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Internet-draft       Media Server Markup Language        February 2006
                                 (MSML)


   SIPPING                                                    A. Saleem
   Internet Draft                                           G. Sharratt
   Expires: August 26, 2006                                    Convedia

                                                      February 26, 2006


                    Media Server Markup Language (MSML)
                           draft-saleem-msml-00

Status of this Memo

   By submitting this Internet-Draft, each author represents that any
   applicable patent or other IPR claims of which he or she is aware
   have been or will be disclosed, and any of which he or she becomes
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   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on August 26, 2006.



Copyright Notice

   Copyright (C) The Internet Society (2006). All Rights Reserved.



Abstract

   The Media Server Markup Language (MSML) is used to control and invoke
   many different types of services on IP Media Servers. Clients can use
   it to define how multimedia sessions interact on a Media Server and
   to apply services to individuals or groups of users. MSML can be


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   used, for example, to control Media Server conferencing features such
   as video layout and audio mixing, create sidebar conferences or
   personal mixes, and set the properties of media streams. As well,
   clients can use MSML to define media processing dialogs, which may be
   used as parts of application interactions with users or conferences.
   Transformation of media streams to and from users or conferences as
   well as IVR dialogs are examples of such interactions, which are
   specified using MSML. MSML clients may also invoke dialogs with
   individual users or with groups of conference participants using
   VoiceXML.



Table of Contents

   1. Introduction...................................................5
   2. Conventions used in this document..............................6
   3. Glossary.......................................................6
   4. MSML SIP Usage.................................................7
   5. Language Structure.............................................9
      5.1 Package Scheme.............................................9
      5.2 Profile Scheme............................................12
   6. Execution Flow................................................13
   7. Media Server Object Model.....................................14
      7.1 Objects...................................................15
      7.2 Identifiers...............................................17
   8. MSML Core Package.............................................19
      8.1 <msml>....................................................20
      8.2 <send>....................................................20
      8.3 <result>..................................................21
      8.4 <event>...................................................21
   9. MSML Conference Core Package..................................22
      9.1 Conferences...............................................22
      9.2 Media Streams.............................................23
      9.3 <createconference>........................................24
         9.3.1 <reserve>............................................26
            9.3.1.1 <resource>......................................26
      9.4 <modifyconference>........................................27
      9.5 <destroyconference>.......................................29
      9.6 <audiomix>................................................29
         9.6.1 <n-loudest>..........................................30
         9.6.2 <asn>................................................30
      9.7 <videolayout>.............................................31
         9.7.1 <root>...............................................31
         9.7.2 <region>.............................................32
         9.7.3 <selector>...........................................35
            9.7.3.1 <vas> Voice Activate Switching..................37
      9.8 <join>....................................................38


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      9.9 <modifystream>............................................40
      9.10 <unjoin>.................................................41
      9.11 <monitor>................................................42
      9.12 <stream>.................................................42
         9.12.1 Audio Stream Properties.............................43
            9.12.1.1 <gain>.........................................44
            9.12.1.2 <clamp>........................................44
         9.12.2 Video Stream Properties.............................44
            9.12.2.1 <visual>.......................................45
   10. MSML Dialog Packages.........................................45
      10.1 Overview.................................................45
      10.2 Primitives...............................................47
      10.3 Events...................................................49
      10.4 MSML Dialog Usage with SIP...............................50
      10.5 MSML Dialog Structure and Modularity.....................52
      10.6 MSML Dialog Core Package.................................52
         10.6.1 <dialogstart>.......................................53
         10.6.2 <dialogend>.........................................55
         10.6.3 <send>..............................................56
         10.6.4 <exit>..............................................57
         10.6.5 <disconnect>........................................57
      10.7 MSML Dialog Base Package.................................57
         10.7.1 <play>..............................................58
            10.7.1.1 <audio>........................................60
            10.7.1.2 <video>........................................61
            10.7.1.3 <media>........................................62
            10.7.1.4 <var>..........................................62
            10.7.1.5 <playexit>.....................................63
         10.7.2 <dtmfgen>...........................................63
            10.7.2.1 <dtmfgenexit>..................................64
         10.7.3 <record>............................................64
            10.7.3.1 <play>.........................................68
            10.7.3.2 <recordexit>...................................68
         10.7.4 <dtmf> or <collect>.................................68
            10.7.4.1 <play>.........................................70
            10.7.4.2 <pattern>......................................70
            10.7.4.3 <detect>.......................................71
            10.7.4.4 <noinput>......................................71
            10.7.4.5 <nomatch>......................................71
            10.7.4.6 <dtmfexit>.....................................72
         10.7.5 <moml>..............................................72
      10.8 MSML Dialog Group Package................................72
         10.8.1 <group>.............................................76
         10.8.2 <groupexit>.........................................76
      10.9 MSML Dialog Transform Package............................76
         10.9.1 <vad>...............................................77
            10.9.1.1 <voice>, <silence>, <tvoice>, <tsilence>.......77
         10.9.2 <gain>..............................................78


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         10.9.3 <agc>...............................................78
         10.9.4 <gate>..............................................79
         10.9.5 <clamp>.............................................79
         10.9.6 <relay>.............................................79
      10.10 MSML Dialog Speech Package..............................79
         10.10.1 <speech>...........................................80
            10.10.1.1 <grammar>.....................................81
            10.10.1.2 <match>.......................................82
            10.10.1.3 <noinput>.....................................82
            10.10.1.4 <nomatch>.....................................82
            10.10.1.5 <speechexit>..................................82
         10.10.2 <play>.............................................83
            10.10.2.1 <tts>.........................................83
      10.11 MSML Dialog Fax Detection Package.......................83
         10.11.1 <faxdetect>........................................83
      10.12 MSML Dialog Fax Send/Receive Package....................84
         10.12.1 <faxsend>..........................................84
            10.12.1.1 <sendobj>.....................................86
            10.12.1.2 <hdrfooter>...................................86
            10.12.1.3 <rxpoll>......................................87
            10.12.1.4 <faxstart>....................................87
            10.12.1.5 <faxnegotiate>................................88
            10.12.1.6 <faxpagedone>.................................88
            10.12.1.7 <faxobjectdone>...............................88
            10.12.1.8 <faxopcomplete>...............................88
            10.12.1.9 <faxpollstarted>..............................89
         10.12.2 <faxrcv>...........................................89
            10.12.2.1 <rcvobj>......................................90
            10.12.2.2 <txpoll>......................................91
   11. Response Codes...............................................91
   12. MSML Conference Examples.....................................93
      12.1 Establishing a Dial-in Conference........................93
      12.2 Example of a Sidebar Audio Conference....................97
      12.3 Example of Removing a Conference.........................99
      12.4 Example of Modifying Video Layout........................99
   13. MSML Dialog Examples........................................100
      13.1 Announcement............................................100
      13.2 Voice Mail Retrieval....................................101
      13.3 Play and Record.........................................102
      13.4 Speech Recognition......................................103
      13.5 Play and Collect........................................104
      13.6 User Controlled Gain....................................106
   14. Change Summary..............................................106
   15. Future Work.................................................107
   16. XML Schema - MSML Core and MSML Conference Core Packages....107
   17. XML Schema – MSML Dialog/Transform/Speech/Fax Packages......118
   18. Security Considerations.....................................138
   19. IANA Considerations.........................................138


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   20. URN Sub-Namespace Registration..............................139
   21. XML Schema Registration.....................................139
   22. References..................................................139
   Acknowledgments.................................................141
   Authors' Addresses..............................................141
   Intellectual Property Statement.................................142
   Copyright Statement.............................................142
   Disclaimer of Validity..........................................143
   Acknowledgement.................................................143


1. Introduction

   Media servers contain dynamic pools of media resources. Control
   Agents and other users of media servers (called media server clients)
   can define and create many different services based on how they
   configure and use those resources. Often, that configuration and the
   ways in which those resources interact will be changed dynamically
   over the course of a call, to reflect changes in the way that an
   application interacts with a user.

   For example, a call may undergo an initial IVR dialog before being
   placed into a conference. Calls may be moved from a main conference
   to a sidebar conference and then back again. Individual calls may be
   directly bridged to create small n-way calls or simple sidebars. None
   of these change the SIP [1] dialog or RTP [15] session. Yet these do
   affect the media flow and processing internal to the media server.

   The Media Server Markup Language (MSML) is an XML [4] language used
   to change the flow of and services on media streams within a media
   server. It is used to invoke many different types of services on
   individual sessions, groups of sessions, and conferences. MSML allows
   the creation of conferences, bridging different sessions together,
   and bridging sessions into conferences.

   MSML may also be used to create user interaction dialogs and allows
   the application of media transforms to media streams. Media
   interaction dialogs created using MSML allow construction of IVR
   dialog sessions to individual users as well as to groups of users
   participating in a conference. Dialogs may also be specified using
   other languages, VoiceXML [7], which support complete single-party
   application logic to be executed on the Media Server.

   MSML is a transport independent language, such that it does not rely
   on underlying transport mechanisms and language semantics are
   independent of transport. However, SIP is a typical and commonly used
   transport mechanism for MSML, invoked using the SIP URI scheme. This



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   specification defines using MSML Dialogs using SIP as the transport
   mechanism.

   A network connection may be established with the media server using
   SIP. Media received and transmitted on that connection will flow
   through different media resources on the media server depending on
   the requested service. Basic Network Media Services with SIP [9]
   defines conventions for associating a basic service with a SIP
   Request-URI. MSML allows services to be dynamically applied and
   changed by a Control Agent during the lifetime of the SIP dialog.

   MSML has been designed to address the control and manipulation of
   media processing operations (e.g., announcement, IVR, play and
   record, ASR/TTS, fax, video), as well as control and relationships of
   media streams (e.g., simple and advanced conferencing). It provides a
   general-purpose media server control architecture. MSML can
   additionally be used to invoke other more complex IVR languages such
   as VoiceXML.

2. Conventions used in this document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [7].

3. Glossary

   Media Server: a general-purpose platform for executing real-time
   media processing tasks. This is a logical function that maps either
   to a single physical device or to a portion of a physical device.

   Media Server Client: an application which originates MSML requests to
   a media server and also referred to as a Control Agent in this
   specification.

   Network Connection: a participant that represents the termination on
   a media server of one or more RTP [15] sessions (for example audio
   and video) associated with a call. Network connections are
   established and removed using a session establishment protocol such
   as SIP. An instance of a network connection is independent of MSML
   processing instructions applied to it.

   Dialog: an automated IVR participant. Examples of dialogs may be
   announcement players, IVR interfaces, or voice recorders. Dialogs may
   be defined in MSML or using VoiceXML [7].

   Conference: an intermediary function that provides multimedia mixing
   and other advanced conferencing services. This specification


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   currently considers conferences with audio and/or video media types,
   but is extensible to other media types.

   Identifier: a name that is used to refer to a specific instance of an
   object on the media server, such as a conference or a dialog.
   Identifiers are composed of one or more terms where each term
   identifies an object class and instance.

   Object: the generic term for a media server entity that terminates,
   originates, or processes media. This specification defines four
   classes of objects and specifies mechanisms to create them, join them
   together, and destroy them.

   Participant Object: an object in a media server that sources original
   media in a call and/or receives and terminates media in a call.

   Intermediary Object: an object in a media server that acts on media
   within a call for the benefit of the participants.

   Independent Object: an object that can exist on a media server
   independent of other objects.

   Operator: an intermediary object class that modifies or transforms a
   media stream. Examples of operators may be audio gain controls, video
   scaling, or voice masking. MSML defines operators as implicit
   objects, which transform media when operations, such as gain control,
   are applied to media streams.

   Media Stream: a single media flow between two objects. A media stream
   has a media type and may be unidirectional or bidirectional.

4. MSML SIP Usage

   SIP is used to create and modify media sessions with a media server
   according to the procedures defined in RFC 3261 [1]. Often, SIP third
   party call control [16] will be used to create sessions to a media
   server on behalf of end users. MSML is used to define and change the
   service which a user connected to a media server will receive. MSML
   clients are application servers, softswitches, or other forms of
   control agents, and SHOULD have an authorized security relationship
   with the media server. MSML itself does not define authorization
   mechanisms.

   MSML transactions are originated based upon events that occur in the
   application domain. These events may be independent from any media or
   user interaction. For example, an application may wish to play an
   announcement to a conference warning that its scheduled completion
   time is approaching. Applications themselves are structured in many


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   different ways. Their structure and requirements contribute to their
   selection of protocols and languages. To accommodate differing
   application needs, MSML has been designed to be neutral to other
   languages and independent of the transport used to carry it.

   Many alternatives exist for a transport mechanism for MSML. There may
   be one or many transport channels used to carry MSML based upon the
   requirements and structure of applications. SIP INVITE and INFO [17]
   requests and responses have been chosen to carry MSML in this release
   of the specification. INFO requests allow asynchronous mid-call
   messages within SIP with few additional semantics. In addition, there
   are existing widely deployed implementations of that method, it aids
   in initial developments which are closely coupled with SIP session
   establishment, and it allows MSML to be directly associated with user
   dialogs when third party call control is used.

   Although INFO is sometimes considered to not be a suitable general-
   purpose transport mechanism for messages within SIP, there have been
   proposals to make it more acceptable. MSML may evolve to include
   other SIP usage and/or to work with other protocols or as a stand-
   alone protocol established through SIP, in future releases of this
   document.

   MSML supports several models for client interaction. When clients use
   3PCC to establish media sessions on behalf of end users, clients will
   have a SIP dialog for each media session. MSML MAY be sent on these
   dialogs. However the targets of MSML actions are not inferred from
   the session associated with the SIP dialog. The targets of MSML
   actions are always explicitly specified using identifiers as
   previously defined.

   An application, after interacting with a user, may want to affect
   multiple objects within a media server. For example, tones or
   messages are often played to a conference when connections are added
   or removed. A separate message may also be played to a participant as
   they are joined, or to moderators. Explicit identifiers, that is, not
   inferred from a transport mechanism allow these multiple actions to
   be easily grouped into a single transaction sent on any SIP dialog.

   MSML also supports a model of dedicated control associations. This
   supports decoupled application architectures where a client can
   control media server services without also establishing all of the
   media sessions itself. Control associations are created using SIP but
   they do not have any associated media session. Although initially
   INFO messages will be sent on this SIP dialog, just as with dialogs
   associated with media sessions, it is possible that in the future,
   the SIP dialog will be used to establish a separate control session



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   (defined in SDP [18]) that does not use SIP as the transport for MSML
   messages.

   A media server using MSML also sends asynchronous events to a client
   using MSML scripts in SIP INFO. Events are sent based on previous
   MSML requests and are sent within the SIP dialog on which the MSML
   request that caused the event to be generated was received. If this
   dialog no longer exists when the event is generated, the event is
   discarded.

   Events may be generated during the execution of a dialog created by a
   <dialogstart> element. For example, dialogs can send events based on
   user input. VoiceXML dialogs, on the other hand, generally interact
   with other servers outside of MSML using HTTP.

   An event is also generated when the execution of a dialog terminates,
   either because of completion or failure. The exact information
   returned is dependent on the dialog language, the capabilities of the
   dialog execution environment, and what was requested by the dialog.
   Both MSML and VoiceXML [7] allow information to be returned when they
   exit. These events may be sent in a SIP INFO or a SIP BYE. SIP BYE is
   used when the dialog itself specifies that the connection should be
   disconnected, for example through the use of the <disconnect>
   element.

   Conferences may also generate events based upon their configuration.
   An example of this is the notification of the set of active speakers.

5. Language Structure

5.1 Package Scheme

   The primary mechanism for extending MSML is the "package". A package
   is an integrated set of one or more XML schemas that define
   additional features and functions via new or extended use of elements
   and attributes. Each package, except for those defined in the current
   document, is defined in a separate standards document, e.g., an
   Internet Draft or an RFC. All packages, that extend the base MSML
   functionality, MUST include references to the MSML base set of
   schemas provided in the Internet drafts. A schema in a package MUST
   only extend MSML, this is, it must not alter the existing
   specification.

   A particular MSML script will include references to all the schemas
   defining the packages whose elements and attributes it makes use of.
   A particular script MUST reference MSML base and optionally extension
   package(s). See IANA Considerations section.



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   Each package MUST define its own namespace so that elements or
   attributes with the same name in different packages do not conflict.
   A script using a particular element or attribute MUST prefix the
   namespace name on that element or attribute's name if it is defined
   in a package (as opposed to being defined in the base).

   MSML consists of a core package which provides structure without
   support for any specific feature set. Additional packages, relying on
   the core package, provide functional features. Any combination of
   additional packages may be used along with the core package. The
   following describes the set of MSML packages defined in this
   document.

                  +----------------------------------------------+
                  |                  MSML Core                   |
                  +----------------------------------------------+
                      /                                     \
                  +--------+                            +--------+
                  | Dialog |                            | Conf   |
                  | Core   |                            | Core   |
             -  - +--------+ - -  -  -  -  -   -   -    +--------+
            /        /          \           \       \
       +--------+  +--------+ +---------+ +------+ +------+
       | Dialog |  | Dialog | |Dialog   | |Dialog| |Dialog|
       | Base   |  | Group  | |Transform| |Speech| |Fax   |
       +--------+  +--------+ +---------+ +------+ +------+



      o MSML Core package (Mandatory)

         Describes the minimum base framework which MUST be implemented
         to support additional core packages.

      o MSML Conference Core package (Conditionally Mandatory, for
         Conferencing)

         Describes the audio and multimedia basic and advanced
         conferencing package, which MAY be implemented.

      o MSML Dialog Core package (Conditionally Mandatory, for Dialogs)

         Describes the dialog core package which MUST be implemented for
         any dialog services. However, systems supporting conferencing
         only, MAY omit support for MSML dialogs. The MSML dialog core
         package specifies the framework within which additional dialog
         packages are supported. The MSML dialog base package MUST be
         supported, while all other dialog packages MAY be supported.


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         o MSML Dialog Base package (Conditionally Mandatory, for
         Dialogs)

         o MSML Dialog Group package (Optional)

         o MSML Dialog Transform package (Optional)

         o MSML Dialog Fax Detection package (Optional)

         o MSML Dialog Fax Send/Receive package (Optional)

         o MSML Dialog Speech package (Optional)

   The formal process for defining extensions to MSML Dialogs is to
   define a new package. The new package MUST provide a text description
   of what extensions are included and how they work. It MUST also
   define an XML schema file (if applicable) that defines the new
   package (which may be through extension, restriction of an existing
   package, or a specific profile of an existing package). Dependencies
   upon other packages MUST be stated. For example a package that
   extends or restricts has a dependency on the original package
   specification. Finally, the new package MUST be assigned a unique
   name and version.

   The types of things which can be defined in new packages are:

      o  new primitives

      o  extensions to existing primitives (events, shadow variables,
         attributes, content)

      o  new recognition grammars for existing primitives

      o  new markup languages for speech generation

      o  languages for specifying a topology schema

      o  new pre-defined topology schemas

      o  new variables / segment types (sets & languages)

      o  new control flow elements

   MSML Packages are assembled together to form a specific MSML profile
   that is shared between different implementations. The base MSML
   Dialog profiles which are defined in this document consist of the
   MSML Core package, MSML Dialog Core package, MSML Dialog Base



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   package, MSML Dialog Group package, MSML Transform package, MSML Fax
   packages, and the MSML Speech package.

   MSML extension packages, which define primitives, MUST define the
   following for each primitive within the package:

      o  the function which the primitive performs

      o  the attributes which may be used to tailor its behavior

      o  the events which it is capable of understanding

      o  the shadow variables which provide access to information
         determined as a result of the primitive's operation.

   The mechanism used to insure that a media server and its client share
   a compatible set of packages is not defined. Currently it is expected
   that provisioning will be used, possibly coupled with a future
   auditing capability. Additionally, when used in SIP networks,
   packages could be defined using feature tags and the procedures
   defined for Indicating User Agent Capabilities in SIP [2] used to
   allow a media server to describe its capabilities to other user
   agents and its domain registrar.

5.2 Profile Scheme

   Not all devices and applications using MSML will need to support the
   entire MSML schema. For example, a media processing device might
   support only audio announcements, only audio simple conferencing, or
   only multimedia IVR. It is highly desirable to have a system for
   describing what portion of MSML a particular media processing device
   or Control Agent supports.

   The Package scheme described earlier allows MSML functionality to be
   functionally grouped, relying on the MSML core package. This scheme
   allows a portion of the complete MSML specification to be
   implemented, on a per package basis and also creates a framework for
   future extension packages. However, within a given package, in some
   cases, only a subset of the package functionality may be required. In
   order to support subsets of packages, with greater degree of
   granularity than at the package level, a profile scheme is required.

   MSML package profiles would identify a subset of a given MSML package
   with specific definitions of elements and attributes. Each MSML
   package profile MUST be accompanied by one or more corresponding
   schemas. To use the examples above, there could be an audio
   announcements profile of the MSML Dialog Base package, an audio



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   simple conferencing profile of the MSML Conference Core package, and
   a multimedia IVR profile of the MSML Dialog Base package.

   MSML package profiles MUST be published separately from the MSML
   specification, in one or more standards documents (e.g., Internet
   Drafts or RFCs) dedicated to MSML package profiles. Profiles would
   not be registered with IANA and any organization would additionally
   be free to create its own profile(s) if required.

6. Execution Flow

   MSML assumes a model where there is a single control context within a
   media server for MSML processing. That context may have one or many
   SIP [1] dialogs associated with it. It is assumed that any SIP
   dialogs associated with the MSML control context have been
   authorized, as appropriate, by mechanisms outside the scope of MSML.

   A media server control context maintains information about the state
   of all media objects and media streams within a media server. It
   receives and processes all MSML requests from authorized SIP dialogs
   and receives all events generated internally by media objects and
   sends them on the appropriate SIP dialog. An MSML request is able to
   create new media objects and streams, and to modify or destroy any
   existing media objects and streams.

   An MSML request may simply specify a single action for a media server
   to undertake. In this case, the document is very similar to a simple
   command request. Often, though, it may be more natural for a client
   to request multiple actions at one time, or the client would like
   several actions to be closely coordinated by the media server.
   Multiple MSML elements received in a single request MUST be processed
   sequentially in document order.

   An example of the first scenario would be to create a conference and
   join it with an initial participant. An example of the second case
   would be to unjoin one or more participants from a main conference
   and join them to a sidebar conference. In the first scenario, network
   latencies may not be an issue, but it is simpler for the client to
   combine the requests. In the second case, the added network latency
   between separate requests could mean perceptible audio loss to the
   participant.

   Each MSML request is processed as a single transaction. A media
   server MUST ensure that it has the necessary resources available to
   carry out the complete transaction before executing any elements of
   the request. If it does not have sufficient resources, it MUST return
   a 520 response and MUST NOT execute the transaction.



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   The MSML request MUST be checked for well-formedness and validated
   against the schema prior to executing any elements. This allows XML
   [4] errors to reported immediately and minimizes failures within a
   transaction and the corresponding execution of only part of the
   transaction.

   Each element is expected to execute immediately. Elements such as
   <dialogstart>, which take an unpredictable amount of time, are
   "forked" and executed in a separate thread (see MSML Dialog
   packages). Once successfully forked, execution continues with the
   element following the </dialogstart>. As such, MSML does not provide
   mechanisms to sequence or coordinate other operations with dialog
   elements.

   Processing within a transaction MUST stop if any errors occur.
   Elements that were executed prior to the error are not rolled back.
   It is the responsibility of the client to determine appropriate
   actions based upon the results indicated in the response. Most
   elements MAY contain an optional "mark" attribute. The value of that
   attribute from the last successfully executed element MUST be
   returned in an error response. Note that errors that occur during the
   execution of a dialog occur outside the context of an MSML
   transaction. These errors will be indicated in an asynchronous event.

   Transaction results are returned as part of the SIP request response.
   The transaction results indicate the success or failure of the
   transaction. The result MUST also include identifiers for any objects
   created by a media server for which the client did not provide an
   instance name. Additionally, if the transaction fails, the reason for
   the failure MUST be returned, as well as an indication of how much of
   the transaction was executed before the failure occurred SHOULD be
   returned.

7. Media Server Object Model

   Media servers are general-purpose platforms for executing real-time
   media processing tasks. These tasks range in complexity from simple
   ones such as serving announcements, to complex ones, such as speech
   interfaces, centralized multimedia conferencing, and sophisticated
   gaming applications.

   Calls are established to a media server using SIP. Clients will often
   use SIP third party call control (3PCC) [16] to establish calls to a
   media server on behalf of end users. However MSML does not require
   that 3PCC be used; only that the client and the media server share a
   common identifier for the call and its associated RTP [15] sessions.




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   Objects represent entities which source, sink, or modify media
   streams. A media streams is a bidirectional or unidirectional media
   flow between objects on a media server. The following subsections
   define the classes of objects that exist on a media server and the
   way these are identified in MSML.

7.1 Objects

   A media object is an endpoint of one or more media streams. It may be
   a connection that terminates RTP sessions from the network or a
   resource that transforms or manipulates media. MSML defines four
   classes of media objects. Each class defines the basic properties of
   how object instances are used within a media server. However most
   classes require that the function of specific instances be defined by
   the client, using MSML or other languages such as VoiceXML.

   The following classes of media processing objects are defined. The
   class names are given in parentheses:

         o network connection (conn)

         o conference (conf)

         o dialog (dialog)

         o operator (oper)



   Network connection is an abstraction for the media processing
   resources involved in terminating the RTP session(s) of a call. For
   audio services a connection instance presents a full-duplex audio
   stream interface within a media server. Multimedia connections have
   multiple media streams of different media types, each corresponding
   to an RTP session. Network connections get instantiated through SIP
   [1].

   A conference represents the media resources and state information
   required for a single logical mix of each media type in the
   conference (e.g. audio and video). MSML models multiple mixes/views
   of the same media type as separate conferences. Each conference has
   multiple inputs. Inputs may be divided into classes that allow an
   application to request different media treatment for different
   participants. For example, the video streams for some participants
   may be assigned to fixed regions of the screen while those for other
   participants may only be shown when they are speaking.




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   A conference has a single logical output per media type. For each
   participant, it consists of the audio conference mix, less any
   contributed audio of the participant, and the video mix shared by all
   conference participants. Video conferences using voice activated
   switching have an optional ability to show the previous speaker to
   the current speaker.

   Conferences are instantiated using the <createconference> element.
   The content of the <createconference> element specifies the
   parameters of the audio and/or video mixes.

   Dialogs are a class of objects that represent automated participants.
   They are similar to network connections from a media flow perspective
   and may have one or more media streams as the abstraction for their
   interface within a media server. Unlike connections however, dialogs
   are created and destroyed through MSML, and the media server itself
   implements the dialog participant. Dialogs are instantiated through
   the <dialogstart> element. Contents of the <dialogstart> element
   define the desired or expected dialog behavior. Dialogs may also be
   invoked by referencing VoiceXML as the dialog description language.

   Operators are implicit functions that are used to filter or transform
   a media stream. The function that an instance of an operator fulfills
   is defined as a property of the media stream. Operators may be
   unidirectional or bidirectional and have a media type. Unidirectional
   operators reflect simple atomic functions such as automatic gain
   control, filtering tones from conferences, or applying specific gain
   values to a stream. Unidirectional operators have a single media
   input, which is connected to the media stream from one object, and a
   single media output, which is connected to the media stream of a
   different object.

   Bidirectional operators have two media inputs and two media outputs.
   One media input and output is associated with the stream to one
   object and the other input and output is associated with a stream to
   a different object. Bidirectional objects may treat the media
   differently in each direction. For example, an operator could be
   defined which changed the media sent to a connection based upon
   recognized speech or DTMF received from the connection. Operators are
   implicitly instantiated when streams are created or modified using
   the elements <join> element and elements <modifystream> respectively.

   The relationships between the different object classes is shown in
   the figure below.






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                   +--------------------------------------+
                   |           Media Server               |
                   |                                      |
                   |------+                      ,---.    |
                   |      |      +------+       /     \   |
        <== RTP ==>| conn |<---->| oper |<---->( conf  )  |
                   |      |      +------+       \     /   |
                   |------+                      `---'    |
                   |   ^                           ^      |
                   |   |                           |      |
                   |   |   +------+    +------+    |      |
                   |   |   |      |    |      |    |      |
                   |   +-->|dialog|    |dialog|<---+      |
                   |       |      |    |      |           |
                   |       +------+    +------+           |
                   +--------------------------------------+


   A single, full-duplex instance of each object class is shown together
   with common relationships between them. An operator (such as gain) is
   shown between a connection and a conference and dialogs are shown
   participating both with an individual connection and with a
   conference. The figure is not meant to imply only one to one
   relationships. Conferences will often have hundreds of participants,
   and either connections or conferences may be interacting with more
   than one dialog. For example, one dialog may be recording a
   conference while other dialogs announce participants joining or
   leaving the conference.

7.2 Identifiers

   Objects are referenced using identifiers that are composed of one or
   more terms. Each term specifies an object class and names a specific
   instance within that class. The object class and instance are
   separated by a colon ":" in an identifier term.

   Identifiers are assigned to objects when they are first created. In
   general, either the MSML client or a media server may specify the
   instance name for an object. Objects for which a client does not
   assign an instance name will be assigned one by a media server. Media
   server assigned instance names are returned to the client as a
   complete object identifier in the response to the request that
   created the object.

   It is meaningful for some classes of objects to exist independently
   on a media server. Network connections may be created through SIP at
   any time. MSML can then be used to associate their media with other
   objects as required to create services. Conferences may be created


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   and have specific resources reserved waiting for participant
   connections.

   Objects from these two classes, connections and conferences, are
   considered independent objects since they can exist on a standalone
   basis. Identifiers for independent objects consist of single term as
   defined above. For example, identifiers for a conference and
   connection could be "conf:abc" or "conn:1234" respectively. Clients
   which choose to assign instance names to independent objects must use
   globally unique instance names. One way to create globally unique
   names is to include the domain name of the client as part of the
   name.

   Dialogs are created to provide a service to independent objects.
   Dialogs may act as a participant in a conference or interact with a
   connection similar to a two participant call. Dialogs depend upon the
   existence of independent objects and this is reflected in the
   composition of their identifiers. Operators modify the media flow
   between other objects, such as application of gain between a
   connection and a conference. As operators are merely media transform
   primitives defined as properties of the media stream, they are not
   represented by identifiers and created implicitly.

   Identifiers for dialogs are composed of a structured list of slash
   ('/') separated terms. The left-most term of the identifier must
   specify a conference or connection. This serves as the root for the
   identifier. An example of an identifier for a dialog acting as a
   conference participant could be:

         conf:abc/dialog:recorder

   All objects except connections are created using MSML. Connections
   are created when media sessions get established through SIP. There
   are several options clients and media servers can use to establish a
   shared instance name for a connection and its media streams.

   When media servers support multiple media types, the instance name
   SHOULD be a call identifier that can be used to identify the
   collection of RTP sessions associated with a call. When MSML is used
   in conjunction with SIP and third party call control, the call
   identifier MUST be the same as the local tag assigned by the media
   server to identify the SIP dialog. This will be the tag the media
   server adds to the "To" header in its response to an initial invite
   transaction. RFC 3261 requires the tag values to be globally unique.

   An example of a connection identifier is: conn:74jgd63956ts.




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   With third party call control, the MSML client acts as a back to back
   user agent (B2BUA) to establish the media sessions. SIP dialogs are
   established between the client and the media server allowing the use
   of the media server local tag as a connection identifier. If third
   party call control is not used, a SIP event package MAY be used to
   allow a media server to notify new sessions to a client that has
   subscribed to this information.

   Identifiers as described above allow every object in a media server
   to be uniquely addressed. They can also be used to refer to multiple
   objects. There are two ways in which this can currently be done:

         wildcards

         common instance names

   An identifier can reference multiple objects when a wildcard is used
   as an instance name. MSML reserves the instance name comprised of a
   single asterisk ('*') to mean all objects that have the same
   identifier root and class. Instance names containing an asterisk
   cannot be created. Wildcards MUST only be used as the right most term
   of an identifier and MUST NOT be used as part of the root for dialog
   identifiers. Wildcards are only allowed where explicitly indicated
   below.

   The following are examples of valid wildcards:

         conf:abc/dialog:*

         conn:*

   Examples of illegal wildcard usage are:

         conf:*/dialog:73849

   Although identifiers share a common syntax, MSML elements restrict
   the class of objects which are valid in a given context. As an
   example, although it is valid to join two connections together, it is
   not valid to join two IVR dialogs.

8. MSML Core Package

   This section describes the core MSML package which MUST be supported
   in order to use any other MSML packages. The core MSML package
   defines a framework, without explicit functionality, over which
   functional packages are used.




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8.1 <msml>

   <msml> is the root element. When received by a media server, it
   defines the set of operations that form a single MSML request.
   Operations are requested by the contents of the element. Each
   operation MAY appear zero or more times as children of <msml>.
   Specific operations are defined within the Conference package and in
   the set of Dialog packages.

   The results of a request or the contents of events sent by a media
   server are also enclosed within the <msml> element. The results of
   the transaction are included as a body in the response to the SIP
   request that contained the transaction. This response will contain
   any identifiers that the media server assigned to newly created
   objects. All messages that a media server generates are correlated to
   an object identifier. Objects and identifiers are discussed in
   section 7 (Media Server Object Model).

   Attributes:

         version: "1.1" Mandatory

8.2 <send>

   Events are used to affect the behavior of different objects within a
   media server. The <send> element is used to send an event to the
   specified recipient within the Media Server.

   Attributes:

         event: the name of an event. Mandatory.

         target: an object identifier. When the identifier is for a
         dialog, it may optionally be appended with a slash "/" followed
         by the target to be included in a MSML Dialog <send>.
         Mandatory.

         valuelist: a list of zero or more parameters that are included
         with the event.

         mark: a token that can be used to identify execution progress
         in the case of errors. The value of the mark attribute from the
         last successfully executed MSML element is returned in an error
         response. Therefore the value of all mark attributes within an
         MSML document should be unique.





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8.3 <result>

   The <result> element is used to report the results of an MSML
   transaction. It is included as a body in the final response to the
   SIP request which initiated the transaction. An optional child
   element <description> may include text which expands on the meaning
   of error responses. Response codes are defined in section 11
   (Response Codes).

   attributes:

         response: a numeric code indicating the overall success or
         failure of the transaction, and in the case of failure, an
         indication of the reason. Mandatory.

         mark: in the case of an error, the value of the mark attribute
         from the last successfully executed element that included the
         mark attribute.

   In the case of failure, a description of the reason SHOULD be
   provided using the child element <description>.

   Three other child elements allow the response to include identifiers
   for objects created by the request but which did not have instance
   names specified by the client. Those elements are <confid> and
   <dialogid>, for objects created though a <createconference> and
   <dialogstart> respectively.

8.4 <event>

   The <event> element is used to notify an event to a media server
   client. Three types of events are defined by MSML Core package;
   "msml.dialog.exit", "msml.conf.nomedia", and "msml.conf.asn". These
   correspond to the termination of an executing dialog, a conference
   being automatically deleted when the last participant has left, and
   the notification of the current set of active speakers for a
   conference, respectively. Events may also be generated by an
   executing dialog. In this case the event type is specified by the
   dialog. (see MSML Dialog Core Package <send>).

   attributes:

         name: the type of event. If the event is generated because of
         the execution MSML Dialog <send>, the value MUST be the value
         of the "event" attribute from the <send> element within the
         MSML Dialog Core package. If the event is generated because of
         the execution of an <exit>, the value MUST be "moml.exit". If
         the event is generated because of the execution of a


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         <disconnect>, the value MUST be "moml.disconnect". If the event
         is generated because of an error, the value must be
         "moml.error". Mandatory.

         id: the identifier of the conference or dialog that generated
         the event or caused the event to be generated. Mandatory.

         <event> has two children, <name> and <value>, which contain the
         name and value respectively of each namelist item associated
         with the event.

9. MSML Conference Core Package

9.1 Conferences

   A conference has a mixer for each type of media that the conference
   supports. Each mix has a corresponding description that defines how
   the media from participants contributes to that mix. A mixer has
   multiple inputs that are combined in a media specific way to create a
   single logical output.

   The elements that describe the mix for each media type are called
   mixer description elements. They are:

   <audiomix> defines the parameters for mixing audio media.

   <videolayout> defines the composition of a video window.

   These elements, defined in sections 9.6 (Audio Mix) and 9.7 (Video
   Layout) respectively, are used as content of the <createconference>
   element to establish the initial properties of a conference. The
   elements are used within the <modifyconference> element to change the
   properties of a conference once it has been created, or within the
   <destroyconference> element to remove individual mixes from the
   conference.

   Conferences may be terminated by an MSML client using the
   <destroyconference> element to remove the entire conference or by
   removing the last mixer(s) associated with the conference.
   Conferences can also be terminated automatically by a media server
   based on criteria specified when the conference is created. When the
   conference is deleted, any remaining participants will have their
   associated SIP dialogs left unchanged or deleted based on the value
   of the "term" attribute specified when the conference was created.






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9.2 Media Streams

   Objects have at least one media input and output for each type of
   media that they support. Each object class defines the number of
   inputs and outputs objects of that class support. Media streams are
   created when objects are joined, either explicitly using <join>, or
   implicitly when dialogs are created using <dialogstart>. Dialog
   creation has two stages, allocating and configuring the resources
   required for the dialog instance, and implicitly joining those
   resources to the dialog target during the dialog execution. Refer to
   MSML Dialog Base package.

   A join operation by default creates a bidirectional audio stream
   between two objects. Video and unidirectional streams may also be
   created. A media stream is created by connecting the output from one
   object to the input of another object and vice versa (assuming a
   bidirectional or full-duplex join).

   Many objects may only support a single input for each type of media.
   Within this specification, only the conference object class supports
   an arbitrary number of inputs. When a stream is requested to be
   created to an object that already has a stream of the same type
   connected to its single input, the result of the request depends upon
   the type of the media stream.

   Audio mixing is done by summing audio signals. Automatically mixing
   audio streams has common and straight forward applications. For
   example, the ability to bridge two streams allows for the easy
   creation of simple three-way calls or to bridge private announcements
   with a [whispered] conference mix for an individual participant. In
   the case of general conferences however, an MSML client SHOULD create
   an audio conference and then join participants to the conference.
   Conference mixers SHOULD subtract the audio of each participant from
   the mix so that they do not hear themselves.

   A media server that receives a request that requires joining an audio
   stream to the single audio input of an object that already has an
   audio stream connected, SHOULD automatically bridge the new stream
   with the existing stream, creating a mix of the two audio streams.
   The maximum number of streams that may be bridged in this manner is
   implementation-specific. It is RECOMMENDED that a media server
   support bridging at least two streams. A media server that cannot
   bridge a new stream with any existing streams MUST fail the operation
   requesting the join.

   Unlike audio mixing, there are many different ways that two video
   streams may be combined and presented. For example, they may be
   presented side by side in separate panes, picture in picture, or in a


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   single pane which displays only a single stream at a time based on a
   heuristic such as active speaker. Each of these options creates a
   very different presentation and require significantly different media
   resources.

   A join operation does not describe how a new stream can be combined
   with an existing stream. Therefore automatic bridging of video is not
   supported. A media server MUST fail requests to join a new video
   stream to an object that only supports a single video input and
   already has a video stream connected to that input. For an object to
   have multiple video streams joined to it, the object itself must be
   capable in supporting multiple video streams. Conference objects can
   support multiple video streams and provide a way to specify the
   mixing presentation for the video streams.

   A media server MUST NOT establish any streams unless the media server
   is able to create all the streams requested by an operation. Streams
   are only able to be created if both objects support a media type and
   at least one of the following conditions is true:

      1. each object that is to receive media is not already receiving a
         stream of that type.

      2. any object that is to receive media and is already receiving a
         stream of that type supports receiving an additional stream of
         that type. The only class of objects defined in this
         specification that directly support receiving multiple streams
         of the same type are conferences.

      3. the media server is able to automatically bridge media streams
         for an object that is to receive media and that is already
         receiving a stream of the requested type. The only type of
         media defined in this specification that MAY be automatically
         bridged is audio.

   The directionality of media streams associated with a connection are
   modeled independently from what SDP [18] allows for the corresponding
   RTP [15] sessions. Media servers MUST respect the SDP in what they
   actually transmit but MUST NOT allow the SDP to affect the
   directionality when joining streams internal to the media server.

9.3 <createconference>

   <createconference> is used to allocate and configure the media mixing
   resources for conferences. A description of the properties for each
   type of media mix required for the conference is defined within the
   content of the <createconference> element. Mixer descriptions are
   described in Audio Mix and Video Layout sections. When no mixer


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   descriptions are specified, the default behavior MUST be equivalent
   to inclusion of a single <audiomix>.

   Clients can request that a media server automatically delete a
   conference when a specified condition occurs by using the
   "deletewhen" attribute. A value of "nomedia" indicates that the
   conference MUST be deleted when no participants remain into the
   conference. When this occurs, an "msml.conf.nomedia" event MUST be
   notified to the MSML client. A value of "nocontrol" indicates the
   conference MUST be deleted when the SIP [1] dialog that carries the
   <createconference> element is terminated. When this occurs, a media
   server MUST terminate all participant dialogs by sending a BYE for
   their associated SIP dialog. A value of "never" MUST leave the
   ability to delete a conference under the control of the MSML client.

   attributes:

         name: the instance name of the conference. If the attribute is
         not present, the media server MUST assign a globally unique
         name for the conference. If the attribute is present but the
         name is already in use, an error (432) will result and MSML
         document execution MUST stop. Events which the conference
         generates use this name as the value of their "id" attribute
         (see section 5.6.2 (<event>)).

         deletewhen: defines whether a media server should automatically
         delete the conference. Possible values are "nomedia",
         "nocontrol", and "never". Default is "nomedia".

         term: when true, the media server MUST send a BYE request on
         all SIP dialogs still associated with the conference when the
         conference is deleted. Setting term equal to false allows
         clients to start dialogs on connections once the conference has
         completed. Default true.

         mark: a token which MAY be used to identify execution progress
         in the case of errors. The value of the mark attribute from the
         last successfully executed MSML element is returned in an error
         response. Therefore the value of all mark attributes within an
         MSML document should be unique.

   An example of creating an audio conference is shown below. This
   conference allows at most two participants to contend to be heard and
   reports the set of active speakers no more frequently than every ten
   seconds.

            <?xml version="1.0" encoding="UTF-8"?>



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            <msml version="1.1">
               <createconference name="example">
                  <audiomix>
                     <n-loudest n="3"/>
                     <asn ri="10s"/>
                  </audiomix>
               </createconference>
            </msml>

9.3.1 <reserve>

   Conference resources may be reserved by including the <reserve>
   element as a child of <createconference>. <reserve> allows the
   specification of a set of resources which a media server will reserve
   for the conference. Any requests for resources beyond those that have
   been reserved should be honored on a best-effort basis by a media
   server.

   attributes:

         required: boolean that specifies whether <createconference>
         should fail if the requested resources are not available. When
         set to false, the conference will be created, with no reserved
         resources, if the complete reservation cannot be honored.
         Default true.

9.3.1.1 <resource>

   The resources to be reserved are defined using <resource>. The
   contents of these elements describe a resource that is to be
   reserved. Descriptions are implementation-dependent. Media servers
   that support MSML Dialogs may use the elements from that package as
   the basis for resource descriptions. Each resource element may use
   the attribute "n" to define the quantity of the resource to reserve.

   For example, the following creates a conference and reserves two
   types of resources. One resource element may represent resources that
   are shared by all participants of the conference while the other may
   represent resources that are reserved for each of the expected
   participants.

   attributes:



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         n: number of resources to be reserved. Default 1.

         type: specifies whether the resource is to be reserved by each
         individual participant or reserved as a shared conference
         resource. Valid values for this attribute are “individual” or
         “shared”. Default “individual”.

      <createconference>
         <reserve>
            <resource n="20">
              <!--description of resources used by each participant-->
            </resource>
            <resource n="2" type=”shared”>
              <!--description of the shared conference resources-->
            </resource>
         </reserve>
      </createconference>

9.4 <modifyconference>

   All of the properties of an audio mix or the presentation of a video
   mix may be changed during the life of a conference using the
   <modifyconference> element. Changes to an audio mix are requested by
   including an <audiomix> element as a child of <modifyconference>.
   This may also be used to add an audio mixer to the conference if none
   was previously allocated. Changes to a video presentation are
   requested by including a <videolayout> element as a child of
   <modifyconference>. Similar to an audio mixer, this may be used to
   add a video mixer if none was previously allocated.

   Mixers are removed by including a mixer description element within
   <destroyconference/>.

   Features and presentation aspects are enabled/added or modified by
   including the element(s) that define the feature or presentation
   aspect within a mixer description. The complete specification of the
   element must be included just as it would be included when the
   conference is created. The new definition completely replaces any
   previous definition that existed. Only things that are defined by
   elements included in the mixer descriptions are affected. Any
   existing configuration aspects of a conference, which are not



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   specified within the <modifyconference/> element, MUST maintain their
   current state in the Media Server.

   For example, if an MSML client wanted to change the minimum reporting
   interval for active speaker notification from that shown in the
   Conference Examples section (<createconference>) it would send the
   following to the media server:

            <?xml version="1.0" encoding="UTF-8"?>
            <msml version="1.1">
               <modifyconference id="conf:example">
                  <audiomix>
                     <asn ri="4"/>
                  </audiomix>
               </modifyconference>
            </msml>

   This would also enable active speaker notification if it had not
   previously been enabled. The N-loudest mixing is unaffected.

   Multiple elements MAY be included in the mixer descriptions similar
   to when conferences are created. For example, in a video conference,
   the video mix description (<videolayout>) could specify that the
   layout of the video being displayed should change such that the
   regions currently displaying participants get smaller and new
   region(s) are created to support additional participants. A media
   server MUST make all of the requested changes or none of the
   requested changes.

   Additional examples of modifying conferences are presented in the
   Conference Examples section.

   attributes:

         id: the identifier for a conference. Wildcards MUST NOT be
         used. Mandatory.

         mark: a token which can be used to identify execution progress
         in the case of errors. The value of the mark attribute from the
         last successfully executed MSML element is returned in an error
         response. Therefore the value of all "mark" attributes within
         an MSML document SHOULD be unique.



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9.5 <destroyconference>

   Destroy conference is used to delete mixers or to delete the entire
   conference and all state and shared resources. When a mixer is
   removed, all of the streams joined to that mixer are unjoined. When a
   conference is destroyed, SIP dialogs for any remaining participants
   MUST be maintained or removed based on the value of the "term"
   attribute when the conference was created.

   When there is no element content, <destroyconference/> deletes the
   entire conference. Individual mixer(s) are removed by including a
   mixer description element identifying the mix(es) to be removed as
   content to <destroyconference/>. <audiomix/> is used remove audio
   mixers and <videolayout/> is used remove video mixers. When one or
   more mixer descriptions are specified, then Media Server MUST only
   delete the specified mixer and MUST NOT affect any other existing
   mixers. When <audiomix/> or <videolayout/> are identified for
   individual removal, other feature aspects of the mix MUST NOT be
   included. If specified, the Media Server MUST ignore any such
   elements. When the last mixer is removed from a conference, a media
   server MUST remove all conference state, leaving or removing any
   remaining SIP dialogs as described above.

   attributes:

         id: the identifier for a conference. Mandatory.

         mark: a token which can be used to identify execution progress
         in the case of errors. The value of the mark attribute from the
         last successfully executed MSML element is returned in an error
         response. Therefore the value of all "mark" attributes within
         an MSML document SHOULD be unique.

9.6 <audiomix>

   The properties of the overall audio mix are specified using the
   <audiomix> element.

   Attributes:

         id: an optional identifier for the audio mix.

   An example of the description for an audio mix is:

      <audiomix id="mix1">
         <asn ri="10s"/>
         <n-loudest n="3">


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      </audiomix>

9.6.1 <n-loudest>

   The <n-loudest> element defines that participants contend to be
   included in the conference mix based upon their audio energy. When
   the element is not present, all participants are mixed.

   Attributes:

         n: the number of participants that will be included in the
         audio mix based upon having the greatest audio energy.

9.6.2 <asn>

   The <asn> element enables notification of active speakers. Active
   speakers MUST be notified using the <event> element with an event
   name of "msml.conf.asn". The namelist of the event consists of the
   set of active speakers. The name of each item is the string "speaker"
   with a value of the connection identifier for the connection.

   Attributes:

         ri: the minimum reporting interval defines the minimum duration
         of time which must pass before changes to active speakers will
         be reported. A value of zero disables active speaker
         notification.

   An example of an active speaker notification is:

      <event name="msml.conf.asn" id="conf:example">
         <name>speaker</name>
         <value>conn:hd93tg5hdf</value>
         <name>speaker</name>
         <value>conn:w8cn59vei7</value>
         <name>speaker</name>
         <value>conn:p78fnh6sek47fg</value>
      </event>







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9.7 <videolayout>

   A video layout is specified using the <videolayout> element. It is
   used as a container to hold elements that describe all of the
   properties of a video mix. The parameters of the window that displays
   the video mix are defined by the <root> element. When the video mix
   in composed of multiple panes, the location and characteristics of
   the panes are defined by one or more <region> elements. A <region>
   element is not required when only a single video stream is displayed
   at one time and none of the visual attributes of regions are
   required.

   Some regions may be used to display a video stream based on a
   selection criteria rather than having a video stream of a single
   participant continuously presented in the region. One such an example
   is a distance learning lecture where the instructor sees each of the
   students periodically displayed in a region. When a region is used to
   display one of a number of streams, it is placed as a child of a
   <selector> element.

   Attributes:

         type: specifies the language used to define the layout. Layouts
         defined using MSML MUST use the value "text/msml-basic-layout".
         This is the same convention as defined for the layout package
         from the W3C SMIL 2.0 specification [19]. The default when
         omitted is "text/msml-basic-layout".

         id: an optional identifier for the video layout.

9.7.1 <root>

   The <root> element describes the root window or virtual screen in
   which the conference video mix will be displayed. Simple conferences
   can display participant video directly within the root window but
   more complex conferences will use regions for this purpose. Areas of
   the window which are not used to display video will show the root
   window background.

   All video presentations require a root window. It MUST be present
   when a video mix is created and it cannot be deleted, however its
   attributes MAY be changed using the <modifyconference> element.

   Attributes:

         size: the size of the root window specified as one of the five
         standard common intermediate formats (e.g. CIF, QCIF, etc.).



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         backgroundcolor: the color for the root window background
         defined using the values for the "background-color" property of
         the CSS2 specification [20].

         backgroundimage: the URI for an image to be displayed as the
         root window background. Transparent portions of the image allow
         the background color to show through.

9.7.2 <region>

   <region> elements define video panes that are used to display
   participant video streams. Regions are rendered on top of the root
   window.

   The size of a region is specified relative to the size of the root
   window using the "relativesize" attribute. Relative sizes are
   expressed as fractions (e.g. 1/4, 1/3) that preserve the aspect ratio
   of the original video stream while allowing for efficient scaling
   implementations.

   Regions are located on the root window based on the value of the
   position attributes "top" and "left". These attributes define the
   position of the top left corner of the region as an offset from the
   top left corner of the root window. Their values may be expressed
   either as a number of pixels or as a percent of the vertical or
   horizontal dimension of the root window. Percent values are appended
   with a percent ('%') character. Percent values of "33%" and "67%"
   should be interpreted as "1/3" and "2/3" to allow easy alignment of
   regions whose size is expressed relative to the size of the root
   window.

   An example of a video layout with six regions is:

         +-------+---+
         |       | 2 |
         |   1   +---+
         |       | 3 |
         +---+---+---+
         | 6 | 5 | 4 |
         +---+---+---+

      <videolayout type="text/msml-basic-layout">
         <root size="CIF"/>
         <region id="1" left="0" top="0" size="2/3"/>
         <region id="2" left="67%" top="0" size="1/3"/>



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         <region id="3" left="67%" top="33%" size="1/3">
         <region id="4" left="67%" top="67%" size="1/3"/>
         <region id="5" left="33%" top="67%" size="1/3"/>
         <region id="6" left="0" top="67%" size="1/3"/>
      </videolayout>

   The area of the root window covered by a region is a function of the
   region's position and its size. When areas of different regions
   overlap, they are layered in order of their "priority" attribute. The
   region with the highest value for the "priority" attribute is below
   all other regions and will be hidden by overlapping regions. The
   region with the lowest non-zero value for the "priority" attribute is
   on top of all other regions and will not be hidden by overlapping
   regions. The priority attribute may be assigned values between 0 and
   1. A value of zero disables the region, freeing any resources
   associated with the region, and unjoining any video stream displayed
   in the region.

   Regions that do not specify a priority will be assigned a priority by
   a media server when a conference is created. The first region within
   the <videolayout> element that does not specify a priority will be
   assigned a priority of one, the second a priority of two, etc. In
   this way, all regions that do not explicitly specify a priority will
   be underneath all regions that do specify a priority. As well, within
   those regions that do not specify a priority, they will be layered
   from top to bottom, in the order they appear within the <videolayout>
   element.

   For example, if a layout was specified as follows:

      <videolayout>
         <root size="CIF"/>
         <region id="a" ... priority=".3" .../>
         <region id="b" ... />
         <region id="c" ... priority=".2" ...>
         <region id="d" ... />
      </videolayout>

   Then the regions would be layered, from top to bottom, c,a,b,d.




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   Portions of regions that extend beyond the root window will be
   cropped. For example, a layout specified as:

      <videolayout>
         <root size="CIF"/>
         <region id="foo" left="50%" top="50%" size="2/3"/>
      </videolayout>

   would appear similar to:



         +-----------+
         |   root    |
         |background |
         |     +-----+--
         |     |     |//
         |     | foo |//
         +-----+-----+//
               |////////


   Visual attributes are used to define aspects of the visual appearance
   of individual regions. A border may be defined together with a title
   and/or logo. Text and logos are displayed as images on top of the
   region's video, below all regions with a lower priority. The visual
   attributes are "title", "titletextcolor", "titlebackgroundcolor",
   "bordercolor", "borderwidth", and "logo".

   Visual attributes can also be defined for individual streams (Video
   Stream Properties). When visual attributes are specified as part of
   both a region and a stream, those associated with the stream MUST
   take precedence. This allows streams that are chosen for display
   automatically (Stream Selection) to have proper text and logos
   displayed. The region visual attributes are displayed when no stream
   is associated with the region.

   Two other attributes associated with a region, "blank" and "freeze",
   define the state of the video displayed in the region. When the blank
   or freeze attribute is assigned the value "true", then the Media
   Server MUST display the region either as a blank region, or the video
   image frozen at the last received frame.

   Open Issue: these attributes are specified for a region and not
   allowed for streams because that appears to be the common use case.


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   Applying them to streams would allow only that stream to be affected
   within a selector while other streams continue to display normally.
   Except for personal mixing scenarios, the same effect can be achieved
   by having the participant mute their own transmission to the media
   server.

   Attributes associated with each region are:

         id: a name that can be used to refer to the region.

         left: the position of the region from the left side of the root
         window.

         top: the position of the region from the top of the root
         window.

         relativesize: the size of the region expressed as a fraction of
         the root window size.

         priority: a number between 0 and 1 that is used to define the
         precedence when rendering overlapping regions. A value of zero
         disables the region.

         title: text to be displayed as the title for the region

         titletextcolor: the color of the text

         titlebackgroundcolor: the color of the text background

         bordercolor: the color of the region border

         borderwidth: the width of the region border

         logo: the URI of an image file to be displayed

         freeze: a boolean value, with a default of false, that defines
         whether the video image should be frozen at the currently
         displayed frame

         blank: a boolean value, with a default of false, that defines
         whether the region should display black instead of the
         associated video stream

9.7.3 <selector>

   It is often desired that one of several video streams be
   automatically selected to be displayed. The <selector> element is
   used to define the selection criteria and its associated parameters.


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   The selection algorithm is specified by the "method" attribute.
   Currently defined selection methods allow for voice activated
   switching and to iterate sequentially through the set of associated
   video streams.

   The regions that will display the selected video stream are placed as
   child elements of the <selector> element. Including regions within a
   <selector> element does not affect their layout with respect to
   regions not subject to the selection. For simple video conferences
   that display the video directly in the root window, the <root>
   element can be placed as a child of <selector>. Region elements MUST
   NOT be used in this case.

   For example, below is a common video layout that allows the video
   stream from the currently active speaker to be displayed in the large
   region ("1") at the top left of the layout while the streams from
   five other participants are displayed in regions located at the
   layout periphery.



         +-------+---+
         |       | 2 |
         |   1   +---+
         |       | 3 |
         +---+---+---+
         | 6 | 5 | 4 |
         +---+---+---+


      <videolayout type="text/msml-basic-layout">
         <root size="CIF"/>
         <selector id="switch" method="vas">
            <region id="1" left="0" top="0" size="2/3"/>
         </selector>
         <region id="2" left="67%" top="0" size="1/3"/>
         <region id="3" left="67%" top="33%" size="1/3">
         <region id="4" left="67%" top="67%" size="1/3"/>
         <region id="5" left="33%" top="67%" size="1/3"/>
         <region id="6" left="0" top="67%" size="1/3"/>
      </videolayout>



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   All selector methods must be defined so that they work if only a
   single region is a child of the selector. Selector methods that
   support more than one child region MUST specify how the method works
   across multiple regions. Media server implementations MAY support
   only a single region for methods that are defined to allow multiple
   regions.

   The selector or region for a participant's video is defined using the
   "display" attribute of <stream> during a join operation. Specifying a
   selector allows the stream to be displayed according to the criteria
   defined by the selector method. Specifying a region supports
   continuous presence display of participants. Some streams may be
   joined with both a selector and a region. In this case, the value of
   <blankothers> attribute defines whether the streams associated with a
   continuous presence region should be blanked when the stream is
   selected for display in one of the selector regions.

   Attributes common to all selector methods are:

         id: a name that can be used to refer to the selector.

         method: the name of the method used to select the video stream.

         status: specifies whether the selector is "active" or
         "disabled".

         blankothers: when "true", video streams that are also displayed
         in continuous presence regions will have the continuous
         presence regions blanked when the stream is displayed in a
         selection region.

9.7.3.1 <vas> Voice Activate Switching

   Voice activated switching (VAS) is used to display the video stream
   that correlates with the participant who is currently speaking. It is
   specified using a selector method value of "vas".

   If the video stream associated with the active speaker is not
   currently displayed in a selection region, then it replaces the video
   in the region that is displaying the video of the speaker that was
   least recently active. If the video of the active speaker is
   currently displayed in a selection region, then there is no change to
   any region. When VAS is applied to a single region, this has the
   effect that the current speaker is displayed in that region.

   Attributes associated with voice activated switching are:




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         si: switching interval is the minimum period of time that must
         elapse before allowing the video to switch to the active
         speaker.

         speakersees: defines whether the active speaker sees the
         "current" speaker (themselves) or the "previous" speaker.

9.8 <join>

   <join> is used to create one or more streams between two independent
   objects. Streams may be audio or video and may be bidirectional or
   unidirectional. A bidirectional stream is implicitly composed of two
   unidirectional streams that can be manipulated independently. The
   streams to be established are specified by <stream> elements (section
   <stream>) as the content of <join>.

   Without any content, <join> by default establishes a bidirectional
   audio stream. When only a stream of a single type has previously been
   created between two objects, or when only a unidirectional stream
   exists, <join> can be used to add a stream of another media type or
   make the stream bidirectional by including the necessary <stream>
   elements. Bidirectional streams are made unidirectional by using
   <unjoin> (section <unjoin>) to remove the unidirectional stream for
   the direction that is no longer required.

   In addition to defining the media type and direction of streams,
   <stream> elements are also used to establish the properties of
   streams, such as gain, voice masking, or tone clamping of audio
   streams, or labels and other visual characteristics of video streams.
   Properties are often defined asymmetrically for a single direction of
   a stream. Creating a bidirectional stream requires two <stream>
   elements within the <join>, one for each direction, if one direction
   is to have different properties from the other direction.

   If a media server can provide services using both compressed or
   uncompressed media, the MSML client may need to distinguish within
   requests which format is to be used. When compressed streams are
   created, both objects must use the same media format or an error
   response (450) is generated.

   attributes:

         id1: an identifier of either a connection or conference.
         Wildcards MUST NOT be used. Any other object class results in a
         440 error.





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         id2: an identifier of either a connection or conference.
         Wildcards MUST NOT be used. Any other object class results in a
         440 error.

         mark: a token which can be used to identify execution progress
         in the case of errors. The value of the mark attribute from the
         last successfully executed MSML element is returned in an error
         response. Therefore the value of all mark attributes within an
         MSML document SHOULD be unique.

   For example, consider a call center coaching scenario where a
   supervisor can listen to the conversation between an agent and a
   customer, and provide hints to the agent, which are not heard by the
   customer. One join establishes a stream between the agent and the
   customer and another join establishes a stream between the agent and
   the supervisor. A third join is used to establish a half-duplex
   stream from the customer to the supervisor. The media server
   automatically bridges the media streams from the customer and the
   supervisor for the agent, and from the customer and the agent for the
   supervisor.

   Assuming the following connections, each with a single audio stream:

         conn:supervisor

         conn:agent

         conn:customer

   The following would create the media flows previously described:

      <?xml version="1.0" encoding="UTF-8"?>
      <msml version="1.1">
         <join id1="conn:supervisor" id2="conn:agent"/>
         <join id1="conn:agent" id2="conn:customer"/>
         <join id1="conn:supervisor" id2="conn:customer">
            <stream media="audio" dir="to-id1"/>
         </join>
      </msml>

   The following example, shows joining a participant to a multimedia
   conference. It assumes that the conference has a video presentation



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   region named "topright". The "display" attribute is explained in
   section Video Stream Properties.

      <?xml version="1.0" encoding="UTF-8"?>
      <msml version="1.1">
         <join id1="conn:hd83t5hf7g3" id2="conf:example">
            <stream type="audio"/>
            <stream type="video" dir="from-id1" display="topright"/>
            <stream type="video" dir="to-id1"/>
      </msml>

9.9 <modifystream>

   Media streams can have different properties such as the gain for an
   audio stream or a visual label for a video stream. These properties
   are specified as the content of <stream> elements (section <stream>).
   <modifystream> is used to change the properties of a stream by
   including one or more <stream> elements that are to have their
   properties changed.

   Stream properties MUST be set as specified by the element <stream> as
   a child element of <modifystream> element. Any properties not
   included in the <stream> element when modifying a stream MUST remain
   unchanged. Setting a property for only one direction of a
   bidirectional stream MUST NOT affect the other direction. The
   directionality of streams can be changed using issuing an <unjoin>
   followed by a <join>. Any streams that exist between the two objects
   that are not included within <modifystream> MUST NOT be affected.

   attributes:

         id1: an identifier of either a conference or a connection. The
         instance name MUST NOT contain a wildcard if "id2" contains a
         wildcard. Mandatory.

         id2: an identifier of either a conference or a connection. The
         instance name MUST NOT contain a wildcard if "id1" contains a
         wildcard. Mandatory.

         mark: a token which can be used to identify execution progress
         in the case of errors. The value of the mark attribute from the
         last successfully executed MSML element is returned in an error
         response. Therefore the value of all mark attributes within an
         MSML document are RECOMMENDED to be unique.


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9.10 <unjoin>

   Unjoin removes one or more media streams between two objects. In the
   absence of any content in <stream> element, all media streams between
   the objects MUST be removed. Individual streams may be removed by
   specifying them using <stream> elements, while the unspecified
   streams MUST NOT be removed. A bidirectional stream is changed to a
   unidirectional stream by unjoining the direction that is no longer
   required, using the <unjoin> element. Operator elements MUST NOT be
   specified within <stream> elements when streams are being unjoined
   using the <unjoin> element. Any specified stream operators MUST be
   ignored.

   <unjoin> and <join> may be used together to move a media stream, such
   as from a main conference to a sidebar conference.

   attributes:

         id1: an identifier of either a conference or a connection. The
         instance name MUST NOT contain a wildcard if "id2" contains a
         wildcard. Mandatory.

         id2: an identifier of either a conference or a connection. The
         instance name MUST NOT contain a wildcard if "id1" contains a
         wildcard. Mandatory.

         mark: a token which can be used to identify execution progress
         in the case of errors. The value of the mark attribute from the
         last successfully executed MSML element is returned in an error
         response. Therefore the value of all mark attributes within an
         MSML document SHOULD be unique.

   The following removes a participant from a conference and plays a
   leave tone for the remaining participants in the conference.

            <?xml version="1.0" encoding="UTF-8"?>
            <msml version="1.1">
               <unjoin id1="conn:jd73ht89sf489f" id2="conf:1"/>
               <dialogstart target="conf:1" type="application/moml+xml">
                  <play>
                     <audio uri="file://leave_tone.wav"/>
                  </play>
               </dialogstart>
            </msml>


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9.11 <monitor>

   Monitor is a specialized unidirectional join that copies the media
   that is destined for a connection object. One example of the use for
   <monitor> may be quality monitoring within a conference. The media
   stream may be removed using the <unjoin> element (see section
   <unjoin>).

   attributes:

         id1: an identifier of the connection to be monitored. Any other
         object class results in a 440 error. Wildcards MUST NOT be
         used.

         id2: an identifier of the object which is to receive the copy
         of the media destined to id1. id2 may be a connection or a
         conference. Any other object class results in a 440 error.
         Wildcards MUST NOT be used.

         compressed: "true" or "false". Specifies whether the join
         should occur before or after compression. When "true", id2 must
         be a connection using the same media format as id1 or an error
         response (450) is generated. Default is "false.

         mark: a token which can be used to identify execution progress
         in the case of errors. The value of the mark attribute from the
         last successfully executed MSML element is returned in an error
         response. Therefore the value of all mark attributes within an
         MSML document SHOULD be unique.

9.12 <stream>

   Individual streams are specified using the <stream> element. They MAY
   be included as a child element in any of the stream manipulation
   elements <join>, <modifystream>, or <unjoin>.

   The type of the stream is specified using a "media" attribute that
   uses values corresponding to the top-level MIME media types as
   defined in RFC 2046 [21]. This specification only addresses audio and
   video media. Other specifications may define procedures for
   additional types.

   A bidirectional stream is identified when no direction attribute
   "dir" is present. A unidirectional stream is identified when a
   direction attribute is present. The "dir" attribute MUST have a value
   of "from-id1" or "to-id1" depending on the required direction. These


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   values are relative to the identifier attributes of the parent
   element.

   The compressed attribute is used to distinguish the compressed nature
   of the stream when necessary. It is implementation specific what is
   used when the attribute is not present. Joining compressed streams
   acts much like an RTP [15] relay.

   The properties of the media streams are specified as the content of
   <stream> elements when the element is used as a child of <join> or
   <modifystream>. Stream elements MUST NOT have any content when they
   are used as a child of <unjoin> to identify specific streams to
   remove.

   Some properties are defined within MSML as additional attributes or
   child elements of <stream> that are media type specific. Ones for
   audio streams and video streams are defined in the following two sub-
   sections. Operators, viewed as properties of the media stream, MAY be
   specified as child elements of the <stream> element.

   attributes:

         media: "audio" or video". Mandatory

         dir: "from-id1" or "to-id1".

         compressed: "true" or "false". Specifies whether the stream
         uses compressed media. Default is implementation specific.

9.12.1 Audio Stream Properties

   Audio mixes can be specified to only mix the N-loudest participants.
   However there may be some "preferred" participants that are always
   able to contribute. When audio streams are joined to a conference
   that uses N-loudest audio mixing, preferred streams need to be
   identified.

   A preferred audio stream is identified using the "preferred"
   attribute. The "preferred" attribute MAY be used for an audio stream
   that is input to a conference and MUST NOT be used for other streams.

   Additional attributes of the <stream> element for audio streams are:

         preferred: a boolean value that defines whether the stream does
         not contend for N-loudest mixing. A value of "true" means that
         the stream MUST always be mixed while a value of "false" means
         that the stream MAY contend for mixing into a conference when
         N-loudest mixing is enabled. Default "false".


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   There are two elements that can be used to change the characteristics
   of an audio stream as defined below.

9.12.1.1 <gain>

   The <gain> element may be used to adjust the volume of an audio media
   stream. It may be set to a specific gain amount, to automatically
   adjust the gain to a desired target level, or to mute the stream.

   Attributes of the <gain> element are:

         amt: a specific gain to apply specified in dB or the string
         "mute" indicating that the stream should be muted. This
         attribute MUST NOT be used if "agc" is present.

         agc: boolean indicating whether automatic gain control is to be
         used. This attribute MUST NOT be used if "amt" is present.

         tgtlvl: the desired target level for AGC specified in dBm0.
         This attribute MUST be specified if "agc" is set to "true".
         This attribute MUST NOT be specified if "agc" is not present.

         maxgain: the maximum gain that AGC may apply. Maxgain is
         specified in dB. This attribute MUST be used if "agc" is
         present and MUST NOT be used when "agc" is not present.

9.12.1.2 <clamp>

   The <clamp> element is used to filter tones and/or audio-band dtmf
   from a media stream.

   Attributes of the <clamp> element are:

         dtmf: boolean indicating whether DTMF tones should be removed.

         tone: boolean indicating whether other tones should be removed.

9.12.2 Video Stream Properties

   Video mixes define a presentation that may have multiple regions,
   such as a quad-split. Each region displays the video from one or more
   participants. When video streams are joined to such a conference, the
   region that will display the video needs to be specified as part of
   the join operation.

   The region that will display the video is specified using the
   "display" attribute. The "display" attribute MUST be used for a video
   stream that is input to a conference and MUST NOT be used for other


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   streams. The value of the attribute MUST identify a <region> (see
   section <region>) or a <selector> (see section <selector>) that is
   defined for the conference. A stream MUST NOT be directly joined to a
   region that is defined within a selector. Changing the value of the
   "display" attribute can be used to change where in a video
   presentation layout a video stream is displayed.

   Additional attributes of the <stream> element for video streams are:

         display: the identifier of a video layout region or selector
         that is to be used to display the video stream.

9.12.2.1 <visual>

   Some regions of video conferences may display different streams
   automatically, such as when voice activated switching is used.
   Connections MAY also be joined directly without the use of video
   mixing. In these cases, the <visual> element may be used to define
   visual display properties for a stream.

   The <visual> element MAY use any of the visual attributes defined for
   regions (see section <region>). This allows the visual aspects of
   regions within a <selector> to be tailored to the selected video
   stream, or for streams that are directly joined to display a name or
   logo.

10. MSML Dialog Packages

10.1 Overview

   MSML Dialog Packages define an XML [4] language for composing complex
   media objects from a vocabulary of simple media resource objects
   called primitives. It is primarily a descriptive or declarative
   language to describe media processing objects. MSML dialogs operate
   on a single or multiple streams which are identified by the MSML
   document outside the scope of the MSML dialog package.

   MSML Dialogs are intended to be used in different environments. As
   such, the language itself does not define how an MSML Dialog is used.
   Each environment in which MSML Dialog is used must define how it is
   used, the set of services provided and the mechanism for passing
   information between the environment and MSML Dialog. The specific
   mechanisms used to realize the interface between MSML Dialog and its
   environment are platform specific.

   MSML Dialog packages provide two models for access to media resources
   and service creation building blocks. Both models MAY be used in
   conjunction with each other in a complementary manner. The first


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   model (referred to as “Media Primitives and Composites”, part of the
   mandatory MSML Dialog Base package) contains media primitives (such
   as digit collection and announcements) and composite functions (such
   as play and collect combined as a single operation). The second model
   (referred to as “Media Groups”, part of the optional MSML Dialog
   Group package) allows the ability to define complex customized
   interactions, via event passing mechanisms, between media primitives,
   if required.

      MSML Dialog Core Package

         Defines core framework over which all MSML dialog packages
         operate.

      MSML Dialog Base Package

         Media Primitives
            <dtmf> or <collect>
                        DTMF digit collection
            <play>
                        Playing of Announcements
            <dtmfgen>
                        Generation of DTMF digits
            <record>
                        Media recording

         Media Composites
            <collect>
                        Supports play and collect operation.
                        Composite function with inclusion of play.
            <record>
                        Supports play and record operation.
                        Composite function with inclusion of play.

      MSML Dialog Group Package

            <group>
                        Allows grouping of media primitives for parallel
                        execution, with an event exchange mechanism
                        between the media primitives to achieve
                        customized media operations. All the above media
                        primitive elements are accepted within the
                        group.

   Following operations MUST be supported using elements described above
   using either the MSML Dialog Base Package or MSML Dialog Group
   Package.



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         Announcement only
                           <play>

         Collection only
                           <dtmf> or <collect>

         Recording only
                           <record>


         Play and Collect
                           <collect>
                              <play/>
                           </collect>


         Play and Record
                           <record>
                              <play/>
                           </record>


   Additional MSML Dialog packages are:

      O MSML Dialog Transform Package

      O MSML Dialog Speech Package

      O MSML Fax Detection Package

      O MSML Fax Send/Receive Package

   MSML Dialogs MAY be used to simply expose primitive media resource
   objects but will be used more often to describe dialog operations and
   media transformation objects which can be controlled via user
   interaction.

   MSML Dialogs do not contain any computation or flow control
   constructs. There are no results automatically generated when media
   operations complete. Results MUST be explicitly requested using a
   <send> or <exit> element within the definition of the MSML Dialog.

10.2 Primitives

   Primitives perform a single function on a media stream or multiple
   streams such as generating audio/video, recognizing speech or DTMF,
   or adjusting the gain. They may be composed so that primitives
   execute concurrently. Primitives not composed for concurrent
   execution MUST simply execute sequentially in the order they occur in
   a MSML document. All concurrently executing primitives in the same
   MSML object (defined in one MSML document) MAY interact with each
   other through events (see MSML Dialog Group package).


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   Currently all primitives use audio media; primitives for text and
   video will be defined in future versions of this specification.
   Primitives can roughly be considered to fall into one of three
   descriptive categories.

      o  recognizers have a media input but no output. They allow
         different things within a media stream to be recognized or
         detected and for events to be generated based upon received
         media.

      o  transformers have one media input and output and may send and
         receive events;

      o  sources and sinks generate or consume media. They have either a
         media input or a media output but not both. They may receive
         and generate events.

      o  composites combine underlying primitives to provide higher-
         level user interaction, without the need for specific event
         based exchange between the primitives. The composite elements
         provide a simpler mechanism for more commonly used services,
         such as play and collect or play and record.

   Primitives may define different media processing behavior (states)
   based upon the events which they receive. Primitives which support
   different processing states must define their default starting state
   and should support the "initial" attribute to allow that state to be
   specified when the primitive is instantiated. All primitives must
   support the "terminate" event class.

   The following types of primitives are defined within this
   specification:

       Recognizers    Transformers   Source/Sink   Composites
       ------------------------------------------------------
         dtmf           agc           play          collect
         faxtone        clamp         record        record
         speech         gain          dtmfgen
         vad            gate          faxsend
                        relay         faxrcv

   Primitives have shadow variables, similar to those within VoiceXML
   [7], which are automatically assigned values when the primitives are
   used. Upon initialization of an MSML Dialog context, all shadow
   variables have the string value "undefined". Each primitive has its
   own instance of shadow variables which are global in scope to the
   entire MSML Dialog context.



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   Names SHOULD be assigned to individual primitives when more than one
   primitive of the same type is used within one MSML document. Shadow
   variables are overwritten if the primitive has not been named and is
   instantiated a second time.

   Shadow variables cannot be modified under user control. They may be
   returned from the MSML Dialog context using the <send> element.

10.3 Events

   Events provide the mechanism for primitives to interact with each
   other and for a MSML context to interact with its external
   environment. The external environment is defined by the way in which
   a MSML context has been invoked. This will often be through MSML but
   other languages and protocols such as SIP may also be used.

   Every primitive and group conceptually implements their own event
   queue. Events sent to them get placed into their associated queue.
   Events are removed from their queues and processed in order.
   Primitives within a group conceptually have their own thread of
   execution. Due to the asynchronous nature of servicing events from
   multiple queues, it cannot be assumed that several events sent in
   sequence to different queues, will be processed in the order in which
   they were sent. For example, if recognition of something led to
   sending events to both a <play> and a <record> in that order, it is
   possible that the <record> may process its event before the <play>.

   Primitives each define the set of events which they support and the
   behavior associated with their handling of each event. This allows
   many types of behaviors to be defined. For example, VCR type controls
   can be constructed by defining primitives which support events
   corresponding to each control. Media recognition/detection can be
   used to cause those events to be generated.

   Alternatively, events can be originated elsewhere, such as from a
   Control Agent, and simply received by the primitive implementing the
   control. Examples of the use of events include adjusting volume
   (gain) and pause and resume of both announcement playout and record
   creation.

   Primitives act on events based upon the longest match of an event
   name. Event names are a period '.' delimited sequence of tokens. The
   first token, or the root of the name, can be considered an event
   class. Matching allows a standard meaning to be defined and then
   extended based upon what triggers an event's generation. For example,
   a record primitive has different behavior depending upon whether it
   completed because a user stopped speaking or because it was



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   cancelled. The recording is retained in the first case but not the
   second.

   Longest match allows new recognizers to be created and used without
   changing how existing primitives are defined. For example, a face
   recognition capability could be created which generates a
   terminate.frowning event when a user looks puzzled. Although no
   primitive directly defines this event, it will still effect a generic
   terminate action. Primitives which require specialized behavior based
   upon frowning may be extended to support this. As well, the event can
   still be exported from the MSML context without requiring that
   primitives receiving the event understand facial expressions.

10.4 MSML Dialog Usage with SIP

   MSML Dialogs MAY be used directly with SIP for dialog interactions
   (e.g., IVR or fax). It can be initially invoked as part of the
   "Prompt and Collect" service described in "Basic Network Media
   Services with SIP" [9]. That defines service indicators for a small
   number of well defined services using the user part of the SIP
   Request-URI (R-URI).

   The prompt and collect service uses "dialog" as the service
   indicator. URI parameters further refine the specific IVR request.
   This document defines an additional parameter "msml-param" for the
   dialog service indicator as follows:

   dialog-parameters = ";" ( dialog-param [ vxml-parameters ] )
                           | moml-param
   dialog-param      = "voicexml=" dialog-url
   moml-param        = "moml=" moml-url

   There are no additional URI parameters when MSML is used as the
   dialog language.

   MSML Dialogs defines discrete IVR dialog commands. These commands MAY
   be included directly in the body of the INVITE to the "dialog"
   service indicator by using the "cid" [12] URL scheme. This scheme
   identifies a message body part which in this case would contain the
   MSML Dialog request. Note that a multipart message body, containing a
   single part, MUST be present even if the INVITE does not contain an
   SDP offer. Subsequent MSML Dialog requests are sent in the body of
   SIP INFO messages as are all messages from a media server.

   An example of SIP URI as described above is:

      sip:dialog@mediaserver.example.net;\
          moml=cid:14864099865376@appserver.example.net


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   The body part that contained the MSML Dialog referenced by the URL
   would have a Content-Id header of:

      Content-Id: <14864099865376@appserver.example.net>

   The results of executing an <exit> or <disconnect>, or of executing a
   <send> which has a "target" attribute value equal to "source", are
   notified in SIP INFO messages using the <event> element from MSML
   Core package. No messages are sent if execution completes normally
   without executing one of these elements.

   If there is an error during validation or execution, then a media
   server MUST notify the error as described above and must include the
   namelist items "moml.error.status" and "moml.error.description". The
   values for these items are defined in section 11.

   A restricted subset of MSML Dialogs can also be used with the
   "Announcement" service defined in [9]. This service uses "annc" as
   the service indicator and defines parameters that describe an
   announcement. The "play=" parameter identifies the URL of a prompt or
   a provisioned announcement sequence. The value of the "play="
   parameter can refer to a MSML Dialog body part using a "cid" URL as
   described above. That body part must only contain the <play>
   primitive.

   Using MSML Dialogs enhances the announcement service by allowing the
   client to specify a sequence of audio segments rather than requiring
   each sequence to be provisioned as well as support for video.
   Moreover, MSML Dialogs define a standard set of variables in contrast
   to [9] which defines a parameterization mechanism but does not
   formally specify any semantics.

   If a media server does not understand the "cid" scheme or does not
   understand MSML Dialogs, it must respond with the SIP response code
   "488 -  not acceptable here". If the MSML Dialog body contains
   elements other than the <play> primitive, or there are errors during
   validation, a media server must respond with a SIP response code "400
   - bad request". Finally, if there is a discrepancy between parameters
   specified in the Request-URI and corresponding attributes defined in
   the MSML Dialog body, the Request-URI parameters must be silently
   ignored.

   MSML Dialogs MUST NOT change the operation of the announcement
   service from that defined in [9]. When the announcement completes, a
   media server issues a SIP BYE request. The INFO method MUST NOT used
   with the announcement service.




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10.5 MSML Dialog Structure and Modularity

   MSML is structured as a set of packages. Only the core and base
   packages are required. The Dialog Core package, defines the framework
   for MSML requests to a media server, without specific functionality.
   It consists of the “primitive” abstraction, an abstract element for
   control flow, the sequential execution model, and the <send> element.
   That is, the MSML Dialog Core package allows for the execution of a
   sequence of one or more media processing primitives with the ability
   to notify events to the invocation environment.

   Primitives are contained within the MSML Dialog Base package, which
   defines the basic <play>, <record>, <dtmf>, <dtmfgen> and <collect>
   elements. Another package, the MSML Dialog Transform package, defines
   the simple half duplex filters. More advanced primitives are defined
   in the speech and fax packages. The MSML speech package depends on
   the MSML Dialog base package as it extends the capability of <play>
   by adding synthesized speech. Finally, the group execution model,
   which is currently the only element which changes the flow of control
   is defined in a separate MSML Dialog Group package. All of these
   packages are optional with the exception that MSML Dialog Core and
   MSML Dialog Base packages MUST be implemented to provide the minimal
   functionality.

10.6 MSML Dialog Core Package

   The MSML Dialog Core package defines the structural framework and
   abstractions for MSML Dialogs(via its schema). It also defines the
   basic elements which are not part of the core primitive or control
   abstractions. This package is dependent on the MSML Core package.
   Events generated by MSML Dialogs, such as prompt completion, digits
   collected, or dialog termination, etc, are communicated by the Media
   Server via the MSML Core Package (see MSML Core Package <event>).

   MSML Dialogs are executed independently from the MSML core context.
   When an MSML Dialog is started, MSML allocates the dialog control
   resources, and if successful, starts those resources executing. MSML
   core execution then continues without waiting for the MSML dialog to
   complete. This forking of MSML dialog invocation from the MSML core
   context is done via the <dialogstart> element. Media streams are
   created between the MSML dialog target and other internal media
   server resources as part of dialog execution. Stream creation is
   subject to the requirements defined in MSML Core package and media
   streams as defined in MSML Conference Core package.






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10.6.1 <dialogstart>

   The <dialogstart> element is used to instantiate an MSML media dialog
   on connections or conferences. The dialog is specified either inline
   or by a URI [8]. Inline dialogs MUST be composed of any of the MSML
   Dialog packages. MSML dialogs MAY be defined externally as VoiceXML
   [7]. The MSML dialog description MUST NOT be inline if the src
   attribute, containing a URI, is present.

   The originator of the MSML dialog is notified using a
   "msml.dialog.exit" event when the dialog completes. Any results
   returned by the dialog when it exits are sent as a namelist to the
   event.

   The "msml.dialog.exit" event is also used when dialogs fail due to
   errors encountered fetching external documents or errors that occur
   within the dialog execution thread. In this case, a namelist
   containing the items "dialog.exit.status" and
   "dialog.exit.description" is returned with the event to inform the
   client of the failure and the failure reason. The values of these
   items are defined within this package and the MSML Core package.
   Information from the failed dialog may be returned as additional
   namelist items.

   attributes:

         target: an identifier of a connection or a conference which
         will interact with the dialog. The identifier must not contain
         wildcards. Mandatory.

         src: the URL of the dialog description. MUST NOT be used if the
         MSML dialog description is inline. Otherwise an error (422)
         will result and MSML document execution will stop.

         type: a MIME type which identifies the type of language used to
         describe the dialog. application/moml+xml and
         application/vxml+xml are used to identify MSML Dialogs and
         VoiceXML [7] respectively.

         name: an instance name for the dialog. If the attribute is not
         present, the media server will assign an identifier to the
         dialog. If the attribute is present but the name is already
         associated with the target, an error (431) will result and MSML
         document execution will stop. Any results that a dialog
         generates will be correlated to its identifier.

         mark: a token which can be used to identify execution progress
         in the case of errors. The value of the mark attribute from the


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         last successfully executed MSML element is returned in an error
         response. Therefore the value of all "mark" attributes within
         an MSML document should be unique.

   The following sections show examples of initiating an external MSML
   dialog, an in-line embedded MSML dialog, and an MSML initiated
   VoiceXML dialog.

   The following example starts a MSML dialog on a connection.

        <?xml version="1.0" encoding="UTF-8"?>
        <msml version="1.1">
           <dialogstart target="conn:abcd1234"
                 type="application/moml+xml"
                 name="sample"
                 src="http://server.example.com/scripts/foo.moml"/>
         </msml>

   The following example starts an in-line embedded MSML dialog on a
   connection.
         <?xml version="1.0" encoding="UTF-8"?>
         <msml version="1.1">
           <dialogstart target=”conn:abcd1234” name=”sample”>
              <play>
                 <audio uri="file://clip1.wav"/>
                 <audio uri="http://host1/clip2.wav"/>
                 <tts uri="http://host2/text.ssml"/>
                 <var type="date" subtype="mdy" value="20030601"/>
              </play>
              <send target="source"
                     event="done"
                     namelist="play.amt play.end"/>
            </dialogstart>
         </msml>

   The following example starts a VoiceXML dialog on a connection.


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         <?xml version="1.0" encoding="UTF-8"?>
         <msml version="1.1">
            <dialogstart target="conn:abcd1234"
                type="application/vxml+xml"
                name="sample"
                src="http://server.example.com/scripts/foo.vxml"/>
         </msml>

   If this dialog fails once its execution thread had begun, for example
   the fetch of the VoiceXML document failed, an example of the event
   which would be returned would be:

         <?xml version="1.0" encoding="UTF-8"?>
         <event name="msml.dialog.exit"
                id="conn:abcd1234/dialog:sample">
            <name>dialog.exit.status</name>
            <value>423</value>
            <name>dialog.exit.description</name>
            <value>External document fetch error</value>
         </event>

10.6.2 <dialogend>

   Dialog end is used to terminate a MSML dialog created through
   <dialogstart> before it completes of its own accord. The operation of
   <dialogend> depends on the dialog language being used by the
   executing context. When that context is VoiceXML, a
   "connection.disconnected" event will be thrown to the VoiceXML
   application. When that context is MSML Dialog, a "terminate" event
   will be sent to the MSML core context.

   <dialogend> allows the executing dialog the opportunity to gracefully
   complete before generating a "msml.dialog.exit" event. Dialog results
   may be returned and will be contained as a namelist to that event.

   attributes:

         id: the identifier of a dialog. Mandatory.



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         mark: a token which can be used to identify execution progress
         in the case of errors. The value of the mark attribute from the
         last successfully executed MSML Dialog element is returned in
         an error response. Therefore the value of all "mark" attributes
         within an MSML document should be unique.

   For example, if the dialog from the previous example was still
   executing, the following would terminate the dialog and generate a
   "msml.dialog.exit" event.

            <?xml version="1.0" encoding="UTF-8"?>
            <msml version="1.1">
               <dialogend id="conn:abcd1234/dialog:sample"/>
            </msml>

10.6.3 <send>

   Sends an event and optional namelist to the recipient identified by
   the target attribute. Event names are defined by the recipient. In
   the case where the recipient is an MSML Dialog group or primitive,
   the events are defined within this document. Other recipients MAY use
   names that are suitable for their environment.

   The "target" attribute specifies the recipient of the event.
   Recipients MAY be other MSML Dialog primitives or groups executing
   within the object, the object itself, or the environment which
   invoked the MSML Dialog. Sending events to media primitives or groups
   is supported by the MSML Dialog Group package. Any target which is
   unknown within the object is assumed to be destined to the external
   environment. By convention, the string "source" SHOULD used to
   address that environment but any target name distinct from the MSML
   Dialog namespace MAY be used.

      Attributes:

         event: the name of an event.

         target: the recipient of the event. The recipient MUST be a
         MSML Dialog primitive, the currently executing group, or the
         MSML Dialog environment. A primitive is specified by a
         primitive type, optionally appended by a period '.' followed by
         the identifier of a primitive. Identifiers are only needed when
         more than one primitive of the same type exists in the object.
         The executing group is specified using the token "group". The
         environment is specified using the token "source", optionally


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         appended by a period '.' followed by any environment specific
         target.

         namelist: a list of zero or more shadow variables which are
         included with the event.

10.6.4 <exit>

   Exit causes execution of the MSML Dialog to terminate.

      Attributes:

         namelist: a list of one or more shadow variables which MAY
         optionally be sent to the context which invoked the MSML Dialog
         object.

10.6.5 <disconnect>

   Disconnect is similar to <exit> but has the additional semantics of
   indicating to the context which invoked the MSML Dialog, that it
   should disconnect from a media server, the media stream associated
   with the object. The method of disconnection depends upon how the
   media stream was initially established. If SIP was used, a
   <disconnect> would cause a media server to issue a BYE request. The
   request would be sent for the SIP dialog associated with media
   session on which the MSML Dialog was operating.

      Attributes:

         namelist: a list of one or more shadow variables which MAY
         optionally be sent to the context which invoked the MSML Dialog
         object.

10.7 MSML Dialog Base Package

   The MSML Dialog Base package defines a required set of base
   functionality for Media Server. It support individual media
   primitives, such as playing an announcement or collection digits, as
   well as composite operations such as play and collect. When this
   package is used in conjunction with MSML Dialog Group package the
   event based mechanism is used to control primitives. This package may
   also be used in conjunction with MSML Speech package to extend the
   functionality of prompts to include TTS and user input collection to
   include ASR.

   In the following sections, subsections of a primitive define child
   elements of that primitive and are not themselves considered
   primitives. They do not receive events or populate shadow variables.


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10.7.1 <play>

   Play is used to generate an audio or video stream. It MUST play in
   sequence the media created by the child media elements <audio>,
   <video>, <media>, <tts>, and <var>. When the play stops, either
   because the terminate event is received or all media generation has
   completed, the <playexit> element, if present, is executed. At least
   one media generation element must be present.

   Play supports two states; generate and suspend. Media generation
   occurs in the generate state and is suspended in the suspend state.
   Once in the suspend state, media generation continues upon receiving
   the generate event. The default initial state is generate.

   Audio MAY be generated in different languages by specifying the
   xml:lang attribute for <play> and/or the child elements of <play>.
   The language is inherited by the child elements but each child MAY
   specify its own language. Except for physical audio clips, it is an
   error if a language is specified but the media server can not render
   the audio in the requested language.

      Attributes:

         id: an optional identifier which may be referenced elsewhere
         for sending events to the play primitive.

         interval: specifies the delay between stopping one iteration
         and beginning another. The attribute has no effect if
         iterations is not also specified. Default is no interval.

         iterate: specifies the number of times the media specified by
         the child media elements should be played. Each iteration is a
         complete play of each of the child media elements in document
         order. Defaults to once '1'.

         initial: defines the initial state for the play element.
         Default is "generate".

         maxtime: defines the maximum allowed time for the <play> to
         complete.

         barge: defines whether or not audio announcements MAY be
         interrupted by DTMF detection during play-out. The DTMF digit
         barging the announcement is stored in the digit buffer. Valid
         values for barge are “true” or “false”, and the attribute is
         mandatory.




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         cleardb: defines whether the digit buffer is cleared or not,
         prior to starting the announcement. Valid values for cleardb
         are “true” or “false”, and the attribute is mandatory.

         offset: defines an offset, measured in units of time, where the
         <play> is to begin media generation. Offset is only valid when
         all child media elements are <audio>.

         skip: an amount, expressed in time, which will be used to skip
         through the media when "forward" and "backward" events are
         received. Default is 3s (three seconds).

         xml:lang: specifies the language to use for content which can
         be rendered in different languages.

      Events:

         Following describes input events to the media primitive object.
         The MSML Dialog Group package allows an event exchange
         mechanism between primitives.

         pause: causes the play to enter the suspend state.

         resume: causes play to enter the generate state.

         forward: skips forward through the media. Only has effect when
         all child media elements are <audio>.

         backward: skips backward through the media. Only has effect
         when all child media elements are <audio>.

         restart: skips to the beginning of the media. Only has effect
         when all child media elements are <audio>.

         toggle-state: causes the suspend / generate state to toggle.

         terminate: terminates the play and assigns values to the shadow
         variables.

      Shadow Variables:

         play.amt: identifies the length of time for which media was
         generated before the play was stopped. This does not include
         time which may have elapsed while the play was in the suspend
         state.





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         play.end: contains the event which caused the play to stop.
         When the play stops because all media generation has completed,
         end is assigned the value "play.complete".

   Note: Attributes barge and cleardb provide a simplified mechanism for
   controlling play operations with implicit DTMF without the use of
   <group> and event exchange mechanism. When using the <play> element
   within the group framework and barge is specified, detection of barge
   condition generates an implicit terminate event to the play
   primitive.

   Following sections describe the child elements of <play>.

10.7.1.1 <audio>

   Identifies pre-recorded audio to play. Local URI references may
   resolve to a single physical audio clip, a logical clip, or a
   provisioned sequence of clips (physical or logical). A logical clip
   is one which can be rendered differently based on the language
   attribute. Logical clips are provisioned for each of the languages
   that a media server supports. Remote URI references are resolved
   according to the capabilities of the remote server.

      Attributes:

         uri: Identifies the location of the audio to be played. The
         file and http schemes are supported.

         format: defines the encoding and file type of the audio
         resource. The format attribute is defined as a string type of
         form “audio/<filetype>;codecs=<codec>”. The keyword ‘audio’
         identifies an audio content. The codecs field identifies the
         audio file’s codec to be used for decoding the audio content.
         If format attribute is not specified, the filetype MUST be
         determined from the URI and the codec information MUST be
         determined from the media resource.

         audiosamplerate: Identifies audio sample rate in kHz. If not
         specified, the sample rate SHOULD be determined from the media
         resource.

         audiosamplesize: Identifies audio sample size in bits. If not
         specified, the sample size SHOULD be determined from the media
         resource.

         iterate: specifies the number of times the audio is to be
         played. Defaults to once '1'.



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         xml:lang: specifies the language to use when the URI identifies
         a logical clip, either directly, or as part of a sequence.

10.7.1.2 <video>

   Identifies pre-recorded multimedia to play. Contents identified by
   the URI attribute may contain audio only, video only, or both audio
   and video. Media Server SHOULD attempt to play both audio and video
   from the identified URI, if both are available in the content.

      Attributes:

         uri: Identifies the location of the video or multimedia to be
         played. The file and http schemes are supported.

         format: defines the encoding and file type of the video or
         multimedia resource. The format attribute is defined as a
         string type of form
         “video/<filetype>;codecs=<codecx>,<codecy>”. The keyword
         ‘video’ identifies video only media or media containing audio
         and video. The “codecs” field identifies the audio and/or video
         codecs to be used for decoding the file content, where the
         order of the codec values is not significant. In the event of
         audio and video content, using ‘video’ keyword, the
         codecs=<codecx>,<codecy> field MAY be used to identify the
         audio codec and the video codec. If not specified, the codec
         information SHOULD be determined from the media file.

         audiosamplerate: Identifies audio sample rate in kHz. If not
         specified, the sample rate SHOULD be determined from the media
         file.

         audiosamplesize: Identifies audio sample size in bits. If not
         specified, the sample size SHOULD be determined from the media
         file.

         codecconfig: Identifies an optional special instruction string
         for codec configuration. Default is to send no special
         configuration string to the codec.

         profile: Identifies a video profile name specific to the codec.
         If not specified, default video profile of the codec SHOULD be
         selected.

         level: Identifies a video profile level to the codec. Default
         is to send no profile information to the codec and allow the
         codec to select an internal default.



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         imagewidth: Identifies the width of video image in pixels.
         Default is to use image width information from media file.

         imageheight: Identifies the height of video image in pixels.
         Default is to use image height information from media file.

         maxbitrate: Identifies the bitrate of the video signal in kbps.
         Default is to use maximum bitrate information from the media
         file.

         framerate: Identifies the video frame rate in frames per
         second. Default is to use frame rate information from the media
         file.

         iterate: specifies the number of times the audio is to be
         played. Defaults to once '1'.

10.7.1.3 <media>

   Identifies multimedia content for play. All content of <media>
   element MUST start to play concurrently. This element may be used to
   generate a multi-media stream from two independent media resources,
   one identifying audio and the other identifying video.

   The <media> element MUST contain at least one child element. Valid
   child elements of <media> are <audio> and <video>, as described
   earlier. <media> element MUST contain at most one <audio> element or
   at most one <video> element.

10.7.1.4 <var>

   Specifies the generation of audio from a variable using prerecorded
   audio segments. A variable represents a semantic concept (such as
   date or number) and dynamically produces the appropriate speech.

   Prerecorded audio allows an application vendor or service provider to
   choose the exact voice for their audio and therefore completely
   control the "sound and feel" of the service provided to end users. It
   provides very high audio quality and allows the variables to blend
   seamlessly into the surrounding audio segments.

   Text to speech (TTS) using SSML may also be used to render variables,
   but may not provide as good quality, or allow as complete control of
   the "sound and feel" or user experience. TTS is normally used for
   reading text such as emails and for very large vocabularies such as
   stock names. TTS results in a very clear difference between the
   variables and the surrounding audio segments. (See MSML Dialog Speech
   package).


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      Attributes:

         type: specifies the type of variable. Mandatory. Variable type
         must be one of "date", "digits", "duration", "month", "money",
         "number", "silence", "time", or "weekday".

         subtype: specifies an optional clarification of type. Specific
         values depend upon the type.

         value: text which should be rendered appropriate to the type
         and subtype attributes.

         xml:lang: specifies the language to use when rendering the
         variable.

10.7.1.5 <playexit>

   The <playexit> element MUST be invoked when generation of all content
   of the <play> has come to completion. The contents of this element
   MAY be used to send events.

      Attributes:

         none

10.7.2 <dtmfgen>

   DTMF generator originates one or more DTMF digits in sequence.

      Attributes:

         id: an optional identifier which may be referenced elsewhere
         for sending events to the dtmfgen primitive.

         digits: A string of characters from the alphabet "0-9a-d#*"
         which correspond to a sequence of DTMF tones. Mandatory.

         level: used to define the power level for which the tones will
         be generated. Expressed in dBm0 in a range of 0 to -96 dBm0.
         Larger negative values express lower power levels. Note that
         values lower than -55 dBm0 will be rejected by most receivers
         (TR-TSY-000181, ITU-T Q.24A). Default is -6 dBm0.

         dur: the duration in milliseconds for which each tone should be
         generated. Implementations may round the value if they only
         support discrete durations. Default 100 ms.




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         interval: the duration in milliseconds of a silence interval
         following each generated tone. Implementations may round the
         value if they only support discrete durations. Default 100 ms.

      Events:

         terminate: terminates DTMF generation and assigns values to the
         shadow variables.

      Shadow Variables:

         dtmfgen.end: contains the event which caused DTMF generation to
         stop.

   The following sections describe the child elements of <dtmfgen>.

10.7.2.1 <dtmfgenexit>

   The <dtmfgenexit> element MUST be invoked when the DTMF generation
   operation completes or is terminated as a result of receiving the
   terminate event. The <dtmfgenexit> element MAY be used to send events
   when the recording has completed.

      Attributes:

         none

10.7.3 <record>

   Record creates a recording. Similar to play, <record> supports two
   states; create and suspend. Received media becomes part of the
   recording when <record> is in the create state and is discarded when
   it is in the suspend state.

   Recording MUST be terminated when a terminate event is received or
   when a nospeech event is received and no audio has yet been recorded.
   <record> differentiates different types of terminate events.

   An optional <play> element MAY be specified as a child element of
   <record>. This mechanism provides a complete play-record operation,
   where the prompt(s) specified within the <play> element are played in
   advance of start of recording.

   Note: Attributes prespeech, postspeech, and termkey provide a
   simplified mechanism for controlling record operations using implicit
   DTMF and VAD, without the use of <group> and event exchange
   mechanism.



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      Attributes:

         id: an optional identifier which may be referenced elsewhere
         for sending events to the record primitive.

         append: a boolean which defines whether the recording is
         allowed to be appended to an existing file if dest already
         exists. Default is "false". The attribute is ignored if the
         scheme is http.

         dest: the destination for the recording, which will contain
         either audio only, video only, or both audio and video
         depending on the stream(s) being recorded. Recording MAY be
         either local or external based upon the attribute value. File
         and http schemes are supported.

         audiodest: the destination for the audio only recording.
         Recording MAY be either local or external based upon the
         attribute value. All combinations of dest, audiodest, and
         videodest are valid. File and http schemes are supported.

         videodest: the destination for the video only recording.
         Recording MAY be either local or external based upon the
         attribute value. All combinations of dest, audiodest, and
         videodest are valid. File and http schemes are supported.

         format: defines the encoding and file type of the recording.
         The format attribute is defined as a string type of form
         “audio|video/filetype;codecs=x,y”. The keyword ‘audio’
         identifies an audio only recording, while the keyword ‘video’
         identifies video only recording or an audio plus video
         recording. The codecs field identifies the audio and/or video
         codecs to be used for the recording, where the order of the
         codec values is not significant. In the event of audio and
         video recording, using ‘video’ keyword, the codecs=x,y field
         MAY be used to identify the audio codec and the video codec.

         codecconfig: Identifies an optional special instruction string
         for codec configuration. Default is to send no special
         configuration string to the codec.

         audiosamplerate: Identifies audio sample rate in kHz. If not
         specified, the sample rate SHOULD be determined from the media
         source.

         audiosamplesize: Identifies audio sample size in bits. If not
         specified, the sample size SHOULD be determined from the media
         source.


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         profile: Identifies a video profile name specific to the codec.
         If not specified, default video profile of the codec SHOULD be
         selected for the recording.

         level: Identifies a video profile level to the codec. Default
         is to send no profile information to the codec and allow the
         codec to select an internal default.

         imagewidth: Identifies the width of video image in pixels.
         Default is to use image width information from the media
         source.

         imageheight: Identifies the height of video image in pixels.
         Default is to use image height information from the media
         source.

         maxbitrate: Identifies the bitrate of the video signal in kbps.
         Default is to use maximum bitrate information from the media
         source.

         framerate: Identifies the video frame rate in frames per
         second. Default is to use frame rate information from the media
         source.

         initial: defines the initial state for the record element.
         Default is "create", which starts the recording as soon as the
         <record> element is executed. The “initial” attribute is
         applicable only when <record> is used within the <group>
         structure.

         maxtime: defines the maximum length of the recording in units
         of time.

         prespeech: defines a timer value, in seconds, for detection of
         absence of audio energy at the start of the record operation.
         If no audio energy is detection for the amount of time
         specified by prespeech, the recording is terminated. Default is
         “0s”, which does not activate the prespeech timer.

         postspeech: defines a timer value, in seconds, for detection of
         absence of audio energy while the recoding is in progress.
         During an in progress recording, if absence of audio energy is
         detected as specified by the postspeech timer, the recording is
         terminated. Default is “0s”, which disables the ability to
         terminate a recording due to postspeech silence.

         termkey: defines a single DTMF key which when detection
         terminates the recording. Absence of this attribute prevents


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         the recording from being terminated due to detection of DTMF
         digits. When termkey is specified, the detected DTMF digit
         terminates the recording and the DTMF digit is not entered in
         the digit buffer.

      Events:

         Following describes input events to the media primitive object.
         The MSML Dialog Group package allows an event exchange
         mechanism between primitives.

         pause: causes the record to enter the suspend state. Received
         media is discarded.

         resume: causes record to resume if it was suspended. It has no
         effect otherwise.

         toggle-state: causes the suspend / create state to toggle.

         terminate: terminates the recording and assigns values to the
         shadow variables.

         terminate.cancelled: terminates the recording and assigns
         values to the shadow variables. If the dest attribute used the
         file scheme, the local recording is deleted. Applications are
         responsible for removing external files created using the http
         scheme.

         terminate.finalsilence: terminates the recording and assigns
         values to the shadow variables. If the dest attribute used the
         file scheme, the final silence is removed from the recording.

         nospeech: terminates the recording and assigns values to the
         shadow variables if it is received and no recording has yet
         been created. The "nospeech" event is ignored if audio has
         already been recorded.

      Shadow Variables:

         record.len: the actual length of the recording measured in
         units of time. This does not include time which may have
         elapsed while the record was in the suspend state.

         record.end: contains the event which caused the record to
         terminate. When the record terminates because maxtime is
         exceeded, end is assigned the value
         "record.complete.maxlength".



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         Record termination due to prespeech silence, results in
         assigned value of “record.failed.prespeech”

         Record termination due to postspeech silence, results in
         assigned value of “record.complete.postspeech”

         Record termination due to DTMF detection, results in assigned
         value of “record.complete.termkey”

   The following sections describe the child elements of <record>.

10.7.3.1 <play>

   The optional <play> element as a child element of <record> allows a
   prompt to be played prior to start of recording. The record operation
   starts at the end of the play sequence or if the play is barged by
   DTMF, assuming that barge=true is specified for <play>. For a
   complete description, refer to <play> element.

10.7.3.2 <recordexit>

   The <recordexit> element MUST be invoked when the record operation
   completes or when the recording is terminated as a result of
   receiving the terminate event. The <recordexit> element MAY be used
   to send events when the recording has completed.

      Attributes:

         none

10.7.4 <dtmf> or <collect>

   DTMF input fulfils several roles within MSML Dialogs. It is used to
   trigger events which will affect the media processing operation of
   other primitives. It is also used to collect DTMF digits from a media
   stream which are to be reported back to the user of MSML Dialog.
   Often DTMF detection is used for both purposes. Barge is the most
   common example, where a prompt is stopped based upon DTMF input but
   more digits may remain to be collected.

   DTMF detection supports multiple simultaneous recognition patterns.
   Different patterns can be used to trigger sending different events in
   order to implement DTMF controls. Alternatively one pattern may be
   used to represent a collection and another pattern, a substring of
   the first, used as a barge indication.

   An optional <play> element MAY be specified as a child element of
   <dtmf> or <collect>. This mechanism provides a complete play-collect


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   operation, where the prompt(s) specified within the <play> element
   are played in advance of DTMF digit collection.

   Note that all patterns share the same digit collection buffer, inter-
   digit timing, a single <nomatch> element, and a single <noinput>
   element. As such, multiple patterns may not be suitable to support
   simultaneous collections for different purposes. When this is
   required, separate <dtmf> elements should be used instead.

   <dtmf> terminates if any of the <pattern>, <noinput>, or <nomatch>
   elements are matched the maximum number of times that they are
   allowed. The number of times they may match may be specified as an
   attribute of <dtmf> or of the individual child elements.

   Element identifier <dtmf> is equivalent to <collect>. However,
   <collect> is the preferred name. MSML clients SHOULD use <collect>,
   while MSML servers SHOULD support both.

      Attributes:

         id: an optional identifier which may be referenced elsewhere
         for sending events to this primitive.

         cleardb: a boolean indication of whether the buffer for digit
         collection should be cleared of any collected digits when the
         element is instantiated. If set to false, any digits currently
         in the buffer MUST be immediately compared against the pattern
         elements.

         fdt: defines the first-digit timer value. The first-digit timer
         is started when DTMF detection is initially invoked. If no DTMF
         digits are detected during this initial interval, the <noinput>
         element MUST be invoked.

         idt: defines the inter-digit timer to be used when digits are
         being collected. When specified, the timers is started when the
         first digit is detected and restarted on each subsequent digit.
         Timer expiration is applied to all patterns. After that, if any
         patterns remain active and a nomatch element is specified, the
         nomatch is executed and DTMF input MUST terminate. The idt
         attribute should only be used when digit collection is being
         performed. No default.

         starttimer: boolean value which defines whether the first digit
         timer (fdt) is started initially. When set to false, the
         starttimer event must be received for it to start. Default
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         iterate: specifies the number of times the <pattern>,
         <noinput>, and <nomatch> elements may be executed unless those
         elements specify differently. The value "forever" MAY be used
         to indicate that these may be executed any number of times.
         Default is once '1'.

      Events:

         Following describes input events to the media primitive object.
         The MSML Dialog Group package allows an event exchange
         mechanism between primitives.

         starttimer: starts the first digit timer (fdt) if it has not
         already been started. Has no effect otherwise.

         terminate: terminates the DTMF input and assigns values to the
         shadow variables.

      Shadow Variables:

         dtmf.digits: the string of DTMF digits which have been received
         (the contents of the digit buffer).

         dtmf.len: the number of digits in the digit buffer.

         dtmf.last: the last digit in the digit buffer.

         dtmf.end: contains the event which caused the <dtmf> to
         terminate or is assigned one of "dtmf.match", "dtmf.noinput",
         or "dtmf.nomatch" depending upon which of the corresponding
         elements reached its maximum.

   The following sections describe the child elements of <dtmf> or
   <collect>.

10.7.4.1 <play>

   The optional <play> element as a child element of <dtmf> or <collect>
   allows a prompt to be played prior to DTMF digit collection. DTMF
   digit collection starts at the end of the play sequence or if the
   play is barged by DTMF, assuming that barge=true is specified for
   <play>. For a complete description, refer to <play> element.

10.7.4.2 <pattern>

   The pattern element describes one or more DTMF digits that are to be
   recognized. When the pattern is matched, the child elements MUST be
   executed.


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      Attributes:

         digits: The digit pattern which should be matched.

         format: an enumerated value which defines the format used to
         express the digit pattern. The format may be "mgcp" or "megaco"
         for patterns expressed as digit map from those specifications,
         or as one of the simple built-in formats defined within this
         specification. Currently, a single built-in format
         "moml+digits" is defined which allows a match based on either
         one or more specific digits, or based upon a specific length
         specification with an optional return key. "moml+digits" is the
         default.

         iterate: specifies the number of times the <pattern> may be
         matched. The value "forever" may be used to indicate that
         <pattern> may be matched any number of times. This value
         overrides any specified in <dtmf>. Default is once '1'.

10.7.4.3 <detect>

   The contents of the <detect> element MUST be executed whenever any
   DTMF is first detected. It MUST be matched at most once.

      Attributes:

         none

10.7.4.4 <noinput>

   The <noinput> element is used when DTMF is being collected. Children
   of the <noinput> element MUST be executed when DTMF has not been
   detected and the first digit timeout occurs.

      Attributes:

         iterate: specifies the number of times the <noinput> may be
         triggered. The value "forever" may be used to indicate that
         <noinput> may be triggered any number of times. This value
         overrides any specified in <dtmf>. Default is once '1'.

10.7.4.5 <nomatch>

   The <nomatch> element is used when DTMF is being collected. Children
   of the <nomatch> element MUST be executed when it is determined that
   none of the individual patterns can be matched.

      Attributes:


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         iterate: specifies the number of times the <nomatch> may be
         triggered. The value "forever" may be used to indicate that
         <nomatch> may be triggered any number of times. This value
         overrides any specified in <dtmf>. Default is once '1'.

10.7.4.6 <dtmfexit>

   The <dtmfexit> element MUST be invoked when the dtmf input completes
   because one of <pattern>, <noinput>, or <nomatch> occurred its
   maximum number of times.

      Attributes:

         None


10.7.5 <moml>

   The root element <moml> MUST be used when the document is a stand-
   alone MSML Dialog, where the invoking application media type
   indicates ‘application/moml+xml’. Additionally, for backwards
   compatibility, the <moml> element MUST be used within <dialogstart>
   which contains an in-line embedded MSML dialog.

   Valid contents of <moml> are all elements described within this MSML
   Dialog Base package.

      Attributes:

         version: "1.0" Mandatory.

         id: an identifier unique to this object. Events returned from
         MSML dialog (the "target" attribute of a <send> is equal to
         "source") will be correlated with this identifier. Mandatory.

      Events:

         terminate: terminates the MOML context. A terminate event gets
         sent to the currently executing <group> or primitive.

10.8 MSML Dialog Group Package

   The group package defines a single control flow construct that
   specifies concurrent execution. Primitives are composed for
   concurrent execution by placing them within a <group> element. Groups
   define how media flows between multiple concurrently executing
   primitives. They have one or more inputs and one or more outputs. A


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   <group> represents the declaration of a complex media processing
   operation. The event interaction between primitives (see the
   following sub-section) is defined within the context of one or more
   groups. However groups themselves do not scope events, they simply
   define that primitives are concurrently executing and a primitive
   must be executing in order to receive an event.

   Placing primitives within a group structure is an optional feature of
   this specification. It allows for complex services to created using
   the event exchange mechanism between the primitives. For simpler
   services, such as play/collect or play/record, the use of group
   mechanism is not necessary. MSML Dialog Group package is dependent on
   the MSML Dialog Base package.

   Groups may also be used to describe media objects which transform a
   media stream while optionally allowing application or user control of
   the transformation. For example a gain control could be defined which
   responds to user speech or DTMF input. In this case a recognition
   primitive would send events to a gain control primitive.

   Groups have one attribute which defines the media flow within them.
   They also have a dimension which defines how many media inputs and
   outputs they have. Currently dimensions of 1 and 2 are supported
   based upon the group topology. These correspond to a group with one
   input and one output and a group with two inputs and two outputs.

   Media flow to and from the primitives within the group is based upon
   a topology attribute of the <group> element. This differs from a
   similar mechanism in Media Policy Manipulation in the Conference
   Policy Control Protocol [3] which explicitly defined connections. The
   topology attribute defines a topology schema and implies the group
   dimension.

   There are several common ways in which primitives are often connected
   together. A schema provides a convenient template which can be
   applied to multiple primitives without having to define all of the
   individual media relationships. The following two schemas are
   initially defined for 1 dimensional groups:

   o  parallel: specifies that media sent to the group is sent to every
   primitive which has an input. The group bridges the output from every
   primitive which has an output into a single common group output;

   o  serial: specifies that the first primitive listed in the group
   receives the media sent to the group. Its output is to be connected
   to the input of the next primitive defined within the group and so on
   until the last primitive within the group which becomes the group
   output.


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   Groups with these topologies are shown in the two diagrams below. The
   group on the left has a parallel topology and that on the right has a
   serial topology.



           /-> P1 --\
          /          \
   G(in) +---> P2 ----> G(out)     G(in) --> P1 --> P2 --> P3 --> G(out)
          \          /
           \-> P3 --/


   More complex media flows MAY be created by nesting groups of serial
   and parallel topologies within each other. For example, the diagram
   below has a group with a serial topology nested within a star
   topology.



                  /-----> P1 ------------------------\
                 /                                    \
         Gs(in) +-> Gp(in) --> P2 --> P3 --> Gp(out) -+> Gs(out)


   This combination could be used to create record operation where DTMF
   was to be clamped from the recording itself, but a DTMF key press is
   still used to stop the recording. In this case, P1 would be a DTMF
   recognizer, P2 would be a clamp primitive, and P3 a recorder as shown
   by the following example. This example omits child elements and
   attributes not concerned with the core concept. The following section
   discusses sending events and the details of each of the primitives is
   defined in section 4.

         <group topology="parallel">
            <dtmf/>
            <group topology="serial">
               <clamp/>
               <record/>
            </group>
         </group>

   A single schema, "fullduplex" is defined for a two dimensional group.
   A full-duplex two dimensional group is has exactly two immediate


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   children. Those children may be primitives or other one dimensional
   groups. A "fullduplex" group must only be used as the top most group
   and must not be nested. Each primitive (P1) and group (G2) becomes
   half of the full-duplex group as shown in the diagram below.

                 G-A(in1)  +-> G2 --> G-B(out1)

                 G-A(out2) <-- P1 <-+ G-B(in2)

   Full duplex groups are symmetrical when both halves are the same.
   They are asymmetrical when they differ. Asymmetric groups need to
   have a name associated with each side. The left side is defined as
   the input of the first child of the full-duplex group combined with
   the output of the second child. The right side is reverse. These
   sides were labeled A and B respectively in the preceding diagram.

   An example of a full-duplex group is the user operated gain control
   mentioned at the beginning of this sub-section. The gain should
   operate on the audio which a user hears, but the gain is controlled
   by recognizing things such as DTMF or spoken commands in media which
   the user originates. The following shows the XML tag grouping which
   would accomplish this and corresponds to the media flow shown in the
   diagram above. If the user's audio is not required for anything other
   than control of the gain, then the <relay> is not required and the
   internal group could be omitted. A complete XML description for this
   is included in the examples section.

         <group topology="fullduplex">
            <group topology="parallel">
               <dtmf/>
               <relay/>
            </group>
            <gain/>
         </group>


   Primitives within a group MUST begin concurrently but MAY finish
   asynchronously based upon events which they receive or their task
   completes. A group MUST terminate when all of the primitives within
   it have completed. If the group contains a <groupexit> element, then
   the contents of that element MUST be executed as part of group
   termination.




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   A group itself MAY receive a terminate event requesting termination.
   A terminate event sent to the group causes a terminate event to be
   sent to each of its currently active primitives. The <groupexit>
   element is not executed until all primitives have processed their
   respective terminate events.

10.8.1 <group>

   The <group> element allows the contained primitives to be executed
   concurrently.

   Attributes:

   topology: specifies a schema which defines the flow of media within
   the group. Three schemas are initially defined. "fullduplex" is
   specified for use with two dimensional groups. "parallel" and
   "serial" are for use with one dimensional groups. The definition of
   these topologies is defined in section 2. Mandatory.

   id: identifies name of the group. Mandatory when groups are nested.

   Events:

   terminate: causes a terminate event to be sent to each element
   contained within the group.

10.8.2 <groupexit>

   The <groupexit> element allows events to be sent when group
   processing completes. Group processing completes when all contained
   primitives terminate.

   Attributes:

   none

   Events:

   none

10.9 MSML Dialog Transform Package

   The MSML Dialog Transform package gathers together the simple
   primitives which work as filters on half duplex media streams.






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10.9.1 <vad>

   Voice activity detection (VAD) is used to detect voice and silence
   when speech recognition is not required. Similar to both speech and
   DTMF, a VAD has different media conditions which it can match. Those
   conditions can be qualified by a minimum length of time which is
   required for them to be considered recognized.

      Attributes:

         starttimer: boolean value which defines whether the timer is
         started to allow recognition of the initial condition (voice,
         silence). When set to false, the starttimer event must be
         received in order for the initial condition to be recognized.
         The timer does not affect recognition of the transition
         conditions. Default false.

      Events:

         starttimer: starts the timer to allow recognition of the
         initial condition if it has not already been started. Has no
         effect otherwise.

         terminate: terminates voice activity detection.

      Shadow Variables:

         none

   The following sections describe the child elements of <vad>.

10.9.1.1 <voice>, <silence>, <tvoice>, <tsilence>

   Each child element corresponds to a condition which a VAD can detect.
   The first two detect when voice or silence has been initially present
   for a minimum length of time since the VAD was started. The second
   two require that a transition to the voice or silence condition first
   occur.

      Attributes:

         len: the length of time the condition must persist in order to
         be recognized. In the case of <tvoice> and <tsilence>, the
         length of time applies only to the final recognized condition.

         sen: the maximum length of time the condition not being
         detected may occur without causing the detector to begin
         measuring that condition.


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10.9.2 <gain>

   Gain MAY be used to adjust of the gain of a media stream by a
   specific amount.

      attributes:

         incr: an increment, expressed in dB, which will be used to
         adjust the gain when "louder" and "softer" events are received.
         Default is 3 dB.

         amt: a specific gain to apply specified in dB.

      events:

         mute: self explanatory.

         unmute: self explanatory.

         reset: sets the gain to zero dB.

         louder: makes the audio on a stream louder.

         softer: makes the audio on a stream quieter.

         amt: sets the gain to the specified value between -96 dB and 9
         dB.

10.9.3 <agc>

   Automatic gain control MAY be used to have a media server
   automatically adjust the gain of a media stream.

      attributes:

         tgtlvl: the desired target level for AGC specified in dBm0.

         maxgain: the maximum gain that AGC will apply specified in dB.

      events:

         mute: self explanatory.

         unmute: self explanatory.






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10.9.4 <gate>

   A simple filter which will pass or halt media, regardless of the
   format of the media stream, based on the events it receives. <gate>
   shares the same mute and unmute events for compatibility with the
   gain primitives <gain> and <agc>.

      attributes:

         initial: the values "pass" and "halt" define whether media is
         initially allowed to pass. Default is to pass.

      events:

         mute: halts media flow through the primitive.

         unmute: allows media to pass through the primitive.

10.9.5 <clamp>

   This element MAY be used to filter DTMF tones from a media stream.
   Media other than DTMF tones is passed unchanged.

      attributes:

         none.

      events:

         none.

10.9.6 <relay>

   This element is a simple primitive which copies its input to its
   output.

      attributes:

         none.

      events:

         none.

10.10 MSML Dialog Speech Package

   The MSML speech package defines functionality which MAY be used for
   automatic speech recognition <speech> and extends the <play>


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   primitive defined in the MSML Dialog Base package to include speech
   synthesis. As such, this package depends on the MSML Dialog Base
   package.

10.10.1 <speech>

   Activates grammars or user input rules associated with speech
   recognition. If multiple grammars are specified, all are activated.
   All active grammars share the same timers, recognition attributes,
   and <noinput> and <nomatch> elements. Each grammar may have its own
   <match> element.

   <speech> terminates if any of the <grammar>, <noinput>, or <nomatch>
   elements are matched the maximum number of times that they are
   allowed. The number of times they may match may be specified as an
   attribute of <speech> or of the individual child elements.

      Attributes:

         noint: specifies a time period during which speech input must
         be started, otherwise the associated <noinput> element is
         invoked.

         norect: specifies a maximum time period during in which speech
         must begin to be matched, otherwise the associated <nomatch>
         element is invoked.

         spcmplt: specifies the length of silence necessary after speech
         before a result will be finalized in the case where there is a
         complete match of an active grammar. Following the silence, the
         appropriate <match> element will be triggered if the result is
         above the confidence level. Otherwise a <nomatch> element will
         be triggered.

         spincmplt: specifies the length of silence necessary after
         speech before a result will be finalized in the case where
         there is a incomplete match of all active grammars. Following
         the silence, the <nomatch> element will be triggered.

         confidence: the minimum confidence level which the recognizer
         must have to consider a recognition result as matching a
         grammar. Expressed as an integer between 1-100.

         sens: specifies the sensitivity of the recognizer to determine
         whether speech is present. Lower sensitivity may be required
         for the recognizer to work well in the presence of high
         background noise or line echo.



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         starttimer: boolean value which defines whether the no input
         (noint) and no recognition (norect) are started initially. When
         set to false, the starttimer event must be received in order to
         start them. Default false.

         iterate: specifies the number of times the <grammar>,
         <noinput>, and <nomatch> elements may be executed unless those
         elements specify differently. The value "forever" may be used
         to indicate that these may be executed any number of times.
         Default is once '1'.

      Events:

         sens: sets the sensitivity of the recognizer as described
         above.

         starttimer: starts the no input (noint) and no recognition
         (norect) timers if they have not already been started. Has no
         effect otherwise.

         terminate: terminates the speech input and assigns values to
         the shadow variables.

      Shadow Variables:

         speech.end: contains the event which caused the <speech> to
         terminate or is assigned one of "speech.match",
         "speech.noinput", or "speech.nomatch" depending upon which of
         the corresponding elements reached its maximum.

         speech.results: contains the results of a matched grammar. The
         results are formatted using the Natural Language Semantics
         Markup Language (NLSML) [6]. When this variable is referenced
         to return results, the results are returned as a separate MIME
         entity.

   The following sections describe the child elements of <speech>.

10.10.1.1 <grammar>

   Specifies and activates a speech grammar based on Speech Recognition
   Grammar Specification (SRGS) [5] XML notation. Grammars may be
   referenced by a URI or defined inline. Child elements of <match> MUST
   be executed when the specified speech grammar is matched.

      Attributes:




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         uri: specifies the location of an SRGS grammar when the grammar
         is not defined inline.

         iterate: specifies the number of times the <grammar> may be
         matched. The value "forever" MAY be used to indicate that
         <grammar> may be matched any number of times. This value
         overrides any specified in <speech>. Default is once '1'.

10.10.1.2 <match>

   <match> is a child of <grammar> and specifies the actions to take
   when the corresponding grammar is matched.

10.10.1.3 <noinput>

   The <noinput> element is used when speech is being recognized.
   Children of the <noinput> element MUST be executed when speech has
   not been detected and the no input timeout (noint) occurs.

      Attributes:

         iterate: specifies the number of times the <noinput> may be
         triggered. The value "forever" may be used to indicate that
         <noinput> may be triggered any number of times. This value
         overrides any specified in <speech>. Default is once '1'.

10.10.1.4 <nomatch>

   The <nomatch> element is used when speech is being recognized.
   Children of the <nomatch> element MUST be executed when it is
   determined that none of the active grammars will match.

      Attributes:

         iterate: specifies the maximum number of times the <nomatch>
         may be triggered. The value "forever" MAY be used to indicate
         that <nomatch> may be triggered any number of times. This value
         overrides any specified in <speech>. Default is once '1'.

10.10.1.5 <speechexit>

   The <speechexit> element MUST be invoked when the speech input
   completes because one of <grammar>, <noinput>, or <nomatch> occurred
   its maximum number of times.

      Attributes:

         none


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10.10.2 <play>

   The <play> element, as defined in the MSML Dialog Base package, is
   extended with a new child element for synthesizing speech. From an
   XML perspective, <tts> is a member of a media substitution group. See
   the schema at the end of this document for details.

   The following sections describe the child elements of <play>.

10.10.2.1 <tts>

   Contents of the <tts> element are rendered using Text To Speech
   services and must be compliant to the SSML specification. Element
   content MAY be plain text, contain the SSML <speak> element, or the
   uri attribute should identify the location of text to be rendered.

      Attributes:

         uri: Identifies the location of the text to be rendered. The
         file and http schemes are supported.

         iterate: specifies the number of times the text to speech block
         is to be rendered. Defaults to once '1'.

         xml:lang: specifies the language to use when it is not
         explicitly specified as an attribute for <speak>.



10.11 MSML Dialog Fax Detection Package

   The fax detection package defines primitives which allow a media
   server to provide facsimile detection services.

10.11.1 <faxdetect>

   Fax tone detection is used to detect the presence of the T.30 CNG
   tone in a media stream. Child elements of <faxtone> are executed when
   the CNG tone is detected.

      Attributes:

         None







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10.12 MSML Dialog Fax Send/Receive Package

10.12.1 <faxsend>

   The <faxsend> primitive provides the functionality of a calling fax
   terminal. This typically means sending a set of pages. However, it
   can also mean requesting the called terminal to send pages instead
   of, or in addition to, sending pages. The fax images to send are
   defined by the <sendobj> elements, described below.

   Requesting the called terminal to send pages happens when the
   <rxpoll> element is included as part of <faxsend>. This element may
   be included in addition to, or instead of, the <sendobj> element. One
   <sendobj> (at a minimum) or <rxpoll> element must be present. When
   both are present, a media server will first send pages and will then
   poll the other terminal, requesting pages.

   Because fax is a distinct media type, the <faxsend> primitive is not
   expected to interact with other primitives. Rather, it will interact
   using fax protocols with a remote fax terminal (or gateway) and will
   send requested status events to its invoking environment. During fax
   operation, shadow variables are used to record the progress and
   parameters of the varying stages of fax operation.

   Status events are requested by including one or more status request
   elements. These elements correspond to different stages or events in
   fax operation and cause pre-defined events to be sent to the invoking
   environment when they occur. Since the only recipient of these events
   is expected to be a fax Control Agent, requests are simplified by
   associating a pre-defined namelist of shadow variables with each
   event. This decision may be revisited to allowed tailored namelists
   based on further implementation experience. Status requests apply
   both to sending and polling operation.

      Attributes:

         lclid: the identifier that a media server uses to identify
         itself.

         minspeed: the minimum acceptable speed to negotiate for the
         operation.

         maxspeed: the maximum speed to negotiate for the operation.
         This attribute is primarily for testing purposes.

         ecm: specifies whether Error Correction Mode (ECM) is allowed
         to be used if supported by the remote terminal. Defaults to
         "true".


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      Events:

         terminate: terminates the fax send operation.

      Shadow Variables:

         fax.rmtid: the identifier of the remote fax terminal.

         fax.rate: the negotiated speed for the operation.

         fax.resolution: identifies the resolution of the image. Both
         metric and inch based resolutions are defined. Metric based
         resolutions are: 75x75, 150x150, 204x98, 204x196, 204x391,
         408x391. Inch based resolutions are: 200x200, 300x300, 400x400,
         600x600.

         fax.pagesize: identifies the negotiated page size. Metric sizes
         are "A3", "A4", "A5", "A6", and "B4". Inch based page sizes are
         "Letter" and "Legal".

         fax.encoding: identifies the image encoding utilized. Valid
         values are "MH", "R", "MMR", and "JPEG".

         fax.ecm: identifies whether ECM operation was used.

         fax.pagebadlines: the number of bad lines in a page.

         fax.objbadlines: the number of bad lines in an object.

         fax.opbadlines: the number of bad lines in an operation.

         fax.objuri: the objuri of the current object.

         fax.resendcount: the number of pages resent due to errors.

         fax.totalpages: the number of pages processed or stored.

         fax.totalobjects: the count of the objects used in the
         operation.

         fax.duration: the duration of the operation expressed as a
         duration in seconds and milliseconds (e.g. "23s250ms").

         fax.result: contains the reason which caused the fax operation
         to complete. When the operation completes successfully, the
         value will be assigned "fax.success". Other values include:
         "fax.partial", "fax.nofax", "fax.remotedisconnect",
         "fax.uri.access.error", and "fax.invalid.startpage".


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   The following sections describe the child elements of <faxsend>.

10.12.1.1 <sendobj>

   <sendobj> is used to define a fax transmission. There MAY be multiple
   instances of the element which will be transmitted in order.

      Attributes:

         objuri: a URI that points to the fax image that will be
         transmitted. Mandatory.

         startpage: the first page of a multi-page objuri to send.

         pagecount: page count.

10.12.1.2 <hdrfooter>

   <hdrfooter> describes the header/footer that a media server MAY put
   on pages. The header or footer may be defined as the content of the
   <format> child element. The <format> element is only allowed if the
   type attribute has a value of "header" or "footer".

      Attributes:

         type: specifies whether a header or a footer should be put on
         pages and identifies the source of the header or footer. The
         following enumerated values may be used:

            "header" indicates that the media server should put a header
                     on pages using the contents of the <format>
                     element.

            "nohdr"  indicates that there should be no header or footer.

            "footer" indicates that the media server should put a footer
                     on pages using the contents of the <format>
                     element.

         style: defines the style of insertion onto a fax page that a
         media server should use for the header or footer. Valid styles
         are "append", "overlay", or "replace".

   <format> is a child of the <hdrfooter> element that defines the style
   format to be used for the header or footer. It uses a "C" language
   style format statement (as shown below) to define the contents and
   layout of the header or footer.



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           code    length   name              format
            %a       3     day of week       3-character abbreviation
            %d       2     date              01-31
            %m       2     month             01-12
            %y       2     year              00-99
            %Y       4     year              0000-9999
            %I       2     12 hour           01-12
            %H       2     24 hour           00-23
            %M       2     minute            00-59
            %S       2     seconds           00-59
            %p       2     AM/PM             AM or PM
            %P       2     page number       01-99
            %T       2     total pages       01-99
            %l       20    local ID (sender) 0-9, + or spaces
            %r       20    remote ID (rcvr)  0-9, + or spaces
            %%       1     percent           display % in header/ftr
10.12.1.3 <rxpoll>

   <rxpoll> provides the information necessary for a receive polling
   operation to occur. The object(s) to be received are defined by one
   or more <rcvobj> elements. The <rcvobj> is defined further under the
   child elements of <faxrcv>. The <rxpoll> element MAY also include a
   description of the header/footer that a media server SHOULD put on
   received pages. The <hdrfooter> element and it's usage is described
   above.

      Attributes:

         rmtid: specifies the identifier of the remote fax terminal that
         to be associated with a polling operation. A media server MUST
         NOT execute a polling operation unless the value of rmtid
         matches that of the connected remote machine.

10.12.1.4 <faxstart>

   Requests that an event be sent when fax operation has begun. When
   triggered, the following will be executed:

   <send target="source" event="fax.start"/>



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10.12.1.5 <faxnegotiate>

   Requests that an event be sent when a negotiation has been completed.
   Multiple events MAY be sent each time a DCS frame is sent or
   received. When triggered, the following will be executed:

   <send target="source" event="fax.negotiate"
      namelist="fax.rmtid
         fax.rate
         fax.resolution
         fax.pagesize
         fax.encoding
         fax.ecm"/>

10.12.1.6 <faxpagedone>

   Requests that an event be sent when a page has been sent or received.
   When triggered, the following will be executed:

   <send target="source" event="fax.pagedone"
         namelist="fax.resolution
         fax.pagesize
         fax.encoding
         fax.pagebadlines
         fax.resendcount"/>

10.12.1.7 <faxobjectdone>

   Requests that an event be sent when an objuri has been completed.
   When triggered, the following will be executed:

   <send target="source" event="fax.objectdone"
         namelist="fax.objuri
         fax.objbadlines
         fax.resendcount
         fax.totalpages
         fax.result"/>

10.12.1.8 <faxopcomplete>

   Requests that an event be sent when an operation has been completed.
   When triggered, the following will be executed:








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   <send target="source" event="fax.opcomplete"
         namelist="fax.totalpages
         fax.opbadlines
         fax.resendcount
         fax.totalobjects
         fax.duration
         fax.result"/>

10.12.1.9 <faxpollstarted>

   Requests that an event be sent when a polling operation has started.
   When triggered, the following will be executed:

   <send target="source" event="fax.opcomplete"
         namelist="fax.rmtid
         fax.rate
         fax.resolution
         fax.pagesize
         fax.encoding
         fax.ecm"/>

10.12.2 <faxrcv>

   The <faxrcv> primitive provides the functionality of a called fax
   terminal. Typically this type of operation is to receive pages.
   However, it can include sending pages instead of, or in addition to,
   receiving them. The fax objects to receive are defined by the
   <rcvobj> elements, described below.

   A media server SHOULD send pages as a polled terminal when the
   <txpoll> element is included as part of <faxrcv>. This element may be
   included in addition to, or instead of, the <rcvobj> element. One
   <rcvobj> or <txpoll> element must be present. When both are present,
   a media server SHOULD first receive pages and will then allow the
   other terminal to poll the media server, requesting pages.

   Because fax is a distinct media type, the <faxrcv> primitive is not
   expected to interact with other primitives. Rather, it will interact
   using fax protocols with a remote fax terminal and will send
   requested status events to its invoking environment. During fax
   operation, shadow variables are used to record the progress and
   parameters of the varying stages of fax operation.

   Status events are requested by including one or more status request
   elements. These elements correspond to different stages or events in
   fax operation and cause pre-defined events to be sent to the invoking
   environment when they occur. Since the only recipient of these events
   is expected to be a fax Control Agent, requests are simplified by


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   associating a pre-defined namelist of shadow variables with each
   event. This decision may be revisited to allowed tailored namelists
   based on further implementation experience. Status requests apply
   both to receiving and polling operation.

      Attributes:

         lclid: the identifier that a media server uses to identify
         itself.

         ecm: specifies whether ECM mode is allowed to be used if
         supported by the remote terminal. Defaults to "true".

      Events:

         terminate: terminates the fax reception operation.

      Shadow Variables:

         <faxrcv> supports the same set of shadow variables as <faxsend>

   The following sections describe the child elements of <faxrcv>.

   In addition to the elements defined below, <faxrcv> MAY also have the
   following child elements which were defined under <faxsend>:

      o  <hdrfooter>
      o  <faxstart>
      o  <faxnegotiate>
      o  <faxpagedone>
      o  <faxobjectdone>
      o  <faxopcomplete>
      o  <faxpollstarted>

   Their meaning and usage is the same as previously defined.

10.12.2.1 <rcvobj>

   <rcvobj> is used to define fax objects that a media server will
   receive. There may be multiple instances of the element which will be
   used in order.

      Attributes:

         objuri: a URI that points to the location that a received image
         is to be stored. Mandatory.




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         maxpages: the maximum number of pages that will be stored in
         objuri.

10.12.2.2 <txpoll>

   <txpoll> provides the information for a polling operation to occur as
   part of a fax receive operation. Multiple object(s) to be send may be
   supplied by one or more <sendobj> elements. In the event of multiple
   occurrences, a media server MUST select the <sendobj> element whose
   rmtid attribute matches that of the remote terminal.

   The <sendobj> element was defined previously as a child element of
   <faxsend>. For <txpoll> is extended with an rmtid attribute that
   specifies the identifier of the remote fax terminal and is used to
   select the specific <sendobj> to send.

   A media server SHOULD put a header/footer on transmitted pages based
   on any <hdrfooter> element included as part of <txpoll>.

      Attributes:

         none

11. Response Codes

   Response codes are used to indicate reasons for failures as well as
   completion status. The appropriate code and description must be
   passed to the invoking environment on failure.

   The response codes defined in this section are returned as the value
   of the response attribute to the <result> element. Some values may
   also be returned as part of a namelist to an "msml.dialog.exit" event
   generated when an executing MSML dialog fails.

      Informational (1xx)

         Reserved for future use

      Success (200)

         200 OK

      Request Error (4xx)

         400  Bad Request
         401  Unknown Element
         402  Unsupported Element


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         403  Missing mandatory element content
         404  Forbidden element content
         405  Invalid element content
         406  Unknown attribute
         407  Attribute not supported
         408  Missing mandatory attribute
         409  Forbidden attribute is present

         410  Invalid attribute value

         420 Unsupported media description language
         421 Unknown media description language
         422 Ambiguous request (both URI and inline description)
         423 External document fetch error
         424 Syntax error in foreign language
         425 Semantic error in foreign language
         426 Unknown error executing foreign language

         430 Object does not exist
         431 Object instance name already used
         432 Conference name already in use
         433 reserved
         434 External document fetch error

         440 Cannot join objects of the specified class
         441 Objects have incompatible media types
         442 reserved
         443 reserved
         444 Number of media inputs exceeded

         450 Objects have incompatible media formats
         451 Incompatible media stream format


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      Server Error (5xx)

         500  Internal media server error
         503  Service Unavailable
         510  Not in service
         511  Service Unavailable
         520  No resource to fulfill request
         521  Internal limit exceeded

12. MSML Conference Examples

   These examples focus on MSML Conference Core package used by an
   Control Agent (CA) to control services on a Media Server (MS). They
   show the relationship between SIP signaling to establish media
   sessions and MSML service control commands. For brevity, only the
   content of MSML messages is shown. The examples assumes that the CA
   and MS use the IPv4 address and UDP port number of the audio stream
   (on the MS) to identify the MSML connection.

12.1 Establishing a Dial-in Conference



           UA                   Control Agent             Media Server
           |                         |                           |
           |                         |        INVITE F1          |
           |                         |-------------------------->|
           |                         |           200 F2          |
           |                         |<--------------------------|
           |                         |           ACK F3          |
           |                         |-------------------------->|
           |                         |                           |
           |                         |     createconference> F4  |
           |                         |-------------------------->|
           |                         |           200 F5          |
           |                         |<--------------------------|
           |    INVITE (SDP UA) F6   |                           |
           |------------------------>|                           |
           |                         |      INVITE (SDP UA) F7   |
           |                         |-------------------------->|
           |                         |        200 (SDP MS) F8    |
           |                         |<--------------------------|
           |                         |           ACK F9          |


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           |                         |-------------------------->|
           |     200 (SDP MS) F10    |                           |
           |<------------------------|                           |
           |        ACK F11          |                           |
           |------------------------>|                           |
           |                         |     <dialogstart> F12     |
           |                         |-------------------------->|
           |                         |           200 F13         |
           |                         |<--------------------------|
           |                         |    HTTP interactions F14  |
           |                         |<------------------------->|
           |                         |  <event>(dialog.exit) F15 |
           |                         |<--------------------------|
           |                         |         <join> F16        |
           |                         |-------------------------->|
           |                         |           200 F17         |
           |                         |<--------------------------|
           |         ...             |            ...            |
           |                         |                           |
           |                         |     <dialogstart> F18     |
           |                         |-------------------------->|
           |                         |           200 F19         |
           |                         |-------------------------->|
           |                         |    HTTP interactions F20  |
           |                         |<--------------------------|
           |                         |  <event>(dialog.exit) F21 |
           |                         |-------------------------->|
           |         ...             |            ...            |
           |                         |                           |


   Steps 1-3: establish an MSML control channel for the conference.
   Alternatively, a control channel could already have been established
   which was used for all CA/MS interactions. A control channel per
   conference is only one possible model. Currently MSML uses SIP INFO
   requests and responses on this SIP dialog. There is a proposal to use
   this message exchange to establish a TCP channel for MSML similar to
   the approach used for MRCPv2. This approach would require that a
   request identifier be added to the <msml> element to correlate
   requests and responses. This currently relies on the SIP INFO request
   and response for this property. MSML messages are shown without
   specifying the transport in this example but it assumes a
   request/response correlation based on transport messages.



   Step 4: create a conference that will mix the loudest two speakers
   and report those speakers to the Control Agent every ten seconds. The


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   media server will automatically terminate remaining media sessions
   and delete the conference and associated resources and when the
   control channel is terminated.

      <msml version="1.1">
         <createconference name="exampleConf" deletewhen="nocontrol">
             <audiomix>
                <n-loudest n="3"/>
                <asn ri="10s"/>
             </audiomix>
         </createconference>
      </msml>

   Step 5: conference created successfully

      <msml version="1.1">
         <result response="200"/>
      </msml>

   Steps 6-11: standard 3PCC establishment of a user initiated media
   session to a media server. This is the equivalent of a dial-in
   conference participant. The "To:" header returned by the MS in the
   200 response of Step F8 was:



   To: <sip:msml@ms.example.com>;tag=jd87dfg4h



   Step 12: request an initial dialog with the participant to prompt for
   their name, desired conference, etc. The dialog completes by
   informing the participant they are joining the conference. If this
   was not the first participant, the dialog could also announce the
   other participants.



      <msml version="1.1">
         <dialogstart target="conn:jd87dfg4h" name=”12345”
             type="application/vxml+xml"
             src="http://server.example.com/scripts/initial.vxml"/>
      </msml>


   Step 13: dialog started successfully. The dialog identifier is
   returned.



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      <msml version="1.1">
         <result response="200"/>
         <dialogid>conn:jd87dfg4h/dialog:12345</dialogid>
      </msml>

   Step 14: sequence of HTTP VoiceXML dialog interactions.



   Step 15: the VoiceXML browser exits (but does not disconnect). If a
   namelist had been specified within the VoiceXML <exit> element, it
   would have been included in the <event> sent to the CA.



      <msml version="1.1">
         <event name="msml.dialog.exit"
                id="conn:jd87dfg4h/dialog:12345"/>
      </msml>

   Step 16: join the participant to the conference and have the volume
   of their contributing audio automatically adjusted to a target level
   of -20 dBm0.



      <msml version="1.1">
         <join id1="conn:jd87dfg4h" id2="conf:exampleConf">
            <stream media="audio" dir="from-id1">
                <gain agc="true" tgtlvl="-20"/>
            </stream>
            <stream media="audio" dir="to-id1"/>
      </msml>

   Step 17: successfully joined to conference



      <msml version="1.1">
         <result response="200"/>
      </msml>

   Steps 6 through 17 are repeated for the second participant.





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   Step 18: play a join tone or message announcing the new participant
   to the conference.



      <msml version="1.1">

         <dialogstart target="conf:exampleConf"

             type="application/vxml+xml"

             src="http://server.example.com/scripts/joinmsg.vxml"/>

      </msml>

   Step 19: dialog started successfully. The dialog identifier is
   returned. Media Server assigned a unique identifier since name
   attribute was not specified in <dialogstart>.



      <msml version="1.1">
         <result response="200"/>
         <dialogid>conf:ExampleConf/dialog:j6fs8745</dialogid>
      </msml>

   Step 20: HTTP VoiceXML dialog interaction(s).



   Step 21: the VoiceXML browser exits.



      <msml version="1.1">
         <event name="msml.dialog.exit"
                id="conf:ExampleConf/dialog:j6fs8745"/>
      </msml>

   Steps 6 through 21 are repeated for the third and subsequent
   participants.

12.2 Example of a Sidebar Audio Conference

   This example assumes that a conference has already been established
   as in the previous example. It creates a sidebar conference that
   hears the main conference as a whisper. Three participants are moved



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   to the sidebar. After some period of time, the sidebar participants
   are returned to the main conference and the sidebar is deleted.

   Step1: the sidebar conference is created. It is joined half-duplex to
   the main conference and a manual gain object is inserted in the media
   stream. Three participants are then moved from the main conference to
   the sidebar. Although not shown, an CA could include the "mark"
   attribute in each element to allow recovery in the event of a mid-
   transaction error.

      <msml version="1.1">
         <createconference name="sidebarConf"
                           deletewhen="nomedia">
             <audiomix/>
         </createconference>
         <join id1="conf:sidebarConf" id2="conf:exampleConf">
             <stream media="audio" dir="to-id1">
                 <gain amt="-20"/>
             </stream>
         </join>
         <unjoin id1="conn:gs5s4-1" id2="conf:exampleConf"/>
         <join id1="conn:gs5s4-1" id2="conf:sidebarConf"/>
         <unjoin id1="conn:hd764gr9-2" id2="conf:exampleConf"/>
         <join id1="conn:hd764gr9-2" id2="conf:sidebarConf"/>
         <unjoin id1="conn:h37frdvgs65-3" id2="conf:exampleConf"/>
         <join id1="conn:h37frdvgs65-3" id2="conf:sidebarConf"/>
      </msml>

   Step 2: sidebar conference created successfully and participants
   joined.

      <msml version="1.1">
         <result response="200"/>
      </msml>

   Step 3: once the sidebar conference has completed, the participants
   are rejoined to the main conference. The sidebar is destroyed
   automatically by the MS when the last media stream is removed as
   specified when the sidebar conference was created.

      <msml version="1.1">
         <unjoin id1="conn:gs5s4-1" id2="conf:sidebarConf"/>
         <join id1="conn:gs5s4-1" id2="conf:exampleConf"/>
         <unjoin id1="conn:hd764gr9-2" id2="conf:sidebarConf"/>
         <join id1="conn:hd764gr9-2" id2="conf:exampleConf"/>
         <unjoin id1="conn:h37frdvgs65-3" id2="conf:sidebarConf"/>
         <join id1="conn:h37frdvgs65-3" id2="conf:exampleConf"/>
      </msml>


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   Step 4: participants successfully moved to main conference and
   sidebar destroyed.

      <msml version="1.1">
         <result response="200"/>
      </msml>

12.3 Example of Removing a Conference

   This example assumes a conference created similar to the first
   example where there is an MSML control channel specific to the
   conference and the conference has been configured to be deleted when
   that channel is removed (using SIP).



   Steps 1-2: the CA signals BYE for the SIP dialog used to establish
   the conference control channel.

   Steps 3-6: the MS initiates terminating the media sessions for each
   participant remaining in the conference.



   The MS deletes the conference and removes all resources when the last
   participant has been removed.

12.4 Example of Modifying Video Layout

   Assume that a conference named "example" is created using the
   following mixer descriptions.



             +---+---+
             | 1 | 2 |
             +---+---+
             | 3 | 4 |
             +---+---+


         <createconference name="quad-split">
            <audiomix>
               <n-loudest n="3"/>
               <asn ri="10s"/>
            </audiomix>
            <videolayout>


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               <root size="CIF" background="white" />
               <selector id="default" method="vas" si="500ms">
                  <region id="1" left="0" top="0" size="1/4"/>
               </selector>
               <region id="2" left="50%" top="0" size="1/4"/>
               <region id="3" left="0%" top="50%" size="1/4">
               <region id="4" left="50%" top="50%" size="1/4"/>
            </videolayout>
         </createconference>

   The following would change the size of the video window to QCIF and
   the background color to the default "black".


         <modifyconference id="conf:example">
            <videolayout>
               <root size="4CIF"/>
            </videolayout>
         </modifyconference>

   The relative location of the regions does not change. However the
   sizes of the regions do change because they are relative to the size
   of the root window. The result is a layout that looks identical but
   half the size.

   The following would freeze the video displayed in region "2" without
   affecting any other attributes of that region.


         <modifyconference id="conf:example">
            <videolayout>
               <region id="2" left="50%" top="0" size="1/4"
                              freeze="true"/>
            </videolayout>
         </modifyconference>

13. MSML Dialog Examples

   These examples focus on the MSML Dialog Base package and the MSML
   Dialog Group package.

13.1 Announcement

   The following is a simple announcement scenario. Two recorded audio
   files are played in sequence followed by generated speech followed by
   a variable. The results are reported once media generation completes.

   <?xml version="1.0" encoding="UTF-8"?>


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   <msml version="1.1">
      <dialogstart target=”conn:12345” name=”12345”>
         <play>
            <audio uri="file://clip1.wav"/>
            <audio uri="http://host1/clip2.wav"/>
            <tts uri="http://host2/text.ssml"/>
            <var type="date" subtype="mdy" value="20030601"/>
         </play>
         <send target="source" event="done" namelist="play.amt
                                            play.end"/>
      </dialogstart>
   </msml>

13.2 Voice Mail Retrieval

   Below is an example which shows a simple voice mail retrieval
   operation consisting of playing a message and allowing the user to
   pause and resume play using '5' to toggle the state. The operation
   would terminate when the play completed or the user entered '#'.
   During the play, the user can advance forward and backward through
   the message as well as rewinding to the beginning.

   <?xml version="1.0" encoding="UTF-8"?>
   <msml version="1.1">
     <dialogstart target=”conn:12345” name=”12345”>
      <group topology="parallel">
         <play>
            <audio uri="file://message.wav"/>
            <playexit>
               <send target="group" event="terminate"/>
            </playexit>
         </play>
         <dtmf iterate="forever">
            <pattern digits="5">
               <send target="play" event="toggle-state"/>
            </pattern>
            <pattern digits="6">
               <send target="play" event="forward"/>
            </pattern>
            <pattern digits="7">
               <send target="play" event="backward"/>
            </pattern>
            <pattern digits="8">
               <send target="play" event="restart"/>
            </pattern>
            <pattern digits="#">
               <send target="play" event="terminate"/>
            </pattern>


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         </dtmf>
      </group>
    </dialogsgtart>
   </msml>

13.3 Play and Record

   A more complex example is a play and record operation. This sources
   and sinks media and uses voice activity DTMF detection and
   recognition to influence behavior. Any DTMF input or voice activity
   will barge the play and cause the record to begin. However, if the
   prompt was barged with a DTMF digit of '#', the record terminates
   without starting. When the play terminates, it send a starttimer
   event to the VAD to allow it to recognize an initial silence
   condition. The recording will be terminated (without starting) when
   the VAD detects an initial 3 seconds of silence.

   Once resumed (based upon voice detection) the recording may be
   terminated under several conditions. It will terminate after 5
   seconds of silence or after 60 seconds elapses. It will also
   terminate if a '#' key is recognized. Every aspect of this behavior
   can be modified by changing what is recognized and the events which
   are sent. The following example uses the MSML Dialog Group package.

   <?xml version="1.0" encoding="UTF-8"?>
   <msml  version="1.1">
    <dialogstart target=”conn:12345” name=”12345”>
      <group topology="parallel">
         <play>
            <audio uri="file://prompt.wav"/>
            <playexit>
               <send target="vad" event="starttimer"/>
            </playexit>
         </play>
         <dtmf>
            <pattern digits="#">
               <send target="record" event="terminate.termkey"/>
            </pattern>
            <detect>
               <send target="play" event="terminate"/>
            </detect>
         </dtmf>
         <vad>
            <voice len="10ms">
               <send target="play" event="terminate"/>
               <send target="record" event="resume"/>
            </voice>
            <silence len="3s">


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               <send target="record" event="nospeech"/>
            </silence>
            <tsilence len="5s">
               <send target="record" event="terminate.finalsilence"/>
            </tsilence>
         </vad>
         <record initial="suspend" maxtime="60s"
                 dest="file://record.wav" format="g729">
            <recordexit>
               <send target="group" event="terminate"/>
            </recordexit>
         </record>
         <groupexit>
            <send target="source" event="done"
                  namelist="record.len record.end"/>
         </groupexit>
      </group>
    </dialogstart>
   </msml>

   The following implements the same functionality, as described above,
   in using the MSML Dialog Base package, using the <record> composite
   mechanism for the play and record operation.

   <?xml version="1.0" encoding="UTF-8"?>
   <msml  version="1.1">
    <dialogstart target=”conn:12345” name=”12345”>
      <record prespeech=”3s” postspeech=”5s” maxtime="60s" termkey=”#”
                 dest="file://record.wav" format="g729">
         <play barge=”true”>
            <audio uri="file://prompt.wav"/>
         </play>
         <recordexit>
            <send target="source" event="done"
                  namelist="record.len record.end"/>
         </recordexit>
      </record>
    </dialogstart>
   </msml>

13.4 Speech Recognition

   The following simple example requests that a user speak the name of a
   city and returns the result.

   <?xml version="1.0" encoding="UTF-8"?>
   <msml version="1.1">
    <dialogstart target=”conn:12345” name=”12345”>


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      <group topology="parallel">
         <play>
            <audio uri="file://prompt.wav"/>
         </play>
         <speech>
            <grammar version="1.0">
               <rule id="city" scope="public">
                  <item>
                     <one-of>
                        <item>vancouver</item>
                        <item>new york</item>
                        <item>london</item>
                     </one-of>
                  </item>
               </rule>
               <match>
                  <send target="group" event="terminate"/>
               </match>
            </grammar>
            <noinput>
               <send target="group" event="terminate"/>
            </noinput>
            <nomatch>
               <send target="group" event="terminate"/>
            </nomatch>
         </speech>
         <groupexit>
            <send target="source" event="done"
                          namelist="speech.end speech.results"/>
         </groupexit>
      </group>
    </dialogstart>
   </msml>

13.5 Play and Collect

   This example prompts a user to enter 4 DTMF digits terminated by the
   '#' key. The prompt will be barged and the user has 10 seconds to
   begin entering input or no input will be indicated.

   <?xml version="1.0" encoding="UTF-8"?>
   <msml version="1.1">
    <dialogstart target=”conn:12345” name=”12345”>
      <group topology="parallel">
         <play>
            <audio uri="file://prompt.wav"/>
            <playexit>
               <send target="dtmf" event="starttimer"/>


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            </playexit>
         </play>
         <dtmf fdt="10s" idt="16s">
            <pattern digits="xxxx#">
               <send target="group" event="terminate"/>
            </pattern>
            <detect>
               <send target="play" event="terminate"/>
            </detect>
            <noinput>
               <send target="group" event="terminate"/>
            </noinput>
            <nomatch>
               <send target="group" event="terminate"/>
            </nomatch>
         </dtmf>
         <groupexit>
            <send target="source" event="done"
                  namelist="dtmf.digits dtmf.end"/>
         </groupexit>
      </group>
    </dialogstart>
   </msml>

   The following implements the same functionality, as described above,
   using the MSML Dialog Base package, using the <collect> composite
   mechanism for the play and collect operation.

   <?xml version="1.0" encoding="UTF-8"?>
   <msml version="1.1">
    <dialogstart target=”conn:12345” name=”12345”>

      <collect fdt="10s" idt="16s">
         <play barge=”true”>
            <audio uri="file://prompt.wav"/>
         </play>
         <pattern digits="xxxx#">
            <send target="source" event="done"
                  namelist="dtmf.digits dtmf.end"/>
         </pattern>
         <noinput>
            <send target="source" event="done"
                  namelist="dtmf.end"/>
         </noinput>
         <nomatch>
            <send target="source" event="done"
                  namelist="dtmf.end"/>
         </nomatch>


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      </dtmf>
    </dialogstart>
   </msml>

13.6 User Controlled Gain

   This shows an example of nesting groups to create an arbitrary full
   duplex media control. DTMF is detected on media flowing in one
   direction and used to adjust the gain applied to media flowing in the
   opposite direction. Additionally, the stream which is used to detect
   DTMF has DTMF removed and its gain automatically adjusted before
   leaving the group. This widget could be used between a conference
   participant and a conference mixer.

   <?xml version="1.0" encoding="UTF-8"?>
   <msml  version="1.0">
    <dialogstart target=”conn:12345” name=”12345”>
      <group topology="fullduplex">
         <group topology="parallel">
            <dtmf>
               <pattern digits="1" iterate="forever">
                  <send target="gain" event="louder"/>
               </pattern>
               <pattern digits="2" iterate="forever">
                  <send target="gain" event="softer"/>
               </pattern>
            </dtmf>
            <group topology="serial">
               <clamp/>
               <agc tgtlvl="0"/>
            </group>
         </group>
         <gain amt="0" incr="5"/>
      </group>
    </dialogstart>
   </msml>

14. Change Summary

   MSML-00 is an initial draft, however it is derived from draft-
   melanchuk-sipping-msml-06 [22] and draft-melanchuk-sipping-moml-06
   [23]. Earlier versions of these specifications were co-authored by
   Tim Melanchuk (while he was an employee of Convedia) and Garland
   Sharratt. All functionality supported in [22] and [23] is supported
   within this MSML specification, no new functionality is introduced in
   this initial version, and there are no XML or SIP interface changes
   introduced, allowing MSML-00 client/server implementations to be
   fully compatible with implementations based on [22] and [23]. This


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   specification completely replaces earlier internet drafts MSML [22]
   and MOML [23].

   Additional sample scripts added and includes minor wording
   corrections.

   Previous versions of MSML specification are defined in this internet
   draft as MSML Core and MSML Conference Core packages.

   Previous versions of MOML specification are defined in this internet
   draft as MSML Dialog Core, MSML Dialog Base, and all other MSML
   Dialog packages.



15. Future Work

   The following capabilities may be added in future versions of this
   draft:

      o Ability for MSML clients to audit or query the Media Server for
         supported set of MSML packages and profiles.

      O Ability for MSML clients to perform state auditing of current
         resources allocated and in use by the Media Server.

      o Ability to version MSML packages and profiles and naming scheme
         for MSML extension packages.

16. XML Schema - MSML Core and MSML Conference Core Packages

   The MSML schema uses one core schema which defines the MSML
   Conference Core package and which includes two other schemas; one
   defines the MSML datatypes, the other defines the MSML Dialog
   packages.



   The schema including MSML Core package and MSML Conference Core
   package is:

   <?xml version="1.0" encoding="UTF-8"?>
   <xs:schema elementFormDefault="qualified"
              attributeFormDefault="unqualified"
              xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xs:include schemaLocation="moml.xsd"/>
    <xs:include schemaLocation="msml-datatypes.xsd"/>
    <xs:element name="msml">


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     <xs:complexType>
      <xs:choice>
       <xs:group ref="msmlRequest" maxOccurs="unbounded"/>
       <xs:element name="event">
        <xs:complexType>
         <xs:choice maxOccurs="unbounded">
          <xs:sequence>
           <xs:element name="name" type="msmlEventNameValue.datatype"/>
           <xs:element name="value">
            <xs:simpleType>
             <xs:restriction base="xs:string">
              <xs:pattern value="[a-zA-Z0-9.]+"/>
             </xs:restriction>
            </xs:simpleType>
           </xs:element>
          </xs:sequence>
         </xs:choice>
         <xs:attribute name="name" type="msmlEventName.datatype"
                       use="required"/>
         <xs:attribute name="id" type="msmlEventSource.datatype"
                       use="required"/>
        </xs:complexType>
       </xs:element>
       <xs:element name="result">
        <xs:complexType>
         <xs:sequence>
          <xs:element name="description" minOccurs="0">
           <xs:simpleType>
            <xs:restriction base="xs:string">
             <xs:pattern value="[a-zA-Z0-9.-_]+"/>
            </xs:restriction>
           </xs:simpleType>
          </xs:element>
          <xs:choice minOccurs="0" maxOccurs="unbounded">
           <xs:element name="confid" type="confID.datatype"/>
           <xs:element name="dialogid" type="dialogID.datatype"/>
          </xs:choice>
         </xs:sequence>
         <xs:attribute name="response">
          <xs:simpleType>
           <xs:restriction base="xs:string">
            <xs:pattern value="\d{3}"/>
           </xs:restriction>
          </xs:simpleType>
         </xs:attribute>
         <xs:attribute name="mark" type="mark.datatype"/>
        </xs:complexType>
       </xs:element>


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      </xs:choice>
      <xs:attribute name="version" type="xs:string"
                    use="required" fixed="1.1"/>
     </xs:complexType>
    </xs:element>
    <xs:group name="msmlRequest">
     <xs:choice>
      <xs:element name="createconference">
       <xs:complexType>
        <xs:all>
         <xs:element name="audioMix" type="audioMixType"/>
         <xs:element name="videoLayout" type="videoLayoutType"/>
         <xs:element name="reserve">
          <xs:complexType>
           <xs:sequence>
            <xs:element name="resource" maxOccurs="unbounded">
             <xs:complexType>
              <xs:sequence>
               <xs:any namespace="##other" processContents="lax"
                       minOccurs="0" maxOccurs="unbounded"/>
              </xs:sequence>
              <xs:attribute name="n" type="xs:positiveInteger"
                            default="1"/>
              <xs:anyAttribute namespace="##any"/>
             </xs:complexType>
            </xs:element>
           </xs:sequence>
           <xs:attribute name="required"
                         type="boolean.datatype" default="true"/>
          </xs:complexType>
         </xs:element>
        </xs:all>
        <xs:attribute name="name" type="msmlInstanceID.datatype"/>
        <xs:attribute name="deletewhen" default="never">
         <xs:simpleType>
          <xs:restriction base="xs:string">
           <xs:enumeration value="nomedia"/>
           <xs:enumeration value="nocontrol"/>
           <xs:enumeration value="never"/>
          </xs:restriction>
         </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="term" type="boolean.datatype"
                      default="true"/>
        <xs:attribute ref="mark"/>
       </xs:complexType>
      </xs:element>
      <xs:element name="modifyconference">


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       <xs:complexType>
        <xs:all>
         <xs:element name="audioMix" type="audioMixType" minOccurs="0"/>
         <xs:element name="videoLayout" type="videoLayoutType"
                     minOccurs="0"/>
        </xs:all>
        <xs:attribute name="id" type="confID.datatype" use="required"/>
        <xs:attribute ref="mark"/>
       </xs:complexType>
      </xs:element>
      <xs:element name="destroyconference">
       <xs:complexType>
        <xs:all>
         <xs:element name="audioMix" type="basicAudioMixType"
                     minOccurs="0"/>
         <xs:element name="videoLayout"
                     type="basicVideoLayoutType" minOccurs="0"/>
        </xs:all>
        <xs:attribute name="id" type="confID.datatype" use="required"/>
        <xs:attribute ref="mark"/>
       </xs:complexType>
      </xs:element>
      <xs:element name="dialogstart">
       <xs:complexType>
        <xs:sequence>
         <xs:group ref="momlRequest"/>
         <xs:group ref="sendType" minOccurs="0"/>
        </xs:sequence>
        <xs:attribute name="target"
                      type="independentID.datatype" use="required"/>
        <xs:attribute name="type"
                      type="dialogLanguage.datatype" use="required"/>
        <xs:attribute name="name" type="msmlInstanceID.datatype"/>
        <xs:attribute name="src" type="xs:anyURI" use="optional"/>
        <xs:attribute ref="mark"/>
       </xs:complexType>
      </xs:element>
      <xs:element name="dialogend">
       <xs:complexType>
        <xs:attribute name="id" type="dialogID.datatype"
                      use="required"/>
        <xs:attribute ref="mark"/>
       </xs:complexType>
      </xs:element>
      <xs:element name="join">
       <xs:complexType>
        <xs:sequence>
         <xs:element name="stream" type="streamType"


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                     minOccurs="0" maxOccurs="4"/>
        </xs:sequence>
        <xs:attribute name="id1" type="independentID.datatype"
                      use="required"/>
        <xs:attribute name="id2" type="independentID.datatype"
                      use="required"/>
        <xs:attribute ref="mark"/>
       </xs:complexType>
      </xs:element>
      <xs:element name="modifystream">
       <xs:complexType>
        <xs:sequence>
         <xs:element name="stream" type="streamType" maxOccurs="4"/>
        </xs:sequence>
        <xs:attribute name="mark" type="mark.datatype"/>
       </xs:complexType>
      </xs:element>
      <xs:element name="unjoin">
       <xs:complexType>
        <xs:sequence>
         <xs:element name="stream" type="basicStreamType"
                     minOccurs="0" maxOccurs="4"/>
        </xs:sequence>
        <xs:attribute name="id1" type="independentID.datatype"
                      use="required"/>
        <xs:attribute name="id2" type="independentID.datatype"
                      use="required"/>
        <xs:attribute ref="mark"/>
       </xs:complexType>
      </xs:element>
      <xs:element name="monitor">
       <xs:complexType>
        <xs:attribute name="id1" type="connID.datatype" use="required"/>
        <xs:attribute name="id2" type="independentID.datatype"
                      use="required"/>
        <xs:attribute name="compressed"
                      type="boolean.datatype" default="false"/>
        <xs:attribute ref="mark"/>
       </xs:complexType>
      </xs:element>
      <xs:element name="send">
       <xs:complexType>
        <xs:attribute name="event" type="msmlEvent.datatype"
                      use="required"/>
        <xs:attribute name="target" type="msmlTarget.datatype"
                      use="required"/>
        <xs:attribute name="valuelist" type="xs:string"/>
        <xs:attribute ref="mark"/>


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       </xs:complexType>
      </xs:element>
     </xs:choice>
    </xs:group>
    <xs:complexType name="basicStreamType">
     <xs:attribute name="dir">
      <xs:simpleType>
       <xs:restriction base="xs:string">
        <xs:enumeration value="to-id1"/>
        <xs:enumeration value="from-id1"/>
       </xs:restriction>
      </xs:simpleType>
     </xs:attribute>
     <xs:attribute name="media">
      <xs:simpleType>
       <xs:restriction base="xs:string">
        <xs:enumeration value="audio"/>
        <xs:enumeration value="video"/>
       </xs:restriction>
      </xs:simpleType>
     </xs:attribute>
    </xs:complexType>
    <xs:complexType name="streamType">
     <xs:complexContent>
      <xs:extension base="basicStreamType">
       <xs:choice minOccurs="0" maxOccurs="unbounded">
        <xs:element name="gain">
         <xs:complexType>
          <xs:attribute name="amt" use="optional">
           <xs:simpleType>
            <xs:restriction base="xs:integer">
             <xs:minInclusive value="-96"/>
             <xs:maxInclusive value="96"/>
            </xs:restriction>
           </xs:simpleType>
          </xs:attribute>
          <xs:attribute name="agc" type="boolean.datatype"/>
          <xs:attribute name="tgtlvl" use="optional">
           <xs:simpleType>
            <xs:restriction base="xs:nonPositiveInteger">
             <xs:minInclusive value="-40"/>
             <xs:maxInclusive value="0"/>
            </xs:restriction>
           </xs:simpleType>
          </xs:attribute>
          <xs:attribute name="maxgain" default="10">
           <xs:simpleType>
            <xs:restriction base="xs:nonNegativeInteger">


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             <xs:minInclusive value="0"/>
             <xs:maxInclusive value="40"/>
            </xs:restriction>
           </xs:simpleType>
          </xs:attribute>
         </xs:complexType>
        </xs:element>
        <xs:element name="clamp">
         <xs:complexType>
          <xs:attribute name="dtmf" type="boolean.datatype"/>
          <xs:attribute name="tones" type="boolean.datatype"/>
         </xs:complexType>
        </xs:element>
        <xs:element name="visual"/>
       </xs:choice>
       <xs:attribute name="preferred" type="boolean.datatype"/>
       <xs:attribute name="display" type="xs:string"/>
      </xs:extension>
     </xs:complexContent>
    </xs:complexType>
    <xs:complexType name="basicAudioMixType">
     <xs:attribute name="id" type="xs:string" use="required"/>
    </xs:complexType>
    <xs:complexType name="audioMixType">
     <xs:complexContent>
      <xs:extension base="basicAudioMixType">
       <xs:all>
        <xs:element name="asn" minOccurs="0">
         <xs:complexType>
          <xs:attribute name="ri" type="posDuration.datatype"/>
         </xs:complexType>
        </xs:element>
        <xs:element name="n-loudest" minOccurs="0">
         <xs:complexType>
          <xs:attribute name="n" type="xs:positiveInteger"
                        use="required"/>
         </xs:complexType>
        </xs:element>
       </xs:all>
      </xs:extension>
     </xs:complexContent>
    </xs:complexType>
    <xs:complexType name="basicVideoLayoutType">
     <xs:attribute name="id" type="xs:string" use="required"/>
     <xs:attribute name="type" type="xs:string"
                   use="required" fixed="text/msml-basic-layout"/>
    </xs:complexType>
    <xs:complexType name="videoLayoutType">


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     <xs:complexContent>
      <xs:extension base="basicVideoLayoutType">
       <xs:choice>
        <xs:element name="selector">
         <xs:complexType>
          <xs:complexContent>
           <xs:extension base="selectorType">
            <xs:sequence>
             <xs:element name="root" type="rootType"/>
            </xs:sequence>
           </xs:extension>
          </xs:complexContent>
         </xs:complexType>
        </xs:element>
        <xs:sequence>
         <xs:element name="root" type="rootType"/>
         <xs:choice maxOccurs="unbounded">
          <xs:element name="selector" minOccurs="0"
                      maxOccurs="unbounded">
           <xs:complexType>
            <xs:complexContent>
             <xs:extension base="selectorType">
              <xs:sequence>
               <xs:element name="region"/>
              </xs:sequence>
             </xs:extension>
            </xs:complexContent>
           </xs:complexType>
          </xs:element>
          <xs:element name="region" minOccurs="0" maxOccurs="unbounded">
           <xs:complexType>
            <xs:complexContent>
             <xs:extension base="regionType"/>
            </xs:complexContent>
           </xs:complexType>
          </xs:element>
         </xs:choice>
        </xs:sequence>
       </xs:choice>
      </xs:extension>
     </xs:complexContent>
    </xs:complexType>
    <xs:complexType name="regionType">
     <xs:attribute name="id" type="xs:string" use="required"/>
     <xs:attribute name="left" type="xs:positiveInteger"/>
     <xs:attribute name="top" type="xs:positiveInteger"/>
     <xs:attribute name="relativeSize">
      <xs:simpleType>


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       <xs:restriction base="xs:string">
        <xs:enumeration value="1/4"/>
        <xs:enumeration value="1/3"/>
        <xs:enumeration value="2/3"/>
        <xs:enumeration value="3/4"/>
        <xs:enumeration value="1"/>
       </xs:restriction>
      </xs:simpleType>
     </xs:attribute>
     <xs:attribute name="priority">
      <xs:simpleType>
       <xs:restriction base="xs:float">
        <xs:minInclusive value="0"/>
        <xs:maxExclusive value="1"/>
       </xs:restriction>
      </xs:simpleType>
     </xs:attribute>
     <xs:attribute name="title" type="xs:string"/>
     <xs:attribute name="titleTextColor" type="xs:string"/>
     <xs:attribute name="titleBackgroundColor" type="xs:string"/>
     <xs:attribute name="borderColor" type="xs:string"/>
     <xs:attribute name="borderWidth" type="xs:positiveInteger"/>
     <xs:attribute name="logo" type="xs:anyURI"/>
    </xs:complexType>
    <xs:complexType name="selectorType">
     <xs:attribute name="id" type="xs:string" use="required"/>
     <xs:attribute name="method" use="required">
      <xs:simpleType>
       <xs:restriction base="xs:string">
        <xs:enumeration value="vas"/>
        <xs:enumeration value="sequence"/>
       </xs:restriction>
      </xs:simpleType>
     </xs:attribute>
     <xs:attribute name="status" default="active">
      <xs:simpleType>
       <xs:restriction base="xs:string">
        <xs:enumeration value="active"/>
        <xs:enumeration value="disabled"/>
       </xs:restriction>
      </xs:simpleType>
     </xs:attribute>
     <xs:attribute name="si" type="posDuration.datatype" default="1s"/>
     <xs:attribute name="blankothers" type="xs:boolean"
                   default="false"/>
     <xs:attribute name="speakersees" default="current">
      <xs:simpleType>
       <xs:restriction base="xs:string">


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        <xs:enumeration value="current"/>
        <xs:enumeration value="previous"/>
       </xs:restriction>
      </xs:simpleType>
     </xs:attribute>
    </xs:complexType>
    <xs:complexType name="rootType">
     <xs:attribute name="size" default="CIF">
      <xs:simpleType>
       <xs:restriction base="xs:string">
        <xs:enumeration value="16CIF"/>
        <xs:enumeration value="4CIF"/>
        <xs:enumeration value="CIF"/>
        <xs:enumeration value="QCIF"/>
       </xs:restriction>
      </xs:simpleType>
     </xs:attribute>
     <xs:attribute name="backgroundcolor" type="xs:string"
                   default="black"/>
     <xs:attribute name="backgroundimage" type="xs:anyURI"/>
    </xs:complexType>
    <xs:attribute name="mark" type="mark.datatype"/>
   </xs:schema>


   Following schema defines the basic MSML datatypes used by the schema
   defined above. Note that several regular expressions required them to
   be split across two lines for formatting reasons.



   <?xml version="1.0" encoding="UTF-8"?>
   <xs:schema elementFormDefault="qualified"
              attributeFormDefault="unqualified"
              xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xs:simpleType name="conferenceType.datatype">
     <xs:restriction base="xs:string">
      <xs:enumeration value="audio.basic"/>
      <xs:enumeration value="audio.advanced"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="msmlInstanceID.datatype">
     <xs:restriction base="xs:string">
      <xs:pattern value="[a-zA-Z0-9.:-_]+"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="connID.datatype">
     <xs:restriction base="xs:string">


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      <xs:pattern value="conn:[a-zA-Z0-9.:-_]+"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="confID.datatype">
     <xs:restriction base="xs:string">
      <xs:pattern value="conf:[a-zA-Z0-9.:-_]+"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="operatorID.datatype">
     <xs:restriction base="xs:string">
      <xs:pattern value="conf:[a-zA-Z0-9.:-_]+"/>
      <xs:pattern value="conn:[a-zA-Z0-9.:-_]+"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="dialogID.datatype">
     <xs:restriction base="xs:string">
      <xs:pattern value="conf:[a-zA-Z0-9.:-_]+/dialog:[a-zA-Z0-9.:-
   _]+"/>
      <xs:pattern value="conn:[a-zA-Z0-9.:-_]+/dialog:[a-zA-Z0-9.:-
   _]+"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="independentID.datatype">
     <xs:restriction base="xs:string">
      <xs:pattern value="conf:[a-zA-Z0-9.:-_]+"/>
      <xs:pattern value="conn:[a-zA-Z0-9.:-_]+"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="duplex.datatype">
     <xs:restriction base="xs:string">
      <xs:enumeration value="half"/>
      <xs:enumeration value="full"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="confclass.datatype">
     <xs:restriction base="xs:string">
      <xs:enumeration value="standard"/>
      <xs:enumeration value="preferred"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="dialogLanguage.datatype">
     <xs:restriction base="xs:string">
      <xs:enumeration value="application/moml+xml"/>
      <xs:enumeration value="application/voicexml+xml"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="msmlEvent.datatype">
     <xs:restriction base="xs:string"/>


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    </xs:simpleType>
    <xs:simpleType name="msmlEventName.datatype">
     <xs:restriction base="xs:string">
      <xs:pattern value="msml.dialog.exit"/>
      <xs:pattern value="msml.conf.asn"/>
      <xs:pattern value="msml.conf.nomedia"/>
      <xs:pattern value="msml.dialog.exit"/>
      <xs:pattern value="[a-zA-Z0-9.:_-]+"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="msmlTarget.datatype">
     <xs:restriction base="xs:string">
      <xs:pattern value="conf:[a-zA-Z0-9.:_-]+(/oper:[a-zA-Z0-9.:_-
   ]+|\*)*"/>
      <xs:pattern value="conn:[a-zA-Z0-9.:_-]+(/oper:[a-zA-Z0-9.:_-
   ]+|\*)+"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="msmlEventSource.datatype">
     <xs:restriction base="xs:string">
      <xs:pattern value="conf:[a-zA-Z0-9.:_-]+"/>
      <xs:pattern
       value="(conf:[a-zA-Z0-9.:_-]+|conn:[a-zA-Z0-9.:_-]+)
             /dialog:[a-zA-Z0-9.:_-]+"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="msmlEventNameValue.datatype">
     <xs:restriction base="xs:string"/>
    </xs:simpleType>
    <xs:simpleType name="mark.datatype">
     <xs:restriction base="xs:string">
      <xs:pattern value="[a-zA-Z0-9.:-_]+"/>
     </xs:restriction>
    </xs:simpleType>
   </xs:schema>

17. XML Schema – MSML Dialog/Transform/Speech/Fax Packages

   The following set of schemas collectively define the MSML Dialog
   packages.



   Note: the following schema is only needed when use of root element
   <moml> is required.

   <?xml version="1.0" encoding="UTF-8"?>
   <xs:schema elementFormDefault="unqualified"


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      attributeFormDefault="unqualified"
      xmlns:xs="http://www.w3.org/2001/XMLSchema">
     <xs:include schemaLocation="moml-group-module.xsd"/>
     <xs:include schemaLocation="moml-basic-primitives-module.xsd"/>
     <xs:include schemaLocation="moml-transform-primitives-module.xsd"/>
     <xs:include schemaLocation="moml-speech-module.xsd"/>
     <xs:element name="moml">
      <xs:complexType>
         <xs:choice>
            <xs:group ref="momlRequest"/>
            <xs:element ref="event"/>
         </xs:choice>
         <xs:attribute name="version" type="xs:string"
             use="required" fixed="1.0"/>
         <xs:attribute name="id" type="momlID.datatype" use="required"/>
      </xs:complexType>
   </xs:element>
   </xs:schema>


   Following is the schema which defines the MSML Dialog datatypes
   (moml-datatypes.xsd). It is included by each of the other MSML Dialog
   packages.

   <?xml version="1.0" encoding="UTF-8"?>
   <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
              elementFormDefault="qualified"
              attributeFormDefault="unqualified">
    <xs:simpleType name="momlID.datatype">
     <xs:restriction base="xs:string">
      <xs:pattern value="[a-zA-Z0-9][a-zA-Z0-9._\-]*"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="momlEvent.datatype">
     <xs:restriction base="xs:string">
      <xs:pattern value="[a-zA-Z0-9][a-zA-Z0-9._\-]*"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="momlNamelist.datatype">
     <xs:restriction base="xs:string"/>
    </xs:simpleType>
    <xs:simpleType name="dtmfDigits.datatype">
     <xs:restriction base="xs:string">
      <xs:pattern value="[0-9#*]+"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="iterate.datatype">
     <xs:union memberTypes="xs:positiveInteger">


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      <xs:simpleType>
       <xs:restriction base="xs:negativeInteger">
        <xs:minInclusive value="-1"/>
       </xs:restriction>
      </xs:simpleType>
      <xs:simpleType>
       <xs:restriction base="xs:string">
        <xs:enumeration value="forever"/>
       </xs:restriction>
      </xs:simpleType>
     </xs:union>
    </xs:simpleType>
    <xs:simpleType name="momlTarget.datatype">
     <xs:restriction base="xs:string">
      <xs:pattern value="[a-zA-Z0-9][a-zA-Z0-9._\-]*"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="boolean.datatype">
     <xs:restriction base="xs:string">
      <xs:enumeration value="true"/>
      <xs:enumeration value="false"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="duration.datatype">
     <xs:restriction base="xs:string">
      <xs:pattern value="(\+|\-)?([0-9]*\.)?[0-9]+(ms|s)"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="posDuration.datatype">
     <xs:restriction base="xs:string">
      <xs:pattern value="(\+)?([0-9]*\.)?[0-9]+(ms|s)"/>
     </xs:restriction>
    </xs:simpleType>
   </xs:schema>


   Following is the schema which defines the Dialog core package (moml-
   core-module.xsd). It is included by each of the other MSML Dialog
   packages.

   <?xml version="1.0" encoding="UTF-8"?>
   <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
      elementFormDefault="unqualified"
      attributeFormDefault="unqualified">
    <xs:include schemaLocation="moml-datatypes.xsd"/>
    <xs:group name="momlRequest">
     <xs:choice maxOccurs="unbounded">
      <xs:group ref="executeType"/>


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      <xs:element ref="send" maxOccurs="unbounded"/>
     </xs:choice>
    </xs:group>
    <xs:element name="primitive" type="primitiveType" abstract="true"/>
    <xs:complexType name="primitiveType">
     <xs:attribute name="id" type="momlID.datatype"/>
    </xs:complexType>
    <xs:element name="control" abstract="true"/>
    <xs:group name="executeType">
     <xs:choice maxOccurs="unbounded">
      <xs:element ref="primitive"/>
      <xs:element ref="control"/>
     </xs:choice>
    </xs:group>
    <xs:group name="sendType">
     <xs:choice>
      <xs:choice>
       <xs:element name="exit" type="exitType"/>
       <xs:element name="disconnect" type="exitType"/>
      </xs:choice>
      <xs:sequence>
       <xs:element ref="send" maxOccurs="unbounded"/>
       <xs:choice minOccurs="0">
        <xs:element name="exit" type="exitType"/>
        <xs:element name="disconnect" type="exitType"/>
       </xs:choice>
      </xs:sequence>
     </xs:choice>
    </xs:group>
    <xs:element name="send">
     <xs:complexType>
      <xs:attribute name="event" type="momlEvent.datatype"
          use="required"/>
      <xs:attribute name="target" type="momlTarget.datatype"
          use="required"/>
      <xs:attribute name="namelist" type="momlNamelist.datatype"/>
     </xs:complexType>
    </xs:element>
    <xs:complexType name="exitType">
     <xs:attribute name="namelist" type="momlNamelist.datatype"/>
    </xs:complexType>
    <xs:element name="event">
     <xs:complexType>
      <xs:sequence maxOccurs="unbounded">
       <xs:element name="name" type="xs:string"/>
       <xs:element name="value" type="xs:string"/>
      </xs:sequence>
      <xs:attribute name="name" type="xs:string" use="required"/>


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      <xs:attribute name="id" type="xs:string" use="required"/>
     </xs:complexType>
    </xs:element>
   </xs:schema>


   The schema for the MSML Dialog Base package (moml-basic-primitives-
   module.xsd) is:

   <?xml version="1.0" encoding="UTF-8"?>
   <xs:schema elementFormDefault="unqualified"
              attributeFormDefault="unqualified"
              xmlns:xs="http://www.w3.org/2001/XMLSchema">

     <xs:include schemaLocation="moml-datatypes.xsd"/>
     <xs:include schemaLocation="moml-core-module.xsd"/>
     <xs:import namespace="http://www.w3.org/XML/1998/namespace"
                schemaLocation="http://www.w3.org/2001/xml.xsd"/>
     <xs:element name="play" substitutionGroup="primitive">
       <xs:complexType>
         <xs:complexContent>
           <xs:extension base="primitiveType">
             <xs:sequence>
               <xs:choice maxOccurs="unbounded">
                 <xs:element name="audio" minOccurs="0"
                             maxOccurs="unbounded">
                   <xs:complexType>
                     <xs:attribute name="uri" type="xs:anyURI"
                                   use="required"/>
                     <xs:attribute name="iterate"
                                   type="iterate.datatype" default="1"/>
                     <xs:attribute name="format" type="xs:string"
                                   use="optional"/>
                     <xs:attribute name="audiosamplerate"
                                   type="xs:positiveInteger"
                                   use="optional"/>
                     <xs:attribute name="audiosamplesize"
                                   type="xs:positiveInteger"
                                   use="optional"/>
                     <xs:attribute ref="xml:lang"/>
                   </xs:complexType>
                 </xs:element>
                 <xs:element name="video" minOccurs="0"
                             maxOccurs="unbounded">
                   <xs:complexType>
                     <xs:attribute name="uri" type="xs:anyURI"
                                   use="required"/>
                     <xs:attribute name="iterate"


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                                   type="iterate.datatype"
                                   use="optional" default="1"/>
                     <xs:attribute name="format" type="xs:string"
                                   use="optional"/>
                     <xs:attribute name="audiosamplerate"
                                   type="xs:positiveInteger"
                                   use="optional"/>
                     <xs:attribute name="audiosamplesize"
                                   type="xs:positiveInteger"
                                   use="optional"/>
                     <xs:attribute name="codecconfig" type="xs:string"
                                   use="optional"/>
                     <xs:attribute name="profile" type="xs:string"
                                   use="optional"/>
                     <xs:attribute name="level" type="xs:string"
                                   use="optional"/>
                     <xs:attribute name="imagewidth"
                                   type="xs:positiveInteger"
                                   use="optional"/>
                     <xs:attribute name="imageheight"
                                   type="xs:positiveInteger"
                                   use="optional"/>
                     <xs:attribute name="maxbitrate"
                                   type="xs:positiveInteger"
                                   use="optional"/>
                     <xs:attribute name="framerate"
                                   type="xs:positiveInteger"
                                   use="optional"/>
                   </xs:complexType>
                 </xs:element>
                 <xs:element name="media" minOccurs="0"
                             maxOccurs="unbounded">
                   <xs:complexType>
                     <xs:choice>
                       <xs:element name="audio" minOccurs="0">
                         <xs:complexType>
                           <xs:attribute name="uri" type="xs:anyURI"
                                         use="required"/>
                           <xs:attribute name="iterate"
                                         type="iterate.datatype"
                                         default="1"/>
                           <xs:attribute name="format" type="xs:string"
                                         use="optional"/>
                           <xs:attribute name="audiosamplerate"
                                         type="xs:positiveInteger"
                                         use="optional"/>
                           <xs:attribute name="audiosamplesize"
                                         type="xs:positiveInteger"


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                                         use="optional"/>
                           <xs:attribute ref="xml:lang"/>
                         </xs:complexType>
                       </xs:element>
                       <xs:element name="video" minOccurs="0">
                         <xs:complexType>
                           <xs:attribute name="uri" type="xs:anyURI"
                                         use="required"/>
                           <xs:attribute name="iterate"
                                         type="iterate.datatype"
                                         use="optional" default="1"/>
                           <xs:attribute name="format" type="xs:string"
                                         use="optional"/>
                           <xs:attribute name="audiosamplerate"
                                         type="xs:positiveInteger"
                                         use="optional"/>
                           <xs:attribute name="audiosamplesize"
                                         type="xs:positiveInteger"
                                         use="optional"/>
                           <xs:attribute name="codecconfig"
                                         type="xs:string"
                                         use="optional"/>
                           <xs:attribute name="profile" type="xs:string"
                                         use="optional"/>
                           <xs:attribute name="level" type="xs:string"
                                         use="optional"/>
                           <xs:attribute name="imagewidth"
                                         type="xs:positiveInteger"
                                         use="optional"/>
                           <xs:attribute name="imageheight"
                                         type="xs:positiveInteger"
                                         use="optional"/>
                           <xs:attribute name="maxbitrate"
                                         type="xs:positiveInteger"
                                         use="optional"/>
                           <xs:attribute name="framerate"
                                         type="xs:positiveInteger"
                                         use="optional"/>
                         </xs:complexType>
                       </xs:element>
                     </xs:choice>
                   </xs:complexType>
                 </xs:element>
                 <xs:element ref="smedia" minOccurs="0"
                             maxOccurs="unbounded"/>
               </xs:choice>
               <xs:choice minOccurs="0">
                 <xs:element name="playexit">


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                   <xs:complexType>
                     <xs:group ref="sendType"/>
                   </xs:complexType>
                 </xs:element>
               </xs:choice>
             </xs:sequence>
             <xs:attribute name="interval" type="posDuration.datatype"
                           use="optional"/>
             <xs:attribute name="iterate" type="iterate.datatype"
                           use="optional" default="1"/>
             <xs:attribute name="offset" type="duration.datatype"
                           use="optional"/>
             <xs:attribute name="initial" use="optional"
                           default="generate">
               <xs:simpleType>
                 <xs:restriction base="xs:string">
                   <xs:enumeration value="generate"/>
                   <xs:enumeration value="suspend"/>
                 </xs:restriction>
               </xs:simpleType>
             </xs:attribute>
             <xs:attribute name="maxtime" type="posDuration.datatype"
                           use="optional"/>
             <xs:attribute name="skip" type="duration.datatype"
                           use="optional" default="3s"/>
             <xs:attribute name="barge" type="boolean.datatype"
                           use="optional" default="false"/>
             <xs:attribute name="cleardb" type="boolean.datatype"
                           use="optional" default="false"/>
             <xs:attribute ref="xml:lang"/>
           </xs:extension>
         </xs:complexContent>
       </xs:complexType>
     </xs:element>
     <xs:element name="record" substitutionGroup="primitive">
       <xs:complexType>
         <xs:complexContent>
           <xs:extension base="primitiveType">
             <xs:choice minOccurs="0">
               <xs:element ref="play" minOccurs="0"/>
               <xs:element name="recordexit">
                 <xs:complexType>
                   <xs:group ref="sendType"/>
                 </xs:complexType>
               </xs:element>
             </xs:choice>
             <xs:attribute name="append" type="boolean.datatype"
                           use="optional" default="false"/>


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             <xs:attribute name="dest" type="xs:anyURI" use="optional"/>
             <xs:attribute name="audiodest" type="xs:anyURI"
                           use="optional"/>
             <xs:attribute name="videodest" type="xs:anyURI"
                           use="optional"/>
             <xs:attribute name="format" use="required">
               <xs:simpleType>
                 <xs:restriction base="xs:string"/>
               </xs:simpleType>
             </xs:attribute>
             <xs:attribute name="codecconfig" use="optional">
               <xs:simpleType>
                 <xs:restriction base="xs:string"/>
               </xs:simpleType>
             </xs:attribute>
             <xs:attribute name="audiosamplerate"
                           type="xs:positiveInteger" use="optional"/>
             <xs:attribute name="audiosamplesize"
                           type="xs:positiveInteger" use="optional"/>
             <xs:attribute name="profile" use="optional">
               <xs:simpleType>
                 <xs:restriction base="xs:string"/>
               </xs:simpleType>
             </xs:attribute>
             <xs:attribute name="level" use="optional">
               <xs:simpleType>
                 <xs:restriction base="xs:string"/>
               </xs:simpleType>
             </xs:attribute>
             <xs:attribute name="imagewidth" type="xs:positiveInteger"
                           use="optional"/>
             <xs:attribute name="imageheight" type="xs:positiveInteger"
                           use="optional"/>
             <xs:attribute name="maxbitrate" type="xs:positiveInteger"
                           use="optional"/>
             <xs:attribute name="framerate" type="xs:positiveInteger"
                           use="optional"/>
             <xs:attribute name="maxtime" type="posDuration.datatype"
                           use="required"/>
             <xs:attribute name="initial" use="optional"
                           default="create">
               <xs:simpleType>
                 <xs:restriction base="xs:string">
                   <xs:enumeration value="create"/>
                   <xs:enumeration value="suspend"/>
                 </xs:restriction>
               </xs:simpleType>
             </xs:attribute>


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             <xs:attribute name="prespeech" type="posDuration.datatype"
                           use="optional" default="0s"/>
             <xs:attribute name="postspeech" type="posDuration.datatype"
                           use="optional" default="0s"/>
             <xs:attribute name="termkey" use="optional">
               <xs:simpleType>
                 <xs:restriction base="xs:string">
                   <xs:pattern value="[0-9#*ABCD]"/>
                   <xs:enumeration value="create"/>
                   <xs:enumeration value="suspend"/>
                 </xs:restriction>
               </xs:simpleType>
             </xs:attribute>
           </xs:extension>
         </xs:complexContent>
       </xs:complexType>
     </xs:element>
     <xs:element name="dtmf" substitutionGroup="primitive">
       <xs:complexType>
         <xs:complexContent>
           <xs:extension base="primitiveType">
             <xs:sequence>
               <xs:element name="pattern" maxOccurs="unbounded">
                 <xs:complexType>
                   <xs:group ref="sendType"/>
                   <xs:attribute name="digits" type="xs:string"
                                 use="required"/>
                   <xs:attribute name="format">
                     <xs:simpleType>
                       <xs:restriction base="xs:string">
                         <xs:enumeration value="mgcp"/>
                         <xs:enumeration value="megaco"/>
                         <xs:enumeration value="moml+digits"/>
                       </xs:restriction>
                     </xs:simpleType>
                   </xs:attribute>
                   <xs:attribute name="iterate" type="iterate.datatype"
                                 default="1"/>
                 </xs:complexType>
               </xs:element>
               <xs:element name="detect" minOccurs="0">
                 <xs:complexType>
                   <xs:group ref="sendType"/>
                 </xs:complexType>
               </xs:element>
               <xs:element name="noinput" type="iterateSendType"
                           minOccurs="0"/>
               <xs:element name="nomatch" type="iterateSendType"


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                           minOccurs="0"/>
               <xs:element name="dtmfexit" minOccurs="0">
                 <xs:complexType>
                   <xs:group ref="sendType"/>
                 </xs:complexType>
               </xs:element>
               <xs:element ref="play" minOccurs="0"/>
             </xs:sequence>
             <xs:attribute name="cleardb" type="boolean.datatype"
                           default="true"/>
             <xs:attribute name="fdt" type="posDuration.datatype"
                           default="0s"/>
             <xs:attribute name="idt" type="posDuration.datatype"
                           default="4s"/>
             <xs:attribute name="edt" type="posDuration.datatype"
                           default="4s"/>
             <xs:attribute name="starttimer" type="boolean.datatype"
                           default="false"/>
             <xs:attribute name="iterate" type="iterate.datatype"
                           default="1"/>
           </xs:extension>
         </xs:complexContent>
       </xs:complexType>
     </xs:element>
     <xs:element name="collect" substitutionGroup="primitive">
       <xs:complexType>
         <xs:complexContent>
           <xs:extension base="primitiveType">
             <xs:sequence>
               <xs:element name="pattern" maxOccurs="unbounded">
                 <xs:complexType>
                   <xs:group ref="sendType"/>
                   <xs:attribute name="digits" type="xs:string"
                                 use="required"/>
                   <xs:attribute name="format">
                     <xs:simpleType>
                       <xs:restriction base="xs:string">
                         <xs:enumeration value="mgcp"/>
                         <xs:enumeration value="megaco"/>
                         <xs:enumeration value="moml+digits"/>
                       </xs:restriction>
                     </xs:simpleType>
                   </xs:attribute>
                   <xs:attribute name="iterate" type="iterate.datatype"
                                 default="1"/>
                 </xs:complexType>
               </xs:element>
               <xs:element name="detect" minOccurs="0">


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                 <xs:complexType>
                   <xs:group ref="sendType"/>
                 </xs:complexType>
               </xs:element>
               <xs:element name="noinput" type="iterateSendType"
                           minOccurs="0"/>
               <xs:element name="nomatch" type="iterateSendType"
                           minOccurs="0"/>
               <xs:element name="dtmfexit" minOccurs="0">
                 <xs:complexType>
                   <xs:group ref="sendType"/>
                 </xs:complexType>
               </xs:element>
               <xs:element ref="play" minOccurs="0"/>
             </xs:sequence>
             <xs:attribute name="cleardb" type="boolean.datatype"
                           default="true"/>
             <xs:attribute name="fdt" type="posDuration.datatype"
                           default="0s"/>
             <xs:attribute name="idt" type="posDuration.datatype"
                           default="4s"/>
             <xs:attribute name="edt" type="posDuration.datatype"
                           default="4s"/>
             <xs:attribute name="starttimer" type="boolean.datatype"
                           default="false"/>
             <xs:attribute name="iterate" type="iterate.datatype"
                           default="1"/>
           </xs:extension>
         </xs:complexContent>
       </xs:complexType>
     </xs:element>
     <xs:element name="dtmfgen" substitutionGroup="primitive">
       <xs:complexType>
         <xs:complexContent>
           <xs:extension base="primitiveType">
             <xs:choice minOccurs="0">
               <xs:element name="dtmfgenexit">
                 <xs:complexType>
                   <xs:group ref="sendType"/>
                 </xs:complexType>
               </xs:element>
             </xs:choice>
             <xs:attribute name="level" use="optional" default="-6">
               <xs:simpleType>
                 <xs:restriction base="xs:nonPositiveInteger">
                   <xs:maxInclusive value="0"/>
                   <xs:minInclusive value="-96"/>
                 </xs:restriction>


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               </xs:simpleType>
             </xs:attribute>
             <xs:attribute name="digits" type="dtmfDigits.datatype"
                           use="required"/>
             <xs:attribute name="dur" type="posDuration.datatype"
                           use="optional" default="100ms"/>
             <xs:attribute name="interval" type="posDuration.datatype"
                           use="optional" default="100ms"/>
           </xs:extension>
         </xs:complexContent>
       </xs:complexType>
     </xs:element>
     <xs:complexType name="iterateSendType">
       <xs:group ref="sendType"/>
       <xs:attribute name="iterate" type="iterate.datatype"
                     default="1"/>
     </xs:complexType>
     <xs:element name="smedia" type="smediaType" abstract="true"/>
     <xs:complexType name="smediaType">
       <xs:attribute ref="xml:lang"/>
       <xs:attribute name="iterate" type="iterate.datatype"/>
     </xs:complexType>
     <xs:element name="var" substitutionGroup="smedia">
       <xs:complexType>
         <xs:complexContent>
           <xs:extension base="smediaType">
             <xs:attribute name="type" use="required">
               <xs:simpleType>
                 <xs:restriction base="xs:string">
                   <xs:enumeration value="date"/>
                   <xs:enumeration value="digits"/>
                   <xs:enumeration value="duration"/>
                   <xs:enumeration value="month"/>
                   <xs:enumeration value="money"/>
                   <xs:enumeration value="number"/>
                   <xs:enumeration value="silence"/>
                   <xs:enumeration value="time"/>
                   <xs:enumeration value="weekday"/>
                 </xs:restriction>
               </xs:simpleType>
             </xs:attribute>
             <xs:attribute name="subtype" type="xs:string"
                           use="optional"/>
             <xs:attribute name="value" type="xs:string"
                           use="required"/>
           </xs:extension>
         </xs:complexContent>
       </xs:complexType>


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     </xs:element>
   </xs:schema>


   The schema for the MSML Dialog Group package (moml-group-module.xsd)
   is:

   <?xml version="1.0" encoding="UTF-8"?>
   <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
      elementFormDefault="unqualified"
      attributeFormDefault="unqualified">
    <xs:include schemaLocation="moml-datatypes.xsd"/>
    <xs:include schemaLocation="moml-core-module.xsd"/>
    <xs:element name="group" substitutionGroup="control">
     <xs:complexType>
      <xs:sequence>
       <xs:group ref="executeType"/>
       <xs:element name="groupexit" minOccurs="0">
        <xs:complexType>
         <xs:group ref="sendType"/>
        </xs:complexType>
       </xs:element>
      </xs:sequence>
      <xs:attribute name="id" type="momlID.datatype"/>
      <xs:attribute name="topology" use="required">
       <xs:simpleType>
        <xs:restriction base="xs:string">
         <xs:enumeration value="serial"/>
         <xs:enumeration value="parallel"/>
         <xs:enumeration value="fullduplex"/>
        </xs:restriction>
       </xs:simpleType>
      </xs:attribute>
     </xs:complexType>
    </xs:element>
   </xs:schema>



   The schema for the MSML Dialog Transform package (moml-transform-
   primitives-module.xsd) is:



   <?xml version="1.0" encoding="UTF-8"?>
   <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
              elementFormDefault="unqualified"
              attributeFormDefault="unqualified">


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    <xs:include schemaLocation="moml-datatypes.xsd"/>
    <xs:include schemaLocation="moml-core-module.xsd"/>
    <xs:import namespace="http://www.w3.org/XML/1998/namespace"
               schemaLocation="http://www.w3.org/2001/xml.xsd"/>
    <xs:element name="vad" substitutionGroup="primitive">
     <xs:complexType>
      <xs:complexContent>
      <xs:extension base="primitiveType">
      <xs:all>
       <xs:element name="voice" type="vadPatternType" minOccurs="0"/>
       <xs:element name="silence" type="vadPatternType" minOccurs="0"/>
       <xs:element name="tvoice" type="vadPatternType" minOccurs="0"/>
       <xs:element name="tsilence" type="vadPatternType" minOccurs="0"/>
      </xs:all>
      <xs:attribute name="starttimer" type="boolean.datatype"
                    default="false"/>
      </xs:extension>
      </xs:complexContent>
     </xs:complexType>
    </xs:element>
    <xs:element name="gain" substitutionGroup="primitive">
     <xs:complexType>
      <xs:complexContent>
      <xs:extension base="primitiveType">
      <xs:attribute name="incr" default="3">
       <xs:simpleType>
        <xs:restriction base="xs:positiveInteger">
         <xs:maxInclusive value="96"/>
        </xs:restriction>
       </xs:simpleType>
      </xs:attribute>
      <xs:attribute name="amt" use="required">
       <xs:simpleType>
        <xs:restriction base="xs:integer">
         <xs:minInclusive value="-96"/>
         <xs:maxInclusive value="96"/>
        </xs:restriction>
       </xs:simpleType>
      </xs:attribute>
      </xs:extension>
      </xs:complexContent>
     </xs:complexType>
    </xs:element>
    <xs:element name="agc" substitutionGroup="primitive">
     <xs:complexType>
      <xs:complexContent>
      <xs:extension base="primitiveType">
      <xs:attribute name="tgtlvl" use="required">


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       <xs:simpleType>
        <xs:restriction base="xs:nonPositiveInteger">
         <xs:minInclusive value="-40"/>
         <xs:maxInclusive value="0"/>
        </xs:restriction>
       </xs:simpleType>
      </xs:attribute>
      <xs:attribute name="maxgain" default="10">
       <xs:simpleType>
        <xs:restriction base="xs:nonNegativeInteger">
         <xs:minInclusive value="0"/>
         <xs:maxInclusive value="40"/>
        </xs:restriction>
       </xs:simpleType>
      </xs:attribute>
      </xs:extension>
      </xs:complexContent>
     </xs:complexType>
    </xs:element>
    <xs:element name="gate" substitutionGroup="primitive">
     <xs:complexType>
      <xs:complexContent>
      <xs:extension base="primitiveType">
      <xs:attribute name="initial" default="pass">
       <xs:simpleType>
        <xs:restriction base="xs:string">
         <xs:enumeration value="pass"/>
         <xs:enumeration value="halt"/>
        </xs:restriction>
       </xs:simpleType>
      </xs:attribute>
      </xs:extension>
      </xs:complexContent>
     </xs:complexType>
    </xs:element>
    <xs:element name="clamp" substitutionGroup="primitive">
     <xs:complexType>
      <xs:complexContent>
       <xs:extension base="primitiveType"/>
      </xs:complexContent>
     </xs:complexType>
    </xs:element>
    <xs:element name="relay" substitutionGroup="primitive">
     <xs:complexType>
      <xs:complexContent>
       <xs:extension base="primitiveType"/>
      </xs:complexContent>
     </xs:complexType>


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    </xs:element>
    <xs:complexType name="vadPatternType">
     <xs:group ref="sendType"/>
     <xs:attribute name="iterate" type="iterate.datatype" default="1"/>
     <xs:attribute name="len" type="posDuration.datatype"
                   use="required"/>
     <xs:attribute name="sen" type="posDuration.datatype"
                   use="optional"/>
    </xs:complexType>
   </xs:schema>


   Following is the schema for the MSML Speech package (moml-speech-
   module.xsd). Note that several URL were split across several lines
   for formatting reasons.

   <?xml version="1.0" encoding="UTF-8"?>
   <xs:schema elementFormDefault="qualified"
              attributeFormDefault="unqualified"
              xmlns:xs="http://www.w3.org/2001/XMLSchema">
    <xs:include schemaLocation="moml-datatypes.xsd"/>
    <xs:include schemaLocation="moml-core-module.xsd"/>
    <xs:include schemaLocation="moml-basic-primitives-module.xsd"/>
    <xs:include schemaLocation="http://www.w3.org/TR/2002/WD-speech-
                synthesis-20020405/synthesis-core.xsd"/>
    <xs:include schemaLocation="http://www.w3.org/TR/speech-
                grammar/grammar-core.xsd"/>
    <xs:element name="speech" substitutionGroup="primitive">
     <xs:complexType>
      <xs:complexContent>
       <xs:extension base="primitiveType">
        <xs:sequence>
         <xs:element name="grammar" maxOccurs="unbounded">
          <xs:complexType>
           <xs:complexContent>
            <xs:extension base="grammar">
             <xs:choice>
              <xs:element name="match" type="iterateSendType"
                          minOccurs="0"/>
             </xs:choice>
             <xs:attribute name="uri" type="xs:anyURI"/>
             <xs:attribute name="iterate" type="iterate.datatype"
                           default="1"/>
            </xs:extension>
           </xs:complexContent>
          </xs:complexType>
         </xs:element>
         <xs:element name="noinput" type="iterateSendType"


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                     minOccurs="0"/>
         <xs:element name="nomatch" type="iterateSendType"
                     minOccurs="0"/>
         <xs:element name="speechexit" minOccurs="0">
          <xs:complexType>
           <xs:group ref="sendType"/>
          </xs:complexType>
         </xs:element>
        </xs:sequence>
        <xs:attribute name="noint" type="posDuration.datatype"/>
        <xs:attribute name="norect" type="posDuration.datatype"/>
        <xs:attribute name="spcmplt" type="posDuration.datatype"/>
        <xs:attribute name="confidence">
         <xs:simpleType>
          <xs:restriction base="xs:positiveInteger">
           <xs:maxInclusive value="100"/>
          </xs:restriction>
         </xs:simpleType>
        </xs:attribute>
        <xs:attribute name="sens" type="xs:positiveInteger"/>
        <xs:attribute name="starttimer" type="boolean.datatype"
                      default="false"/>
        <xs:attribute name="iterate" type="iterate.datatype"
                      default="1"/>
       </xs:extension>
      </xs:complexContent>
     </xs:complexType>
    </xs:element>
    <xs:element name="tts" type="smediaType"
                substitutionGroup="smedia"/>
   </xs:schema>


   Following is the schema for the MSML Fax packages (moml-fax-
   module.xsd).

   <?xml version="1.0" encoding="UTF-8"?>
   <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
              elementFormDefault="qualified"
              attributeFormDefault="unqualified">
    <xs:include schemaLocation="moml-datatypes.xsd"/>
    <xs:include schemaLocation="moml-core-module.xsd"/>
    <xs:element name="faxdetect" substitutionGroup="primitive">
     <xs:complexType>
      <xs:choice>
       <xs:group ref="sendType"/>
      </xs:choice>
     </xs:complexType>


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    </xs:element>
    <xs:element name="faxsend" substitutionGroup="primitive">
     <xs:complexType>
      <xs:sequence>
       <xs:element name="sendobj" type="sendobjType" minOccurs="0"
                   maxOccurs="unbounded"/>
       <xs:element name="hdrfooter" type="hdrfooterType" minOccurs="0"/>
       <xs:element name="rxpoll" minOccurs="0">
        <xs:complexType>
         <xs:sequence>
          <xs:element name="rcvobj" type="rcvobjType"
                      maxOccurs="unbounded"/>
          <xs:element name="hdrfooter" type="hdrfooterType"
                      minOccurs="0"/>
         </xs:sequence>
         <xs:attribute name="rmtid" type="faxid.datatype"
                       use="required"/>
        </xs:complexType>
       </xs:element>
       <xs:group ref="faxstatusrequest"/>
      </xs:sequence>
      <xs:attribute name="lclid" type="faxid.datatype" use="optional"/>
      <xs:attribute name="minspeed" type="faxspeed.datatype"
                    use="optional"/>
      <xs:attribute name="maxspeed" type="faxspeed.datatype"
                    use="optional"/>
      <xs:attribute name="ecm" type="boolean.datatype" use="optional"/>
     </xs:complexType>
    </xs:element>
    <xs:element name="faxrecv" substitutionGroup="primitive">
     <xs:complexType>
      <xs:sequence>
       <xs:element name="rcvobj" type="rcvobjType" minOccurs="0"
                   maxOccurs="unbounded"/>
       <xs:element name="hdrfooter" type="hdrfooterType" minOccurs="0"/>
       <xs:element name="txpoll" minOccurs="0">
        <xs:complexType>
         <xs:sequence>
          <xs:element name="sendobj" type="sendobjType"
                      maxOccurs="unbounded"/>
          <xs:element name="hdrfooter" type="hdrfooterType"
                      minOccurs="0"/>
         </xs:sequence>
         <xs:attribute name="rmtid" type="faxid.datatype"/>
        </xs:complexType>
       </xs:element>
       <xs:group ref="faxstatusrequest"/>
      </xs:sequence>


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      <xs:attribute name="lclid" type="faxid.datatype" use="optional"/>
      <xs:attribute name="ecm" type="boolean.datatype" default="true"/>
     </xs:complexType>
    </xs:element>
    <xs:group name="faxstatusrequest">
     <xs:all>
      <xs:element name="faxstart" minOccurs="0"/>
      <xs:element name="faxnegotiate" minOccurs="0"/>
      <xs:element name="faxpagedone" minOccurs="0"/>
      <xs:element name="faxobjectdone" minOccurs="0"/>
      <xs:element name="faxopcomplete" minOccurs="0"/>
      <xs:element name="faxpollstart" minOccurs="0"/>
     </xs:all>
    </xs:group>
    <xs:complexType name="hdrfooterType">
     <xs:choice>
      <xs:element name="format" type="xs:string" minOccurs="0"
                  maxOccurs="unbounded"/>
     </xs:choice>
     <xs:attribute name="type" type="hdrfooter.datatype"/>
     <xs:attribute name="style" type="hdrfooterstyle.datatype"/>
    </xs:complexType>
    <xs:complexType name="formatType">
     <xs:simpleContent>
      <xs:extension base="xs:string">
       <xs:attribute name="style">
        <xs:simpleType>
         <xs:restriction base="xs:string">
          <xs:enumeration value="append"/>
          <xs:enumeration value="overlay"/>
          <xs:enumeration value="replace"/>
         </xs:restriction>
        </xs:simpleType>
       </xs:attribute>
      </xs:extension>
     </xs:simpleContent>
    </xs:complexType>
    <xs:complexType name="rcvobjType">
     <xs:attribute name="objuri" type="xs:anyURI" use="required"/>
     <xs:attribute name="maxpages" type="xs:positiveInteger"/>
    </xs:complexType>
    <xs:complexType name="sendobjType">
     <xs:attribute name="objuri" type="xs:anyURI" use="required"/>
     <xs:attribute name="startpage" type="xs:positiveInteger"/>
     <xs:attribute name="pagecount" type="xs:positiveInteger"/>
    </xs:complexType>
    <xs:simpleType name="faxid.datatype">
     <xs:restriction base="xs:string">


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      <xs:pattern value="[0-9+*- ]{20}"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="faxspeed.datatype">
     <xs:restriction base="xs:string">
      <xs:enumeration value="2400"/>
      <xs:enumeration value="4800"/>
      <xs:enumeration value="7200"/>
      <xs:enumeration value="9600"/>
      <xs:enumeration value="12000"/>
      <xs:enumeration value="14400"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="hdrfooter.datatype">
     <xs:restriction base="xs:string">
      <xs:enumeration value="header"/>
      <xs:enumeration value="footer"/>
      <xs:enumeration value="autohdr"/>
      <xs:enumeration value="nohdr"/>
     </xs:restriction>
    </xs:simpleType>
    <xs:simpleType name="hdrfooterstyle.datatype">
     <xs:restriction base="xs:string">
      <xs:enumeration value="append"/>
      <xs:enumeration value="overlay"/>
      <xs:enumeration value="replace"/>
     </xs:restriction>
    </xs:simpleType>
   </xs:schema>


18. Security Considerations

   MSML is invoked through other languages and protocols and as such
   security considerations depend on those environments.

   MSML being an XML based language, security considerations as defined
   by RFC 3023 [14] are applicable.

19. IANA Considerations

   IANA registrations for ‘application/msml+xml’, ‘text/msml-basic-
   layout’, and ‘application/moml+xml’ media types are planned.

   MGCP and Megaco/H.248 packages are registered with IANA so that there
   is no conflict between packages developed by different authors. The
   package scheme planned for future extensibility of MSML will also
   require IANA registry of packages.


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20. URN Sub-Namespace Registration

   The namespace URI for elements defined within this specification is a
   URN [24]. It uses the namespace identifier 'ietf' defined by [25] and
   extended by RFC 3688 [26]. The regisgtration of URN
   (urn:ietf:params:xml:ns:msml) is planned.

21. XML Schema Registration

   The XML schema associated with the MSML specification, is planned for
   registration as per the guidelines in RFC 3688 [26].

22. References

   [1] J. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J.
   Peterson, R. Sparks, M. Handley, and E. Schooler, "SIP: Session
   Initiation Protocol", RFC3261, Internet Engineering Taskforce, June
   2002.

   [2] J. Rosenberg, H. Schulzrinne, and P. Kyzivat, "Indicating User
   Agent Capabilities in the Session Initiation Protocol (SIP)",
   Internet Engineering Taskforce, December 2003. Work in progress.

   [3] R. Mahy and N. Ismail, "Media Policy Manipulation in the
   Conference Policy Control Protocol", Internet Draft, Internet
   Engineering Taskforce, Feb. 2003. Work in progress.

   [4] Bray, T., Paoli, J., Sperberg-McQueen, C., and E. Maler,
   “Extensible Markup Language (XML) 1.0 (Second Edition),” W3C
   FirstEdition REC-xml-20001006, October 2000.

   [5] World Wide Web Consortium, "Speech Recognition Grammar
   Specification Version 1.0" (SRGS), W3C Candidate Recommendation, June
   26, 2002

   [6] World Wide Web Consortium, "Natural Language Semantics Markup
   Language (NLSML) for the Speech Interface Framework", W3C Working
   Draft, May 2001.

   [7] World Wide Web Consortium, "Voice Extensible Markup Language
   (VoiceXML) Version 2.0, W3C Candidate Recommendation, February 20,
   2003

   [8] Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource
   Identifiers (URI): Generic Syntax,” RFC 2396, August 1998.





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   [9] J. Van Dyke, E. Burger, A. Spitzer, "Basic Network Media Services
   with SIP", Internet Draft, Internet Engineering Task Force, February
   2005. Work in progress.

   [10] C. Jennings, SIP Support for Application Initiation, Internet
   Draft, Internet Engineering Taskforce, Oct. 2002. Work in progress.

   [11] A. B. Roach, Session Initiation Protocol (SIP)-Specific Event
   Notification, RFC 3265, Internet Engineering Taskforce, June 2002.

   [12] E. Levinson, "Content-ID and Message-ID Uniform Resource
   Locators", RFC 2392, Internet Engineering Taskforce, August 1998.

   [13] S. Bradner, “Key words for use in RFCs to Indicate Requirement
   Levels,” RFC 2119, Internet Engineering Taskforce, March 1997.

   [14] M. Murata, S. St.Laurent, and D. Kohn, “XML Media Types,” RFC
   3023, Internet Engineering Taskforce, January 2001.

   [15] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson,
   “RTP Profile for Audio and Video Conferences with Minimal Control,”
   RFC 3550, July 2003.

   [16] Rosenberg, J., Peterson, J., Schulzrinne, H., and G. Camarillo,
   “Best Current Practices for Third Party Call Control (3pcc) in the
   Session Initiation Protocol (SIP),” RFC 3725, April 2004.

   [17] Donovan, S., “The SIP INFO Method,” RFC 2976, October 2000.

   [18] Handley, M. and V. Jacobson, “SDP: Session Description
   Protocol,” RFC 2327, April 1998.

   [19] Ossenbruggen, J., Rutledge, L., Saccocio, B., Schmitz, P., Kate,
   W., Ayars, J., Bulterman, D., Cohen, A., Day, K., Hodge, E., Hoschka,
   P., Hyche, E., Jourdan, M., Kubota, K., Lanphier, R., Layaïda, N.,
   Michel, T., and D. Newman, “Synchronized Multimedia Integration
   Language (SMIL 2.0) Specification,” W3C REC REC-smil20-20010807,
   August 2001.

   [20] Bos, B., Lie, H., Lilley, C., and I. Jacobs, “Cascading Style
   Sheets, level 2 (CSS2) Specification,” W3C REC REC-CSS2-19980512, May
   1998.

   [21] Freed, N. and N. Borenstein, “Multipurpose Internet Mail
   Extensions (MIME) Part Two: Media Types,” RFC 2046, November 1996.

   [22] Saleem, A. and Sharratt, G., “Media Sessions Markup Language”
   Internet Draft (draft-melanchuk-sipping-msml-06), October 21, 2005.


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   [23] Saleem, A. and Sharratt, G., “Media Objects Markup Language”
   Internet Draft (draft-melanchuk-sipping-moml-06), October 21, 2005.

   [24] Moats, R., "URN Syntax", RFC 2141, May 1997.

   [25] Moats, R., "A URN Namespace for IETF Documents", RFC 2648,
   August 1999.

   [26] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, January
   2004.



Acknowledgments

   Yong Xin and Sergiu Stambolian of Convedia provided key insights,
   both theoretic and through development experience, on several
   versions of the drafts.

   Stephen Buko and George Raskulinec of Intel made numerous valuable
   contributions towards enhancements of multimedia playback and record
   operations.

   David Asher of NMS Communications provided valuable insights towards
   creation of standard profiles and a modularization scheme based on
   packages for better interoperability.

   Gilles Compienne of Ubiquity Software has provided feedback on
   several earlier versions of this draft.

   Chris Boulton and Ben Smith, both of Ubiquity, and Michael Rice of
   VocalData helped clarify several issues, while Bruce Walsh and Kevin
   Fitzgerald, both of Spectel/Avaya, provided important feedback. Cliff
   Schornak of Commetrex significantly contributed to the facsimile
   work. Peter Danielsen of Lucent has contributed thoughtful and
   detailed reviews for several earlier versions of the draft.

Authors' Addresses

   Adnan Saleem
   Convedia
   4190 Still Creek Drive, Suite 300
   Vancouver, BC, V5C 6C6
   Canada

   Phone: +1 604 918 6376
   Email: asaleem@convedia.com



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   Garland Sharratt
   Convedia
   4190 Still Creek Drive, Suite 300
   Vancouver, BC, V5C 6C6
   Canada

   Phone: +1 604 918 6393
   Email: gsharratt@convedia.com





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Copyright Statement

   Copyright (C) The Internet Society (2005). This document is subject
   to the rights, licenses and restrictions contained in BCP 78, and
   except as set forth therein, the authors retain all their rights






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Disclaimer of Validity

   This document and the information contained herein are provided on an
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