. All Rights Reserved.
77
Inbound call using TDM connections
• 1st-party call control: VoiceXML server handles call
routing/setup/answer
PSTN
VoiceXML
Server
Caller
© 2007 Ken Rehor. All Rights Reserved.
78
Inbound call using VoIP (SIP and RTP)
• 1st-party call control: VoIP gateway routes call to VoiceXML
server, which handles call routing/setup/answer
PSTN
VoIP
Gateway
1. INVITE
2. RTP
VoiceXML
Server
customer
© 2007 Ken Rehor. All Rights Reserved.
79
Why VoIP?
• Flexible network topology
• Simplified integration of voice dialog resources
• Vendor independence for network elements
• Separation of concerns: voice dialog resources vs. call
control
© 2007 Ken Rehor. All Rights Reserved.
80
Inbound Call using 3rd Party Call Control
• 3rd party application handles call routing/setup/answer
Call Routing
Application
PSTN
VoIP
Gateway
1. INVITE
2. INVITE
3. RTP
VoiceXML
Server
caller
© 2007 Ken Rehor. All Rights Reserved.
81
Outbound call using 3rd Party Call Control
• 3rd party application handles outbound call
initiation/setup/routing
• “Attaches” VoiceXML dialog to connection
Outbound
Calling
Application
PSTN
VoIP
Gateway
1. INVITE
2. INVITE
3. RTP
VoiceXML
Server
caller
© 2007 Ken Rehor. All Rights Reserved.
82
What is CCXML?
• XML-based language that manages the connections and
resources used in phone calls
• Designed for 3rd-party call control applications
• Allows for easy integration into back end web applications
very similar to VoiceXML’s model
• Uses the finite state machine model
– Event handlers move from one state to the next using markup tags
• CCXML provides commands to run a “dialog” on a call leg
© 2007 Ken Rehor. All Rights Reserved.
83
Why is CCXML Needed?
• VoiceXML was designed primarily for voice dialogs
– 1st-party call control: <disconnect> and a several predefined common
<transfer> types
• Connection management requires full asynchronous event
handling
– Connection/telephony events can occur any time during a call and must be
handled
– VoiceXML specifically limits asynchronous events to simplify the execution
and programming model
• 1st-party Call Control can be useful but has limited flexibility
– VoiceXML 2.1 <transfer> adds "consultation" feature for network
redirect
© 2007 Ken Rehor. All Rights Reserved.
84
CCXML System Architecture
Telephony
Web
Application
Voice
Web
Application
CCXML
VXML
HTTP
Conference
Server
PSTN
Telephony
Interface
HTTP
CCXML
Server
Telephony
Control
Interface
Dialog
Control
Interface
Dialog
Server
Media
Caller
© 2007 Ken Rehor. All Rights Reserved.
85
CCXML features
• Telephony channel control: voice paths and signaling
– <createcall>, <accept>, <disconnect>,
<reject>, <redirect>
• Media control: Conference Bridges and Mixers
– <join>, <unjoin>, <createconference>,
<destroyconference>
• Dialog control: Add a VoiceXML (or other dialog)
resource to a connection
– <dialogstart>, <dialogprepare>,
<dialogterminate>
© 2007 Ken Rehor. All Rights Reserved.
86
Integration of CCXML and VoiceXML
• Dialogs are created using <dialogstart>
– You pass the URL of the document that you want to run
• Dialogs can be ended using <dialogterminate>
– This allows CCXML to end a dialog based on a external event such as
someone calling you on a second line
• Dialogs can return data back to the CCXML platform
– In VoiceXML use <exit namelist="a b c"/>
– This is exposed in the CCXML dialog.exit event
© 2007 Ken Rehor. All Rights Reserved.
87
W3C CCXML 1.0 status
• Nearing "Candidate Recommendation" status
– Language complete
– Test suite under development
– Certification Program under consideration
• Growing support throughout the world
• Several open source projects underway
– See http://www.sourceforge.net
© 2007 Ken Rehor. All Rights Reserved.
88
Next-Generation Technologies
© 2007 Ken Rehor. All Rights Reserved.
89
Next-Generation Technologies
• Speaker Biometrics-based authentication
– Speaker Identification
– Speaker Verification
• Video IVR --VoiceXML augmented with video
– Early stages of commercial deployment now
– Simple extension to standard platforms
– Straightforward step towards full multimodal
• Multimodal
– Multiple input modalities: speech recognition, keypad, handwriting,
biometrics (voice, fingerprint, iris, etc.), geolocation, motion
– Multiple output modalities: graphics, audio (speech, TTS, music, polyphonic
tones)
© 2007 Ken Rehor. All Rights Reserved.
90
Speaker Biometrics
© 2007 Ken Rehor. All Rights Reserved.
91
Why Speaker Biometrics?
• Identify an individual for remote transactions
• Text / DTMF PINs are inadequate
– Easily compromised
– Easily forgotten
– Does not identify an individual
• US Federal Regulations
– FFIEC guidelines for financial services
© 2007 Ken Rehor. All Rights Reserved.
92
Speaker Identification and Verification (SIV)
• Authentication
– The process of confirming one or more identities.
• Speaker Identification (one-to-many)
– Authentication with multiple identity claims.
• Speaker Verification (one-to-one)
– Authentication with a single identity claim.
© 2007 Ken Rehor. All Rights Reserved.
93
Types of SIV
• Text independent
– SIV technology that can operate on any freeform or structured spoken input.
• Text dependent
– SIV technology (usually verification technology) that requires the voice input
of one or more specific passwords or pass phrases (having been enrolled).
• Text prompted
– SIV technology (usually verification) that randomly selects words and/or
phrases and prompts the speaker to repeat them. The term is also called
challenge-response.
© 2007 Ken Rehor. All Rights Reserved.
94
Fundamental Phases of SIV
• Enrollment
– Capture one or more user utterances to ‘train’ the system
• Verification
– Capture one or more user utterances to make an identity claim
• Adaptation & Scoring
– Judge how close the user’s verification utterance is to the enrolled
utterance
– Refine the existing enrolled utterance with information from the
verification utterance
© 2007 Ken Rehor. All Rights Reserved.
95
Video and Multimodal
© 2007 Ken Rehor. All Rights Reserved.
96
“Video” VoiceXML
• Video extensions to VoiceXML
– 3G Wireless
– VoIP phones
• VoiceXML is just a dialog language
– Initially only for voice input/output
• Example
– Videomail is a dialog application very similar to voicemail
• Video and audio are somewhat analogous
– VoiceXML can be ‘hacked’ to handle video now:
• <audio src="foo.au“/> could “play” a video file
via <audio src=“foo.mpeg4”/>
– VoiceXML 3.0 might add a new language feature
• e.g. <video src="foo.avi"> or <media src="foo.mpeg4">
© 2007 Ken Rehor. All Rights Reserved.
97
“Video” VoiceXML
Deployment and Standardization
• Simple extension to standard platforms
– Easy integration with current platforms
– Doesn’t “break” existing functionality
– Well aligned with “VoiceXML model”
• Early stages of commercial deployment
– Several vendors have deployed large-scale commercial systems
• Step towards full multimodal
© 2007 Ken Rehor. All Rights Reserved.
98
Multimodal Applications
• W3C Multimodal Interaction Working Group
– Defining new standards based on extensive industry experience
• IBM / Motorola / Opera X+V 1.2
– Early stages of commercial deployment
– Freely available from Opera
http://dev.opera.com/articles/voice/
For more information, see:
W3C Multimodal Interaction Working Group
http://www.w3.org/2002/mmi
© 2007 Ken Rehor. All Rights Reserved.
99
VoiceXML 3.0
© 2007 Ken Rehor. All Rights Reserved.
100
VoiceXML 3.0
• Modularization
– Cleanly separate functions to enable integration with other modalities
– Enables code reuse
• New media processing
–
–
–
–
Video
Voice processing
Navigation
Speaker biometrics
• Separation of data, control flow and presentation
– Control flow embodied in new language: SCXML
• Clean data model
© 2007 Ken Rehor. All Rights Reserved.
101
References
• W3C Voice Browser Working Group http://www.w3.org/voice
– VoiceXML 2.0 Recommendation
• http://www.w3.org/TR/voicexml20/
– VoiceXML 2.1 Working Draft
• http://www.w3.org/TR/voicexml21/
– Semantic Interpretation Working Draft
• http://www.w3.org/TR/semantic-interpretation/
– SRGS 1.0 Recommendation
• http://www.w3.org/TR/speech-grammar/
– SSML
• 1.0 Recommendation
http://www.w3.org/TR/speech-synthesis/
• 1.1 Working Draft http://www.w3.org/TR/speech-synthesis11/
– CCXML 1.0
• http://www.w3.org/TR/ccxml/
– SCXML
• http://www.w3.org/TR/scxml/
• IETF http://www.ietf.org
© 2007 Ken Rehor. All Rights Reserved.
102
Ken Rehor
http://www.kenrehor.com
VoiceXML Forum
Co-founder and past-Chair
Chair, VoiceXML Forum Conformance Committee
Co-Chair, VoiceXML Forum Speaker Biometrics Committee
W3C
Co-editor: VoiceXML 1.0, 2.0, 2.1, 3.0
Co-editor: CCXML 1.0
© 2007 Ken Rehor. All Rights Reserved.
103