Network Working Group                                         C. Boulton
Internet-Draft                                           NS-Technologies
Intended status: Standards Track                              L. Miniero
Expires: October 15, November 24, 2011                                      Meetecho
                                                               G. Munson
                                                                    AT&T
                                                          April 13,
                                                            May 23, 2011

                        Media Resource Brokering
                      draft-ietf-mediactrl-mrb-08
                      draft-ietf-mediactrl-mrb-09

Abstract

   The MediaCtrl work group in the IETF has proposed an architecture for
   controlling media services.  The Session Initiation Protocol (SIP) is
   used as the signalling protocol which provides many inherent
   capabilities for message routing.  In addition to such signalling
   properties, a need exists for intelligent, application level media
   service selection based on non-static signalling properties.  This is
   especially true when considered in conjunction with deployment
   architectures that include 1:M and M:N combinations of Application
   Servers and Media Servers.  This document introduces a Media Resource
   Broker (MRB) entity which manages the availability of Media Servers
   and the media resource demands of Application Servers.  The document
   includes potential deployment options for an MRB and appropriate
   interfaces to Application Servers and Media Servers.

Status of this Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on October 15, November 24, 2011.

Copyright Notice

   Copyright (c) 2011 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Conventions and Terminology . . . . . . . . . . . . . . . . .   7
   3.  Problem Discussion  . . . . . . . . . . . . . . . . . . . . .   8
   4.  Deployment Scenario Options . . . . . . . . . . . . . . . . .   9
     4.1.  Query MRB . . . . . . . . . . . . . . . . . . . . . . . .   9
       4.1.1.  Hybrid Query MRB  . . . . . . . . . . . . . . . . . .  10
     4.2.  In-Line MRB . . . . . . . . . . . . . . . . . . . . . . .  11
   5.  MRB Interface Definitions . . . . . . . . . . . . . . . . . .  14
     5.1.  Media Server Resource Publish Interface . . . . . . . . .  14
       5.1.1.  Control Package Definition  . . . . . . . . . . . . .  15
       5.1.2.  Element Definitions . . . . . . . . . . . . . . . . .  17
       5.1.3.  <mrbrequest>  . . . . . . . . . . . . . . . . . . . .  17
       5.1.4.  <mrbnotification> . . . . . . . . . . . . . . . . . .  19
       5.1.5.  <mrbresponse> . . . . . . . . . . . . . . . . . . . .  28  29
     5.2.  Media Service Resource Consumer Interface . . . . . . . .  30
       5.2.1.  Query Mode / HTTP Consumer Interface Usage  . . . . .  30  31
       5.2.2.  In-Line Aware Mode / SIP Consumer Interface Usage . .  31  32
       5.2.3.  Consumer Interface Lease Mechanism  . . . . . . . . .  33  34
       5.2.4.  Media Service Resource Request  . . . . . . . . . . .  36
       5.2.5.  Media Service Resource Response . . . . . . . . . . .  48
     5.3.  In-Line Unaware MRB Interface . . . . . . . . . . . . . .  50
   6.  MRB acting as a B2BUA . . . . . . . . . . . . . . . . . . . .  52
   7.  Multi-modal MRB Implementations . . . . . . . . . . . . . . .  53
   8.  Relative Merits of Query Mode, IAMM, and IUMM . . . . . . . .  54
   9.  Examples  . . . . . . . . . . . . . . . . . . . . . . . . . .  56
     9.1.  Publish Example . . . . . . . . . . . . . . . . . . . . .  56
     9.2.  Consumer Example  . . . . . . . . . . . . . . . . . . . .  62
       9.2.1.  Query Example . . . . . . . . . . . . . . . . . . . .  62
       9.2.2.  IAMM Example  . . . . . . . . . . . . . . . . . . . .  65
   10. Media Service Resource Publisher Interface XML Schema . . . .  80  81
   11. Media Service Resource Consumer Interface XML Schema  . . . . 102 103
   12. Security Considerations . . . . . . . . . . . . . . . . . . . 123 124
   13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 124 125
     13.1. Control Package Registration  . . . . . . . . . . . . . . 124 125
     13.2. application/mrb-publish+xml MIME Type . . . . . . . . . . 124 125
     13.3. application/mrb-consumer+xml MIME Type  . . . . . . . . . 125 126
     13.4. URN Sub-Namespace Registration for mrb-publish  . . . . . 126 127
     13.5. URN Sub-Namespace Registration for mrb-consumer . . . . . 126 127
     13.6. XML Schema Registration for mrb-publish . . . . . . . . . 126 127
     13.7. XML Schema Registration for mrb-consumer  . . . . . . . . 126 127
   14. Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . 128 129
     14.1. Changes from 07 08 Version . . . . . . . . . . . . . . . . . 128 129
     14.2. Changes from 06 07 Version . . . . . . . . . . . . . . . . . 128 129
     14.3. Changes from 05 06 Version . . . . . . . . . . . . . . . . . 128 129
     14.4. Changes from 04 05 Version . . . . . . . . . . . . . . . . . 129
     14.5. Changes from 03 04 Version . . . . . . . . . . . . . . . . . 129 130
     14.6. Changes from 02 03 Version . . . . . . . . . . . . . . . . . 129 130
     14.7. Changes from 01 02 Version . . . . . . . . . . . . . . . . . 130
     14.8. Changes from 01 Version . . . . . . . . . . . . . . . . . 131
     14.9. Changes from 00 Version . . . . . . . . . . . . . . . . . 130 131
   15. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 131 132
   16. References  . . . . . . . . . . . . . . . . . . . . . . . . . 132 133
     16.1. Normative References  . . . . . . . . . . . . . . . . . . 132 133
     16.2. Informative References  . . . . . . . . . . . . . . . . . 133 134
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . 135 136

1.  Introduction

   The topic of Media Resource management has been in discussion for a
   number of years with varying proprietary solutions being used today.
   It is clear that, as we move towards a consistent architecture and
   protocol for Media Server Control, a standard mechanism is required
   for accurate media resource selection.

   As IP based multimedia infrastructures mature, the complexity and
   demands from deployments increase.  Such complexity will result in a
   wide variety of capabilities from a range of vendors that should all
   be interoperable using the architecture and protocols produced by the
   MediaCtrl work group.  It should be possible for a controlling entity
   to be assisted in Media Server selection so that the most appropriate
   resource is selected for a particular operation.  The importance
   increases when you introduce a flexible level of deployment
   scenarios, as specified in the RFC 5167 [RFC5167] and RFC 5567
   [RFC5567] documents.  These documents make statements like "it should
   be possible to have a many-to-many relationship between Application
   Servers and Media Servers that use this protocol".  This leads to the
   following deployment architectures being possible when considering
   media resources.

   The simplest deployment view is illustrated in Figure 1.

   +---+-----+---+                         +---+-----+---+
   | Application |                         |    Media    |
   |   Server    |<-------MS Control------>|    Server   |
   +-------------+                         +-------------+

                       Figure 1: Basic Architecture

   This simply involves a single Application Server and Media Server.
   Expanding on this view, it is also possible for an Application Server
   to control multiple (greater that 1) Media Server instances at any
   one time.  This deployment view is illustrated in Figure 2.
   Typically, such architectures are associated with application logic
   that requires high demand media services.  It is more than possible
   that each media server possesses a different media capability set.
   Media servers may offer different media services as specified in the
   Mediactrl architecture document.  A Media server may have similar
   media functionality but may have different capacity or media codec
   support.

                                           +---+-----+---+
                                           |    Media    |
                                    +----->|    Server   |
                                    |      +-------------+
                                    |
   +---+-----+---+                  |      +---+-----+---+
   | Application |                  |      |    Media    |
   |   Server    |<--MS Control-----+----->|    Server   |
   +-------------+                  |      +-------------+
                                    |
                                    |      +---+-----+---+
                                    +----->|    Media    |
                                           |    Server   |
                                           +-------------+

                     Figure 2: Multiple Media Servers

   Figure 3 conveys the opposite view to that in Figure 2.  In this
   model there are a number of (greater than 1) application servers,
   possibly supporting dissimilar applications, controlling a single
   media server.  Typically, such architectures are associated with
   application logic that requires low demand media services.

   +---+-----+---+
   | Application |
   |   Server    |<-----+
   +-------------+      |
                        |
   +---+-----+---+      |                  +---+-----+---+
   | Application |      |                  |    Media    |
   |   Server    |<-----+-----MS Control-->|    Server   |
   +-------------+      |                  +-------------+
                        |
   +---+-----+---+      |
   | Application |      |
   |   Server    |<-----+
   +-------------+

                  Figure 3: Multiple Application Servers

   The final deployment view is the most complex.  In this model (M:N)
   there exists any number of Application Servers and any number of
   Media Servers.  It is again possible in this model that media servers
   might not be homogenous and have different capability sets and
   capacity.

   +---+-----+---+                         +---+-----+---+
   | Application |                         |    Media    |
   |   Server    |<-----+            +---->|    Server   |
   +-------------+      |            |     +-------------+
                        |            |
   +---+-----+---+      |            |     +---+-----+---+
   | Application |      |            |     |    Media    |
   |   Server    |<-----+-MS Control-+---->|    Server   |
   +-------------+      |            |     +-------------+
                        |            |
   +---+-----+---+      |            |     +---+-----+---+
   | Application |      |            +---->|    Media    |
   |   Server    |<-----+                  |    Server   |
   +-------------+                         +---+-----+---+

                       Figure 4: Basic Architecture

   The high level deployment options discussed in this section rely on
   network architecture and policy to prohibit inappropriate use.  Such
   policies are out of the scope of this document.

   This document will take a look at the specific problem areas related
   to such deployment architectures.  It is recognised that the
   solutions proposed in this document should be equally adaptable to
   all of the previously described deployment models.  It is also
   recognised that the solution is far more relevant to some of the
   previously discussed deployment models and can almost be viewed as
   redundant on others.

2.  Conventions and Terminology

   In this document, BCP 14/RFC 2119 [RFC2119] defines the key words
   "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
   "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL".

   This document inherits terminology proposed in RFC 5567 [RFC5567] and
   Media Control Channel Framework
   [I-D.ietf-mediactrl-sip-control-framework] documents.  In addition,
   the following terms are defined for use in this document and for use
   in the context of the MediaCtrl Work group in the IETF:

   Media Resource Broker (MRB):   A logical entity that is responsible
      for both collection of appropriate published Media Server (MS)
      information and selecting appropriate MS resources on behalf of
      consuming entities.

   Query MRB:   An instantiation of an MRB (See previous definition)
      that provides an interface for an Application Server to retrieve
      the address of an appropriate Media Server.  The result returned
      to the Application Server can be influenced by information
      contained in the query request.

   In-line MRB:   An instantiation of an MRB (See definition) that
      directly receives requests on the signalling path.  There is no
      separate query.

   Within the context of In-line MRBs, additional terms are defined:

   In-line Aware MRB Mode (IAMM):   Defined in Section 5.2.2.1.

   In-line Unaware MRB Mode (IUMM):   Defined in Section 5.3.

   The document will often specify when a specific identifier in a
   protocol message needs to be unique.  Unless differently stated, such
   uniqueness will always need to be intended within the scope of the
   Media Servers controlled by the same Media Resource Broker.  The
   interaction among different Media Resource Brokers, as the
   partitioning of a logical Media Resource Broker, is out of scope to
   this document.

3.  Problem Discussion

   As anticipated in Section 1, the main aim of the MediaCtrl group is
   to produce a solution that must service a wide variety of deployment
   architectures.  These range from the simplest 1:1 relationship
   between Media Servers and Application Servers to potentially linearly
   scaling 1:M, M:1 and M:N deployments.

   This still does not seem like a major issue for the proposed solution
   until you add a number of additional factors into the equation that
   increase complexity.  As Media Servers evolve it must be taken into
   consideration that, where many can exist in a deployment, they may
   not have been produced by the same vendor and may not have the same
   capability set.  It should be possible for an Application Server that
   exists in a deployment to select a Media Service based on a common,
   appropriate capability set.  In conjunction with capabilities, it is
   also important to take available resources into consideration.  The
   ability to select an appropriate Media Service function is an
   extremely useful feature but becomes even more powerful when
   considered with available resources for servicing a request.

   In conclusion, the intention is to create a tool set that allows
   MediaCtrl deployments to effectively utilize the available media
   resources.  It should be noted that in the simplest deployments where
   only a single media server exists, an MRB function is probably not
   required.  Only a single capability set exists and resource
   unavailability can be handled using the appropriate underlying
   signalling, e.g., SIP response.  This document does not prohibit such
   uses of an MRB, it simply provides the tools for various entities to
   interact where appropriate.  It is also worth noting that the tools
   provided in this document aim to provide a 'best effort' view of
   media resources at the time of request for initial Media Server
   routing decisions.  Any dramatic change in media capabilities after a
   request has taken place should be handled by the underlying protocol.

   Please note that there may be additional information that it is
   desirable for the MRB to have for purposes of selecting an MS
   resource, such as resource allocation rules across different
   applications, planned or unplanned downtime of Media Server
   resources, the planned addition of future Media Server resources, or
   MS resource capacity models.  How the MRB acquires such information
   is outside the scope of this document.  The techniques used for
   selecting an appropriate Media Resource by an MRB is outside the
   scope of this document.

4.  Deployment Scenario Options

   On researching Media Resource Brokering it became clear that a couple
   of high level models exist.  The general principles of "in-line" and
   "query" MRB concepts are discussed in the rest of this section.

4.1.  Query MRB

   The "Query" model for MRB interactions provides the ability for a
   client of media services (for example an Application Server) to "ask"
   an MRB for an appropriate Media Server, as illustrated in Figure 5.

                        +---+-----+---+
          +------------>|     MRB     |<----------+----<-----+---+
          |             +-------------+        (1)|          |   |
          |                                       |          |   |
          |(2)                             +---+--+--+---+   |   |
          |                                |    Media    |   |   |
          |                          +---->|    Server   |   |   |
          |                          |     +-------------+   |   |
          |                          |                    (1)|   |
   +---+--+--+---+                   |     +---+-----+---+   |   |
   | Application |                   |     |    Media    |   |   |
   |   Server    |<-----+-MS Control-+---->|    Server   |->-+   |
   +-------------+          (3)      |     +-------------+       |
                                     |                           |
                                     |     +---+-----+---+    (1)|
                                     +---->|    Media    |       |
                                           |    Server   |--->---+
                                           +---+-----+---+

                            Figure 5: Query MRB

   In this deployment, the Media Servers use the "Media Server Resource
   Publish Interface", as discussed in Section 5.1, to convey capability
   sets as well as resource information.  This is depicted by (1) in
   Figure 5.  It is then the MRB's responsibility to accumulate all
   appropriate information relating to media services in the logical
   deployment cluster.  The Application Server (or other media services
   client) is then able to query the MRB for an appropriate resource (as
   identified by (2) in Figure 5).  Such a query would carry specific
   information related to the Media Service required and enable the MRB
   to provide an increased accuracy in its response.  This particular
   interface is discussed in "Media Resource Consumer Interface" in
   Section 5.2.  The Application Server is then able to direct control
   commands (for example create conference) and Media Dialogs to the
   appropriate Media Server, as shown by (3) in Figure 5.  Additionally,
   with Query MRB, the MRB is not in the signaling path between the AS
   and the selected MS resource.

4.1.1.  Hybrid Query MRB

   As mentioned previously, it is the intention that a tool kit is
   provided for MRB functionality within a MediaCtrl architecture.  It
   is expected that in specific deployment scenarios the role of the MRB
   might be co-hosted as a hybrid logical entity with an Application
   Server, as shown in Figure 6.

          +------------<----------------<---------+----<-----+---+
          |                     (1)               |          |   |
          |                                       |          |   |
          |                                +---+--+--+---+   |   |
          |                                |    Media    |   |   |
          V                          +---->|    Server   |   |   |
   +------+------+                   |     +-------------+   |   |
   |     MRB     |                   |                       |   |
   +---+--+--+---+                   |     +---+-----+---+   |   |
   | Application |                   |     |    Media    |   |   |
   |   Server    |<-----+-MS Control-+---->|    Server   |->-+   |
   +-------------+                   |     +-------------+       |
                                     |                           |
                                     |     +---+-----+---+       |
                                     +---->|    Media    |       |
                                           |    Server   |--->---+
                                           +---+-----+---+

                  Figure 6: Hybrid Query MRB - AS Hosted

   This diagram is identical to that in Figure 5 with the exception that
   the MRB is now hosted on the Application Server.  The "Media Server
   Publish Interface" is still being used to accumulate resource
   information at the MRB but as it is co-hosted on the Application
   Server, the "Media Server Consumer Interface" has collapsed.  It
   might still exist within the Application Server/MRB interaction but
   this is an implementation issue.  This type of deployment suits a
   single Application Server environment but it should be noted that a
   "Media Server Consumer Interface" could then be offered from the
   hybrid if required.

   In a similar manner, the Media Server could also act as a hybrid for
   the deployment cluster, as illustrated in Figure 7.

                                   (1)                 +---+-----+---+
   +---+---+------------->---------------->----------->|     MRB     |
   |   |   |   +---+--+--+---+                         +---+-----+---+
   |   |   +-<-| Application |                         |    Media    |
   |   |       |   Server    |<--+-MS Control-+------->|    Server   |
   |   |       +-------------+                   |     +-------------+
   |   |                                         |
   |   |       +---+--+--+---+                   |
   |   +---<---| Application |                   |
   |           |   Server    |<--+-MS Control-+--+
   |           +-------------+                   |
   |                                             |
   |           +---+--+--+---+                   |
   +---<-------| Application |                   |
               |   Server    |<--+-MS Control-+--+
               +-------------+

                  Figure 7: Hybrid Query MRB - MS Hosted

   This time the MRB has collapsed and is co-hosted by the Media Server.
   The "Media Server Consumer Interface" is still available to the
   Application Servers (1) to query Media Server resources.  This time
   the "Media Server Publish Interface" has collapsed onto the Media
   Server.  It might still exist within the Media Server/MRB interaction
   but this is an implementation issue.  This type of deployment suits a
   single Media Server environment but it should be noted that a "Media
   Server Publish Interface" could then be offered from the hybrid if
   required.  A typical use case scenario for such a topology would be a
   single MS representing a pool of MSs in a cluster.  In that case, the
   MRB would actually be handling a cluster of MSs, rather than one.

4.2.  In-Line MRB

   The "In-line" MRB is architecturally different from the "Query" model
   that was discussed in the previous section.  The concept of a
   separate query disappears.  The client of the MRB simply uses the
   media resource control and media dialog signalling to involve the
   MRB.  This type of deployment is illustrated in Figure 8.

                               +-------<----------+----<-------+---+
                               |                  | (1)        |   |
                               |                  |            |   |
                               |             +---+--+--+---+   |   |
                               |             |    Media    |   |   |
                               |     +------>|    Server   |   |   |
                               |     |(3)    +-------------+   |   |
                               |     |                      (1)|   |
   +---+--+--+---+             |     |       +---+-----+---+   |   |
   | Application |  (2) +---+--V--+---+  (3) |    Media    |   |   |
   |   Server    |----->|     MRB     |----->|    Server   |->-+   |
   +-------------+      +---+-----+---+      +-------------+       |
                                     |                             |
                                     |   (3) +---+-----+---+    (1)|
                                     +------>|    Media    |       |
                                             |    Server   |--->---+
                                             +---+-----+---+

                           Figure 8: In-line MRB

   The Media Servers still use the 'Media Server Publish Interface' to
   convey capabilities and resources to the MRB - as illustrated by (1).
   The media server Control (and Media dialogs as well, if required) is
   sent to the MRB (2) which then selects an appropriate Media Server
   (3) and would stay in the signaling path between the AS and the MS
   resource for the handled dialogs.

   In-line MRB can be split into two distinct logical roles which can be
   applied on a per request basis.  They are:

   In-line Unaware MRB Mode (IUMM):  Allows an MRB to act on behalf of
      clients requiring media services who are not aware of an MRB or
      its operation.  In this case the AS does not provide explicit
      information on the kind of MS resource it needs (as in
      Section 5.2) and the MRB is left to deduce it by potentially
      inspecting other information in the request from the AS; for
      example, SDP content, or address of the requesting AS, or
      additional Request-URI parameters as per RFC 4240 [RFC4240].

   In-line Aware MRB Mode (IAMM):  Allows an MRB to act on behalf of
      clients requiring media services who are aware of an MRB and its
      operation.  In particular it allows the AS to explicitly the
      convey the same kinds of MS characteristics desired as does the
      Query MRB mode (as in Section 5.2).

   In either role, the MRB would deduce that the selected MS resources
   are no longer needed when the AS or MS terminates the corresponding
   dialog.  The two modes are discussed in more detail in Section 5.3.

5.  MRB Interface Definitions

   As discussed in previous sections in this document, the intention is
   to provide a toolkit for a variety of deployment architectures where
   media resource brokering can take place.  As a result, two main
   interfaces are required to support the differing requirements.  The
   two interfaces are described in the remainder of this section and
   have been named the 'Media Server Resource Publish' and 'Media Server
   Resource Consumer' interfaces.  These two interfaces have extremely
   differing responsibilities and usages which is reflected in the
   choice of solutions.

   It is beyond the scope of this document to define exactly how to
   construct an MRB.  This includes interpreting the data for the Media
   Service Consumer interface supplied by the Media Server Publish
   interface.  It is, however, important that the two interfaces are
   complimentary so that development of appropriate MRB functionality is
   supported.

5.1.  Media Server Resource Publish Interface

   The Media Server Resource Publish interface is responsible for
   providing an MRB with appropriate Media Server resource information.
   As such, this interface is assumed to provide both general and
   specific details related to Media Server resources.  This information
   needs to be conveyed using an industry standard mechanism to provide
   increased levels of adoption and interoperability.  A Control Package
   for the Media Control Channel Framework will be specified to fulfil
   this interface requirement.  It provides an establishment and
   monitoring mechanism to enable a Media Server to report appropriate
   statistics to an MRB.  The Publish interface is used with both Query
   and In-line modes of MRB operation.

   As already anticipated in the introduction, the MRB view of MS
   resource availability will in practice be approximate - i.e., partial
   and imperfect.  The MRB Publish interface does not provide an
   exhaustive view of current MS resource consumption, the MS may in
   some cases provide a best-effort computed view of resource
   consumption parameters conveyed in the Publish interface (e.g., DSP's
   with a fixed number of streams versus GPU's with CPU availability),
   there may be licensing constraints not factored in (e.g., even if
   lots of CPU and memory are available, licensing or other
   configuration elements may restrict the number of stream types), and
   MS resource information may only be reported periodically over the
   Publish interface to MRB.  Nevertheless, despite such limitations it
   is assumed that the provided information is enough to allow MRB
   implementors to realize its functionality.

   It is also worth noting that, while the scope of the MRB is
   definitely on providing interested Application Servers with the
   available resources, the MRB also allows for the retrieval of
   information about the currently occupied resources.  While this is of
   course a relevant piece of information (e.g., for monitoring
   purposes), such a functionality inevitably raises security
   considerations, and implementations should take this into account.
   See Section 12 for more details.

   The MRB Publish interface uses the Media Control Channel Framework
   ([I-D.ietf-mediactrl-sip-control-framework]) as the basis for
   interaction between a Media Server and an MRB.  The Media Control
   Channel Framework uses an extension mechanism to allow specific
   usages which are known as control packages.  Section 5.1.1 defines
   the control package that MUST be implemented by any Media Server
   wanting to interact with an MRB entity.

   Please note that it is out of scope how an MRB knows what MSs should
   be queried for publishing information.

5.1.1.  Control Package Definition

   This section fulfills the mandatory requirement for information that
   must be specified during the definition of a Control Framework
   Package, as detailed in Section 8 of
   [I-D.ietf-mediactrl-sip-control-framework].

5.1.1.1.  Control Package Name

   The Media Channel Control Framework requires a Control Package
   definition to specify and register a unique name and version.

   The name and version of this Control Package is "mrb-publish/1.0".

5.1.1.2.  Framework Message Usage

   The MRB publish interface allows a media server to convey available
   capabilities and resources to an MRB entity.

   This package defines XML elements in Section 5.1.2 and provides an
   XML Schema in Section 10.

   The XML elements in this package are split into requests, responses
   and event notifications.  Requests are carried in CONTROL message
   bodies; <mrbrequest> element is defined as a package request.  This
   request can be used for creating new subscriptions and updating/
   removing existing subscriptions.  Event notifications are also
   carried in CONTROL message bodies; the <mrbnotification> element is
   defined for package event notifications.  Responses are carried
   either in REPORT message or Control Framework 200 response bodies;
   the <mrbresponse> element is defined as a package level response.

   Note that package responses are different from framework response
   codes.  Framework error response codes (see Section 7 of
   [I-D.ietf-mediactrl-sip-control-framework]) are used when the request
   or event notification is invalid; for example, a request has invalid
   XML (400), or is not understood (500).  Package level responses are
   carried in framework 200 response or REPORT message bodies.  This
   package's response codes are defined in Section 5.1.5.

5.1.1.3.  Common XML Support

   The Media Control Channel Framework
   [I-D.ietf-mediactrl-sip-control-framework] requires a Control Package
   definition to specify if the attributes for media dialog or
   conference references are required.

   The Publish interface defined in Section 10 does import and make use
   of the common XML schema defined in the Media Control Channel
   Framework.

   The Consumer interface defined in Section 11 does import and make use
   of the common XML schema defined in the Media Control Channel
   Framework.

5.1.1.4.  CONTROL Message Body

   A valid CONTROL body message MUST conform to the schema defined in
   Section 10 and described in Section 5.1.2.  XML messages appearing in
   CONTROL messages MUST contain either a <mrbrequest> or
   <mrbnotification> element.

5.1.1.5.  REPORT Message Body

   A valid REPORT body MUST conform to the schema defined in Section 10
   and described in Section 5.1.2.  XML messages appearing in REPORT
   messages MUST contain a <mrbresponse> element.

5.1.1.6.  Audit

   The 'mrb-publish/1.0' Media Control Channel Framework package does
   not require any additional auditing capability.

5.1.2.  Element Definitions

   This section defines the XML elements for the Publish interface Media
   Control Channel package defined in Section 5.1.  The formal XML
   schema definition for the Publish interface can be found in
   Section 10.

   The root element is <mrbpublish>.  All other XML elements (requests,
   responses, notifications) are contained within it.  The MRB Publish
   interface request element is detailed in Section 5.1.3.  The MRB
   Publish interface notification element is detailed in Section 5.1.4.
   MRB Publish interface response element is contained in Section 5.1.5.

   The <mrbpublish> element has the following attributes:

   version:  a token specifying the mrb-publish package version.  The
      value is fixed as '1.0' for this version of the package.  The
      attribute MUST be present.

   The <mrbpublish> element has the following child element, only one of
   which is allowed to occur in a request.

      <mrbrequest> for sending an MRB request.  See Section 5.1.3.

      <mrbresponse> for sending an MRB response.  See Section 5.1.5.

      <mrbnotification> for sending an MRB notification.  See
      Section 5.1.4.

5.1.3.  <mrbrequest>

   This section defines the <mrbrequest> element used to initiate
   requests from an MRB to a Media Server.  The element is a container
   for information relevant for the interrogation of a media server.

   The <mrbrequest> element has no defined attributes.

   The <mrbrequest> element has the following sub-elements which are
   defined in the remainder of this section:

      <subscription> for initiating a subscription to a Media Server
      from an MRB.  See Section 5.1.3.1.

5.1.3.1.  <subscription>

   The <subscription> element is included in a request from an MRB to a
   Media Server to provide the details relating to the configuration of
   updates.  This element can be used either to request a new
   subscription or to update an existing one (e.g., to change the
   frequency of the updates), and to remove ongoing subscriptions as
   well (e.g., to stop an indefinite update).  The MRB will inform the
   Media Server how long it wishes to receive updates for and the
   frequency that updates should be sent.  Updates related to the
   subscription are sent using the <mrbnotification> element.

   The <subscription> element has the following attributes:

   id:  indicates a unique token representing the subscription session
      between the MRB and the Media Server.  The attribute MUST be
      present.

   seqnumber:  indicates a sequence number to be used in conjunction
      with the subscrition session id to identify a specific
      subscription command.  The first subscription MUST have 1 as
      'seqnumber', and following subscriptions MUST increment by 1 the
      previous 'seqnumber' value.  The attribute MUST be present.

   action:  provides the operation that should be carried out on the
      subscription:

      *  The value of 'create' instructs the MS to attempt to setup a
         new subscription.

      *  The value of 'update' instructs the MS to attempt to update an
         existing subscription.

      *  The value of 'remove' instructs the MS to attempt to remove an
         existing subscription and consequently stop any ongoing related
         notification.

      The attribute MUST be present.

   The <subscription> element has the following child elements:

   expires:   Provides the amount of time in seconds that a subscription
      should be installed for notifications at the Media Server.  Once
      the amount of time has passed, the subscription expires and the
      MRB has to subscribe again in case it is still interested in
      receiving notifications from the MS.  The element MAY be present.

   frequency:

   minfrequency:   Provides the minimum frequency in seconds that the
      MRB wishes to receive notifications from the MS.  The element MAY
      be present.

   maxfrequency:   Provides the maximum frequency in seconds that the
      MRB wishes to receive notifications from the MS.  The element MAY
      be present.

   Please note that these two three optional pieces of information provided
   by the MRB only act as a suggestion: the MS MAY change the proposed
   values if it considers the suggestions unacceptable (e.g., if the MRB
   has requested a too high notification frequency).  In such case, the
   request would not fail, but the updated, acceptable values would be
   reported in the <mrbresponse> accordingly.

5.1.4.  <mrbnotification>

   The <mrbnotification> element is included in a request from a Media
   Server to an MRB to provide the details relating current status.  The
   Media Server will inform the MRB of its current status as defined by
   the information in the <subscription> element.  Updates are sent
   using the <mrbnotification> element.

   The <mrbnotification> element has the following attributes:

   id:  indicates a unique token representing the session between the
      MRB and the Media Server and is the same as the one appearing in
      the <subscription> element.  The attribute MUST be present.

   seqnumber:  indicates a sequence number to be used in conjunction
      with the subscription session id to identify a specific
      notification update.  The first notification MUST have 1 as
      'seqnumber', and following notifications MUST increment by 1 the
      previous 'seqnumber' value.  The attribute MUST be present.

   The following subsections provide details on the child elements that
   are contained within an <mrbnotification> element.

5.1.4.1.  <media-server-id>

   The <media-server-id> element provides a unique system wide
   identifier for a Media Server instance.  The element MUST be present.

5.1.4.2.  <supported-packages>

   The <supported-packages> element provides the list of Media Control
   Channel Packages supported by the media server.  The element MAY be
   present.

   The <supported-packages> element has no attributes.

   The <supported-packages> element has the following child element:

   package:   The <package> element represents the name of a package
      supported by the media server.  The <package> element has a single
      attribute, 'name', which represents the name of the supported
      Media Control Channel Framework package, compliant with the
      specification in the related IANA registry (e.g., "msc-ivr/1.0").

5.1.4.3.  <active-rtp-sessions>

   The <active-rtp-sessions> element provides information detailing the
   current active Real-time Transport Protocol(RTP) sessions.  The
   element MAY be present.

   The <active-rtp-sessions> element has no attributes.

   The <active-rtp-sessions> element has the following child element:

   rtp-codec:   Is a container which represents a supported codec and
      the associated active sessions.  The <rtp-codec> element has one
      attribute.  The attribute 'name' represents the name of the codec
      being represented.  A valid value is a MIME media type which,
      depending on its definition, can include additional parameters
      (e.g., [RFC4281]).  The <rtp-codec> element has two child
      elements.  The child element, <decoding>, represents the number of
      RTP sessions for the specified codec being decoded.  The child
      element, <encoding>, represents the number of RTP sessions for the
      specified codec being encoded.

5.1.4.4.  <active-mixer-sessions>

   The <active-mixer-sessions> element provides information detailing
   the current active mixed RTP sessions.  The element MAY be present.

   The <active-mixer-sessions> element has no attributes.

   The <active-mixer-sessions> element has the following child element:

   active-mix:   Is a container which represents a mixed active RTP
      session.  The <active-mix> element has one attribute.  The
      attribute 'conferenceid' represents the name of the mix being
      represented.  The <active-mix> element has one child element.  The
      child element, <rtp-codec>, contains the same information relating
      to RTP sessions as defined in Section 5.1.4.3.  The element MAY be
      present.

5.1.4.5.  <non-active-rtp-sessions>

   The <non-active-rtp-sessions> element provides information detailing
   the currently available inactive RTP sessions.  The element MAY be
   present.

   The <non-active-rtp-sessions> element has no attributes.

   The <non-active-rtp-sessions> element has the following child
   element:

   rtp-codec:   Is a container which represents a supported codec and
      the inactive sessions.  The <rtp-codec> element has one attribute.
      The attribute 'name' represents the name of the codec being
      represented.  A valid value is a MIME media type which, depending
      on its definition, can include additional parameters (e.g.,
      [RFC4281]).  The <rtp-codec> element has two child elements.  The
      first child element, <decoding>, represents the number of
      available incoming (decoding) RTP session for the specified codec.
      The second child element, <encoding>, represents the number of
      available outgoing (encoding) RTP sessions for the specified
      codec.  The element MAY be present.

5.1.4.6.  <non-active-mixer-sessions>

   The <non-active-mixer-sessions> element provides information
   detailing the current inactive mixed RTP sessions.  The element MAY
   be present.

   The <non-active-rtp-sessions> element has no attributes.

   The <non-active-mixer-sessions> element has the following child
   element:

   non-active-mix:   Is a container which representing an available
      mixed RTP session.  The <non-active-mix> element has one
      attribute.  The attribute 'available' represents the number of
      mixes that could be used using that profile.  The <non-active-mix>
      element has one child element.  The child element, <rtp-codec>,
      contains the same information relating to RTP sessions as defined
      in Section 5.1.4.5.  The element MAY be present.

5.1.4.7.  <media-server-status>

   The <media-server-status> element provides information detailing the
   current status of the media server.  The element MUST be present.  It
   can return one of the following values:

   active:   Indicating that the Media Server is available for service.

   deactivated:   Indicating that the Media Server has been withdrawn
      from service, and as such should not be contacted before it
      becomes 'active' again.

   unavailable:   Indicating that the Media Server continues to process
      past requests but cannot accept new requests, and as such should
      not be contacted before it becomes 'active' again.

   The <media-server-status> element has no attributes.

   The <media-server-status> element has no child elements.

5.1.4.8.  <supported-codecs>

   The <supported-codecs> element provides information detailing the
   current codecs supported by a media server and associated actions.
   The element MAY be present.

   The <supported-codecs> element has no attributes.

   The <supported-codecs> element has the following child element:

   supported-codec:   has a single attribute, 'name', which provides the
      name of the codec providing information.  A valid value is a MIME
      media type which, depending on its definition, can include
      additional parameters (e.g., [RFC4281]).  The <supported-codec>
      element then has a further child element, <supported-codec-
      package>.  The <supported-codec-package> element has a single
      attribute, 'name', which provides the name of the Media Control
      Channel Framework package, compliant with the specification in the
      related IANA registry (e.g., "msc-ivr/1.0"), for which the codec
      support applies.  The <supported-codec-package> element has one
      further child element, <supported-actions>, which provide the
      actions that a Media Server can apply to this codec:

      *  'decode', meaning a decoder for this codec is available;

      *  'encode', meaning an encoder for this codec is available;

      *  'passthrough', meaning the MS is able to pass a stream encoded
         using that codec through without re-encoding.

5.1.4.9.  <application-data>

   The <application-data> element provides arbitrary application level
   data.  This data is meant to only have meaning at the application
   level logic and as such is arbitrary.  The element MAY be present.

   The <application-data> element has no attributes.

   The <application-data> element has no child elements.

5.1.4.10.  <file-formats>

   The <file-formats> element provides a list of file formats supported
   for the purpose of playing media.  The element MAY be present.

   The <file-formats> element has no attributes.

   The <file-formats> element has the following child element:

   supported-format:   has a single attribute, 'name', which provides
      the type of file format that is supported.  A valid value is a
      MIME media type which, depending on its definition, can include
      additional parameters (e.g., [RFC4281]).  The <supported-format>
      element then has a further child element, <supported-file-
      package>.  The <supported-file-package> element provides the name
      of the Media Control Channel Framework package, compliant with the
      specification in the related IANA registry (e.g., "msc-ivr/1.0"),
      for which the file format support applies.

5.1.4.11.  <max-prepared-duration>

   The <max-prepared-duration> element provides the amount of time a
   media dialog can be prepared in the system before it is executed.
   The element MAY be present.

   The <max-prepared-duration> element has no attributes.

   The <max-prepared-duration> element has the following child element:

   max-time:   has a single attribute, 'max-time-seconds', which
      provides the amount of time in seconds that a media dialog can be
      in the prepared state.  The <max-time> element then has a further
      child element, <max-time-package>.  The <max-time-package> element
      provides the name of the Media Control Channel Framework package,
      compliant with the specification in the related IANA registry
      (e.g., "msc-ivr/1.0"), for which the time period applies.

5.1.4.12.  <dtmf-support>

   The <dtmf-support> element supplies the supported methods to detect
   DTMF tones and to generate them.  The element MAY be present.

   The <dtmf-support> element has no attributes.

   The <dtmf-support> element has the following child elements:

   detect:   Indicates the support for DTMF detection.  The <detect>
      element has no attributes.  The <detect> element then has a
      further child element, <dtmf-type>.  The <dtmf-type> element has
      two attributes, 'name' and 'package.  The 'name' attribute
      provides the type of DTMF being used, and it can only be either
      'RFC4733' [RFC4733] or 'Media' (tones as signals in the audio
      stream).  The 'package' attribute provides the name of the Media
      Control Channel Framework package, compliant with the
      specification in the related IANA registry (e.g., "msc-ivr/1.0"),
      for which the DTMF type applies.

   generate:   Indicates the support for DTMF generation.  The
      <generate> element has no attributes.  The <generate> element then
      has a further child element, <dtmf-type>.  The <dtmf-type> element
      has two attributes, 'name' and 'package.  The 'name' attribute
      provides the type of DTMF being used, and it can only be either
      'RFC4733' [RFC4733] or 'Media' (tones as signals in the audio
      stream).  The 'package' attribute provides the name of the Media
      Control Channel Framework package, compliant with the
      specification in the related IANA registry (e.g., "msc-ivr/1.0"),
      for which the DTMF type applies.

   passthrough:   Indicates the support for passing DTMF through without
      re-encoding.  The <passthrough> element has no attributes.  The
      <passthrough> element then has a further child element, <dtmf-
      type>.  The <dtmf-type> element has two attributes, 'name' and
      'package.  The 'name' attribute provides the type of DTMF being
      used, and it can only be either 'RFC4733' [RFC4733] or 'Media'
      (tones as signals in the audio stream).  The 'package' attribute
      provides the name of the Media Control Channel Framework package,
      compliant with the specification in the related IANA registry
      (e.g., "msc-ivr/1.0"), for which the DTMF type applies.

5.1.4.13.  <mixing-modes>

   The <mixing-modes> element provides information about the support for
   audio and video mixing of a Media Server, specifically a list of
   supported algorithms to mix audio and a list of supported video
   presentation layouts.  The element MAY be present.

   The <mixing-modes> element has no attributes.

   The <mixing-modes> element has the following child elements:

   audio-mixing-modes:   Is a container representing the available
      algorithms for audio mixing.  The <audio-mixing-modes> element has
      no attributes.  The <audio-mixing-modes> element has one child
      element.  The child element, <audio-mixing-mode>, contains a
      specific available algorithm.  It has a single attribute,
      'package'.  The attribute 'package' provides the name of the Media
      Control Channel Framework package, compliant with the
      specification in the related IANA registry (e.g., "msc-ivr/1.0"),
      for which the algorithm support applies.

   video-mixing-modes:   Is a container representing the available video
      presentation layouts and the supported functionality for what
      concerns video mixing.  The <video-mixing-modes> element has two
      attributes, 'vas' and 'activespeakermix'.  The 'vas' attribute is
      of type boolean with a value of 'true' indicating the Media Server
      supports automatic Voice Activated Switching.  The
      'activespeakermix' is of type boolean with a value of 'true'
      indicating that the Media Server is able to prepare an additional
      video stream for the loudest speaker participant without its
      contribution.  The <video-mixing-modes> element has one child
      element.  The child element, <video-mixing-mode>, contains the
      name of a specific video presentation layout.  The name may refer
      to one of predefined video layouts defined in the XCON conference
      information data model, or to non-XCON layouts as well, as long as
      they are properly prefixed.  The <video-mixing-mode> element has a
      single attribute, 'package'.  The attribute 'package' provides the
      name of the Media Control Channel Framework package, compliant
      with the specification in the related IANA registry (e.g., "msc-
      ivr/1.0"), for which the algorithm support applies.

5.1.4.14.  <supported-tones>

   The <supported-tones> element provides information about which tones
   a media server supports.  In particular, the support is reported
   referring to both country codes support (ISO 3166-1 [ISO.3166-1]) and
   supported functionality (ITU-T Recommendation Q.1950 [ITU-T.Q.1950]).
   The element MAY be present.

   The <supported-tones> element has no attributes.

   The <supported-tones> element has the following child elements:

   supported-country-codes:   Is a container representing the supported
      country codes with respect to tones.  The <supported-country-
      codes> element has no attributes.  The <supported-country-codes>
      has one child element.  The child element, <country-code>, reports
      support for a specific country code, compliant with the ISO 3166-1
      [ISO.3166-1] specification.  The <country-code> element has a
      single attribute, 'package'.  The attribute 'package' provides the
      name of the Media Control Channel Framework package, compliant
      with the specification in the related IANA registry (e.g., "msc-
      ivr/1.0"), in which the tones from the specified country code are
      supported.

   supported-h248-codes:   Is a container representing the supported
      H.248 codes with respect to tones.  The <supported-h248-codes>
      element has no attributes.  The <supported-h248-codes> has one
      child element.  The child element, <h248-code>, reports support
      for a specific H.248 code, compliant with the ITU-T Recommendation
      Q.1950 [ITU-T.Q.1950] specification.  The codes can be either
      specific (e.g., cg/dt to only report the Dial Tone from the Call
      Progress Tones package) or generic (e.g., cg/* to report all the
      tones from the Call Progress Tones package) using wildcards.  The
      <h248-code> element has a single attribute, 'package'.  The
      attribute 'package' provides the name of the Media Control Channel
      Framework package, compliant with the specification in the related
      IANA registry (e.g., "msc-ivr/1.0"), in which the specified codes
      are supported.

5.1.4.15.  <streaming-modes>

   The <streaming-modes> element allows the Media Server to specify
   which protocols are supported for streaming to a Media Server for
   each Media Control Channel Framework package type.  For example,
   whether the Media Server supports audio streaming via RTSP, HTTP,
   NFS, etc protocols.  The element MAY be present.

   The <streaming-modes> element has no attributes.

   The <streaming-modes> element has the following child element:

   stream-mode:   has two attributes, 'name' and 'package'.  The 'name'
      attribute provides the type of protocol that can be used for
      streaming (e.g., "HTTP", "RTSP", etc.).  The 'package' attribute
      provides the name of the Media Control Channel Framework package,
      compliant with the specification in the related IANA registry
      (e.g., "msc-ivr/1.0"), for which the streaming protocol applies.

5.1.4.16.  <asr-tts-support>

   The <asr-tts-support> element provides information about the support
   for Automatic Speech Recognition (ASR) and Text-to-Speech (TTS)
   functionality in a media server.  The functionality are reported by
   referring to the supported languages (using ISO-639-1 [ISO.639.1988]
   codes) for what regards both ASR and TTS.  The element MAY be
   present.

   The <asr-tts-support> element has no attributes.

   The <asr-tts-support> element has the following child elements:

   asr-support:   Is a container representing the available languages
      for ASR.  The <asr-support> element has no attributes.  The <asr-
      support> has one child element.  The child element, <language>,
      reports the MS supports ASR for a specific language.  The
      <language> element has a single attribute, 'xml:lang'.  The
      attribute 'xml:lang' contains the ISO-639-1 [ISO.639.1988] code of
      the supported language.

   tts-support:   Is a container representing the available languages
      for TTS.  The <tts-support> element has no attributes.  The <tts-
      support> has one child element.  The child element, <language>,
      reports the MS supports tts for a specific language.  The
      <language> element has a single attribute, 'xml:lang'.  The
      attribute 'xml:lang' contains the ISO-639-1 [ISO.639.1988] code of
      the supported language.

5.1.4.17.  <vxml-support>

   The <vxml-support> element specifies if the Media Server supports
   VoiceXML and if it does which protocols the support is exposed
   through (e.g., via the control framework, RFC4240 [RFC4240], or
   RFC5552 [RFC5552]).  The element MAY be present.

   The <vxml-support> element has a single attribute 'support'.  The
   'support' attribute is of type boolean with a value of 'true'
   indicating that the media server does support VXML, and a value of
   'false' indicating it does not support VXML.  The default value is
   'false'.

   The <vxml-support> element has the following child element:

   vxml-mode:   has two attributes, 'package' and 'support'.  The
      'package' attribute provides the name of the Media Control Channel
      Framework package, compliant with the specification in the related
      IANA registry (e.g., "msc-ivr/1.0"), for which the VXML support
      applies.  The 'support' attribute provides the type of VXML
      support provided by the Media Server (RFC5552 [RFC5552], RFC4240
      [RFC4240] or IVR-Package
      [I-D.ietf-mediactrl-ivr-control-package]).

5.1.4.18.  <media-server-location>

   The <media-server-location> element provides information about the
   civic location of a media server.  Its description makes use of the
   Civic Address Schema standardized in RFC 5139 [RFC5139].  The element
   MAY be present.

   The <media-server-location> element has no attributes.

   The <media-server-location> element one child element:

   civicAddress:   Is a container representing the civic address
      location of the media server, whose representation refers to the
      Section 4 of RFC 5139 [RFC5139].

5.1.4.19.  <label>

   The <label> element allows a Media Server to declare a piece of
   information that will be understood by the MRB.  For example, the
   Media Server can declare if it's a blue or green one.  It's a string
   to allow arbitrary values to be returned to allow arbitrary
   classification, and as such is not meant to provide any explicit
   information associated with the features of a MS.  The element MAY be
   present.

   The <label> element has no attributes.

   The <label> element has no child elements.

5.1.4.20.  <media-server-address>

   The <media-server-address> element allows a Media Server to provide a
   direct SIP URI address where it can be reached (e.g., the URI AS
   would call to in order to setup a Control Channel and relay call
   legs).  The element MAY be present.

   The <media-server-address> element has a single attribute.

   The <media-server-address> element has no child elements.

5.1.4.21.  <encryption>

   The <encyption> element allows a Media Server to declare support for
   encrypting RTP media streams using RFC 3711 [RFC3711].  A value of
   'true' indicates that a Media Server does support RFC 3711 [RFC3711]
   for RTP.  A value of 'false' indicates that a Media Server does not
   support RFC 3711 [RFC3711] for RTP.  The element MAY be present.

   The <encryption> element has no attributes.

   The <encryption> element has no child elements.

5.1.5.  <mrbresponse>

   Responses to requests are indicated by a <response> element from
   Section 10.

   The <response> element has following attributes:

   status:  numeric code indicating the response status.  The attribute
      MUST be present.

   reason:  string specifying a reason for the response status.  The
      attribute MAY be present.

   The following status codes are defined for 'status':

   +-----------+-------------------------------------------------------+
   | code      | description                                           |
   +-----------+-------------------------------------------------------+
   | 200       | OK                                                    |
   |           |                                                       |
   | 400       | Syntax error                                          |
   |           |                                                       |
   | 401       | Unable to create Subscription                         |
   |           |                                                       |
   | 402       | Unable to update Subscription                         |
   |           |                                                       |
   | 403       | Unable to remove Subscription                         |
   |           |                                                       |
   | 404       | Subscription does not exist                           |
   |           |                                                       |
   | 405       | Subscription already exists                           |
   |           |                                                       |
   | 420       | Unsupported attribute or element                      |
   +-----------+-------------------------------------------------------+

                    Table 1: <mrbresponse> status codes

   In case a new subscription request made by an MRB (action='create')
   has been accepted, the MS MUST reply with a <mrbresponse> with status
   code 200.  The same rule applies whenever a request to update
   (action='update') or remove (action='remove') an existing transaction
   can be fulfilled by the MS.

   A subscription request, nevertheless, may fail for several reasons.
   In such a case, the status codes defined in Table 1 must be used
   instead.  Specifically, if the MS fails to handle a request due to a
   syntax error in the request itself (e.g., incorrect XML, violation of
   the schema constraints or invalid values in any of the attributes/
   elements) the MS MUST reply with a <mrbresponse> with status code
   400.  If a syntactically correct request fails because the request
   also includes any attribute/element the MS doesn't understand, the MS
   MUST reply with a <mrbresponse> with status code 420.  If a
   syntactically correct request fails because the MRB wants to create a
   new subscription, but the provided intended id for the subscription
   already exists, the MS MUST reply with a <mrbresponse> with status
   code 405.  If a syntactically correct request fails because the MRB
   wants to update/remove a subscription that doesn't exist, the MS MUST
   reply with a <mrbresponse> with status code 404.  If the MS is unable
   to accept a request for any other reason (e.g., the MRB has no more
   resources to fulfil the request), the MS MUST reply with a
   <mrbresponse> with status code 401/402/403, depending on the action
   the MRB provided in its request:

   o  action='create' --> 401;

   o  action='update' --> 402;

   o  action='remove' --> 403;

   As explained in Section 5.1.3.1, even in case of an accepted
   subscription request the MS might change the suggested 'expires' 'expires',
   'minfrequency' and
   'frequency' 'maxfrequency' values provided by the MRB in its
   <mrbrequest>, if it considers them unacceptable (e.g., the requested
   frequency range is too high).  In such a case, the MS MUST add an
   additional <subscription> element to the response, including the
   updated values, to inform the MRB about the change.  The MS MAY
   include such element if the values have been accepted or were omitted
   in the request.

5.2.  Media Service Resource Consumer Interface

   The Media Server Consumer interface provides the ability for clients
   of an MRB, such as Application Servers, to request an appropriate
   Media Server to satisfy specific criteria.  The interface allows a
   client to pass detailed meta-information to the MRB to help select an
   appropriate Media Server.  The MRB is then able to make an informed
   decision and provide the client with an appropriate media server
   resource.  The MRB Consumer interface includes both 1) In-Line Aware
   MRB Mode (IAMM) that uses the Session Initiation Protocol (SIP) and
   2) Query mode that uses the Hypertext Transfer Protocol (HTTP)
   [RFC2616].  The MRB Consumer interface does not include In-Line
   Unaware Mode (IUMM) which is further explained in Section 5.3.  The
   following subsections provide guidance on using the Consumer
   interface, as defined by the 'application/mrb-consumer+xml MIME type
   in Section 11, with HTTP and SIP.

5.2.1.  Query Mode / HTTP Consumer Interface Usage

   An appropriate interface for such a 'query' style interface is in
   fact a HTTP usage.  Using HTTP and XML combined reduces complexity
   and encourages use of common tools that are widely available in the
   industry today.  The following information explains the primary
   operations required to request and then receive information from an
   MRB.  The following description will describe the use of HTTP
   [RFC2616] and HTTPS [RFC2818] as transport for a query for media
   resource and the appropriate response.

   The media resource query, as defined by the <mediaResourceRequest>
   element from Section 11, MUST be carried in the body of an HTTP/HTTPS
   POST request.  The MIME type contained in the HTTP/HTTPS request/
   response MUST be 'application/mrb-consumer+xml'.  This value MUST be
   reflected in the appropriate HTTP headers like 'Content-Type' and
   'Accept'.  The body of the HTTP/HTTPS POST request MUST only contain
   the 'mediaResourceRequest' element as defined in Section 11.  The
   'mediaResourceRequest' element is the primary container of
   information related to a media resource request.

   The media resource response to a query, as defined by the
   <mediaResourceResponse> element from Section 11, MUST be carried in
   the body of an HTTP/HTTPS 200 response to the original HTTP/HTTPS
   POST request.  The MIME type contained in the HTTP/HTTPS request/
   response MUST be 'application/mrb-consumer+xml'.  This value MUST be
   reflected in the appropriate HTTP headers like 'Content-Type' and
   'Accept'.  The body of the HTTP/HTTPS 200 response MUST only contain
   the 'mediaResourceResponse' element as defined in Section 11.  The
   'mediaResourceResponse' element is the primary container of
   information related to a media resource response.

   When an application server wants to release previously awarded media
   resources granted through a prior request/response exchange with MRB,
   it will send a new request with an <action> element with value
   'remove' as described in Section Section 5.2.3 about the use of the
   Consumer interface lease mechanism.

5.2.2.  In-Line Aware Mode / SIP Consumer Interface Usage

   This document provides a complete toolkit for MRB deployment which
   includes the ability to interact with an MRB using SIP for the
   Consumer interface.  The following information explains the primary
   operations required to request and then receive information from an
   MRB.  The following description will describe the use of SIP
   [RFC3261] as transport for a request for media resources and the
   appropriate response when used with IAMM of operation (as discussed
   in Section 5.2.2.1).

   Use of IAMM, besides having the MRB select an appropriate media
   resource on behalf of a client application, includes setting up
   either a Control Framework control channel between an application
   server and media server (Section 5.2.2.1) or a call leg media session
   between an application server and a media server (Section 5.2.2.2).
   Note that in either case the SIP address of the selected media server
   is made known to the requesting application server in the SIP 200 OK
   response as the media-server-address element in the <response-
   session-info> element (Section 5.2.5).

5.2.2.1.  IAMM and Setting up a Control Framework Control Channel

   The media resource request information, as defined by the
   <mediaResourceRequest> element from Section 11, MUST be carried in a
   SIP INVITE request.  The INVITE request will be constructed as it
   would have been to connect to a media server, as defined by the Media
   Control Channel Framework [I-D.ietf-mediactrl-sip-control-framework].
   The following additional steps MUST be followed when using the
   Consumer interface:

   o  Include a payload in the SIP INVITE request of type 'multipart/
      mixed'[RFC2046].  One of the parts to be included in the
      'multipart/mixed' payload MUST be the 'application/sdp' format
      which is constructed as specified in the Media Control Channel
      Framework [I-D.ietf-mediactrl-sip-control-framework].

   o  Another part of the 'multipart/mixed' payload MUST be of type
      'application/mrb-consumer+xml', as specified in this document and
      defined in Section 11.  Only the <mediaResourceRequest> and its
      child elements can be included in the payload.

   o  The INVITE request will then be dispatched to the MRB, as defined
      by [I-D.ietf-mediactrl-sip-control-framework].

   On receiving a SIP INVITE request containing the multipart mixed
   payload as specified previously, the MRB will complete a number of
   steps to fulfill the request.  It will:

   o  Extract the multipart MIME payload from the SIP INVITE request.
      It will then use the contextual information provided by the client
      in the 'application/mrb-consumer+xml' part to determine which
      media server should be selected to service the request.

   o  Extract the 'application/sdp' part from the payload and use it to
      populate a new SIP INVITE request for connecting the client to the
      selected media server, as defined in the Media Channel Control
      Framework [I-D.ietf-mediactrl-sip-control-framework].

   The MRB acts as a Back-to-Back-UA (B2BUA) that extracts the
   'application/mrb-consumer+xml' information from the SIP INVITE
   request and then sends a corresponding SIP INVITE request to the
   selected Media Server.

   Once the MRB receives the SIP response from the selected media
   resource (i.e., media server), it will in turn respond to the
   requesting client (i.e., application server).

   The media resource response by MRB to a request, as defined by the
   <mediaResourceResponse> element from Section 11, MUST be carried in
   the payload of a SIP 2xx class response to the original SIP INVITE
   request.  The 2xx class response will be constructed as it would have
   been to connect from a media server, as defined by the Media Control
   Channel Framework [I-D.ietf-mediactrl-sip-control-framework].  The
   following additional steps MUST be followed when using the Consumer
   interface:

   o  Include a payload in the SIP 2xx class response of type
      'multipart/mixed' as perRFC 2046 [RFC2046].  One of the parts to
      be included in the 'multipart/mixed' payload MUST be the
      'application/sdp' format which is constructed as specified in the
      Media Control Channel Framework
      [I-D.ietf-mediactrl-sip-control-framework].

   o  Another part of the 'multipart/mixed' payload MUST be of type
      'application/mrb-consumer+xml', as specified in this document and
      defined in Section 11.  Only the <mediaResourceResponse> and its
      child elements can be included in the payload.

   o  The SIP 2xx class response will then be dispatched from the MRB.

   o  A SIP ACK to the 2xx class response will then be sent back to the
      MRB.

   An MRB implementation may be programmed to conclude that the
   requested resources are no longer needed when it receives a SIP BYE
   from the application server or media server that concludes the SIP
   dialog that initiated the request, or when the lease interval
   expires.

5.2.2.2.  IAMM and Setting up a Call Leg

   This scenario is identical to the description in the prior section
   for setting up a Control Framework control channel, except for the
   difference that the application/sdp payload conveys content
   appropriate for setting up the call leg to the media resource, as per
   RFC 3261 [RFC2046], instead of application/sdp payload for setting up
   a control channel.

5.2.3.  Consumer Interface Lease Mechanism

   The Consumer interface defined in Section 5.2 and Section 11 allows a
   client to request an appropriate media resource based on information
   included in the request (either a HTTP POST or SIP INVITE message).
   In case of success, the response that is returned to the client MUST
   contain a <session-info> element in either the SIP 2xx class or HTTP
   200 response.  The information contained in the <response-session-
   info> element allows a Consumer client to monitor the life time of
   the resources it has successfully requested, as well as amending
   them.

   Before delving into the details of such lease mechanism, though, it's
   worthwhile to first clarify its role within the context of the
   Consumer interface.  As explained in Section 5.1, the knowledge the
   MRB has of the resources of all the MS it handles is imperfect.  As
   such, how an MRB actually manages such resources depends on how it is
   implemented: one may choose to have the MRB keeping track and state
   of the allocated resources, or simply depend on the MS themselves to
   provide the information by means of the publishing interface
   notifications.  Further information may be inferred by the
   signalling, in case the MRB is in the path of call legs.

   That said, the <mediaResourceResponse> element returned from the MRB
   contains a <response-session-info> element if the request is
   successful.  The <response-session-info> element has the following
   child elements which provide the appropriate resource session
   information:

   o  <session-id> is a unique identifier that enables a Consumer client
      and MRB to correlate future media resource requests related to an
      initial media resource request.  The <session-id> MUST be included
      in all future related requests (see <session-id> use later in this
      section when constructing a subsequent request).

   o  <seq> is a numeric value returned to the Consumer client.  On
      issuing any future requests related to the media resource session
      (as determined by the <session-id> element) the consumer client
      MUST increment the value returned in the <seq> element and include
      in the request (see <seq> use later in this section when
      constructing a subsequent request).

   o  <expires> provides a value which represents the number of seconds
      the request for media resources is deemed alive.  The Consumer
      client should issue a refresh of the request, as discussed later
      in this section, if the expires timer is due to fire and the media
      resources are still required.

   o  <media-server-address> provides information representing the
      assigned MS.

   The <mediaResourceRequest> element is used in subsequent Consumer
   interface requests if the client wishes to manipulate the session.
   The Consumer client MUST include the <session-info> element which
   enables the receiving MRB to determine an existing media resource
   allocation session.  The <session-info> element has the following
   child elements which provide the appropriate resource session
   information to the MRB:

   o  <session-id> is a unique identifier that allows a Consumer client
      to indicate the appropriate existing media resource session to be
      manipulated by the MRB for this request.  The value was provided
      by the MRB in the initial request for media resources, as
      discussed earlier in this section (<session-id> element included
      as part of the <session-info> element in the initial
      <mediaResourceResponse>).

   o  <seq> is a numeric value returned to Consumer client in the
      initial request for media resources, as discussed earlier in this
      section (<seq> element included as part of the <session-info>
      element in the initial <mediaResourceResponse>).  On issuing any
      future requests related to the specific media resource session (as
      determined by the <session-id> element) the consumer client MUST
      increment the value returned in the <seq> element from the initial
      response (contained in the <mediaResourceResponse>) for every new
      request.  The value of the <seq> element in requests acts as a
      counter to and in conjunction with the unique <session-id> allows
      for unique identification of a request.

   o  <action> element provides the operation to be carried out by the
      MRB on receiving the request:

      *  The value of 'update' is a request by the Consumer client to
         update the existing session at the MRB with alternate
         requirements which are contained in the remainder of the
         request.  If the requested resource information is identical to
         the existing MRB session, the MRB will attempt a session
         refresh.  If the information has changed, the MRB will attempt
         to update the existing session with the new information.  If
         the operation is successful, the 200 status code in the
         response is returned in the status attribute of the
         <mediaResourceResponseType> element.  If the operation is not
         successful, a 409 status code in the response is returned in
         the status attribute of the <mediaResourceResponseType>
         element.

      *  The value of 'remove' is a request by the Consumer client to
         remove the session at the MRB.  This provides a mechanism for
         Consumer clients to release unwanted resources before they
         expire.  If the operation is successful, a 200 status code in
         the response is returned in the status attribute of the
         <mediaResourceResponseType> element.  If the operation is not
         successful, a 410 status code in the response is returned in
         the status attribute of the <mediaResourceResponseType>
         element.

   Omitting the 'action' attribute means requesting a new set of
   resources.

   When used with SIP the <session-info> element MUST be included in
   either a SIP re-INVITE (as defined in [RFC3261]) or a SIP UPDATE (as
   defined in[RFC3311]) request.  When used with HTTP the <session-info>
   element MUST be included in a HTTP POST message (as defined in
   [RFC2616]).

   With IAMM, the application server or media server will eventually
   send a SIP BYE to end the SIP session, whether it was for a control
   channel or a call leg.  That BYE contains no Consumer interface lease
   information.  An MRB can be programmed to know that receipt of such a
   BYE also means to free up the media resources that had been requested
   and awarded related to that session.

5.2.4.  Media Service Resource Request

   This section defines the XML elements for the Consumer interface.
   The formal XML schema definition for the Consumer interface can be
   found in Section 11.

   The root element is <mrbconsumer>.  All other XML elements (requests,
   responses) are contained within it.  The MRB Consumer interface
   request element is detailed in Section 5.2.4.1.  MRB Consumer
   interface response element is contained in Section 5.2.5.1.

   The <mrbconsumer> element has the following attributes:

   version:   a token specifying the mrb-consumer package version.  The
      value is fixed as '1.0' for this version of the package.  The
      attribute MUST be present.

   The <mrbconsumer> element has the following child elements, only one
   of which is allowed to occur.

      <mediaResourceRequest> for sending a Consumer request.  See
      Section 5.2.4.1.

      <mediaResourceResponse> for sending a Consumer response.  See
      Section 5.2.5.1.

5.2.4.1.  <mediaResourceRequest> element

   The <mediaResourceRequest> element provides a container for clients
   wishing to query an external MRB entity.  The <mediaResourceRequest>
   element has <generalInfo>, <ivrInfo> and <mixerInfo> as child
   elements.  These three elements are used to describe the requirements
   of a client requesting a Media Server and are covered in the
   following sub-sections.

5.2.4.1.1.  <generalInfo> element

   The <generalInfo> element provides a container for general Consumer
   request information that is neither IVR or Mixer specific.  This
   includes session information that can be used for subsequent requests
   as part of the leasing mechanism described in Section 5.2.3.  The
   following sub-sections describe the elements of the <generalInfo>
   element, <session-info> and <packages>.

5.2.4.1.1.1.  <session-info> element

   The <session-info> element is included in Consumer requests when an
   update is being made to an existing media resource session.  The
   ability to change and remove an existing media resource session is
   described in more detail in Section 5.2.3.  The element MAY be
   present.

   The <session-info> element has no attributes.

   The <session-info> element has the following child elements:

   session-id:   is a unique identifier that explicitly references an
      existing media resource session on the MRB.  The identifier is
      included to update the existing session and is described in more
      detail in Section 5.2.3.

   seq:   is used in association with the <session-id> element in a
      subsequent request to update an existing media resource session on
      an MRB.  The <seq> number is incremented from its original value
      returned in response to the initial request for media resources.
      More information about its use is provided in Section 5.2.3.

   action:   provides the operation that should be carried out on an
      existing media resource session on an MRB:

      *  The value of 'update' instructs the MRB to attempt to update
         the existing media resource session with the information
         contained in the <ivrInfo> and <mixerInfo> elements.

      *  The value of 'remove' instructs the MRB to attempt to remove
         the existing media resource session.  More information on its
         use is provided in Section 5.2.3.

5.2.4.1.1.2.  <packages> element

   The <packages> element provides a list of Media Control Channel
   Framework compliant packages that are required by the Consumer
   client.  The element MAY be present.

   The <packages> element has no attributes.

   The <packages> element has the following child element:

   package:   child element contains a string representing the Media
      Control Channel Framework package required by the Consumer client.
      The <package> element can appear multiple times.  A valid value is
      a Control Package name as specified in the related IANA registry
      (e.g., "msc-ivr/1.0")

5.2.4.1.2.  <ivrInfo> element

   The <ivrInfo> element provides a container for general Consumer
   request information that is IVR specific.  The following sub-sections
   describe the elements of the <ivrInfo> element, <ivr-sessions>,
   <file-formats>, <dtmf>, <tones>, <asr-tts>, <vxml>, <location>,
   <encryption>, <application-data>, <max-prepared-duration> and
   <stream-mode>.

5.2.4.1.2.1.  <ivr-sessions> element

   The <ivr-sessions> element indicates the number of IVR sessions a
   Consumer client requires from a media resource.  The element MAY be
   present.

   The <ivr-sessions> element has no attributes.

   The <ivr-sessions> element has the following child element:

   rtp-codec:   child element contains has a single attribute, 'name'.
      The 'name' attribute provides the name of the codec required for
      an IVR session and is an appropriately registered token.  A valid
      value is a MIME media type which, depending on its definition, can
      include additional parameters (e.g., [RFC4281]).  The <rtp-codec>
      element has two child elements.  The child element, <decoding>,
      represents the number of RTP sessions for which decoding using the
      specified codec is requested.  The child element, <encoding>,
      represents the number of RTP sessions for which encoding using the
      specified codec is requested.

5.2.4.1.2.2.  <file-formats> element

   The <file-formats> element provides a list of file formats required
   for the purpose of playing media.  The element MAY be present.

   The <file-formats> element has no attributes.

   The <file-formats> element has the following child element:

   required-format:   has a single attribute, 'name', which provides the
      type of file format that is required.  A valid value is a MIME
      media type which, depending on its definition, can include
      additional parameters (e.g., [RFC4281]).  The <supported-format>
      element then has a further child element, <required-file-package>.
      The <required-file-package> element provides the name of the Media
      Control Channel Framework package, compliant with the
      specification in the related IANA registry (e.g., "msc-ivr/1.0"),
      for which the file format support applies.

5.2.4.1.2.3.  <dtmf> element

   The <dtmf> element supplies the required methods to detect DTMF tones
   and to generate them.  The element MAY be present.

   The <dtmf> element has no attributes.

   The <dtmf> element has the following child elements:

   detect:   Indicates the required support for DTMF detection.  The
      <detect> element has no attributes.  The <detect> element then has
      a further child element, <dtmf-type>.  The <dtmf-type> element has
      two attributes, 'name' and 'package.  The 'name' attribute
      provides the type of DTMF being needed, and it can only be either
      'RFC4733' [RFC4733] or 'Media' (tones as signals in the audio
      stream).  The 'package' attribute provides the name of the Media
      Control Channel Framework package, compliant with the
      specification in the related IANA registry (e.g., "msc-ivr/1.0"),
      for which the DTMF type applies.

   generate:   Indicates the required support for DTMF generation.  The
      <generate> element has no attributes.  The <generate> element then
      has a further child element, <dtmf-type>.  The <dtmf-type> element
      has two attributes, 'name' and 'package.  The 'name' attribute
      provides the type of DTMF being needed, and it can only be either
      'RFC4733' [RFC4733] or 'Media' (tones as signals in the audio
      stream).  The 'package' attribute provides the name of the Media
      Control Channel Framework package, compliant with the
      specification in the related IANA registry (e.g., "msc-ivr/1.0"),
      for which the DTMF type applies.

   passthrough:   Indicates the required support for passing DTMF
      through without re-encoding.  The <passthrough> element has no
      attributes.  The <passthrough> element then has a further child
      element, <dtmf-type>.  The <dtmf-type> element has two attributes,
      'name' and 'package.  The 'name' attribute provides the type of
      DTMF being needed, and it can only be either 'RFC4733' [RFC4733]
      or 'Media' (tones as signals in the audio stream).  The 'package'
      attribute provides the name of the Media Control Channel Framework
      package, compliant with the specification in the related IANA
      registry (e.g., "msc-ivr/1.0"), for which the DTMF type applies.

5.2.4.1.2.4.  <tones>

   The <tones> element provides requested tones a media server must
   support for IVR.  In particular, the request refers to both country
   codes support (ISO 3166-1 [ISO.3166-1]) and requested functionality
   (ITU-T Recommendation Q.1950 [ITU-T.Q.1950]).  The element MAY be
   present.

   The <tones> element has no attributes.

   The <tones> element has the following child elements:

   country-codes:   Is a container representing the requested country
      codes with respect to tones.  The <country-codes> element has no
      attributes.  The <country-codes> has one child element.  The child
      element, <country-code>, requests a specific country code,
      compliant with the ISO 3166-1 [ISO.3166-1] specification.  The
      <country-code> element has a single attribute, 'package'.  The
      attribute 'package' provides the name of the Media Control Channel
      Framework package, compliant with the specification in the related
      IANA registry (e.g., "msc-ivr/1.0"), in which the tones from the
      specified country code are requested.

   h248-codes:   Is a container representing the requested H.248 codes
      with respect to tones.  The <h248-codes> element has no
      attributes.  The <h248-codes> has one child element.  The child
      element, <h248-code>, requests a specific H.248 code, compliant
      with the ITU-T Recommendation Q.1950 [ITU-T.Q.1950] specification.
      The codes can be either specific (e.g., cg/dt to only report the
      Dial Tone from the Call Progress Tones package) or generic (e.g.,
      cg/* to report all the tones from the Call Progress Tones package)
      using wildcards.  The <h248-code> element has a single attribute,
      'package'.  The attribute 'package' provides the name of the Media
      Control Channel Framework package, compliant with the
      specification in the related IANA registry (e.g., "msc-ivr/1.0"),
      in which the specified codes are requested.

5.2.4.1.2.5.  <asr-tts>

   The <asr-tts-support> element requests information about the support
   for Automatic Speech Recognition (ASR) and Text-to-Speech (TTS)
   functionality in a media server.  The functionality is requested by
   referring to the supported languages (using ISO-639-1 [ISO.639.1988]
   codes) for what regards both ASR and TTS.  The <asr-tts-support>
   element has no attributes.  The <asr-tts-support> element has the
   following child elements:

   asr-support:   Is a container representing the available languages
      for ASR.  The <asr-support> element has no attributes.  The <asr-
      support> has one child element.  The child element, <language>,
      requests the MS supports ASR for a specific language.  The
      <language> element has a single attribute, 'xml:lang'.  The
      attribute 'xml:lang' contains the ISO-639-1 [ISO.639.1988] code of
      the supported language.

   tts-support:   Is a container requesting the available languages for
      TTS.  The <tts-support> element has no attributes.  The <tts-
      support> has one child element.  The child element, <language>,
      requests the MS supports tts for a specific language.  The
      <language> element has a single attribute, 'xml:lang'.  The
      attribute 'xml:lang' contains the ISO-639-1 [ISO.639.1988] code of
      the supported language.

5.2.4.1.2.6.  <vxml> element

   The <vxml> element specifies if the Consumer client required VoiceXML
   and if it does which protocols the support is exposed through (e.g.,
   via the control framework, RFC4240 [RFC4240], or RFC5552 [RFC5552]).
   The element MAY be present.

   The <vxml> element has a single attribute 'support'.  The 'support'
   attribute is of type boolean with a value of 'true' indicating that
   the Consumer client requires VXML support, and a value of 'false'
   indicating it does not require VXML support.  The default value is
   'false'.

   The <vxml> element has the following child element:

   vxml-mode:   has two attributes, 'package' and 'require'.  The
      'package' attribute provides the name of the Media Control Channel
      Framework package, compliant with the specification in the related
      IANA registry (e.g., "msc-ivr/1.0"), for which the VXML support
      applies.  The 'require' attribute specifies the type of VXML
      support required by the Consumer client (RFC5552 [RFC5552],
      RFC4240 [RFC4240] or IVR-Package
      [I-D.ietf-mediactrl-ivr-control-package]).

5.2.4.1.2.7.  <location>

   The <location> element requests a civic location for an IVR media
   server.  The request makes use of the Civic Address Schema
   standardized in RFC 5139 [RFC5139].  The element MAY be present.

   The <location> element has no attributes.

   The <location> element one child element:

   civicAddress:   Is a container representing the civic address
      location of the requested media server, whose representation
      refers to Section 4 of RFC 5139 [RFC5139].

5.2.4.1.2.8.  <encryption>

   The <encryption> element allows a Consumer client to request support
   for encrypting RTP media streams using RFC 3711 [RFC3711].  A value
   of 'true' indicates that Consumer client requires support of RFC 3711
   [RFC3711] for RTP.  A value of 'false' indicates that a Consumer
   client does not require support of RFC 3711 [RFC3711] for RTP.  The
   element MAY be present.  The default value is 'false'

   The <encryption> element has no attributes.

   The <encryption> element has no child elements.

5.2.4.1.2.9.  <application-data>

   The <application-data> element provides IVR application level data.
   The element MAY be present.

   The <application-data> element has no attributes.

   The <application-data> element has no child elements.

5.2.4.1.2.10.  <max-prepared-duration>

   The <max-prepared-duration> element provides the amount of time
   required by the Consumer client that a media dialog can be prepared
   in the system before it is executed.  The element MAY be present.

   The <max-prepared-duration> element has no attributes.

   The <max-prepared-duration> element has the following child element:

   max-time:   has a single attribute, 'max-time-seconds', which
      provides the amount of time in seconds that a media dialog can be
      in the prepared state.  The <max-time> element then has a further
      child element, <max-time-package>.  The <max-time-package> element
      provides the name of the Media Control Channel Framework package,
      compliant with the specification in the related IANA registry
      (e.g., "msc-ivr/1.0"), for which the time period applies.

5.2.4.1.2.11.  <streaming-modes>

   The <streaming-modes> element allows the Consumer client to specify
   which protocols are required for streaming to a Media Server for each
   Media Control Channel Framework package type.  For example does the
   Media Server supports audio streaming via RTSP, HTTP, NFS, etc
   protocols.  The element MAY be present.

   The <streaming-modes> element has no attributes.

   The <streaming-modes> element has the following child element:

   stream-mode:   has two attributes, 'name' and 'package'.  The 'name'
      attribute provides the type of protocol required for streaming.
      The 'package' attribute provides the name of the Media Control
      Channel Framework package, compliant with the specification in the
      related IANA registry (e.g., "msc-ivr/1.0"), for which the
      streaming protocol applies.

5.2.4.1.3.  <mixerInfo> element

   The <mixerInfo> element provides a container for general Consumer
   request information that is Mixer specific.  The following sub-
   sections describe the elements of the <mixerInfo> element, <mixers>,
   <file-formats>, <dtmf-type>, <tones>, <mixing-mode>, <application-
   data>, <location> and <encryption>.

5.2.4.1.3.1.  <mixers>

   The <mixers> element provides information detailing the required
   mixed RTP sessions.  The element MAY be present.

   The <mixers> element has no attributes.

   The <mixers> element has the following child element:

   mix:   Is a container which represents a required mixed RTP session.
      The <mix> element has one attribute.  The attribute 'users'
      represents the number of participants required in the mix.  The
      <mix> element has one child element.  The child element, <rtp-
      codec>, contains the same information relating to RTP sessions as
      defined in Section 5.1.4.3.  The element MAY be present.

5.2.4.1.3.2.  <file-formats>

   The <file-formats> element provides a list of file formats required
   by the Consumer client for the purpose of playing media to a mix.
   The element MAY be present.

   The <file-formats> element has no attributes.

   The <file-formats> element has the following child element:

   required-format:   has a single attribute, 'name', which provides the
      type of file format that is supported.  A valid value is a MIME
      media type which, depending on its definition, can include
      additional parameters (e.g., [RFC4281]).  The <required-format>
      element then has a further child element, <required-file-package>.
      The <required-file-package> element provides the name of the Media
      Control Channel Framework package, compliant with the
      specification in the related IANA registry (e.g., "msc-ivr/1.0"),
      for which the file format support applies.

5.2.4.1.3.3.  <dtmf> element

   The <dtmf> element supplies the required methods to detect DTMF tones
   and to generate them in a mix.  The element MAY be present.

   The <dtmf> element has no attributes.

   The <dtmf> element has the following child elements:

   detect:   Indicates the required support for DTMF detection.  The
      <detect> element has no attributes.  The <detect> element then has
      a further child element, <dtmf-type>.  The <dtmf-type> element has
      two attributes, 'name' and 'package.  The 'name' attribute
      provides the type of DTMF being used, and it can only be either
      'RFC4733' [RFC4733] or 'Media' (tones as signals in the audio
      stream).  The 'package' attribute provides the name of the Media
      Control Channel Framework package, compliant with the
      specification in the related IANA registry (e.g., "msc-ivr/1.0"),
      for which the DTMF type applies.

   generate:   Indicates the required support for DTMF generation.  The
      <generate> element has no attributes.  The <generate> element then
      has a further child element, <dtmf-type>.  The <dtmf-type> element
      has two attributes, 'name' and 'package.  The 'name' attribute
      provides the type of DTMF being used, and it can only be either
      'RFC4733' [RFC4733] or 'Media' (tones as signals in the audio
      stream).  The 'package' attribute provides the name of the Media
      Control Channel Framework package, compliant with the
      specification in the related IANA registry (e.g., "msc-ivr/1.0"),
      for which the DTMF type applies.

   passthrough:   Indicates the required support for passing DTMF
      through without re-encoding.  The <passthrough> element has no
      attributes.  The <passthrough> element then has a further child
      element, <dtmf-type>.  The <dtmf-type> element has two attributes,
      'name' and 'package.  The 'name' attribute provides the type of
      DTMF being used, and it can only be either 'RFC4733' [RFC4733] or
      'Media' (tones as signals in the audio stream).  The 'package'
      attribute provides the name of the Media Control Channel Framework
      package, compliant with the specification in the related IANA
      registry (e.g., "msc-ivr/1.0"), for which the DTMF type applies.

5.2.4.1.3.4.  <tones>

   The <tones> element provides requested tones a media server must
   support for a mix.  In particular, the request refers to both country
   codes support (ISO 3166-1 [ISO.3166-1]) and requested functionality
   (ITU-T Recommendation Q.1950 [ITU-T.Q.1950]).  The element MAY be
   present.

   The <tones> element has no attributes.

   The <tones> element has the following child elements:

   country-codes:   Is a container representing the requested country
      codes with respect to tones.  The <country-codes> element has no
      attributes.  The <country-codes> has one child element.  The child
      element, <country-code>, requests a specific country code,
      compliant with the ISO 3166-1 [ISO.3166-1] specification.  The
      <country-code> element has a single attribute, 'package'.  The
      attribute 'package' provides the name of the Media Control Channel
      Framework package, compliant with the specification in the related
      IANA registry (e.g., "msc-ivr/1.0"), in which the tones from the
      specified country code are requested.

   h248-codes:   Is a container representing the requested H.248 codes
      with respect to tones.  The <h248-codes> element has no
      attributes.  The <h248-codes> has one child element.  The child
      element, <h248-code>, requests a specific H.248 code, compliant
      with the ITU-T Recommendation Q.1950 [ITU-T.Q.1950] specification.
      The codes can be either specific (e.g., cg/dt to only report the
      Dial Tone from the Call Progress Tones package) or generic (e.g.,
      cg/* to report all the tones from the Call Progress Tones package)
      using wildcards.  The <h248-code> element has a single attribute,
      'package'.  The attribute 'package' provides the name of the Media
      Control Channel Framework package, compliant with the
      specification in the related IANA registry (e.g., "msc-ivr/1.0"),
      in which the specified codes are requested.

5.2.4.1.3.5.  <mixing-modes>

   The <mixing-modes> element requests information about the support for
   audio and video mixing of a Media Server, specifically a list of
   supported algorithms to mix audio and a list of supported video
   presentation layouts.  The element MAY be present.

   The <mixing-modes> element has no attributes.

   The <mixing-modes> element has the following child elements:

   audio-mixing-modes:   Is a container representing the requested
      algorithms for audio mixing.  The <audio-mixing-modes> element has
      no attributes.  The <audio-mixing-modes> element has one child
      element.  The child element, <audio-mixing-mode>, contains a
      specific requested algorithm.  It has a single attribute,
      'package'.  The attribute 'package' provides the name of the Media
      Control Channel Framework package, compliant with the
      specification in the related IANA registry (e.g., "msc-ivr/1.0"),
      for which the algorithm support is requested.

   video-mixing-modes:   Is a container representing the requested video
      presentation layouts for video mixing.  The <video-mixing-modes>
      element has two attributes, 'vas' and 'activespeakermix'.  The
      'vas' attribute is of type boolean with a value of 'true'
      indicating that the Consumer Client requires automatic Voice
      Activated Switching.  The 'activespeakermix' attribute is of type
      boolean with a value of 'true' indicating that the Consumer Client
      requires an additional video stream for the loudest speaker
      participant without its contribution.  The <video-mixing-modes>
      element has one child element.  The child element, <video-mixing-
      mode>, contains the name of a specific video presentation layout.
      The name may refer to one of predefined video layouts defined in
      the XCON conference information data model, or to non-XCON layouts
      as well, as long as they are properly prefixed.  The <video-
      mixing-mode> element has a single attribute, 'package'.  The
      attribute 'package' provides the name of the Media Control Channel
      Framework package, compliant with the specification in the related
      IANA registry (e.g., "msc-ivr/1.0"), for which the algorithm
      support is requested.

5.2.4.1.3.6.  <application-data>

   The <application-data> element provides application level data.  The
   element MAY be present.

   The <application-data> element has no attributes.

   The <application-data> element has no child elements.

5.2.4.1.3.7.  <location>

   The <location> element requests a civic location for a mixer media
   server.  The request makes use of the Civic Address Schema
   standardized in RFC 5139 [RFC5139].  The element MAY be present.

   The <location> element has no attributes.

   The <location> element one child element:

   civicAddress:   Is a container representing the civic address
      location of the requested media server, whose representation
      refers to Section 4 of RFC 5139 [RFC5139].

5.2.4.1.3.8.  <encryption>

   The <encryption> element allows a Consumer client to request support
   for encrypting mixed RTP media streams using RFC 3711 [RFC3711].  A
   value of 'true' indicates that Consumer client requires support of
   RFC 3711 [RFC3711] for RTP.  A value of 'false' indicates that a
   Consumer client does not require support of RFC 3711 [RFC3711] for
   RTP.  The element MAY be present.  The default value is 'false'

   The <encryption> element has no attributes.

   The <application-data> element has no child elements.

5.2.5.  Media Service Resource Response

   This section provides the element definitions for use in Consumer
   interface responses.  The responses are carried in the
   <mediaResourceResponse> container element.

5.2.5.1.  <mediaResourceResponse> element

   The <mediaResourceResponse> element provides a container for clients
   receiving response information from an external MRB entity.

   The <mediaResourceResponse> element has a single attribute 'status'
   which indicates the status code of the operation.  The following
   status codes are defined for 'status':

   +-----------+-------------------------------------------------------+
   | code      | description                                           |
   +-----------+-------------------------------------------------------+
   | 200       | OK                                                    |
   |           |                                                       |
   | 400       | Syntax error                                          |
   |           |                                                       |
   | 408       | Unable to find Resource                               |
   |           |                                                       |
   | 409       | Unable to update Resource                             |
   |           |                                                       |
   | 410       | Unable to remove Resource                             |
   |           |                                                       |
   | 420       | Unsupported attribute or element                      |
   +-----------+-------------------------------------------------------+
                     Table 2: <response> status codes

   In case a new media resource request made by an AS (no action) has
   been accepted, the MRB MUST reply with a <mediaResourceResponse> with
   status code 200.  The same rule applies whenever a request to update
   (action='update') or remove (action='remove') an existing transaction
   can be fulfilled by the MRB.

   A media resource request, nevertheless, may fail for several reasons.
   In such a case, the status codes defined in Table 1 must be used
   instead.  Specifically, if the MRB fails to handle a request due to a
   syntax error in the request itself (e.g., incorrext XML, violation of
   the schema constraints or invalid values in any of the attributes/
   elements) the MRB MUST reply with a <mediaResourceResponse> with
   status code 400.  If a syntactically correct request fails because
   the request also includes any attribute/element the MRB doesn't
   understand, the MRB MUST reply with a <mediaResourceResponse> with
   status code 420.  If a syntactically correct request fails because
   the MRB couldn't find any MS able to fulfil the requirements
   presented by the AS in its request, the MRB MUST reply with a
   <mediaResourceResponse> with status code 408.  If a syntactically
   correct request fails because the MRB couldn't update an existing
   request according to the new requirements presented by the AS in its
   request, the MRB MUST reply with a <mediaResourceResponse> with
   status code 409.  If a syntactically correct request fails because
   the MRB couldn't remove an existing request and release the related
   resources as requested by the AS, the MRB MUST reply with a
   <mediaResourceResponse> with status code 410.

   Further details on status codes 409 and 410 are presented in
   Section 5.2.3, where the leasing mechanism, together with its related
   scenarios, is described.

   The <mediaResourceResponse> element only has <response-session-info>
   as a child element.  This element is used to describe the response of
   a Consumer interface query and is covered in the following sub-
   section.

5.2.5.1.1.  <response-session-info> element

   The <response-session-info> element is included in Consumer
   responses.  This applies to responses to both requests for new
   resources and requests to update an existing media resource session.
   The ability to change and remove an existing media resource session
   is described in more detail in Section 5.2.3.  The element MAY be
   present: specifically, the element MUST be included in case the
   request was successful, while it would not appear otherwise (e.g., in
   case the request ended up with an error).

   The <response-session-info> element has no attributes.

   The <response-session-info> element has the following child elements:

   session-id:   is a unique identifier that explicitly references an
      existing media resource session on the MRB.  The identifier is
      included to update the existing session and is described in more
      detail in Section 5.2.3.

   seq:   is used in association with the <session-id> element in a
      subsequent request to update an existing media resource session on
      an MRB.  The <seq> number is incremented from its original value
      returned in response to the initial request for media resources.
      More information its use is provided in Section 5.2.3.

   expires:   includes the number of seconds that the media resources
      are reserved as part of this interaction.  If the lease is not
      refreshed before expiry, the MRB will re-claim the resources and
      they will no longer be guaranteed.  It is RECOMMENDED that a
      minimum value of 300 seconds be used for the value of the
      'expires' attribute.  It is also RECOMMENDED that a Consumer
      client refresh the lease at an interval that is not too close to
      the expiry time.  A value of 80% of the timeout period could be
      used.  For example, if the timeout period is 300 seconds, the
      Server would refresh the transaction at 240 seconds.  More
      information on its use is provided in Section 5.2.3.

   media-server-address:   provides information to reach the MS handling
      the requested media resource.  The <media-server-address> element
      has a single attribute named 'uri' which supplies the direct
      address to a media server.  It also has three optional elements
      <connection-id>, <ivr-sessions>, and <mixers>.  The <ivr-sessions>
      and <mixers> are defined in Section 5.2.4.1.2.1 and
      Section 5.2.4.1.3.1 and have the same meaning but are applied to
      individual media server instances as a subset of the overall
      resources reported in the <connection-id> element.  For more
      information on the use of the <connection-id> element see
      Section 6.

5.3.  In-Line Unaware MRB Interface

   An entity acting as an In-Line MRB can act in one of two roles for a
   request, as introduced in Section 4.2.  In-Line Unaware MRB Mode
   (IUMM) of operation and In-Line Aware MRB Mode (IAMM) of operation.
   This section further describes IUMM.

   It should be noted that the introduction of an MRB entity into the
   network, as specified in this document, requires interfaces to be
   implemented by those requesting media server resources (for example
   an application server).  This applies when using the Consumer
   interface as discussed in Section 5.2.1(Query mode) and
   Section 5.2.2(IAMM).  Nevertheless, an MRB is conceived to also be
   able to act in a client unaware mode when it is deployed into the
   network.  This allows any SIP compliant client entity, as defined by
   RFC 3261 [RFC3261] and its extensions, to send requests to an MRB
   which in turn will select an appropriate media server based on
   knowledge of media server resources it currently has available
   transparently to the client entity.  Using an MRB in this mode allows
   for easy migration of current applications and services that are
   unaware of the MRB concept and would simply require a configuration
   change resulting in the MRB being set as a SIP outbound proxy for
   clients requiring media services.

   With IUMM, the MRB may conclude that an assigned media resource is no
   longer needed when it receives a SIP BYE from the application server
   or media server that ends that SIP dialog that initiated the request.

   As with IAMM, in IUMM the SIP INVITE from the application server
   could convey application/sdp payload to either set up a call leg or a
   Control Framework control channel.  In either case, if the ultimate
   intent is to correlate a call leg with a control channel to the same
   media server, the MRB should be acting as a SIP proxy (and not a
   B2BUA) so that the SIP address of the targeted media server can be
   transparently passed back to the application server in the SIP
   response and so that the SIP dialog information is between the
   application server and the media server.

   While IUMM has the least impact on legacy application servers, it
   also provides the least versatility.  See Section 8.

6.  MRB acting as a B2BUA

   An MRB entity can potentially act as a SIP Back-2-Back-User-Agent
   (B2BUA) or a SIP Proxy Server as defined in RFC 3261 [RFC3261].  When
   acting as a B2BUA issues can arise when using Media Control Channel
   packages such as the IVR
   Package[I-D.ietf-mediactrl-ivr-control-package] and Mixer Packages
   [I-D.ietf-mediactrl-mixer-control-package].  Specifically the
   Framework attribute 'connectionid' provided in the appendix titled
   'Appendix: Common Package Components' of Media Control Channel
   Framework[I-D.ietf-mediactrl-sip-control-framework] uses a
   concatenation of the SIP dialog identifiers to be used for
   referencing SIP dialogs within the media control channel.  When a
   request traverses an MRB acting as a B2BUA, the SIP dialog
   identifiers change and so the 'connectionid' can not be used as
   intended due to the SIP dialog identifiers changing.  For this reason
   when a MRB wishes to act as a SIP B2BUA when handling a request from
   an AS to set up a call leg to a MS it MUST include the optional
   <connection-id> element in a Consumer interface response with a value
   that represents the equivalent for the 'connectionid' ('Local Dialog
   Tag' + 'Remote Dialog Tag') for the far side of the B2BUA.  If
   present, this value MUST be used as the value for the 'connectionid'
   in packages where the Common Package Components are used.  The
   <connection-id> element MUST not be included in a HTTP Consumer
   interface response.

7.  Multi-modal MRB Implementations

   An MRB implementation may operate multi-modally with a collection of
   application server clients all sharing the same pool of media
   resources.  I.e., an MRB may be simultaneously operating in Query
   mode, IAMM and IUMM.  It knows in which mode to act on any particular
   request from a client depending on the nature of the request:

   o  If the received quest is HTTP Post with application/
      mrb-consumer+xml content, then MRB processes it in Query mode.

   o  If the received request is a SIP INVITE with application/
      mrb-consumer+xml content and application/sdp content, then MRB
      processes it in IAMM.

   o  If the received request is a SIP INVITE without application/
      mrb-consumer+xml content but with application/sdp content then MRB
      processes it in IUMM.

8.  Relative Merits of Query Mode, IAMM, and IUMM

   At a high level, the possible application server MRB interactions can
   be distinguished among the following basic types:

   a.  Query mode, in which the client is requesting the assignment by
       MRB of suitable MS resources

   b.  IAMM in which the client is requesting the assignment by MRB of
       suitable MS resources and the establishment of a call leg to the
       MS

   c.  IAMM in which the client is requesting the assignment by MRB of
       suitable MS resources and the establishment of a CFW control
       channel to the MS

   d.  IUMM where the client is requesting the establishment of a call
       leg to MS resources

   e.  IUMM where the client is requesting the establishment of a CFW
       control channel to MS resources

   Each type of interaction has advantages and disadvantages compared to
   the others, where such considerations may have to do with the
   versatility of what MRB can provide, technical aspects such as
   efficiency in different application scenarios, complexity, delay, use
   with legacy application servers, or use with the Media Control
   Channel Framework.  Depending on the characteristics of a particular
   setting that an MRB is intended to support, some of the above
   interaction types may be more appropriate than others.  This section
   makes a few observations on relative merits, but is not intended to
   be exhaustive.  Some constraints of a given interaction type may be
   subtle.

   o  About operation with other types of media control: Any of the
      types of interactions work with the use RFC 4240 [RFC4240] and RFC
      5552 [RFC5552] where initial control instructions are conveyed in
      the SIP INVITE from the application server for the call leg to the
      media server and subsequent instructions may be fetched using
      HTTP.  Query mode (a), IAMM/call leg (b) and IUMM/call leg (d)
      work with MSML as per RFC 5705 [RFC5705] or MSCML as per RFC 4722
      [RFC4722].

   o  As stated previously, IUMM has no interface impacts on an
      application server.  On the other hand, with IUMM the application
      server does not specify the characteristics of the type of media
      resource it needs because the <mediaResourceRequest> element is
      not passed to the MRB.  For IUMM call leg (d) the best the MRB can
      do to deduce an appropriate media resource gleaned from examining
      other information in the SIP INVITE, such as the SDP information
      for the call leg, or initial control information in the SIP
      Request URI as per RFC 4240 [RFC4240].  With IUMM/control channel
      (e) there is even less information for the MRB to use.

   o  If using IUMM/control channel (e), the subsequent sending of the
      call leg to the media server should not be done using IUMM/call
      leg.  I.e., the SIP signaling to send the call leg to the selected
      media server must be directly between the application server and
      that media server, and not through the MRB.  Otherwise, MRB might
      send the call leg to a different media server.  Likewise, if using
      IUMM/call leg (d), the subsequent establishment of a control
      channel should not be done with IUMM/control channel (e).

   o  Query mode (a) and IAMM/control channel (c) lend themselves to
      requesting in advance a pool of media resources (e.g., a number of
      IVR or conferencing ports) in advance of use and retaining their
      use over a period of time, independent of whether there are call
      legs to those resources at any given moment, whereas the other
      types of interactions do not.  Likewise for making a subsequent
      request to increase or decrease the amount of resources previously
      awarded.

   o  While Query mode (a) and IAMM/control channel (c) are the most
      versatile interaction types, the former is completely decoupled
      from the use or not of a control channel, whereas the latter
      requires the use of a control channel.

   o  When Media Control Channel Framework control channels are to be
      used in conjunction with the use of MRB, Query mode (a) would
      typically result in fewer such channels being established over
      time as compared to IAMM/control channel (c).  That is because the
      latter would involve setting up an additional control channel
      every time an AS has a new request for MBR for media resources.

9.  Examples

   This section provides examples of both the Publish and Consumer
   interfaces.  For what concerns the Consumer interface, both Query and
   Inline modes are addressed.

   Note that due to RFC formatting conventions, this section often
   splits HTTP, SIP/SDP and CFW across lines whose content would exceed
   72 characters.  A backslash character marks where this line folding
   has taken place.  This backslash and its trailing CRLF and whitespace
   would not appear in the actual protocol contents.  Besides, also note
   that the indentation of the XML content is only provided for
   readability: actual messages will follow strict XML syntax, which
   allows for, but does not require, indentation.

9.1.  Publish Example

   The following example assumes a control channel has been established
   and synced as described in the Media Control Channel Framework
   ([I-D.ietf-mediactrl-sip-control-framework]).

   Figure 9 shows the subscription/notification mechanism the Publish
   interface is based on, as defined in Section 5.1.  The MRB subscribes
   for information at the MS (message A1.), and the MS accepts the
   subscription (A2).  Notifications are triggered by the MS (A3.) and
   acknowledged by the MRB (A4.).

         MRB                                            MS
          |                                              |
          | A1. CONTROL (MRB subscription)               |
          |--------------------------------------------->|
          |                                   A2. 200 OK |
          |<---------------------------------------------|
          |                                              |
          .                                              .
          .                                              .
          |                                              |
          |                                              |--+ collect
          |                                              |  | up-to-date
          |                                              |<-+ info
          |               B1. CONTROL (MRB notification) |
          |<---------------------------------------------|
          | B2. 200 OK                                   |
          |--------------------------------------------->|
          |                                              |
          .                                              .
          .                                              .

                Figure 9: Publish Example: Sequence Diagram

   The rest of this section includes a full dump of the messages
   associated with the previous sequence diagram, specifically:

   1.  the subscription (A1), in an <mrbrequest> (CFW CONTROL);

   2.  the MS accepting the subscription (A2), in an <mrbresponse> (CFW
       200);

   3.  a notification (A3), in a <mrbnotification> (CFW CONTROL event);

   4.  the ack to the notification (A4), in a framework level 200
       message (CFW 200);

A1. MRB -> MS (CONTROL, publish request)
----------------------------------------
CFW lidc30BZObiC CONTROL
Control-Package: mrb-publish/1.0
Content-Type: application/mrb-publish+xml
Content-Length: 337

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<mrbpublish version="1.0" xmlns="urn:ietf:params:xml:ns:mrb-publish">
    <mrbrequest>
        <subscription action="create" seqnumber="1" id="p0T65U">
            <expires>600</expires>
            <frequency>20</frequency>
            <minfrequency>20</minfrequency>
            <maxfrequency>20</maxfrequency>
        </subscription>
    </mrbrequest>
</mrbpublish>

A2. MRB <- MS (200 to CONTROL, request accepted)
------------------------------------------------
CFW lidc30BZObiC 200
Timeout: 10
Content-Type: application/mrb-publish+xml
Content-Length: 139

<mrbpublish version="1.0" xmlns="urn:ietf:params:xml:ns:mrb-publish">
        <mrbresponse status="200" reason="OK: Request accepted"/>
</mrbpublish>

B1. MRB <- MS (CONTROL, event notification from MS)
---------------------------------------------------
CFW 03fff52e7b7a CONTROL
Control-Package: mrb-publish/1.0
Content-Type: application/mrb-publish+xml
Content-Length: 4242

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
   <mrbpublish version="1.0" \
             xmlns="urn:ietf:params:xml:ns:mrb-publish">
    <mrbnotification seqnumber="1" id="QQ6J3c">
        <media-server-id>a1b2c3d4</media-server-id>
        <supported-packages>
            <package name="msc-ivr/1.0"/>
            <package name="msc-mixer/1.0"/>
            <package name="mrb-publish/1.0"/>
            <package name="msc-example-pkg/1.0"/>
        </supported-packages>
        <active-rtp-sessions>
            <rtp-codec name="audio/basic">
                <decoding>10</decoding>
                <encoding>20</encoding>
            </rtp-codec>
        </active-rtp-sessions>
        <active-mixer-sessions>
            <active-mix conferenceid="7cfgs43">
                <rtp-codec name="audio/basic">
                    <decoding>3</decoding>
                    <encoding>3</encoding>
                </rtp-codec>
            </active-mix>
        </active-mixer-sessions>
        <non-active-rtp-sessions>
            <rtp-codec name="audio/basic">
                <decoding>50</decoding>
                <encoding>40</encoding>
            </rtp-codec>
        </non-active-rtp-sessions>
        <non-active-mixer-sessions>
            <non-active-mix available="15">
                <rtp-codec name="audio/basic">
                    <decoding>15</decoding>
                    <encoding>15</encoding>
                </rtp-codec>
            </non-active-mix>
        </non-active-mixer-sessions>
        <media-server-status>active</media-server-status>
        <supported-codecs>
            <supported-codec name="audio/basic">
                <supported-codec-package name="msc-ivr/1.0">
                    <supported-actions>encoding</supported-actions>
                    <supported-actions>decoding</supported-actions>
                </supported-codec-package>
                <supported-codec-package name="msc-mixer/1.0">
                    <supported-actions>encoding</supported-actions>
                    <supported-actions>decoding</supported-actions>
                </supported-codec-package>
            </supported-codec>
        </supported-codecs>
        <application-data>TestbedPrototype</application-data>
        <file-formats>
            <supported-format name="audio/x-wav">
                <supported-file-package>
                    msc-ivr/1.0
                </supported-file-package>
            </supported-format>
        </file-formats>
        <max-prepared-duration>
            <max-time max-time-seconds="3600">
                <max-time-package>msc-ivr/1.0</max-time-package>
            </max-time>
        </max-prepared-duration>
        <dtmf-support>
            <detect>
                <dtmf-type package="msc-ivr/1.0" name="RFC4733"/>
                <dtmf-type package="msc-mixer/1.0" name="RFC4733"/>
            </detect>
            <generate>
                <dtmf-type package="msc-ivr/1.0" name="RFC4733"/>
                <dtmf-type package="msc-mixer/1.0" name="RFC4733"/>
            </generate>
            <passthrough>
                <dtmf-type package="msc-ivr/1.0" name="RFC4733"/>
                <dtmf-type package="msc-mixer/1.0" name="RFC4733"/>
            </passthrough>
        </dtmf-support>
        <mixing-modes>
            <audio-mixing-modes>
                <audio-mixing-mode package="msc-ivr/1.0">
                     nbest
                </audio-mixing-mode>
            </audio-mixing-modes>
            <video-mixing-modes activespeakermix="true" vas="true">
                <video-mixing-mode package="msc-mixer/1.0">
                     single-view
                </video-mixing-mode>
                <video-mixing-mode package="msc-mixer/1.0">
                     dual-view
                </video-mixing-mode>
                <video-mixing-mode package="msc-mixer/1.0">
                     dual-view-crop
                </video-mixing-mode>
                <video-mixing-mode package="msc-mixer/1.0">
                     dual-view-2x1
                </video-mixing-mode>
                <video-mixing-mode package="msc-mixer/1.0">
                     dual-view-2x1-crop
                </video-mixing-mode>
                <video-mixing-mode package="msc-mixer/1.0">
                     quad-view
                </video-mixing-mode>
                <video-mixing-mode package="msc-mixer/1.0">
                     multiple-5x1
                </video-mixing-mode>
                <video-mixing-mode package="msc-mixer/1.0">
                     multiple-3x3
                </video-mixing-mode>
                <video-mixing-mode package="msc-mixer/1.0">
                     multiple-4x4
                </video-mixing-mode>

            </video-mixing-modes>
        </mixing-modes>
        <supported-tones>
            <supported-country-codes>
                <country-code package="msc-ivr/1.0">GB</country-code>
                <country-code package="msc-ivr/1.0">IT</country-code>
                <country-code package="msc-ivr/1.0">US</country-code>
            </supported-country-codes>
            <supported-h248-codes>
                <h248-code package="msc-ivr/1.0">cg/*</h248-code>
                <h248-code package="msc-ivr/1.0">biztn/ofque</h248-code>
                <h248-code package="msc-ivr/1.0">biztn/erwt</h248-code>
                <h248-code package="msc-mixer/1.0">conftn/*</h248-code>
            </supported-h248-codes>
        </supported-tones>
        <streaming-modes>
            <stream-mode package="msc-ivr/1.0" name="HTTP"/>
        </streaming-modes>
        <asr-tts-support>
            <asr-support>
                <language xml:lang="en"/>
            </asr-support>
            <tts-support>
                <language xml:lang="en"/>
            </tts-support>
        </asr-tts-support>
        <vxml-support support="true">
            <vxml-mode package="msc-ivr/1.0" support="IVR-Package"/>
        </vxml-support>
        <media-server-location>
            <civicAddress xml:lang="it">
                <country>IT</country>
                <A1>Campania</A1>
                <A3>Napoli</A3>
                <A6>Via Claudio</A6>
                <HNO>21</HNO>
                <LMK>University of Napoli Federico II</LMK>
                <NAM>Dipartimento di Informatica e Sistemistica</NAM>
                <PC>80210</PC>
            </civicAddress>
        </media-server-location>
        <label>TestbedPrototype-01</label>
        <media-server-address>
            sip:MediaServer@ms.example.net
        </media-server-address>
        <encryption>false</encryption>
    </mrbnotification>
   </mrbpublish>

B2. MRB -> MS (200 to CONTROL)
------------------------------
CFW 03fff52e7b7a 200

9.2.  Consumer Example

   As specified in Section 5.2, the Consumer interface can be involved
   in two different modes: Query and Inline-aware.  When in Query mode,
   Consumer messages are transported in HTTP messages: an example of
   such an approach is presented in Section 9.2.1.  When in Inline-aware
   mode, instead, messages are transported as part of SIP negotiations:
   considering this SIP negotiations may be related to either the
   creation of a control channel or to a UAC call leg, two separate
   examples of such an approach are presented in Section 9.2.2.

9.2.1.  Query Example

   The following example assumes the interested AS already knows the
   HTTP URL where an MRB is listening for Consumer messages.

   Figure 10 shows the HTTP-based transaction between the AS and the
   MRB.  The AS sends a consumer request as payload of an HTTP POST
   message (1.), and the MRB provides an answer in an HTTP 200 OK
   message (2.).  Specifically, as it will be shown in the dumps, the AS
   is interested in 100 IVR ports: the MRB finds two MS that can satisfy
   the request (one providing 60 ports, the other 40 ports) and reports
   them to the AS.

     AS                                             MRB
      |                                              |
      | 1. HTTP POST (Consumer request)              |
      |--------------------------------------------->|
      |                                              |
      |                                              |
      |                                              |--+ Parse request
      |                                              |  | and see if any
      |                                              |<-+ MS applies
      |                                              |
      |                2. 200 OK (Consumer response) |
      |<---------------------------------------------|
      |                                              |
      |--+ Parse response and                        |
      |  | start session (SIP/COMEDIA/CFW)           |
      |<-+ with first MS reported by MRB             |
      |                                              |
      .                                              .
      .                                              .

           Figure 10: Consumer Example (Query): Sequence Diagram

   The rest of this section includes a full dump of the messages
   associated with the previous sequence diagram, specifically:

   1.  the Consumer request (1), in a <mediaResourceRequest> (HTTP POST,
       Content-Type 'application/mrb-consumer+xml');

   2.  the Consumer response (2), in an <mediaResourceResponse> (HTTP
       200 OK, Content-Type 'application/mrb-consumer+xml').

1. AS -> MRB (HTTP POST, Consumer request)
------------------------------------------
POST /Mrb/Consumer HTTP/1.1
Content-Length: 879
Content-Type: application/mrb-consumer+xml
Host: mrb.example.net:8080
Connection: Keep-Alive
User-Agent: Apache-HttpClient/4.0.1 (java 1.5)

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<mrbconsumer version="1.0" xmlns="urn:ietf:params:xml:ns:mrb-consumer">
    <mediaResourceRequest>
        <generalInfo>
            <packages>
                <package>msc-ivr/1.0</package>
                <package>msc-mixer/1.0</package>
            </packages>
        </generalInfo>
        <ivrInfo>
            <ivr-sessions>
                <rtp-codec name="audio/basic">
                    <decoding>100</decoding>
                    <encoding>100</encoding>
                </rtp-codec>
            </ivr-sessions>
            <file-formats>
                <required-format name="audio/x-wav"/>
            </file-formats>
            <streaming-modes>
                <stream-mode package="msc-ivr/1.0" name="HTTP"/>
            </streaming-modes>
        </ivrInfo>
    </mediaResourceRequest>
</mrbconsumer>

2. AS <- MRB (200 to POST, Consumer response)
---------------------------------------------
HTTP/1.1 200 OK
X-Powered-By: Servlet/2.5
Server: Sun GlassFish Communications Server 1.5
Content-Type: application/mrb-consumer+xml;charset=ISO-8859-1
Content-Length: 1133
Date: Mon, 12 Apr 2011 14:59:26 GMT

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<mrbconsumer version="1.0" xmlns="urn:ietf:params:xml:ns:mrb-consumer" >
    <mediaResourceResponse reason="Resource found" status="200">
        <response-session-info>
            <session-id>5t3Y4IQ84gY1</session-id>
            <seq>1</seq>
            <expires>3600</expires>
            <media-server-address \
                              uri="sip:MediaServer@ms.example.com:5080">
                <ivr-sessions>
                    <rtp-codec name="audio/basic">
                        <decoding>60</decoding>
                        <encoding>60</encoding>
                    </rtp-codec>
                </ivr-sessions>
            </media-server-address>
            <media-server-address \
                       uri="sip:OtherMediaServer@pool.example.net:5080">
                <ivr-sessions>
                    <rtp-codec name="audio/basic">
                        <decoding>40</decoding>
                        <encoding>40</encoding>
                    </rtp-codec>
                </ivr-sessions>
            </media-server-address>
        </response-session-info>
    </mediaResourceResponse>
</mrbconsumer>

   The rest of the scenario is omitted for brevity.  After having
   received the 'mediaResourceResponse', the AS has the address of two
   MS able to fulfil its media requirements, and can start a Control
   Dialog with one or both of them.

9.2.2.  IAMM Example

   As anticipated, two separate examples are presented for the IAMM
   case: in fact, IAMM-mode can take advantage of two different
   approaches with respect to the SIP dialogs to be exploited to carry
   consumer messages, i.e.: i) a SIP control dialog to create a control
   channel, and, ii) a UAC call leg to attach to a MS.  To make things
   clearer for the reader, the same consumer request as the one
   presented in the Query mode will be sent, in order to clarify how the
   behaviour of the involved parties may differ.

9.2.2.1.  IAMM Example: CFW-based approach

   The following example assumes the interested AS already knows the SIP
   URI where an MRB is listening as an UAS.

   Figure 11 shows the first approach, i.e.  SIP-based transactions
   involving the AS interested in setting up a control channel, the MRB
   and the MS that will be chosen eventually.  The diagram is more
   complex than before.  This is basically a scenario envisaging the MRB
   as a B2BUA.  The AS sends a SIP INVITE (1.), containing both a CFW-
   related SDP and a Consumer request (multipart body).  The MRB sends a
   provisional response to the AS (2.) and starts working on the
   request.  First of all, it makes use of the Consumer request from the
   AS to determine which MS should be exploited.  Once the right MS have
   been chosen, the MRB sends a new SIP INVITE to one of the MS by just
   including the SDP part of the original request (3.).  The MS
   negotiates this INVITE as specified in
   [I-D.ietf-mediactrl-sip-control-framework] (4., 5., 6.), providing
   the MRB with its own CFW-related SDP.  The MRB replies to the
   original AS INVITE preparing a SIP 200 OK with another multipart body
   (7.): this multipart body includes the Consumer response used by the
   MRB to determine the right MS and the SDP returned by the MS in 5.
   The AS finally acknowledges the 200 OK (8.), and can start a CFW
   connection towards the MS.

   Please note that, to ease the reading of the protocol contents, a
   simple '=_Part' is used whenever a boundary for a 'multipart/mixed'
   payload is provided, instead of the actual boundary that would be
   inserted in the SIP messages.

   AS                  MRB                          MS
    |                       |                           |
    | 1. INVITE             |                           |
    | (multipart/mixed)     |                           |
    |---------------------->|                           |
    |       2. 100 (Trying) |                           |
    |<----------------------|                           |
    |                       |--+ Extract SDP and        |
    |                       |  | MRB payloads; handle   |
    |                       |<-+ Consumer request to    |
    |                       |    know    pick MS to use                |
    |                       |                           |
    |                       | 3. INVITE                 |
    |                       | (only copy SDP from 1.)   |
    |                       |-------------------------->|
    |                       |           4. 100 (Trying) |
    |                       |<--------------------------|
    |                       |                           |--+ Negotiate
    |                       |                           |  | CFW Control
    |                       |                           |<-+ Channel
    |                       |                 5. 200 OK |
    |                       |<--------------------------|
    |                       | 6. ACK                    |
    |                       |-------------------------->|
    |        Prepare new +--|                           |
    |       payload with |  |                           |
    |    SDP from MS and +->|                           |
    |     Consumer reply    |                           |
    |                       |                           |
    |             7. 200 OK |                           |
    |     (multipart/mixed) |                           |
    |<----------------------|                           |
    | 8. ACK                |                           |
    |---------------------->|                           |
    |                       |                           |
    |--+ Read Cons. reply   |                           |
    |  | and use SDP to     |                           |
    |<-+ create CFW Chn.    |                           |
    |                       |                           |
    |                                                   |
    |<<############## TCP CONNECTION #################>>|
    |                                                   |
    | CFW SYNC                                          |
    |++++++++++++++++++++++++++++++++++++++++++++++++++>|
    |                                                   |
    .                       .                           .
    .                       .                           .

         Figure 11: Consumer Example (IAMM-CFW): Sequence Diagram

   The rest of this section includes an almost full dump of the messages
   associated with the previous sequence diagram.  Only the relevant SIP
   messages are shown (both the INVITEs and the 200 OKs), and only the
   relevant headers are preserved for brevity (Content-Type and
   multipart-related information).  Specifically:

   1.  the original INVITE (1), containing both a CFW-related SDP
       (COMEDIA information to negotiate a new Control Channel) and a
       Consumer <mediaResourceRequest>;

   2.  the INVITE sent by the MRB to the MS as a B2BUA (3.), containing
       only the CFW-related SDP from the original INVITE;.

   3.  the 200 OK sent by the MS back to the MRB (5.), to complete the
       CFW-related negotiation (SDP only);

   4.  the 200 OK sent by the MRB back to the AS in response to the
       original INVITE (7.), containing both the CFW-related information
       sent by the MS and a Consumer <mediaResourceRequest> documenting
       the MRB's decision to use that MS.

1. AS -> MRB (INVITE multipart/mixed)
-------------------------------------
   [..]
   Content-Type: multipart/mixed;boundary="=_Part"

   =_Part
   Content-Type: application/sdp

   v=0
   o=- 2890844526 2890842807 IN IP4 as.example.com
   s=MediaCtrl
   c=IN IP4 as.example.com
   t=0 0
   m=application 48035 TCP cfw
   a=connection:new
   a=setup:active
   a=cfw-id:vF0zD4xzUAW9
   a=ctrl-package:msc-mixer/1.0
   a=ctrl-package:msc-ivr/1.0

   =_Part
   Content-Type: application/mrb-consumer+xml
   <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
   <mrbconsumer version="1.0" \
                xmlns="urn:ietf:params:xml:ns:mrb-consumer">
    <mediaResourceRequest>
        <generalInfo>
            <packages>
                <package>msc-ivr/1.0</package>
                <package>msc-mixer/1.0</package>
            </packages>
        </generalInfo>
        <ivrInfo>
            <ivr-sessions>
                <rtp-codec name="audio/basic">
                    <decoding>100</decoding>
                    <encoding>100</encoding>
                </rtp-codec>
            </ivr-sessions>
            <file-formats>
                <required-format name="audio/x-wav"/>
            </file-formats>
            <streaming-modes>
                <stream-mode package="msc-ivr/1.0" name="HTTP"/>
            </streaming-modes>
        </ivrInfo>
    </mediaResourceRequest>
   </mrbconsumer>

   =_Part

3. MRB -> MS (INVITE sdp only)
------------------------------
   [..]
   Content-Type: application/sdp

   v=0
   o=- 2890844526 2890842807 IN IP4 as.example.com
   s=MediaCtrl
   c=IN IP4 as.example.com
   t=0 0
   m=application 48035 TCP cfw
   a=connection:new
   a=setup:active
   a=cfw-id:vF0zD4xzUAW9
   a=ctrl-package:msc-mixer/1.0
   a=ctrl-package:msc-ivr/1.0

5. MRB <- MS (200 OK sdp)
-------------------------
   [..]
   Content-Type: application/sdp

   v=0
   o=lminiero 2890844526 2890842808 IN IP4 ms.example.net
   s=MediaCtrl
   c=IN IP4 ms.example.net
   t=0 0
   m=application 7575 TCP cfw
   a=connection:new
   a=setup:passive
   a=cfw-id:vF0zD4xzUAW9
   a=ctrl-package:msc-mixer/1.0
   a=ctrl-package:msc-ivr/1.0
   a=ctrl-package:mrb-publish/1.0
   a=ctrl-package:msc-example-pkg/1.0

7. AS <- MRB (200 OK multipart/mixed)
-------------------------------------
   [..]
   Content-Type: multipart/mixed;boundary="=_Part"

   =_Part
   Content-Type: application/sdp

   v=0
   o=lminiero 2890844526 2890842808 IN IP4 ms.example.net
   s=MediaCtrl
   c=IN IP4 ms.example.net
   t=0 0
   m=application 7575 TCP cfw
   a=connection:new
   a=setup:passive
   a=cfw-id:vF0zD4xzUAW9
   a=ctrl-package:msc-mixer/1.0
   a=ctrl-package:msc-ivr/1.0
   a=ctrl-package:mrb-publish/1.0
   a=ctrl-package:msc-example-pkg/1.0

   =_Part
   Content-Type: application/mrb-consumer+xml

   <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
   <mrbconsumer version="1.0" \
                xmlns="urn:ietf:params:xml:ns:mrb-consumer" >
    <mediaResourceResponse reason="Resource found" status="200">
        <response-session-info>
            <session-id>z1skKYZQ3eFu</session-id>
            <seq>1</seq>
            <expires>3600</expires>
            <media-server-address \
                              uri="sip:MediaServer@ms.example.com:5080">
                <connection-id>32pbdxZ8:KQw677BF</connection-id>
                <ivr-sessions>
                    <rtp-codec name="audio/basic">
                        <decoding>60</decoding>
                        <encoding>60</encoding>
                    </rtp-codec>
                </ivr-sessions>
            </media-server-address>
            <media-server-address \
                       uri="sip:OtherMediaServer@pool.example.net:5080">
                <ivr-sessions>
                    <rtp-codec name="audio/basic">
                        <decoding>40</decoding>
                        <encoding>40</encoding>
                    </rtp-codec>
                </ivr-sessions>
            </media-server-address>
        </response-session-info>
    </mediaResourceResponse>
   </mrbconsumer>

   =_Part

   As it can be evinced from the dumps, the only difference in the
   response the MRB provides the AS with is in the 'connection-id'
   attribute that is added to the first allocated MS instance: this
   allows the AS to understand the MRB has sent the CFW channel
   negotiation to that specific MS, and that the connection-id to be
   used (should the SIP control dialog also include media-related SDP
   later on) is the one provided.  This will be more carefully described
   in the next section, for the call leg-based approach.

   The continuation of the scenario (the AS connecting to the MS to
   start the Control Channel, the SYNC message, etc.) are omitted for
   brevity.

9.2.2.2.  IAMM Example: Call leg-based approach

   The following example assumes the interested AS already knows the SIP
   URI where an MRB is listening as an UAS.

   Figure 12 shows the second approach, i.e.  SIP-based transactions
   related to a UAC call leg the AS wants to attach to a MS, the MRB and
   the MS that will be chosen eventually.  The interaction is basically
   the same as before (e.g. for what concerns the multipart body) but
   considering a new party is involved in the communication, the diagram
   is slightly more complex than before.  As before, the MRB acts as a
   B2BUA.  A UAC sends a SIP INVITE to a SIP URI handled by the AS,
   since it is interested to its services (1.).  The AS sends a
   provisional response (2.) and, since it doesn't have the resources
   yet, sends to the MRB a new SIP INVITE (3.), containing both the UAC
   media-related SDP and a Consumer request (multipart body).  The MRB
   sends a provisional response to the AS (4.) and starts working on the
   request.  First of all, it makes use of the Consumer request from the
   AS to determine which MS should be exploited. chosen.  Once the right MS have
   been chosen, the MRB sends a new SIP INVITE to one of the MS by just
   including the SDP part of the original request (5.).  The MS
   negotiates this INVITE as specified in
   [I-D.ietf-mediactrl-sip-control-framework] (6., 7., 8.) to allocate
   the needed media resources to handle the new call leg, eventually
   providing the MRB with its own media-related SDP.  The MRB replies to
   the original AS INVITE preparing a SIP 200 OK with another multipart
   body (9.): this multipart body includes the Consumer response used by from
   the MRB to determine indicating the right chosen MS and the SDP returned by the MS in 7.
   The AS finally acknowledges the 200 OK (10.), and ends the scenario
   by eventually providing the UAC with the SDP it needs to setup the
   RTP channels with the chosen MS: a separate direct SIP control dialog
   may be initiated by the AS to the same MS in order to set up a
   control channel to manipulate the call leg media.

   As with the IAMM - CFW example in the prior section, this example has
   the MRB selecting MS resources across two MS instances.  And here
   again the convention can be that the MRB sent the SIP INVITE to the
   first MS in the list provided to the AS in the Consumer response
   information.

   Please note that, to ease the reading of the protocol contents, a
   simple '=_Part' is used whenever a boundary for a 'multipart/mixed'
   payload is provided, instead of the actual boundary that would be
   inserted in the SIP messages.

 UAC              AS                     MRB                          MS
  |               |                       |                           |
  | 1. INVITE     |                       |                           |
  | (media SDP)   |                       |                           |
  |-------------->|                       |                           |
  | 2. 100 Trying |                       |                           |
  |<--------------|                       |                           |
  |               | 3. INVITE             |                           |
  |               | (multipart/mixed)     |                           |
  |               |---------------------->|                           |
  |               |       4. 100 (Trying) |                           |
  |               |<----------------------|                           |
  |               |                       |--+ Extract SDP and        |
  |               |                       |  | MRB payloads; handle   |
  |               |                       |<-+ Consumer request to    |
  |               |                       |    pick Media Servers     |
  |               |                       |                           |
  |               |                       | 5. INVITE                 |
  |               |                       | (only copy SDP from 3.)   |
  |               |                       |-------------------------->|
  |               |                       |           6. 100 (Trying) |
  |               |                       |<--------------------------|
  |               |                       |                        +--|
  |               |                       |        Handle call leg |  |
  |               |                       |        (connection-id) +->|
  |               |                       |                           |
  |               |                       |                 7. 200 OK |
  |               |                       |<--------------------------|
  |               |                       | 8. ACK                    |
  |               |                       |-------------------------->|
  |               |        Prepare new +--|                           |
  |               |       payload with |  |                           |
  |               |    SDP from MS and +->|                           |
  |               |     Consumer reply    |                           |
  |               |                       |                           |
  |               |             9. 200 OK |                           |
  |               |     (multipart/mixed) |                           |
  |               |<----------------------|                           |
  |               | 10. ACK               |                           |
  |               |---------------------->|                           |
  |               |                       |                           |
  |               |--+ Read Cons. reply   |                           |
  |               |  | and send SDP       |                           |
  |               |<-+ back to UAC        |                           |
  |    11. 200 OK |                       |                           |
  |<--------------|                       |                           |
  | 12. ACK       |                       |                           |
  |-------------->|                       |                           |
  |               |                       |                           |
  |<<*************************** RTP *******************************>>|
  |               |                       |                           |
  |               |--+ Negotiate          |                           |
  |               |  | CFW channel        |                           |
  |               |<-+ towards MS         |                           |
  |               |    (if needed)        |                           |
  .               .                       .                           .
  .               .                       .                           .
  |               |                       |                           |
  |               |<<############## TCP CONNECTION #################>>|
  |               |                                                   |
  |               | CFW SYNC                                          |
  |               |++++++++++++++++++++++++++++++++++++++++++++++++++>|
  |               |                                                   |
  .               .                       .                           .
  .               .                       .                           .

       Figure 12: Consumer Example (IAMM-CallLeg): Sequence Diagram

   The rest of this section includes an almost full dump of the messages
   associated with the previous sequence diagram.  Only the relevant SIP
   messages are shown (both the INVITEs and the 200 OKs), and only the
   relevant headers are preserved for brevity (Content-Type, From/To and
   multipart-related information).  Specifically:

   1.  the original INVITE (1), containing the media-related SDP sent by
       a UAC;

   2.  the original INVITE (3), containing both the media-related SDP
       and a Consumer <mediaResourceRequest>;

   3.  the INVITE sent by the MRB to the MS as a B2BUA (5.), containing
       only the media-related SDP from the original INVITE;

   4.  the 200 OK sent by the MS back to the MRB (7.), to complete the
       media-related negotiation (SDP only);

   5.  the 200 OK sent by the MRB back to the AS in response to the
       original INVITE (9.), containing both the media-related
       information sent by the MS and a Consumer <mediaResourceRequest>
       documenting the MRB's decision to use that MS;

   6.  the 200 OK sent by the AS back to the UAC to have it setup the
       RTP channel(s) with the MS (11.).

1. UAC -> AS (INVITE with media SDP)
------------------------------------
   [..]
   From: <sip:lminiero@users.example.com>;tag=1153573888
   To: <sip:mediactrlDemo@as.example.com>
   [..]
   Content-Type: application/sdp

   v=0
   o=lminiero 123456 654321 IN IP4 4.3.2.1
   s=A conversation
   c=IN IP4 4.3.2.1
   t=0 0
   m=audio 7078 RTP/AVP 0 3 8 101
   a=rtpmap:0 PCMU/8000/1
   a=rtpmap:3 GSM/8000/1
   a=rtpmap:8 PCMA/8000/1
   a=rtpmap:101 telephone-event/8000
   a=fmtp:101 0-11
   m=video 9078 RTP/AVP 98

3. AS -> MRB (INVITE multipart/mixed)
-------------------------------------
   [..]
   From: <sip:ApplicationServer@as.example.com>;tag=fd4fush5
   To: <sip:Mrb@mrb.example.org>
   [..]
   Content-Type: multipart/mixed;boundary="=_Part"

   =_Part
   Content-Type: application/sdp

   v=0
   o=lminiero 123456 654321 IN IP4 4.3.2.1
   s=A conversation
   c=IN IP4 4.3.2.1
   t=0 0
   m=audio 7078 RTP/AVP 0 3 8 101
   a=rtpmap:0 PCMU/8000/1
   a=rtpmap:3 GSM/8000/1
   a=rtpmap:8 PCMA/8000/1
   a=rtpmap:101 telephone-event/8000
   a=fmtp:101 0-11
   m=video 9078 RTP/AVP 98

   =_Part
   Content-Type: application/mrb-consumer+xml

   <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
   <mrbconsumer version="1.0" \
                xmlns="urn:ietf:params:xml:ns:mrb-consumer">
    <mediaResourceRequest>
        <generalInfo>
            <packages>
                <package>msc-ivr/1.0</package>
                <package>msc-mixer/1.0</package>
            </packages>
        </generalInfo>
        <ivrInfo>
            <ivr-sessions>
                <rtp-codec name="audio/basic">
                    <decoding>100</decoding>
                    <encoding>100</encoding>
                </rtp-codec>
            </ivr-sessions>
            <file-formats>
                <required-format name="audio/x-wav"/>
            </file-formats>
            <streaming-modes>
                <stream-mode package="msc-ivr/1.0" name="HTTP"/>
            </streaming-modes>
        </ivrInfo>
    </mediaResourceRequest>
   </mrbconsumer>

   =_Part

5. MRB -> MS (INVITE sdp only)
------------------------------
   [..]
   From: <sip:Mrb@mrb.example.org:5060>;tag=32pbdxZ8
   To: <sip:MediaServer@ms.example.com:5080>
   [..]
   Content-Type: application/sdp

   v=0
   o=lminiero 123456 654321 IN IP4 4.3.2.1
   s=A conversation
   c=IN IP4 4.3.2.1
   t=0 0
   m=audio 7078 RTP/AVP 0 3 8 101
   a=rtpmap:0 PCMU/8000/1
   a=rtpmap:3 GSM/8000/1
   a=rtpmap:8 PCMA/8000/1
   a=rtpmap:101 telephone-event/8000
   a=fmtp:101 0-11
   m=video 9078 RTP/AVP 98

7. MRB <- MS (200 OK sdp)
-------------------------
   [..]
   From: <sip:Mrb@mrb.example.org:5060>;tag=32pbdxZ8
   To: <sip:MediaServer@ms.example.com:5080>;tag=KQw677BF
   [..]
   Content-Type: application/sdp

   v=0
   o=lminiero 123456 654322 IN IP4 1.2.3.4
   s=MediaCtrl
   c=IN IP4 1.2.3.4
   t=0 0
   m=audio 63442 RTP/AVP 0 3 8 101
   a=rtpmap:0 PCMU/8000
   a=rtpmap:3 GSM/8000
   a=rtpmap:8 PCMA/8000
   a=rtpmap:101 telephone-event/8000
   a=fmtp:101 0-15
   a=ptime:20
   a=label:7eda834
   m=video 33468 RTP/AVP 98
   a=rtpmap:98 H263-1998/90000
   a=fmtp:98 CIF=2
   a=label:0132ca2

9. AS <- MRB (200 OK multipart/mixed)
-------------------------------------
   [..]
   From: <sip:ApplicationServer@as.example.com>;tag=fd4fush5
   To: <sip:Mrb@mrb.example.org>;tag=117652221
   [..]
   Content-Type: multipart/mixed;boundary="=_Part"

   =_Part
   Content-Type: application/sdp

   v=0
   o=lminiero 123456 654322 IN IP4 1.2.3.4
   s=MediaCtrl
   c=IN IP4 1.2.3.4
   t=0 0
   m=audio 63442 RTP/AVP 0 3 8 101
   a=rtpmap:0 PCMU/8000
   a=rtpmap:3 GSM/8000
   a=rtpmap:8 PCMA/8000
   a=rtpmap:101 telephone-event/8000
   a=fmtp:101 0-15
   a=ptime:20
   a=label:7eda834
   m=video 33468 RTP/AVP 98
   a=rtpmap:98 H263-1998/90000
   a=fmtp:98 CIF=2
   a=label:0132ca2

   =_Part
   Content-Type: application/mrb-consumer+xml

   <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
   <mrbconsumer version="1.0" \
                xmlns="urn:ietf:params:xml:ns:mrb-consumer" >
    <mediaResourceResponse reason="Resource found" status="200">
        <response-session-info>
            <session-id>z1skKYZQ3eFu</session-id>
            <seq>1</seq>
            <expires>3600</expires>
            <media-server-address \
                              uri="sip:MediaServer@ms.example.com:5080">
                <connection-id>32pbdxZ8:KQw677BF</connection-id>
                <ivr-sessions>
                    <rtp-codec name="audio/basic">
                        <decoding>60</decoding>
                        <encoding>60</encoding>
                    </rtp-codec>
                </ivr-sessions>
            </media-server-address>
            <media-server-address \
                       uri="sip:OtherMediaServer@pool.example.net:5080">
                <ivr-sessions>
                    <rtp-codec name="audio/basic">
                        <decoding>40</decoding>
                        <encoding>40</encoding>
                    </rtp-codec>
                </ivr-sessions>
            </media-server-address>
        </response-session-info>

    </mediaResourceResponse>
   </mrbconsumer>

   =_Part

11. UAC <- AS (200 OK sdp)
--------------------------
   [..]
   From: <sip:lminiero@users.example.com>;tag=1153573888
   To: <sip:mediactrlDemo@as.example.com>;tag=bcd47c32
   [..]
   Content-Type: application/sdp

   v=0
   o=lminiero 123456 654322 IN IP4 1.2.3.4
   s=MediaCtrl
   c=IN IP4 1.2.3.4
   t=0 0
   m=audio 63442 RTP/AVP 0 3 8 101
   a=rtpmap:0 PCMU/8000
   a=rtpmap:3 GSM/8000
   a=rtpmap:8 PCMA/8000
   a=rtpmap:101 telephone-event/8000
   a=fmtp:101 0-15
   a=ptime:20
   a=label:7eda834
   m=video 33468 RTP/AVP 98
   a=rtpmap:98 H263-1998/90000
   a=fmtp:98 CIF=2
   a=label:0132ca2

   As it can be evinced from the dumps, as in the IAMM-CFW example the
   MRB provides the AS with a 'connection-id' attribute in the consumer
   response: this connection-id allows the AS to understand the MRB has
   sent the SDP media negotiation to that specific MS, and that the
   connection-id to be used in CFW requests is the one provided.  This
   attribute is needed, since, according to the framework specification,
   the AS should build this connection-id out of the From/To tags
   extracted from the negotiation with the MS: since the MRB acts as a
   B2BUA in this scenario, without that attribute the AS and the MS
   would refer to different tags and, as a consequence, different
   connection-ids, thus preventing the CFW protocol to work as expected.

   The continuation of the scenario (the AS connecting to the MS to
   start the Control Channel, the SYNC message, etc.) are omitted for
   brevity.

10.  Media Service Resource Publisher Interface XML Schema

   This section gives the XML Schema Definition [W3C.REC-xmlschema-1-
   20041028], [W3C.REC-xmlschema-2-20041028] of the "application/
   mrb-publish+xml" format.

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema targetNamespace="urn:ietf:params:xml:ns:mrb-publish"
 elementFormDefault="qualified" blockDefault="#all"
 xmlns="urn:ietf:params:xml:ns:mrb-publish"
 xmlns:fw="urn:ietf:params:xml:ns:control:framework-attributes"
 xmlns:ca="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr"
 xmlns:xsd="http://www.w3.org/2001/XMLSchema">

 <xsd:annotation>
  <xsd:documentation>
   IETF MediaCtrl MRB 1.0

   This is the schema of the IETF MediaCtrl MRB package.

   The schema namespace is urn:ietf:params:xml:ns:mrb-publish

  </xsd:documentation>
 </xsd:annotation>

 <!--
  #############################################################

  SCHEMA IMPORTS

  #############################################################
 -->

 <xsd:import namespace="http://www.w3.org/XML/1998/namespace"
  schemaLocation="http://www.w3.org/2001/xml.xsd">
  <xsd:annotation>
   <xsd:documentation>
    This import brings in the XML attributes for
    xml:base, xml:lang, etc
   </xsd:documentation>
  </xsd:annotation>
 </xsd:import>

<xsd:import
  namespace="urn:ietf:params:xml:ns:control:framework-attributes"
  schemaLocation="framework.xsd">
  <xsd:annotation>
   <xsd:documentation>
    This import brings in the framework attributes for
    conferenceid and connectionid.
   </xsd:documentation>
  </xsd:annotation>
</xsd:import>

<xsd:import
  namespace="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr"
  schemaLocation="civicAddress.xsd">
  <xsd:annotation>
   <xsd:documentation>
    This import brings in the civicAddress specification
    from RFC5139.
   </xsd:documentation>
  </xsd:annotation>
</xsd:import>

<!--
  #####################################################

  Extensible core type

  #####################################################
 -->

 <xsd:complexType name="Tcore">
  <xsd:annotation>
   <xsd:documentation>
    This type is extended by other (non-mixed) component types to
    allow attributes from other namespaces.
   </xsd:documentation>
  </xsd:annotation>
  <xsd:sequence/>
  <xsd:anyAttribute namespace="##other" processContents="lax" />
 </xsd:complexType>

<!--
  #####################################################

  TOP LEVEL ELEMENT: mrbpublish

  #####################################################
 -->

<xsd:complexType name="mrbpublishType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
     <xsd:choice>
      <xsd:element ref="mrbrequest" />
      <xsd:element ref="mrbresponse" />
      <xsd:element ref="mrbnotification" />
      <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
     </xsd:choice>
    </xsd:sequence>
    <xsd:attribute name="version" type="version.datatype"
      use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="mrbpublish" type="mrbpublishType" />

<!--
  #####################################################

  mrbrequest TYPE

  #####################################################
 -->

<!--  mrbrequest -->

 <xsd:complexType name="mrbrequestType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
     <xsd:element ref="subscription" />
     <xsd:any namespace="##other" minOccurs="0"
      maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="mrbrequest" type="mrbrequestType" />

<!--  subscription -->
<xsd:complexType name="subscriptionType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
     <xsd:element name="expires" type="xsd:nonNegativeInteger"
      minOccurs="0" maxOccurs="1" />
     <xsd:element name="frequency" name="minfrequency" type="xsd:nonNegativeInteger"
      minOccurs="0" maxOccurs="1" />
     <xsd:element name="maxfrequency" type="xsd:nonNegativeInteger"
      minOccurs="0" maxOccurs="1" />
     <xsd:any namespace="##other" minOccurs="0"
      maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="id" type="id.datatype" use="required" />
    <xsd:attribute name="seqnumber" type="xsd:nonNegativeInteger"
      use="required" />
    <xsd:attribute name="action" type="action.datatype"
      use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="subscription" type="subscriptionType" />

<!--
  #####################################################

  mrbresponse TYPE

  #####################################################
 -->

<!--  mrbresponse -->

 <xsd:complexType name="mrbresponseType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
     <xsd:element ref="subscription" minOccurs="0" maxOccurs="1" />
     <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="status" type="status.datatype"
     use="required" />
    <xsd:attribute name="reason" type="xsd:string" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />

   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="mrbresponse" type="mrbresponseType" />

<!--
  #####################################################

  mrbnotification TYPE

  #####################################################
 -->

<!--  mrbnotification -->

<xsd:complexType name="mrbnotificationType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
     <xsd:element name="media-server-id"
        type="subscriptionid.datatype"/>
     <xsd:element ref="supported-packages" minOccurs="0" />
     <xsd:element ref="active-rtp-sessions" minOccurs="0" />
     <xsd:element ref="active-mixer-sessions" minOccurs="0" />
     <xsd:element ref="non-active-rtp-sessions" minOccurs="0" />
     <xsd:element ref="non-active-mixer-sessions" minOccurs="0" />
     <xsd:element ref="media-server-status" minOccurs="0" />
     <xsd:element ref="supported-codecs" minOccurs="0" />
     <xsd:element ref="application-data" minOccurs="0"
      maxOccurs="unbounded" />
     <xsd:element ref="file-formats" minOccurs="0" />
     <xsd:element ref="max-prepared-duration" minOccurs="0" />
     <xsd:element ref="dtmf-support" minOccurs="0" />
     <xsd:element ref="mixing-modes" minOccurs="0" />
     <xsd:element ref="supported-tones" minOccurs="0" />
     <xsd:element ref="streaming-modes" minOccurs="0" />
     <xsd:element ref="asr-tts-support" minOccurs="0" />
     <xsd:element ref="vxml-support" minOccurs="0" />
     <xsd:element ref="media-server-location" minOccurs="0" />
     <xsd:element ref="label" minOccurs="0" />
     <xsd:element ref="media-server-address" minOccurs="0" />
     <xsd:element ref="encryption" minOccurs="0" />
     <xsd:any namespace="##other" minOccurs="0"
      maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
     <xsd:attribute name="id" type="subscriptionid.datatype"
      use="required" />
     <xsd:attribute name="seqnumber" type="xsd:nonNegativeInteger"
      use="required" />
     <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="mrbnotification" type="mrbnotificationType" />

<!--  supported-packages -->

 <xsd:complexType name="supported-packagesType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="package" minOccurs="0"
        maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

<xsd:element name="supported-packages" type="supported-packagesType"/>

 <xsd:complexType name="packageType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="name" type="xsd:string" use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="package" type="packageType" />

<!--  active-rtp-sessions -->
 <xsd:complexType name="active-rtp-sessionsType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="rtp-codec" minOccurs="0"
        maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

<xsd:element name="active-rtp-sessions" type="active-rtp-sessionsType"/>

 <xsd:complexType name="rtp-codecType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element name="decoding" type="xsd:nonNegativeInteger" />
      <xsd:element name="encoding" type="xsd:nonNegativeInteger" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="name" type="xsd:string" use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="rtp-codec" type="rtp-codecType" />

<!--  active-mixer-sessions -->

<xsd:complexType name="active-mixer-sessionsType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="active-mix" minOccurs="0"
        maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>

  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="active-mixer-sessions"
  type="active-mixer-sessionsType" />

<xsd:complexType name="active-mixType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="rtp-codec" minOccurs="0"
        maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attributeGroup ref="fw:framework-attributes" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="active-mix" type="active-mixType" />

<!--  non-active-rtp-sessions -->

<xsd:complexType name="non-active-rtp-sessionsType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="rtp-codec" minOccurs="0"
        maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="non-active-rtp-sessions"
  type="non-active-rtp-sessionsType" />

<!--  non-active-mixer-sessions -->

<xsd:complexType name="non-active-mixer-sessionsType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="non-active-mix" minOccurs="0"
        maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="non-active-mixer-sessions"
  type="non-active-mixer-sessionsType" />

 <xsd:complexType name="non-active-mixType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="rtp-codec" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="available" type="xsd:nonNegativeInteger"
      use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="non-active-mix" type="non-active-mixType" />

<!--  media-server-status -->

 <xsd:element name="media-server-status" type="msstatus.datatype" />

<!--  supported-codecs -->

<xsd:complexType name="supported-codecsType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:element ref="supported-codec"
         minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
         maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />

   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="supported-codecs" type="supported-codecsType" />

 <xsd:complexType name="supported-codecType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="supported-codec-package"
         minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="name" type="xsd:string" use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="supported-codec" type="supported-codecType" />

 <xsd:complexType name="supported-codec-packageType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:element name="supported-actions" type="actions.datatype"
        minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="name" type="xsd:string" use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="supported-codec-package"
  type="supported-codec-packageType" />

<!--  application-data -->

<xsd:element name="application-data" type="appdata.datatype" />

<!--  file-formats -->
<xsd:complexType name="file-formatsType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:element ref="supported-format"
         minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
         maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="file-formats" type="file-formatsType" />

 <xsd:complexType name="supported-formatType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="supported-file-package"
         minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="name" type="xsd:string" use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="supported-format" type="supported-formatType" />

 <xsd:element name="supported-file-package"
  type="xsd:string" />

<!--  max-prepared-duration -->

<xsd:complexType name="max-prepared-durationType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="max-time" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>

  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="max-prepared-duration"
  type="max-prepared-durationType" />

 <xsd:complexType name="max-timeType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element name="max-time-package" type="xsd:string" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="max-time-seconds" type="xsd:nonNegativeInteger"
     use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="max-time" type="max-timeType" />

<!--  dtmf-support -->

<xsd:complexType name="dtmf-supportType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:element ref="detect" />
       <xsd:element ref="generate" />
       <xsd:element ref="passthrough" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="dtmf-support" type="dtmf-supportType" />

 <xsd:complexType name="detectType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:element ref="dtmf-type"
        minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="detect" type="detectType" />

 <xsd:complexType name="generateType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:element ref="dtmf-type"
        minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="generate" type="generateType" />

 <xsd:complexType name="passthroughType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:element ref="dtmf-type"
        minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="passthrough" type="passthroughType" />

 <xsd:complexType name="dtmf-typeType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="name" type="dtmf.datatype" use="required" />
    <xsd:attribute name="package" type="xsd:string" use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="dtmf-type" type="dtmf-typeType" />

<!--  mixing-modes -->

<xsd:complexType name="mixing-modesType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
      <xsd:element ref="audio-mixing-modes"
        minOccurs="0" maxOccurs="1" />
      <xsd:element ref="video-mixing-modes"
        minOccurs="0" maxOccurs="1" />
      <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:anyAttribute namespace="##other" processContents="lax" />
  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="mixing-modes" type="mixing-modesType" />

<xsd:complexType name="audio-mixing-modesType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
     <xsd:element ref="audio-mixing-mode"
        minOccurs="0" maxOccurs="unbounded" />
      <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:anyAttribute namespace="##other" processContents="lax" />
  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="audio-mixing-modes" type="audio-mixing-modesType" />
<xsd:complexType name="audio-mixing-modeType" mixed="true">
 <xsd:sequence>
    <xsd:any namespace="##other" minOccurs="0"
     maxOccurs="unbounded" processContents="lax" />
 </xsd:sequence>
 <xsd:attribute name="package" type="xsd:string" use="required" />
 <xsd:anyAttribute namespace="##other" processContents="lax" />
</xsd:complexType>

<xsd:element name="audio-mixing-mode" type="audio-mixing-modeType" />

<xsd:complexType name="video-mixing-modesType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
     <xsd:element ref="video-mixing-mode"
        minOccurs="0" maxOccurs="unbounded" />
      <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:attribute name="vas" type="boolean.datatype"
     default="false" />
   <xsd:attribute name="activespeakermix" type="boolean.datatype"
     default="false" />
   <xsd:anyAttribute namespace="##other" processContents="lax" />
  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="video-mixing-modes" type="video-mixing-modesType" />

<xsd:complexType name="video-mixing-modeType" mixed="true">
 <xsd:sequence>
    <xsd:any namespace="##other" minOccurs="0"
     maxOccurs="unbounded" processContents="lax" />
 </xsd:sequence>
 <xsd:attribute name="package" type="xsd:string" use="required" />
 <xsd:anyAttribute namespace="##other" processContents="lax" />
</xsd:complexType>

<xsd:element name="video-mixing-mode" type="video-mixing-modeType" />

<!--  supported-tones -->

<xsd:complexType name="supported-tonesType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
      <xsd:element ref="supported-country-codes"
        minOccurs="0" maxOccurs="1" />
      <xsd:element ref="supported-h248-codes"
        minOccurs="0" maxOccurs="1" />
      <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:anyAttribute namespace="##other" processContents="lax" />
  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="supported-tones" type="supported-tonesType" />

<xsd:complexType name="supported-country-codesType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
     <xsd:element ref="country-code"
        minOccurs="0" maxOccurs="unbounded" />
      <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:anyAttribute namespace="##other" processContents="lax" />
  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="supported-country-codes"
  type="supported-country-codesType" />

<xsd:complexType name="country-codeType" mixed="true">
 <xsd:sequence>
    <xsd:any namespace="##other" minOccurs="0"
     maxOccurs="unbounded" processContents="lax" />
 </xsd:sequence>
 <xsd:attribute name="package" type="xsd:string" use="required" />
 <xsd:anyAttribute namespace="##other" processContents="lax" />
</xsd:complexType>

<xsd:element name="country-code" type="country-codeType" />

<xsd:complexType name="supported-h248-codesType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
     <xsd:element ref="h248-code"
        minOccurs="0" maxOccurs="unbounded" />
      <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:anyAttribute namespace="##other" processContents="lax" />
  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="supported-h248-codes"
  type="supported-h248-codesType" />

<xsd:complexType name="h248-codeType" mixed="true">
 <xsd:sequence>
    <xsd:any namespace="##other" minOccurs="0"
     maxOccurs="unbounded" processContents="lax" />
 </xsd:sequence>
 <xsd:attribute name="package" type="xsd:string" use="required" />
 <xsd:anyAttribute namespace="##other" processContents="lax" />
</xsd:complexType>

<xsd:element name="h248-code" type="h248-codeType" />

<!--  streaming-modes -->

 <xsd:complexType name="streaming-modesType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="stream-mode"
        minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="streaming-modes" type="streaming-modesType" />

 <xsd:complexType name="stream-modeType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />

    </xsd:sequence>
    <xsd:attribute name="name" type="streammode.datatype"
     use="required" />
    <xsd:attribute name="package" type="xsd:string" use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>
 <xsd:element name="stream-mode" type="stream-modeType" />

<!--  asr-tts-support -->

<xsd:complexType name="asr-tts-supportType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
      <xsd:element ref="asr-support"
        minOccurs="0" maxOccurs="1" />
      <xsd:element ref="tts-support"
        minOccurs="0" maxOccurs="1" />
      <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:anyAttribute namespace="##other" processContents="lax" />
  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="asr-tts-support" type="asr-tts-supportType" />

<xsd:complexType name="asr-supportType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
     <xsd:element ref="language"
        minOccurs="0" maxOccurs="unbounded" />
      <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:anyAttribute namespace="##other" processContents="lax" />
  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="asr-support" type="asr-supportType" />

<xsd:complexType name="tts-supportType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
     <xsd:element ref="language"
        minOccurs="0" maxOccurs="unbounded" />
      <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:anyAttribute namespace="##other" processContents="lax" />
  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="tts-support" type="tts-supportType" />

<xsd:complexType name="languageType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
      <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:attribute ref="xml:lang" />
   <xsd:anyAttribute namespace="##other" processContents="lax" />
  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="language" type="languageType" />

<!--  media-server-location -->

<xsd:complexType name="media-server-locationType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:element name="civicAddress" type="ca:civicAddress"
                        minOccurs="1" maxOccurs="1" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

<xsd:element name="media-server-location"
  type="media-server-locationType" />

<!--  vxml-support -->

 <xsd:complexType name="vxml-supportType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="vxml-mode"
        minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="support" type="boolean.datatype"
     default="false" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="vxml-support" type="vxml-supportType" />

 <xsd:complexType name="vxml-modeType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="package" type="xsd:string" use="required" />
    <xsd:attribute name="support" type="vxml.datatype" use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="vxml-mode" type="vxml-modeType" />

<!--  label -->

 <xsd:element name="label" type="label.datatype" />

<!-- media-server-address -->

 <xsd:element name="media-server-address" type="xsd:anyURI" />

<!--  encryption -->

<xsd:element name="encryption" type="boolean.datatype" />

<!--
  ####################################################

  DATATYPES

  ####################################################
 -->

 <xsd:simpleType name="version.datatype">
  <xsd:restriction base="xsd:NMTOKEN">
   <xsd:enumeration value="1.0" />
  </xsd:restriction>
 </xsd:simpleType>

<xsd:simpleType name="id.datatype">
  <xsd:restriction base="xsd:NMTOKEN" />
 </xsd:simpleType>

 <xsd:simpleType name="status.datatype">
  <xsd:restriction base="xsd:positiveInteger">
   <xsd:pattern value="[0-9][0-9][0-9]" />
  </xsd:restriction>
 </xsd:simpleType>

 <xsd:simpleType name="msstatus.datatype">
  <xsd:restriction base="xsd:NMTOKEN">
   <xsd:enumeration value="active" />
   <xsd:enumeration value="deactivated" />
   <xsd:enumeration value="unavailable" />
  </xsd:restriction>
 </xsd:simpleType>

 <xsd:simpleType name="action.datatype">
  <xsd:restriction base="xsd:NMTOKEN">
   <xsd:enumeration value="create" />
   <xsd:enumeration value="update" />
   <xsd:enumeration value="remove" />
  </xsd:restriction>
 </xsd:simpleType>

 <xsd:simpleType name="actions.datatype">
  <xsd:restriction base="xsd:NMTOKEN">
   <xsd:enumeration value="encoding" />
   <xsd:enumeration value="decoding" />
   <xsd:enumeration value="passthrough" />
  </xsd:restriction>
 </xsd:simpleType>

 <xsd:simpleType name="appdata.datatype">
  <xsd:restriction base="xsd:NMTOKEN" />
 </xsd:simpleType>

 <xsd:simpleType name="dtmf.datatype">
  <xsd:restriction base="xsd:NMTOKEN">
   <xsd:enumeration value="RFC4733" />
   <xsd:enumeration value="Media" />
  </xsd:restriction>
 </xsd:simpleType>

 <xsd:simpleType name="streammode.datatype">
  <xsd:restriction base="xsd:NMTOKEN" />
 </xsd:simpleType>

 <xsd:simpleType name="boolean.datatype">
  <xsd:restriction base="xsd:NMTOKEN">
   <xsd:enumeration value="true" />
   <xsd:enumeration value="false" />
  </xsd:restriction>
 </xsd:simpleType>

  <xsd:simpleType name="vxml.datatype">
  <xsd:restriction base="xsd:NMTOKEN">
   <xsd:enumeration value="RFC4240" />
   <xsd:enumeration value="RFC5552" />
   <xsd:enumeration value="IVR-Package" />
  </xsd:restriction>
 </xsd:simpleType>

 <xsd:simpleType name="label.datatype">
  <xsd:restriction base="xsd:NMTOKEN" />
 </xsd:simpleType>

 <xsd:simpleType name="subscriptionid.datatype">
  <xsd:restriction base="xsd:NMTOKEN" />
 </xsd:simpleType>

</xsd:schema>

                                 Figure 13

11.  Media Service Resource Consumer Interface XML Schema

   This section gives the XML Schema Definition [W3C.REC-xmlschema-1-
   20041028], [W3C.REC-xmlschema-2-20041028] of the "application/
   mrb-consumer+xml" format.

<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema targetNamespace="urn:ietf:params:xml:ns:mrb-consumer"
 elementFormDefault="qualified" blockDefault="#all"
 xmlns="urn:ietf:params:xml:ns:mrb-consumer"
 xmlns:ca="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr"
 xmlns:xsd="http://www.w3.org/2001/XMLSchema">

 <xsd:annotation>
  <xsd:documentation>
   IETF MediaCtrl MRB 1.0

   This is the schema of the IETF MediaCtrl MRB Consumer interface.

   The schema namespace is urn:ietf:params:xml:ns:mrb-consumer

  </xsd:documentation>
 </xsd:annotation>

 <!--
  #############################################################

  SCHEMA IMPORTS

  #############################################################
 -->

 <xsd:import namespace="http://www.w3.org/XML/1998/namespace"
  schemaLocation="http://www.w3.org/2001/xml.xsd">
  <xsd:annotation>
   <xsd:documentation>
    This import brings in the XML attributes for
    xml:base, xml:lang, etc
   </xsd:documentation>
  </xsd:annotation>
 </xsd:import>

<xsd:import
  namespace="urn:ietf:params:xml:ns:pidf:geopriv10:civicAddr"
  schemaLocation="civicAddress.xsd">
  <xsd:annotation>
   <xsd:documentation>
    This import brings in the civicAddress specification
    from RFC5139.
   </xsd:documentation>
  </xsd:annotation>
</xsd:import>

<!--
  #####################################################

  Extensible core type

  #####################################################
 -->

 <xsd:complexType name="Tcore">
  <xsd:annotation>
   <xsd:documentation>
    This type is extended by other (non-mixed) component types to
    allow attributes from other namespaces.
   </xsd:documentation>
  </xsd:annotation>
  <xsd:sequence/>
  <xsd:anyAttribute namespace="##other" processContents="lax" />
 </xsd:complexType>

<!--
  #####################################################

  TOP LEVEL ELEMENT: mrbconsumer

  #####################################################
 -->

<xsd:complexType name="mrbconsumerType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
     <xsd:choice>
      <xsd:element ref="mediaResourceRequest" />
      <xsd:element ref="mediaResourceResponse" />
      <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
     </xsd:choice>
    </xsd:sequence>
    <xsd:attribute name="version" type="version.datatype"
      use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

 <xsd:element name="mrbconsumer" type="mrbconsumerType" />

<!--
  #####################################################

  mediaResourceRequest TYPE

  #####################################################
 -->

<!--  mediaResourceRequst -->

 <xsd:complexType name="mediaResourceRequestType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="generalInfo" minOccurs="0" />
      <xsd:element ref="ivrInfo" minOccurs="0" />
      <xsd:element ref="mixerInfo" minOccurs="0" />
     <xsd:any namespace="##other" minOccurs="0"
      maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="mediaResourceRequest"
         type="mediaResourceRequestType" />

<!--
  #####################################################

  generalInfo TYPE

  #####################################################
-->

<!--  generalInfo -->

<xsd:complexType name="generalInfoType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="session-info" minOccurs="0" />
      <xsd:element ref="packages" minOccurs="0" />
      <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

<xsd:element name="generalInfo" type="generalInfoType" />

<!--  session-info -->

<xsd:complexType name="session-infoType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:element name="session-id" type="id.datatype"/>
       <xsd:element name="seq" type="xsd:nonNegativeInteger"/>
       <xsd:element name="action" type="action.datatype"/>
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

<xsd:element name="session-info" type="session-infoType" />

<!--  packages -->

<xsd:complexType name="packagesType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element name="package" type="xsd:string" minOccurs="0"
        maxOccurs="unbounded" />
      <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>

</xsd:complexType>

<xsd:element name="packages" type="packagesType"/>

<!--
  #####################################################

  ivrInfo TYPE

  #####################################################
-->

<!--  ivrInfo -->

<xsd:complexType name="ivrInfoType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="ivr-sessions" minOccurs="0" />
      <xsd:element ref="file-formats" minOccurs="0" />
      <xsd:element ref="dtmf-type" minOccurs="0" />
      <xsd:element ref="tones" minOccurs="0" />
      <xsd:element ref="asr-tts" minOccurs="0" />
      <xsd:element ref="vxml" minOccurs="0" />
      <xsd:element ref="location" minOccurs="0" />
      <xsd:element ref="encryption" minOccurs="0" />
      <xsd:element ref="application-data" minOccurs="0" />
      <xsd:element ref="max-prepared-duration" minOccurs="0" />
      <xsd:element ref="streaming-modes" minOccurs="0" />
      <xsd:any namespace="##other" minOccurs="0"
      maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

<xsd:element name="ivrInfo" type="ivrInfoType" />

<!--
  #####################################################

  mixerInfo TYPE

  #####################################################
-->
<!--  mixerInfo -->

<xsd:complexType name="mixerInfoType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="mixers" minOccurs="0"/>
      <xsd:element ref="file-formats" minOccurs="0"/>
      <xsd:element ref="dtmf-type" minOccurs="0"/>
      <xsd:element ref="tones" minOccurs="0"/>
      <xsd:element ref="mixing-modes" minOccurs="0"/>
      <xsd:element ref="application-data" minOccurs="0"/>
      <xsd:element ref="location" minOccurs="0"/>
      <xsd:element ref="encryption" minOccurs="0"/>
      <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

<xsd:element name="mixerInfo" type="mixerInfoType" />

<!--
  #####################################################

  mediaResourceResponse TYPE

  #####################################################
 -->

<!--  mediaResourceResponse -->

 <xsd:complexType name="mediaResourceResponseType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:element ref="response-session-info" minOccurs="0" />
       <xsd:any namespace="##other" minOccurs="0"
          maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="status" type="status.datatype"
     use="required" />
    <xsd:attribute name="reason" type="xsd:string" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>

  </xsd:complexContent>
 </xsd:complexType>

 <xsd:element name="mediaResourceResponse"
         type="mediaResourceResponseType" />

<!--
  ####################################################

  ELEMENTS

  ####################################################
 -->

<!--  session-info -->

<xsd:complexType name="response-session-infoType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:element name="session-id" type="id.datatype"/>
       <xsd:element name="seq" type="xsd:nonNegativeInteger"/>
       <xsd:element name="expires" type="xsd:nonNegativeInteger"/>
       <xsd:element ref="media-server-address"
          minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
         maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

<xsd:element name="response-session-info"
   type="response-session-infoType" />

<!-- media-server-address -->

<xsd:complexType name="media-server-addressTYPE">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
     <xsd:element name="connection-id" type="xsd:string"
         minOccurs="0" maxOccurs="unbounded" />
     <xsd:element ref="ivr-sessions" minOccurs="0"/>
     <xsd:element ref="mixers" minOccurs="0"/>
     <xsd:any namespace="##other" minOccurs="0"
         maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="uri" type="xsd:anyURI" use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:element name="media-server-address"
    type="media-server-addressTYPE" />

<!--  ivr-sessions -->

<xsd:complexType name="ivr-sessionsType">
 <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="rtp-codec" minOccurs="0"
        maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

<xsd:element name="ivr-sessions" type="ivr-sessionsType" />

<xsd:complexType name="rtp-codecType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element name="decoding" type="xsd:nonNegativeInteger" />
      <xsd:element name="encoding" type="xsd:nonNegativeInteger" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="name" type="xsd:string" use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

<xsd:element name="rtp-codec" type="rtp-codecType" />
<!-- file-format -->

<xsd:complexType name="file-formatsType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:element ref="required-format"
         minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
         maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:element name="file-formats" type="file-formatsType" />

<xsd:complexType name="required-formatType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="required-file-package"
         minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="name" type="xsd:string" use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:element name="required-format" type="required-formatType" />

<xsd:complexType name="required-file-packageType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:element name="required-file-package-name" type="xsd:string"
        minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>
<xsd:element name="required-file-package"
  type="required-file-packageType" />

<!--  dtmf-type -->

<xsd:complexType name="dtmfType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:element ref="detect" />
       <xsd:element ref="generate" />
       <xsd:element ref="passthrough" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:element name="dtmf" type="dtmfType" />

<xsd:complexType name="detectType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:element ref="dtmf-type"
        minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:element name="detect" type="detectType" />

<xsd:complexType name="generateType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:element ref="dtmf-type"
        minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />

   </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:element name="generate" type="generateType" />

<xsd:complexType name="passthroughType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:element ref="dtmf-type"
        minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:element name="passthrough" type="passthroughType" />

<xsd:complexType name="dtmf-typeType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="name" type="dtmf.datatype" use="required" />
    <xsd:attribute name="package" type="xsd:string" use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:element name="dtmf-type" type="dtmf-typeType" />

<!--  tones -->

<xsd:complexType name="required-tonesType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
      <xsd:element ref="country-codes"
        minOccurs="0" maxOccurs="1" />
      <xsd:element ref="h248-codes"
        minOccurs="0" maxOccurs="1" />

      <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:anyAttribute namespace="##other" processContents="lax" />
  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="tones" type="required-tonesType" />

<xsd:complexType name="required-country-codesType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
     <xsd:element ref="country-code"
        minOccurs="0" maxOccurs="unbounded" />
      <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:anyAttribute namespace="##other" processContents="lax" />
  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="country-codes"
   type="required-country-codesType" />

<xsd:complexType name="country-codeType" mixed="true">
 <xsd:sequence>
    <xsd:any namespace="##other" minOccurs="0"
     maxOccurs="unbounded" processContents="lax" />
 </xsd:sequence>
 <xsd:attribute name="package" type="xsd:string" use="required" />
 <xsd:anyAttribute namespace="##other" processContents="lax" />
</xsd:complexType>

<xsd:element name="country-code" type="country-codeType" />

<xsd:complexType name="required-h248-codesType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
     <xsd:element ref="h248-code"
        minOccurs="0" maxOccurs="unbounded" />
      <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:anyAttribute namespace="##other" processContents="lax" />

  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="h248-codes"
   type="required-h248-codesType" />

<xsd:complexType name="h248-codeType" mixed="true">
 <xsd:sequence>
    <xsd:any namespace="##other" minOccurs="0"
     maxOccurs="unbounded" processContents="lax" />
 </xsd:sequence>
 <xsd:attribute name="package" type="xsd:string" use="required" />
 <xsd:anyAttribute namespace="##other" processContents="lax" />
</xsd:complexType>

<xsd:element name="h248-code" type="h248-codeType" />

<!--  asr-tts -->

<xsd:complexType name="asr-ttsType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
      <xsd:element ref="asr-support"
        minOccurs="0" maxOccurs="1" />
      <xsd:element ref="tts-support"
        minOccurs="0" maxOccurs="1" />
      <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:anyAttribute namespace="##other" processContents="lax" />
  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="asr-tts" type="asr-ttsType" />

<xsd:complexType name="asr-supportType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
     <xsd:element ref="language"
        minOccurs="0" maxOccurs="unbounded" />
      <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:anyAttribute namespace="##other" processContents="lax" />

  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="asr-support" type="asr-supportType" />

<xsd:complexType name="tts-supportType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
     <xsd:element ref="language"
        minOccurs="0" maxOccurs="unbounded" />
      <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:anyAttribute namespace="##other" processContents="lax" />
  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="tts-support" type="tts-supportType" />

<xsd:complexType name="languageType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
      <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:attribute ref="xml:lang" />
   <xsd:anyAttribute namespace="##other" processContents="lax" />
  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="language" type="languageType" />

<!--  vxml -->

<xsd:complexType name="vxmlType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="vxml-mode"
        minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />

    </xsd:sequence>
    <xsd:attribute name="support" type="boolean.datatype"
     default="false" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:element name="vxml" type="vxmlType" />

<xsd:complexType name="vxml-modeType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="package" type="xsd:string" use="required" />
    <xsd:attribute name="require" type="vxml.datatype" use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:element name="vxml-mode" type="vxml-modeType" />

<!--  location -->

<xsd:complexType name="locationType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:element ref="ca:civicAddress"
                        minOccurs="1" maxOccurs="1" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
 </xsd:complexType>

<xsd:element name="location" type="locationType" />

<!--  encryption -->

<xsd:element name="encryption" type="boolean.datatype" />
<!--  application-data -->

<xsd:element name="application-data" type="appdata.datatype" />

<!--  max-prepared-duration -->

<xsd:complexType name="max-prepared-durationType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="max-time" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:element name="max-prepared-duration"
  type="max-prepared-durationType" />

<xsd:complexType name="max-timeType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element name="max-time-package" type="xsd:string" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="max-time-seconds" type="xsd:nonNegativeInteger"
     use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:element name="max-time" type="max-timeType" />

<!--  stream-mode -->

<xsd:complexType name="streaming-modesType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="stream-mode"
        minOccurs="0" maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:element name="streaming-modes" type="streaming-modesType" />

<xsd:complexType name="stream-modeType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="name" type="streammode.datatype"
     use="required" />
    <xsd:attribute name="package" type="xsd:string" use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:element name="stream-mode" type="stream-modeType" />

<!--  mixers -->

<xsd:complexType name="mixerssessionsType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="mix" minOccurs="0"
        maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:element name="mixers" type="mixerssessionsType" />

<xsd:complexType name="mixType">
  <xsd:complexContent>
   <xsd:extension base="Tcore">
    <xsd:sequence>
      <xsd:element ref="rtp-codec" minOccurs="0"
        maxOccurs="unbounded" />
       <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
    </xsd:sequence>
    <xsd:attribute name="users" type="xsd:nonNegativeInteger"
     use="required" />
    <xsd:anyAttribute namespace="##other" processContents="lax" />
   </xsd:extension>
  </xsd:complexContent>
</xsd:complexType>

<xsd:element name="mix" type="mixType" />

<!--  mixing-modes -->

<xsd:complexType name="mixing-modesType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
      <xsd:element ref="audio-mixing-modes"
        minOccurs="0" maxOccurs="1" />
      <xsd:element ref="video-mixing-modes"
        minOccurs="0" maxOccurs="1" />
      <xsd:any namespace="##other" minOccurs="0"
        maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:anyAttribute namespace="##other" processContents="lax" />
  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="mixing-modes" type="mixing-modesType" />

<xsd:complexType name="audio-mixing-modesType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
     <xsd:element ref="audio-mixing-mode"
        minOccurs="0" maxOccurs="unbounded" />
      <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:anyAttribute namespace="##other" processContents="lax" />
  </xsd:extension>

 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="audio-mixing-modes" type="audio-mixing-modesType" />

<xsd:complexType name="audio-mixing-modeType" mixed="true">
 <xsd:sequence>
    <xsd:any namespace="##other" minOccurs="0"
     maxOccurs="unbounded" processContents="lax" />
 </xsd:sequence>
 <xsd:attribute name="package" type="xsd:string" use="required" />
 <xsd:anyAttribute namespace="##other" processContents="lax" />
</xsd:complexType>

<xsd:element name="audio-mixing-mode" type="audio-mixing-modeType" />

<xsd:complexType name="video-mixing-modesType">
 <xsd:complexContent>
  <xsd:extension base="Tcore">
   <xsd:sequence>
     <xsd:element ref="video-mixing-mode"
        minOccurs="0" maxOccurs="unbounded" />
      <xsd:any namespace="##other" minOccurs="0"
       maxOccurs="unbounded" processContents="lax" />
   </xsd:sequence>
   <xsd:attribute name="vas" type="boolean.datatype"
     default="false" />
   <xsd:attribute name="activespeakermix" type="boolean.datatype"
     default="false" />
   <xsd:anyAttribute namespace="##other" processContents="lax" />
  </xsd:extension>
 </xsd:complexContent>
</xsd:complexType>

<xsd:element name="video-mixing-modes" type="video-mixing-modesType" />

<xsd:complexType name="video-mixing-modeType" mixed="true">
 <xsd:sequence>
    <xsd:any namespace="##other" minOccurs="0"
     maxOccurs="unbounded" processContents="lax" />
 </xsd:sequence>
 <xsd:attribute name="package" type="xsd:string" use="required" />
 <xsd:anyAttribute namespace="##other" processContents="lax" />
</xsd:complexType>

<xsd:element name="video-mixing-mode" type="video-mixing-modeType" />
<!--
  ####################################################

  DATATYPES

  ####################################################
 -->

<xsd:simpleType name="version.datatype">
  <xsd:restriction base="xsd:NMTOKEN">
   <xsd:enumeration value="1.0" />
  </xsd:restriction>
</xsd:simpleType>

<xsd:simpleType name="id.datatype">
  <xsd:restriction base="xsd:NMTOKEN" />
</xsd:simpleType>

<xsd:simpleType name="status.datatype">
  <xsd:restriction base="xsd:positiveInteger">
   <xsd:pattern value="[0-9][0-9][0-9]" />
  </xsd:restriction>
</xsd:simpleType>

<xsd:simpleType name="streammode.datatype">
  <xsd:restriction base="xsd:NMTOKEN"/>
</xsd:simpleType>

<xsd:simpleType name="action.datatype">
  <xsd:restriction base="xsd:NMTOKEN">
   <xsd:enumeration value="remove" />
   <xsd:enumeration value="update" />
  </xsd:restriction>
</xsd:simpleType>

<xsd:simpleType name="dtmf.datatype">
  <xsd:restriction base="xsd:NMTOKEN">
   <xsd:enumeration value="RFC4733" />
   <xsd:enumeration value="Media" />
  </xsd:restriction>
</xsd:simpleType>

<xsd:simpleType name="boolean.datatype">
  <xsd:restriction base="xsd:NMTOKEN">
   <xsd:enumeration value="true" />
   <xsd:enumeration value="false" />
  </xsd:restriction>
</xsd:simpleType>
<xsd:simpleType name="vxml.datatype">
  <xsd:restriction base="xsd:NMTOKEN">
   <xsd:enumeration value="RFC4240" />
   <xsd:enumeration value="RFC5552" />
   <xsd:enumeration value="IVR-Package" />
  </xsd:restriction>
</xsd:simpleType>

<xsd:simpleType name="appdata.datatype">
  <xsd:restriction base="xsd:NMTOKEN" />
 </xsd:simpleType>

</xsd:schema>

                                 Figure 14

12.  Security Considerations

   The MRB network entity has two primary interfaces, Publish and
   Consumer, that carry sensitive information and must therefore be
   appropriately protected and secured.

   The Publish interface, as defined in and described in Section 5.1,
   uses the Media Control Channel Framework
   [I-D.ietf-mediactrl-sip-control-framework] as a mechanism to connect
   an MRB to a media server.  The appropriate Security Considerations
   included in the Media Control Channel Framework specification MUST be
   used in conjunction with this specification to protect interactions
   between an MRB and a media server.

   The Consumer interface, as defined in and described in Section 5.2,
   uses either the Hypertext Transfer Protocol (HTTP) or Session
   Initiation Protocol (SIP) as the mechanism for clients to connect to
   an MRB to request media resources.  In the case of the HTTP use, any
   binding using the Consumer interface MUST be capable of being
   transacted over TLS, as described in RFC 2818 [RFC2818].  In the case
   of the SIP use, the appropriate security considerations included in
   the Media Control Channel Framework specification MUST be used in
   conjunction with this specification to protect interactions between a
   client requesting media resources and an MRB.

   It is also worth noting that in In-line mode (both IAMM and IUMM) the
   MRB may act as a Back-to-Back User Agent (B2BUA).  This means that,
   as a B2BUA, the MRB may happen to modify SIP bodies: it is the case,
   for instance, of the IAMM handling multipart/mixed payloads.  This
   impacts the ability to use any SIP security feature that protects the
   body (e.g., RFC4474, s/mime, etc.) unless the MRB intermediates the
   security association.  This should be taken into account when
   implementing an MRB compliant with this specification.

   Finally, it is worthwhile to also discuss authorization issues
   related to the specification.  Neither the Publishing nor the
   Consumer interface provide an explicit means for implementing
   authentication, i.e., they do not envisage protocol messages to make
   sure, for instance, that only authorized Application Servers can make
   use of the services provided by a MRB.  Nevertheless, considering
   both the interfaces are transported in well-established protocols
   (HTTP, SIP, CFW), support for such an functionality can be expressed
   by means of the authentication mechanisms provided by the protocol
   themselves.  Therefore, any MRB-aware entity (Application Servers,
   Media Servers, Media Resource Brokers themselves) MUST support the
   HTTP and SIP Digest access authentication.  That said, the usage of
   such Digest access authentications is recommended and not mandatory,
   which means MRB-aware entities MAY exploit it in deployment.

13.  IANA Considerations

   There are several IANA considerations associated with this
   specification.

13.1.  Control Package Registration

   This section registers a new Media Control Channel Framework package,
   per the instructions in Section 13.1 of
   [I-D.ietf-mediactrl-sip-control-framework].

   To:   ietf-sip-control@iana.org

   Subject:   Registration of new Channel Framework package

   Package Name:   mrb-publish/1.0 [NOTE TO IANA/RFC-EDITOR: Please
      replace XXXX with the RFC number for this specification.]

   Published Specification(s):   RFCXXXX Person and email address to
      contact for further information: IETF, MEDIACTRL working group,
      (mediactrl@ietf.org), Chris Boulton (chris@ns-technologies.com).

13.2.  application/mrb-publish+xml MIME Type

   MIME media type name:   application

   MIME subtype name:   mrb-publish+xml

   Mandatory parameters:   none

   Optional parameters:   Same as charset parameter application/xml as
      specified in RFC 3023 [RFC3023].

   Encoding considerations:   Same as encoding considerations of
      application/xml as specified in RFC 3023 [RFC3023].

   Security considerations:   See Section 10 of RFC 3023 [RFC3023] and
      Section 8 of RFCXXXX [[NOTE TO RFC-EDITOR/IANA: Please replace
      XXXX with the RFC number of this specification.]].

   Interoperability considerations:   none.

   Published specification:   This document.

   Applications which use this media type:   This document type has been
      used to support a Media Resource Broker (MRB) entity.

   Additional Information:

   Magic Number:   None

   File Extension:   .xdf

   Macintosh file type code:   "TEXT"

   Personal and email address for further information:   Chris Boulton,
      chris@ns-technologies.com

   Intended usage: COMMON

   Author/Change controller:   The IETF.

13.3.  application/mrb-consumer+xml MIME Type

   MIME media type name:   application

   MIME subtype name:   mrb-consumer+xml

   Mandatory parameters:   none

   Optional parameters:   Same as charset parameter application/xml as
      specified in RFC 3023 [RFC3023].

   Encoding considerations:   Same as encoding considerations of
      application/xml as specified in RFC 3023 [RFC3023].

   Security considerations:   See Section 10 of RFC 3023 [RFC3023] and
      Section 8 of RFCXXXX [[NOTE TO RFC-EDITOR/IANA: Please replace
      XXXX with the RFC number of this specification.]].

   Interoperability considerations:   none.

   Published specification:   This document.

   Applications which use this media type:   This document type has been
      used to support a Media Resource Broker (MRB) entity.

   Additional Information:

   Magic Number:   None

   File Extension:   .xdf
   Macintosh file type code:   "TEXT"

   Personal and email address for further information:   Chris Boulton,
      chris@ns-technologies.com

   Intended usage: COMMON

   Author/Change controller:   The IETF.

13.4.  URN Sub-Namespace Registration for mrb-publish

   Please register the URN name space
   "urn:ietf:params:xml:ns:mrb-publish", with the ID of "mrb-publish".
   The template is in Section 10.

13.5.  URN Sub-Namespace Registration for mrb-consumer

   Please register the URN name space
   "urn:ietf:params:xml:ns:mrb-consumer", with the ID of "mrb-consumer".
   The template is in Section 11.

13.6.  XML Schema Registration for mrb-publish

   Please register the schema for mrb-publish:

   URI:   urn:ietf:params:xml:ns:mrb-publish

   ID:   mrb-publish

   Filename:   mbr-publish

   Registrant Contact:   IETF, MEDIACTRL working group
      (mediactrl@ietf.org)

   Schema:   The XML for the schema is in Section 10 of this document.

13.7.  XML Schema Registration for mrb-consumer

   Please register the schema for mrb-consumer:

   URI:   urn:ietf:params:xml:ns:mrb-consumer

   ID:   mrb-consumer

   Filename:   mbr-consumer
   Registrant Contact:   IETF, MEDIACTRL working group
      (mediactrl@ietf.org)

   Schema:   The XML for the schema is in Section 11 of this document.

14.  Changes

   Note to RFC Editor: Please remove this whole section.

14.1.  Changes from 08 Version

   o  Fixed Nits.

   o  Added range for reporting period - as per mailing list.

14.2.  Changes from 07 Version

   o  Corrected some errors in the Consumer schema: a few elements were
      not declared optional as they should have been, and some were
      incorrectly defined as choices instead of sequences;

   o  Corrected examples after validation tests;

   o  Fixed a few typos in the text.

   o  Clarified language in various places.

   o  Added 'Multi-modal MRB Implementations' section.

   o  Added 'Relative Merits of Query Mode, IAMM, and IUMM' section.

   o  Clarifying text related to IAMM and IUMM.

   o  Expanded media-server-address for extra information and to allow
      multiples.

   o  New B2BUA section.

   o  Updated Examples.

14.2.

14.3.  Changes from 06 Version

   o  Added the missing <encoding> and <decoding> elements to the <rtp-
      codec> instances, where needed.

   o  Fixed a few typos in the text.

14.3.

14.4.  Changes from 05 Version

   o  Clarifier that video layouts may refer to either XCON-defined
      layouts or others.

   o  Added RFC4240 as an option for VXML support.

   o  Fixed a few typos in the text and in the schemas.

14.4.

14.5.  Changes from 04 Version

   o  Corrected some typos and leftovers in both 'session-info' and
      'response-session-info' definitions.

   o  Clarified that 'response-session-info' is not only included in
      reply to updates, but also to new requests; besides, clarified
      that it is an optional element, in the sense that it is mandatory
      in successful responses (200), while not needed otherwise (any
      error).

   o  Corrected the Query example flow which included a 'session'info'
      in a new request.

14.5.

14.6.  Changes from 03 Version

   o  Addressed comments per the Expert RAI Review by Ben Campbell.

   o  Several editorial changes (fixes, typos, nits).

   o  Removed the 3xx class responses for the IAMM, per discussion in
      Anaheim (feature had been added in the -02 version).

   o  Clarified that backslashes and XML indentation in the Examples are
      only provided for readability.

   o  Clarified the distinction between 'deactivated' and 'unavailable'.

   o  Added text to the status codes in both Publish and Consumer
      responses, in order to clarify when they are involved.

   o  Added some text to better clarify the role of leasing in the
      Consumer interface.

   o  Added additional IANA considerations, that were missing in the
      previous versions of the document.

   o  Added text to the security considerations.

14.6.

14.7.  Changes from 02 Version

   o  Added examples in Section 9.

   o  Fixed some nits in the schemas (encryption and required mixed=true
      elements).

   o  Completed review nit review comments from Gary Munson.

14.7.

14.8.  Changes from 01 Version

   o  Added description of lease mechanism.

   o  Added specific HTTP and SIP usage of Consumer interface.

   o  Completed Publish interface schema + associated text.

   o  Included Consumer interface schema + associated text.

   o  Included supported-packages element.

   o  Removed announce-var element from doc.

   o  Expanded Abstract.

   o  General scrub of text - input from Simon Romano.

   o  Added IANA Considerations section.

   o  Added Security Considerations section.

14.8.

14.9.  Changes from 00 Version

   o  Included In-line text based on strawman proposal.

   o  Included first attempt at publish interface based on design team
      work.

15.  Acknowledgments

   The authors would like to thank the members of the Publish Interface
   design team who provided valuable input into this document.  The
   design team consisted of Adnan Saleem, Michael Trank, Victor
   Paulsamy, Martin Dolly, and Scott McGlashan.  The authors would also
   like to thank John Dally, Bob Epley, Simon Romano, Henry Lum,
   Christian Groves and Jonathan Lennox for input into this
   specification.

   Ben Campbell carried out the RAI expert review on this specification
   and provided a great deal of invaluable input.

16.  References

16.1.  Normative References

   [ISO.3166-1]
              International Organization for Standardization, "Codes for
              the representation of names of countries and their
              subdivisions - Part 1: Country codes", ISO Standard 3166-
              1:1997, 1997.

   [ISO.639.1988]
              International Organization for Standardization, "Code for
              the representation of names of languages, 1st edition",
              ISO Standard 639, 1988.

   [ITU-T.Q.1950]
              International Telecommunication Union - Telecommunication
              Standardization Bureau, "Call Bearer Control (CBC)
              Protocol", ITU-T Recommendation Q.1950.

   [RFC2046]  Freed, N. and N. Borenstein, "Multipurpose Internet Mail
              Extensions (MIME) Part Two: Media Types", RFC 2046,
              November 1996.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2616]  Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
              Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
              Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.

   [RFC2818]  Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.

   [RFC3023]  Murata, M., St. Laurent, S., and D. Kohn, "XML Media
              Types", RFC 3023, January 2001.

   [RFC3261]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
              A., Peterson, J., Sparks, R., Handley, M., and E.
              Schooler, "SIP: Session Initiation Protocol", RFC 3261,
              June 2002.

   [RFC3311]  Rosenberg, J., "The Session Initiation Protocol (SIP)
              UPDATE Method", RFC 3311, October 2002.

   [RFC3711]  Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K.
              Norrman, "The Secure Real-time Transport Protocol (SRTP)",
              RFC 3711, March 2004.

   [RFC4722]  Van Dyke, J., Burger, E., and A. Spitzer, "Media Server
              Control Markup Language (MSCML) and Protocol", RFC 4722,
              November 2006.

   [RFC5139]  Thomson, M. and J. Winterbottom, "Revised Civic Location
              Format for Presence Information Data Format Location
              Object (PIDF-LO)", RFC 5139, February 2008.

   [RFC5705]  Rescorla, E., "Keying Material Exporters for Transport
              Layer Security (TLS)", RFC 5705, March 2010.

   [W3C.CR-wsdl20-20051215]
              Chinnici, R., Moreau, J., Ryman, A., and S. Weerawarana,
              "Web Services Description Language (WSDL) Version 2.0 Part
              1: Core Language", W3C CR CR-wsdl20-20051215,
              December 2005.

   [W3C.REC-soap12-part1-20030624]
              Mendelsohn, N., Gudgin, M., Nielsen, H., Hadley, M., Moreau, J., and N.
              Mendelsohn,
              M. Hadley, "SOAP Version 1.2 Part 1: Messaging Framework",
              World Wide Web Consortium FirstEdition REC-
              soap12-part1-20030624, REC-soap12-part1-
              20030624, June 2003,
              <http://www.w3.org/TR/2003/REC-soap12-part1-20030624>.

   [W3C.REC-soap12-part2-20030624]
              Mendelsohn, N., Nielsen, H., Gudgin, M., Moreau, J., Hadley, M., and
              M. Gudgin, H.
              Nielsen, "SOAP Version 1.2 Part 2: Adjuncts", World Wide
              Web Consortium FirstEdition REC-soap12-part2-20030624,
              June 2003,
              <http://www.w3.org/TR/2003/REC-soap12-part2-20030624>.

16.2.  Informative References

   [I-D.ietf-mediactrl-ivr-control-package]
              McGlashan, S., Melanchuk, T., and C. Boulton, "An
              Interactive Voice Response (IVR) Control Package for the
              Media Control Channel Framework",
              draft-ietf-mediactrl-ivr-control-package-11 (work in
              progress), January 2011.

   [I-D.ietf-mediactrl-mixer-control-package]
              McGlashan, S., Melanchuk, T., and C. Boulton, "A Mixer
              Control Package for the Media Control Channel Framework",
              draft-ietf-mediactrl-mixer-control-package-14 (work in
              progress), January 2011.

   [I-D.ietf-mediactrl-sip-control-framework]
              Boulton, C., Melanchuk, T., and S. McGlashan, "Media
              Control Channel Framework",
              draft-ietf-mediactrl-sip-control-framework-12 (work in
              progress), September 2010.

   [RFC4240]  Burger, E., Van Dyke, J., and A. Spitzer, "Basic Network
              Media Services with SIP", RFC 4240, December 2005.

   [RFC4281]  Gellens, R., Singer, D., and P. Frojdh, "The Codecs
              Parameter for "Bucket" Media Types", RFC 4281,
              November 2005.

   [RFC4733]  Schulzrinne, H. and T. Taylor, "RTP Payload for DTMF
              Digits, Telephony Tones, and Telephony Signals", RFC 4733,
              December 2006.

   [RFC5167]  Dolly, M. and R. Even, "Media Server Control Protocol
              Requirements", RFC 5167, March 2008.

   [RFC5552]  Burke, D. and M. Scott, "SIP Interface to VoiceXML Media
              Services", RFC 5552, May 2009.

   [RFC5567]  Melanchuk, T., "An Architectural Framework for Media
              Server Control", RFC 5567, June 2009.

Authors' Addresses

   Chris Boulton
   NS-Technologies

   Email: chris@ns-technologies.com

   Lorenzo Miniero
   Meetecho
   Via Carlo Poerio 89
   Napoli  80100
   Italy

   Email: lorenzo@meetecho.com

   Gary Munson
   AT&T
   200 Laurel Avenue South
   Middletown
   New Jersey  07748
   USA

   Email: gamunson@att.com