XEP-0298: Delivering Conference Information to Jingle Participants (Coin)

Abstract
This specification defines an XMPP extension for tightly coupled conference calls. It allows users who participate in multiparty Jingle calls via a focus agent (mixer) to retrieve information and receive notifications about the state of the call and the other participants. This extension is also meant to provide a straightforward way of connecting SIP and XMPP clients to the same conference room.
Authors
  • Emil Ivov
  • Enrico Marocco
  • Saúl Ibarra Corretgé
Copyright
© 1999 – 2020 XMPP Standards Foundation. SEE LEGAL NOTICES.
Status

Deferred

WARNING: This document has been automatically Deferred after 12 months of inactivity in its previous Experimental state. Implementation of the protocol described herein is not recommended for production systems. However, exploratory implementations are encouraged to resume the standards process.
Type
Standards Track
Version
0.2 (2015-07-02)
Document Lifecycle
  1. Experimental
  2. Deferred
  3. Proposed
  4. Draft
  5. Final

1. Introduction

Jingle (XEP-0166) [1] defines a way for XMPP agents to establish and control one-to-one media sessions. It is possible for either participant in such a session to also establish additional conversations and then serve as a media mixer. This could be viewed as a classic conference call scenario and is also often referred to as a tightly coupled conference.

Basic participation or hosting of tightly coupled conferences requires no specific protocol support. With the exception of the mixing agent, call members, however, all perceive the session as a regular one-to-one call. They have no way of obtaining additional information about how many and what other users are participating.

The Coin extension (short for Conference Information) allows media mixers to deliver to participants additional information about the status of the call, and that of its members.

A conference participant exchanges Coin IQs only with the agent they have established a session with. This means that it can also be used in cases where only a subset of the users on a call are using XMPP while others are connected via alternative mechanisms such as SIP conferencing as defined in RFC 4579 [2]

2. Terminology

Mixer
Throughout this document the term is used to depict an entity that is responsible for mixing and delivering to conference participants both signalling and media. Other specifications refer to mixers and focus agents as two distinct entities but we find this separation to be unnecessary in the current specification and view both as a single logical entity. This entity may be a person hosting the conference and doing the mixing or a dedicated entity to which participants connect in order to establish a conference. For the purposes of this specification, both scenarios are equivalent.

3. Requirements

The extension defined herein is designed to meet the following requirements:

  1. Provide a means for mixer agents in tightly coupled conferences to advertise call and member state information to the call participants.
  2. Reuse the existing format and XML schema already defined in RFC 4575.
  3. Impose no requirements on agents joining the call other than those necessary to establish a regular one-to-one call.
  4. Allow straightforward interoperability with other conferencing mechanisms such as RFC 4579 [2] or Multiparty Jingle (XEP-0272) [3]

4. How It Works

This section provides a friendly introduction to Coin.

In essence Coin allows clients that establish Jingle calls to determine whether their peer is acting as a mixer or to announce themselves as such. This way non-mixer participants would know when they are participating in a conference call and would be able to notify the user accordingly.

Once in a call, participants and mixers can use Coin to exchange RFC 4575 [4] conference information indicating what participants are currently on the call and what their status is.

5. Creating a conference call

When creating conference calls mixers SHOULD indicate the nature of the call as early as possible. This is necessary in order to allow other participating user agents to adapt their user interface in an appropriate way.

A mixer sends session-initiate for a conference call
    
<iq from='romeo@montague.lit/orchard'
    id='zid615d9'
    to='juliet@capulet.lit/balcony'
    type='set'>
  <jingle xmlns='urn:xmpp:jingle:1'>
          action='session-initiate'
          initiator='romeo@montague.lit/orchard'
          sid='a73sjjvkla37jfea'>
    <content creator='initiator' name='this-is-a-stub'>
      <description xmlns='urn:xmpp:jingle:apps:stub:0'/>
      <transport xmlns='urn:xmpp:jingle:transports:stub:0'/>
    </content>
    <conference-info xmlns='urn:xmpp:coin:1' isfocus='true'/>
  </jingle>
</iq>

Similarly mixers being dialed by new participants SHOULD indicate the nature of the call by including the <conference-info/> element into the Jingle session-accept message.

Finally, when transforming an existing one-to-one session into a conference or vice-versa a mixer SHOULD send a Jingle session-info message with the appropriate <conference-info/> element.

Note that presence of the <conference-info/> element is only determines whether the party sending it is currently acting as a mixer or not. If multiple peers in a call are independently acting as mixers they should all indicate their status accordingly.

6. Delivering conference information

Once a conference call has been established and advertised as such, a mixer MAY at any point send information describing the state of the call and its current participants.

Mixer sends information about the current state of the call
    
<iq from='romeo@montague.lit/orchard'
    id='zid615d9'
    to='juliet@capulet.lit/balcony'
    type='set'>
    <jingle xmlns='urn:xmpp:jingle:1' sid='a73sjjvkla37jfea'/>
    <conference-info xmlns="urn:ietf:params:xml:ns:conference-info"
                     entity="xmpp:romeo@monague.lit/orchard"
                     state="full"
                     version="1">

     <!-- CONFERENCE INFO -->
     <conference-description>
       <subject>Ending a relationship</subject>
     </conference-description>

     <!-- CONFERENCE STATE -->
     <conference-state>
       <user-count>3</user-count>
     </conference-state>

     <!-- USERS -->
     <users>
       <user entity="xmpp:romeo@montague.lit" state="full">
         <display-text>Romeo</display-text>

         <!-- ENDPOINTS -->
         <endpoint entity="xmpp:romeo@montague.lit/orchard">
           <display-text>Romeo's smartphone</display-text>
           <status>disconnected</status>
           <disconnection-info>
             <when>2011-01-31T20:00:00Z</when>
             <reason>poisoned</reason>
           </disconnection-info>

           <!-- MEDIA -->
           <media id="1">
             <display-text>main audio</display-text>
             <type>audio</type>
             <src-id>432424</src-id>
           </media>
         </endpoint>
       </user>

       <user entity="xmpp:juliet@capulet.lit" state="full">
         <display-text>Juliet</display-text>

         <!-- ENDPOINTS -->
         <endpoint entity="juliet@capulet.lit/balcony">
           <display-text>Juliet's netbook</display-text>
           <status>connected</status>

           <!-- MEDIA -->
           <media id="1">
             <type>audio</type>
             <src-id>2124</src-id>
           </media>
         </endpoint>
       </user>

       <!-- USER -->
       <user entity="sip:alice@example.com" state="full">
         <display-text>Alice</display-text>

         <!-- ENDPOINTS -->
         <endpoint entity="sip:4kfk4j392jsu@example.com;grid=433kj4j3u">
           <status>connected</status>

           <!-- MEDIA -->
           <media id="1">
             <type>audio</type>
             <src-id>534232</src-id>
           </media>
         </endpoint>
       </user>
     </users>
   </conference-info>
</iq>

The IQ message containing the conference info document MAY also contain a jingle element with the session id attribute indicting the session to which the conference information refers to.

7. Determining Support

If an entity supports Coin, it SHOULD advertise that fact by returning a feature of "urn:xmpp:coin:1" in response to a Service Discovery (XEP-0030) [5] information request.

Example 1. Service Discovery Information Request
<iq from='kingclaudius@shakespeare.lit/castle'
    id='ku6e51v3'
    to='laertes@shakespeare.lit/castle'
    type='get'>
  <query xmlns='http://jabber.org/protocol/disco#info'/>
</iq>
Example 2. Service Discovery Information Response
<iq from='laertes@shakespeare.lit/castle'
    id='ku6e51v3'
    to='kingclaudius@shakespeare.lit/castle'
    type='result'>
  <query xmlns='http://jabber.org/protocol/disco#info'>
    <feature var='urn:xmpp:coin:1'/>
  </query>
</iq>

In order for an application to determine whether an entity supports this protocol, where possible it SHOULD use the dynamic, presence-based profile of service discovery defined in Entity Capabilities (XEP-0115) [6]. However, if an application has not received entity capabilities information from an entity, it SHOULD use explicit service discovery instead.

8. Security Considerations

PENDING: RFC 4575 mostly talks about authentication conference-info subscriptions but these are not part of this specification. The authors are hence currently unaware of any other Coin specific security considerations

9. Open Issues

This document provides a basic description of a simple way to support tightly coupled conference calls. It is in many respects still a stub and a number of open issues require the attention of the community:

  1. Need to define best practices for user agents to easily determine whether the request of user to establish a conference call should result in a Muji or a Coin conference.

10. XML Schemas

10.1 Advertising Conf Calls

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

<xs:schema
    xmlns:xs='http://www.w3.org/2001/XMLSchema'
    targetNamespace='urn:xmpp:coin:1'
    xmlns='urn:xmpp:coin:1'
    elementFormDefault='qualified'>

  <xs:annotation>
    <xs:documentation>
      The protocol documented by this schema is defined in
      XEP-0298: http://www.xmpp.org/extensions/xep-0298.html
    </xs:documentation>
  </xs:annotation>

  <xs:element name="conference-info" type="empty">
    <xs:complexType>
      <xs:attribute name='isfocus' type='xs:boolean' required='true'/>
    </xs:complexType>
  </xs:element>

</xs:schema>

10.2 Conference Info

<?xml version="1.0" encoding="UTF-8" ?>
   <xs:schema
   targetNamespace="urn:ietf:params:xml:ns:conference-info"
   xmlns:tns="urn:ietf:params:xml:ns:conference-info"
   xmlns:xs="http://www.w3.org/2001/XMLSchema"
   xmlns="urn:ietf:params:xml:ns:conference-info"
   elementFormDefault="qualified"
   attributeFormDefault="unqualified">

   <xs:annotation>
    <xs:documentation>
      The protocol documented by this schema is defined in
      RFC 4575: http://tools.ietf.org/html/rfc4575  and reused by
      XEP-0298 http://www.xmpp.org/extensions/xep-0298.html
    </xs:documentation>
  </xs:annotation>

   <!--
     This imports the xml:language definition
   -->
      <xs:import namespace="http://www.w3.org/XML/1998/namespace"
       schemaLocation="http://www.w3.org/2001/03/xml.xsd"/>
   <!--
     CONFERENCE ELEMENT
   -->
      <xs:element name="conference-info" type="conference-type"/>
      <!--
         CONFERENCE TYPE
      -->
      <xs:complexType name="conference-type">
       <xs:sequence>
        <xs:element name="conference-description"
         type="conference-description-type" minOccurs="0"/>
        <xs:element name="host-info"
         type="host-type" minOccurs="0"/>
        <xs:element name="conference-state"
         type="conference-state-type" minOccurs="0"/>
        <xs:element name="users"
         type="users-type" minOccurs="0"/>
        <xs:element name="sidebars-by-ref"
         type="uris-type" minOccurs="0"/>
        <xs:element name="sidebars-by-val"
         type="sidebars-by-val-type" minOccurs="0"/>
        <xs:any namespace="##other" processContents="lax"
         minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:attribute name="entity"
        type="xs:anyURI" use="required"/>
       <xs:attribute name="state"
        type="state-type" use="optional" default="full"/>
       <xs:attribute name="version"
        type="xs:unsignedInt" use="optional"/>
       <xs:anyAttribute namespace="##other" processContents="lax"/>
      </xs:complexType>
      <!--
         STATE TYPE
      -->
      <xs:simpleType name="state-type">
       <xs:restriction base="xs:string">
        <xs:enumeration value="full"/>
        <xs:enumeration value="partial"/>
        <xs:enumeration value="deleted"/>
       </xs:restriction>
      </xs:simpleType>
      <!--
         CONFERENCE DESCRIPTION TYPE
      -->
      <xs:complexType name="conference-description-type">
       <xs:sequence>
        <xs:element name="display-text"
         type="xs:string" minOccurs="0"/>
        <xs:element name="subject"
         type="xs:string" minOccurs="0"/>
        <xs:element name="free-text"
         type="xs:string" minOccurs="0"/>
        <xs:element name="keywords"
         type="keywords-type" minOccurs="0"/>
        <xs:element name="conf-uris"
         type="uris-type" minOccurs="0"/>
        <xs:element name="service-uris"
         type="uris-type" minOccurs="0"/>
        <xs:element name="maximum-user-count"
         type="xs:unsignedInt" minOccurs="0"/>
        <xs:element name="available-media"
         type="conference-media-type" minOccurs="0"/>
        <xs:any namespace="##other" processContents="lax"
         minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##other" processContents="lax"/>
      </xs:complexType>
      <!--
         HOST TYPE
      -->
      <xs:complexType name="host-type">
       <xs:sequence>
        <xs:element name="display-text" type="xs:string"
         minOccurs="0"/>
        <xs:element name="web-page" type="xs:anyURI"
         minOccurs="0"/>
        <xs:element name="uris" type="uris-type"
         minOccurs="0"/>
        <xs:any namespace="##other" processContents="lax"
         minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##other" processContents="lax"/>
      </xs:complexType>
      <!--
         CONFERENCE STATE TYPE
      -->
      <xs:complexType name="conference-state-type">
       <xs:sequence>
        <xs:element name="user-count" type="xs:unsignedInt"
         minOccurs="0"/>
        <xs:element name="active" type="xs:boolean"
         minOccurs="0"/>
        <xs:element name="locked" type="xs:boolean"
         minOccurs="0"/>
        <xs:any namespace="##other" processContents="lax"
         minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##other" processContents="lax"/>
      </xs:complexType>
      <!--
         CONFERENCE MEDIA TYPE
      -->
      <xs:complexType name="conference-media-type">
       <xs:sequence>
        <xs:element name="entry" type="conference-medium-type"
         maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##other" processContents="lax"/>
      </xs:complexType>
      <!--
         CONFERENCE MEDIUM TYPE
      -->
      <xs:complexType name="conference-medium-type">
       <xs:sequence>
        <xs:element name="display-text" type="xs:string"
         minOccurs="0"/>
        <xs:element name="type" type="xs:string"/>
        <xs:element name="status" type="media-status-type"
         minOccurs="0"/>
        <xs:any namespace="##other" processContents="lax"
         minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:attribute name="label" type="xs:string"
        use="required"/>
       <xs:anyAttribute namespace="##other" processContents="lax"/>
      </xs:complexType>
      <!--
         URIs TYPE
      -->
      <xs:complexType name="uris-type">
       <xs:sequence>
        <xs:element name="entry" type="uri-type"
         maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:attribute name="state" type="state-type"
        use="optional" default="full"/>
       <xs:anyAttribute namespace="##other" processContents="lax"/>
      </xs:complexType>
      <!--
         URI TYPE
      -->
      <xs:complexType name="uri-type">
       <xs:sequence>
        <xs:element name="uri" type="xs:anyURI"/>
        <xs:element name="display-text" type="xs:string"
         minOccurs="0"/>
        <xs:element name="purpose" type="xs:string"
         minOccurs="0"/>
        <xs:element name="modified" type="execution-type"
         minOccurs="0"/>
        <xs:any namespace="##other" processContents="lax"
         minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##other" processContents="lax"/>
      </xs:complexType>
      <!--
         KEYWORDS TYPE
      -->
      <xs:simpleType name="keywords-type">
       <xs:list itemType="xs:string"/>
      </xs:simpleType>
      <!--
         USERS TYPE
      -->
      <xs:complexType name="users-type">
       <xs:sequence>
        <xs:element name="user" type="user-type"
         minOccurs="0" maxOccurs="unbounded"/>
        <xs:any namespace="##other" processContents="lax"
         minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:attribute name="state" type="state-type"
        use="optional" default="full"/>
       <xs:anyAttribute namespace="##other" processContents="lax"/>
      </xs:complexType>
      <!--
         USER TYPE
      -->
      <xs:complexType name="user-type">
       <xs:sequence>
        <xs:element name="display-text" type="xs:string"
         minOccurs="0"/>
        <xs:element name="associated-aors" type="uris-type"
         minOccurs="0"/>
        <xs:element name="roles" type="user-roles-type"
         minOccurs="0"/>
        <xs:element name="languages" type="user-languages-type"
         minOccurs="0"/>
        <xs:element name="cascaded-focus" type="xs:anyURI"
         minOccurs="0"/>
        <xs:element name="endpoint" type="endpoint-type"
         minOccurs="0" maxOccurs="unbounded"/>
        <xs:any namespace="##other" processContents="lax"
         minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:attribute name="entity" type="xs:anyURI"/>
       <xs:attribute name="state" type="state-type"
        use="optional" default="full"/>
       <xs:anyAttribute namespace="##other" processContents="lax"/>
      </xs:complexType>
      <!--
         USER ROLES TYPE
      -->
      <xs:complexType name="user-roles-type">
       <xs:sequence>
        <xs:element name="entry" type="xs:string"
         maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##other" processContents="lax"/>
      </xs:complexType>
      <!--
         USER LANGUAGES TYPE
      -->
      <xs:simpleType name="user-languages-type">
       <xs:list itemType="xs:language"/>
      </xs:simpleType>
      <!--
         ENDPOINT TYPE
      -->
      <xs:complexType name="endpoint-type">
       <xs:sequence>
        <xs:element name="display-text" type="xs:string"
         minOccurs="0"/>
        <xs:element name="referred" type="execution-type"
         minOccurs="0"/>
        <xs:element name="status" type="endpoint-status-type"
         minOccurs="0"/>
        <xs:element name="joining-method" type="joining-type"
         minOccurs="0"/>
        <xs:element name="joining-info"
         type="execution-type"
         minOccurs="0"/>
        <xs:element name="disconnection-method"
         type="disconnection-type"
         minOccurs="0"/>
        <xs:element name="disconnection-info"
         type="execution-type"
         minOccurs="0"/>
        <xs:element name="media" type="media-type"
         minOccurs="0" maxOccurs="unbounded"/>
        <xs:element name="call-info" type="call-type"
         minOccurs="0"/>
        <xs:any namespace="##other" processContents="lax"
         minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:attribute name="entity" type="xs:string"/>
       <xs:attribute name="state" type="state-type"
        use="optional" default="full"/>
       <xs:anyAttribute namespace="##other" processContents="lax"/>
      </xs:complexType>
      <!--
         ENDPOINT STATUS TYPE
      -->
      <xs:simpleType name="endpoint-status-type">
       <xs:restriction base="xs:string">
        <xs:enumeration value="pending"/>
        <xs:enumeration value="dialing-out"/>
        <xs:enumeration value="dialing-in"/>
        <xs:enumeration value="alerting"/>
        <xs:enumeration value="on-hold"/>
        <xs:enumeration value="connected"/>
        <xs:enumeration value="muted-via-focus"/>
        <xs:enumeration value="disconnecting"/>
        <xs:enumeration value="disconnected"/>
       </xs:restriction>
      </xs:simpleType>
      <!--
         JOINING TYPE
      -->
      <xs:simpleType name="joining-type">
       <xs:restriction base="xs:string">
        <xs:enumeration value="dialed-in"/>
        <xs:enumeration value="dialed-out"/>
        <xs:enumeration value="focus-owner"/>
       </xs:restriction>
      </xs:simpleType>
      <!--
         DISCONNECTION TYPE
      -->
      <xs:simpleType name="disconnection-type">
       <xs:restriction base="xs:string">
        <xs:enumeration value="departed"/>
        <xs:enumeration value="booted"/>
        <xs:enumeration value="failed"/>
        <xs:enumeration value="busy"/>
       </xs:restriction>
      </xs:simpleType>
      <!--
         EXECUTION TYPE
      -->
      <xs:complexType name="execution-type">
       <xs:sequence>
        <xs:element name="when" type="xs:dateTime"
         minOccurs="0"/>
        <xs:element name="reason" type="xs:string"
         minOccurs="0"/>
        <xs:element name="by" type="xs:anyURI"
         minOccurs="0"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##other" processContents="lax"/>
      </xs:complexType>
     <!--
         CALL TYPE
      -->
      <xs:complexType name="call-type">
       <xs:choice>
        <xs:element name="sip" type="sip-dialog-id-type"/>
        <xs:any namespace="##other" processContents="lax"
         minOccurs="0" maxOccurs="unbounded"/>
       </xs:choice>
       <xs:anyAttribute namespace="##other" processContents="lax"/>
      </xs:complexType>
      <!--
         SIP DIALOG ID TYPE
      -->
      <xs:complexType name="sip-dialog-id-type">
       <xs:sequence>
        <xs:element name="display-text" type="xs:string"
         minOccurs="0"/>
        <xs:element name="call-id" type="xs:string"/>
        <xs:element name="from-tag" type="xs:string"/>
        <xs:element name="to-tag" type="xs:string"/>
        <xs:any namespace="##other" processContents="lax"
         minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:anyAttribute namespace="##other" processContents="lax"/>
      </xs:complexType>
      <!--
         MEDIA TYPE
      -->
      <xs:complexType name="media-type">
       <xs:sequence>
        <xs:element name="display-text" type="xs:string"
         minOccurs="0"/>
        <xs:element name="type" type="xs:string"
         minOccurs="0"/>
        <xs:element name="label" type="xs:string"
         minOccurs="0"/>
        <xs:element name="src-id" type="xs:string"
         minOccurs="0"/>
        <xs:element name="status" type="media-status-type"
         minOccurs="0"/>
        <xs:any namespace="##other" processContents="lax"
         minOccurs="0" maxOccurs="unbounded"/>
       </xs:sequence>
       <xs:attribute name="id" type="xs:string"
        use="required"/>
       <xs:anyAttribute namespace="##other" processContents="lax"/>
      </xs:complexType>
      <!--
         MEDIA STATUS TYPE
      -->
      <xs:simpleType name="media-status-type">
       <xs:restriction base="xs:string">
        <xs:enumeration value="recvonly"/>
        <xs:enumeration value="sendonly"/>
        <xs:enumeration value="sendrecv"/>
        <xs:enumeration value="inactive"/>
       </xs:restriction>
      </xs:simpleType>
       <!--
         SIDEBARS BY VAL TYPE
       -->
       <xs:complexType name="sidebars-by-val-type">
        <xs:sequence>
         <xs:element name="entry" type="conference-type"
          minOccurs="0" maxOccurs="unbounded"/>
        </xs:sequence>
        <xs:attribute name="state" type="state-type"
         use="optional" default="full"/>
        <xs:anyAttribute namespace="##other" processContents="lax"/>
       </xs:complexType>
      </xs:schema>

</xs:schema>

11. Acknowledgements

Jitsi's participation in this specification is funded by the NLnet Foundation.

Appendices

Appendix A: Document Information

Series
XEP
Number
0298
Publisher
XMPP Standards Foundation
Status
Deferred
Type
Standards Track
Version
0.2
Last Updated
2015-07-02
Approving Body
XMPP Council
Dependencies
XEP-0167
Supersedes
None
Superseded By
None
Short Name
coin
Source Control
HTML

This document in other formats: XML  PDF

Appendix B: Author Information

Emil Ivov
Email
emcho@jitsi.org
JabberID
emcho@jit.si
Enrico Marocco
Email
enrico.marocco@telecomitalia.it
JabberID
enrico@tilab.com
Saúl Ibarra Corretgé
Email
saul@ag-projects.com
JabberID
saul@ag-projects.com

Copyright

This XMPP Extension Protocol is copyright © 1999 – 2020 by the XMPP Standards Foundation (XSF).

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Permission is hereby granted, free of charge, to any person obtaining a copy of this specification (the "Specification"), to make use of the Specification without restriction, including without limitation the rights to implement the Specification in a software program, deploy the Specification in a network service, and copy, modify, merge, publish, translate, distribute, sublicense, or sell copies of the Specification, and to permit persons to whom the Specification is furnished to do so, subject to the condition that the foregoing copyright notice and this permission notice shall be included in all copies or substantial portions of the Specification. Unless separate permission is granted, modified works that are redistributed shall not contain misleading information regarding the authors, title, number, or publisher of the Specification, and shall not claim endorsement of the modified works by the authors, any organization or project to which the authors belong, or the XMPP Standards Foundation.

Disclaimer of Warranty

## NOTE WELL: This Specification is provided on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, express or implied, including, without limitation, any warranties or conditions of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. ##

Limitation of Liability

In no event and under no legal theory, whether in tort (including negligence), contract, or otherwise, unless required by applicable law (such as deliberate and grossly negligent acts) or agreed to in writing, shall the XMPP Standards Foundation or any author of this Specification be liable for damages, including any direct, indirect, special, incidental, or consequential damages of any character arising from, out of, or in connection with the Specification or the implementation, deployment, or other use of the Specification (including but not limited to damages for loss of goodwill, work stoppage, computer failure or malfunction, or any and all other commercial damages or losses), even if the XMPP Standards Foundation or such author has been advised of the possibility of such damages.

IPR Conformance

This XMPP Extension Protocol has been contributed in full conformance with the XSF's Intellectual Property Rights Policy (a copy of which can be found at <https://xmpp.org/about/xsf/ipr-policy> or obtained by writing to XMPP Standards Foundation, P.O. Box 787, Parker, CO 80134 USA).

Visual Presentation

The HTML representation (you are looking at) is maintained by the XSF. It is based on the YAML CSS Framework, which is licensed under the terms of the CC-BY-SA 2.0 license.

Appendix D: Relation to XMPP

The Extensible Messaging and Presence Protocol (XMPP) is defined in the XMPP Core (RFC 6120) and XMPP IM (RFC 6121) specifications contributed by the XMPP Standards Foundation to the Internet Standards Process, which is managed by the Internet Engineering Task Force in accordance with RFC 2026. Any protocol defined in this document has been developed outside the Internet Standards Process and is to be understood as an extension to XMPP rather than as an evolution, development, or modification of XMPP itself.

Appendix E: Discussion Venue

There exists a special venue for discussion related to the technology described in this document: the <jingle@xmpp.org> mailing list.

The primary venue for discussion of XMPP Extension Protocols is the <standards@xmpp.org> discussion list.

Discussion on other xmpp.org discussion lists might also be appropriate; see <http://xmpp.org/about/discuss.shtml> for a complete list.

Errata can be sent to <editor@xmpp.org>.

Appendix F: Requirements Conformance

The following requirements keywords as used in this document are to be interpreted as described in RFC 2119: "MUST", "SHALL", "REQUIRED"; "MUST NOT", "SHALL NOT"; "SHOULD", "RECOMMENDED"; "SHOULD NOT", "NOT RECOMMENDED"; "MAY", "OPTIONAL".

Appendix G: Notes

1. XEP-0166: Jingle <https://xmpp.org/extensions/xep-0166.html>.

2. RFC 4579: Session Initiation Protocol (SIP) Call Control - Conferencing for User Agents <http://tools.ietf.org/html/rfc4579>.

3. XEP-0272: Multiparty Jingle <https://xmpp.org/extensions/xep-0272.html>.

4. RFC 4575: A Session Initiation Protocol (SIP) Event Package for Conference State <http://tools.ietf.org/html/rfc4575>.

5. XEP-0030: Service Discovery <https://xmpp.org/extensions/xep-0030.html>.

6. XEP-0115: Entity Capabilities <https://xmpp.org/extensions/xep-0115.html>.

Appendix H: Revision History

Note: Older versions of this specification might be available at http://xmpp.org/extensions/attic/

  1. Version 0.2 (2015-07-02)

    Correcting errors in grammar and examples; aligning closer to dependent specifications.

    sic
  2. Version 0.1 (2011-06-09)

    Initial published version.

    psa
  3. Version 0.0.1 (2011-06-09)

    First draft.

    ei/em

END