´╗┐ SIPPING J. Rosenberg Internet-Draft dynamicsoft Expires:
August 15,November 19, 2004 H. Schulzrinne Columbia University O. Levin, Ed. Microsoft Corporation February 15,May 21, 2004 A Session Initiation Protocol (SIP) Event Package for Conference State draft-ietf-sipping-conference-package-03draft-ietf-sipping-conference-package-04 Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. 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." The list of current Internet-Drafts can be accessed at http:// www.ietf.org/ietf/1id-abstracts.txt.http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on August 15,November 19, 2004. Copyright Notice Copyright (C) The Internet Society (2004). All Rights Reserved. Abstract This document defines a conference event package for the Session Initiation Protocol (SIP) Events framework, along with a data format used in notifications for this package. The conference package allows users to subscribe to a conference URI. Notifications are sent about changes in the membership of this conference, the status of users' participation in the conference,conference and the sidebarsoptionally about changes in the conference.state of additional conference components. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Conference Event Package . . . . . . . . . . . . . . . . . . . 5 3.1 Event Package Name . . . . . . . . . . . . . . . . . . . . 5 3.2 SUBSCRIBE Bodies . . . . . . . . . . . . . . . . . . . . . 5 3.3 Subscription Duration . . . . . . . . . . . . . . . . . . 5 3.4 NOTIFY Bodies . . . . . . . . . . . . . . . . . . . . . . 6 3.5 Notifier Processing of SUBSCRIBE Requests . . . . . . . . 6 3.6 Notifier Generation of NOTIFY Requests . . . . . . . . . . 6 3.7 Subscriber Processing of NOTIFY Requests . . . . . . . . . 7 3.8 Handling of Forked Requests . . . . . . . . . . . . . . . 7 3.9 Rate of Notifications . . . . . . . . . . . . . . . . . . 7 3.10 State Agents . . . . . . . . . . . . . . . . . . . . . . . 7 4. Conference Data Format . . . . . . . . . . . . . . . . . . 8. . 9 4.1 Conference Information . . . . . . . . . . . . . . . . . . 89 4.1.1 User Element . . . . . . . . . . . . . . . . . . . . . . .9 18.104.22.168 User StatusesAttributes . . . . . . . . . . . . . . . . . 10 22.214.171.124 User Status Elements . . . . . 9 126.96.36.199 Media Stream Information. . . . . . . . . . 10 188.8.131.52 Media Stream Information . . . . . . . 10 4.1.2 Sidebar. . . . . . 12 4.1.2 Sidebar Element . . . . . . . . . . . . . . . . . . . 1113 4.1.3 Additional Conference Identifiers . . . . . . . . . . . . 1113 4.1.4 Policy URIs . . . . . . . . . . . . . . . . . . . . . . . 1113 4.2 Constructing Coherent State . . . . . . . . . . . . . . . 1113 4.2.1 User and Sidebar Updates . . . . . . . . . . . . . . . 14 4.2.2 Conference and Policy Identifiers Updates . . . . . . 14 4.3 Schema . . . . . . . . . . . . . . . . . . . . . . . . . . 1215 4.4 Example . . . . . . . . . . . . . . . . . . . . . . . . . 1517 5. Security Considerations . . . . . . . . . . . . . . . . . 16. . 19 6. IANA Considerations . . . . . . . . . . . . . . . . . . . 17. . 20 6.1 conference Event Package Registration . . . . . . . . . . 1720 6.2 application/conference-info+xml MIME Registration . . . . 1720 6.3 URN Sub-Namespace Registration for urn:ietf:params:xml:ns:conference-info . . . . . . . . . . 1820 6.4 XML Schema Registration . . . . . . . . . . . . . . . . . 1921 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . 20. . 22 8. Changes History . . . . . . . . . . . . . . . . . . . . . . . 23 8.1 Changes since -03 . . . . . . . . . . . . . . . . . . . . 23 8.2 Changes since -02 . . . . . . . . . . . . . . . . . . . . 21 9.23 8.3 Changes since -01 . . . . . . . . . . . . . . . . . . . . 2223 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 24 9.1 Normative References . . . . . . . . . . . . . . . . . . . 23. 24 9.2 Informative References . . . . . . . . . . . . . . . . . . . 24 Authors' Addresses . . . . . . . . . . . . . . . . . . . . 24. . 25 Intellectual Property and Copyright Statements . . . . . . 26. . 27 1. Introduction The Session Initiation Protocol (SIP)  Events framework Events Framework  defines general mechanisms for subscribing to, and receiving notifications of, events within SIP networks. It introduces the notion of a package, which is a specific "instantiation" of the events framework for a well-defined set of events. Here, we define an event package for SIP conferences. This package provides the conference notification service as outlined in the SIP conferencing framework .. As described there, subscriptions to a conference URI are routed to the focus that is handling the conference. It acts as the notifer,notifier, and provides clients with updates on conference state. The information provided by this package is comprised of conference identifier(s), conference participants (optionally with their statuses and media types)description), conference sidebars, and conference sidebars.policy URIs. 2. Terminology In this document, the key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" are to be interpreted as described in RFC 2119  and indicate requirement levels for compliant implementations. 3. Conference Event Package The conference event package allows a user to subscribe to a conference. In SIP, conferences are represented by URIs. These URIs route to a SIP user agent, called a focus, that is responsible for ensuring that all users in the conference can communicate with each other .other, as described in Conferencing Framework . The focus has sufficient information about the state of the conference to inform subscribers about it. It is possible a participant in the conference may in fact be another focus. In order to provide a more complete participant list, the focus MAY subscribe to the conference package of the other focus to discover the participant list in the cascaded conference. This information can then be included in notifications by using of the "cascaded-focus" attribute as specified by this package. This section provides the details for defining a SIP Events package, as specified by .RFC 3265 . 3.1 Event Package Name The name of this event package is "conference". This package name is carried in the Event and Allow-Events header, as defined in .RFC 3265 . 3.2 SUBSCRIBE Bodies A SUBSCRIBE for a conference package MAY contain a body. This body defines a filter to apply to the subscription. Filter documents are not specified in this document, and at the time of writing, are expected to be the subject of future standardization activity. A SUBSCRIBE for a conference package MAY be sent without a body. This implies the default subscription filtering policy. The default policy is: o Notifications are generated every time there is any change in the state of the conference. o Notifications do not normally contain full state; rather, they only indicate the state that has changed. The exception is a NOTIFY sent in response to a SUBSCRIBE. These NOTIFYs contain the full state of the information requested by the subscriber. 3.3 Subscription Duration The default expiration time for a subscription to a conference is one hour. Once the conference ends, all subscriptions to that particular conference are terminated, with a reason of "noresource" .RFC 3265 . 3.4 NOTIFY Bodies As described in RFC 3265 ,, the NOTIFY message will contain bodies that describe the state of the subscribed resource. This body is in a format listed in the Accept header field of the SUBSCRIBE, or a package-specific default if the Accept header field was omitted from the SUBSCRIBE. In this event package, the body of the notification contains a conference information document. This document describes the state of a conference. All subscribers and notifiers MUST support the "application/conference-info+xml" data format described in Section 4. The subscribe request MAY contain an Accept header field. If no such header field is present, it has a default value of "application/ conference-info+xml". If the header field is present, it MUST include "application/conference-info+xml", and MAY include any other types capable of representing dialog state. Of course, the notifications generated by the server MUST be in one of the formats specified in the Accept header field in the SUBSCRIBE request. 3.5 Notifier Processing of SUBSCRIBE Requests The conference information contains very sensitive information. Therefore, all subscriptions SHOULD be authenticated and then authorized before approval. Authorization policy is at the discretion of the administrator, as always. However, a few recommendations can be made. It is RECOMMENDED that all users in the conference be allowed to subscribe to the conference. 3.6 Notifier Generation of NOTIFY Requests Notifications SHOULD be generated for the conference whenever there is a change in the state in any of the information delivered to the subscriber. The changes generally occur when a new participant joins, a participant leaves,joins (i.e. gets "connected" to) or a participant is put on-hold.leaves (i.e. gets "disconnected" from) the conference. Subject to a local focus policy, additional changes in participant's status, changes in its media typestypes, and other optional media attributes MAY be reported by the focus. In addition, creation and deletion of sidebars together with theirChanges in sidebar rosters MAYSHOULD be reported by the focus, subjectfocus to their participants and MAY be reported to others, subject to itslocal policy. Changes in conference identifiers and policy URIs SHOULD be reported by the focus to the conference participants. 3.7 Subscriber Processing of NOTIFY Requests The SIP Events framework expects packages to specify how a subscriber processes NOTIFY requests in any package specific ways, and in particular, how it uses the NOTIFY requests to contruct a coherent view of the state of the subscribed resource. Typically, the NOTIFY for the conference package will only contain information about those users whose state in the conference has changed. To construct a coherent view of the total state of all users, a subscriber to the conference package will need to combine NOTIFYs received over time. Notifications within this package can convey partial information; that is, they can indicate information about a subset of the state associated with the subscription. This means that an explicit algorithm needs to be defined in order to construct coherent and consistent state. The details of this mechanism are specific to the particular document type. See Section 4.2 for information on constructing coherent information from an application/ conference-info+xml document. 3.8 Handling of Forked Requests By their nature, the conferences supported by this package are centralized. Therefore, SUBSCRIBE requests for a conference should not generally fork. Users of this package MUST NOT install more than a single subscription as a result of a single SUBSCRIBE request. 3.9 Rate of Notifications For reasons of congestion control, it is important that the rate of notifications not become excessive. As a result, it is RECOMMENDED that the server not generate notifications for a single subscriber at a rate faster than once every 5 seconds. 3.10 State Agents Conference state is ideally maintained in the element in which the conference resides. Therefore, the elements that maintain the conference are the ones best suited to handle subscriptions to it. Therefore, the usage of state agents is NOT RECOMMENDED for this package. 4. Conference Data Format Conference information is an XML document that MUST be well-formed and SHOULD be valid. Dialog information documents MUST be based on XML 1.0 and MUST be encoded using UTF-8. This specification makes use of XML namespaces for identifying dialog information documents and document fragments. The namespace URI for elements defined by this specification is a URN ,, using the namespace identifier 'ietf' defined by  and extended by .. This URN is: urn:ietf:params:xml:ns:conference-info A conference information document begins with the root element tag "conference-info". 4.1 Conference Information Conference information begins with the top level element "conference-info". This element has three mandatory and one optional attributes: version: This mandatory attribute allows the recipient of conference information documents to properly order them. Versions start at 0 and increment by one for each new document sent to a subscriber. Versions are scoped within a subscription. Versions MUST be represented using a 32 bit integer. state: This mandatory attribute indicates whether the document contains the full conference information, or whether it contains only the information that has changed since the previous document (partial). entity: This mandatory attribute contains the conference URI that identifies the conference being described in the document. recording: This optional attribute indicates whether the conference is being recorded at this moment ("on") or not ("off"). The "conference-info" element has zero or more "user" sub-elements which contain information on the users in the conference. This is followed by zero or more "sidebar" sub-elements which contain information on the sidebars in the conference. This is followed by zero or more "conf-uri" sub-elements which contain information on additional URIs that the conference can be accessed by. This is followed by zero or more "policy-uri" sub-elements which contain information on additional URIs that the conference policies can be accessed by. 4.1.1 User Element 184.108.40.206 User Attributes The user element has one mandatory attribute, "uri" that indicates the URI for the user in the conference. This is a logical identifier, not a machine specific one (i.e., it's taken fromwhich corresponds to the authenticated identity of the participant).participant. The "uri" attribute MUST be unique in the user element list because it is used as the key in partial notifications about users' state. If a conference participant has more than a single signaling dialog associated with the conference, the conference focus MAY present the user's aggregated information (e.g. the statuses) and display all its media streams under a single user element. Note, that the optional element "dialog-uri" of "media-stream" (see below) MAY be used in this case to specify the actual signaling dialog for each media stream. An anonymous participant in a conference SHOULD be represented by an anonymous URI generated by the focus. For multiple anonymous participants, the focus must ensure that each anonymous URI is unique. The guidelines for generating anonymous URIs in RFC 3323  should be followed. For example, "Anonymous1" <sip:email@example.com> could be used for a participant requesting privacy. The optional attribute "display-name" contains a display name for the user. The standard "xml:lang" language attribute can also be present to indicate the language of the display-name. The optional attribute "cascaded-focus" contains a conference URI (different from the main conference URI) for users that are connected to the main conference as a result of focus cascading. In accordance with the SIP conferencing framework ,, this definedpackage allows for representation of peer-to-peer (i.e. "flat") focus cascading only. The actual cascading graph iscan not explicitly expressedbe deduced from the information provided in thisthe package because mostalone. Advanced applications do not care about the actual topology of the cascaded focuses as long as the information about their participants is available. In addition, an advanced applicationcan construct the graph by subscribing to both this package and the Dialog Package  of the involved focusescascaded foci and correlating the requiredrelevant information. 220.127.116.11.1.1.2 User StatusesStatus Elements Three optional status elements are defined: status, joining-mode, and disconnection-reason. o "status": provides information about user's current level of participation in the conference. o "joining-mode": if present, provides information about the way the user joined the conference. o "disconnection-reason": if present, provides information about the way the user left the conference. The following statuses are defined for the "status" element: connected: The user is a participant in the conference. Depending on the media policies, he/she can send and receive media to and from other participants. disconnected: The user is not a participant in the conference and no active dialog exists between the user and the focus. on-hold: Active SIP dialog exists between a user and a focus, but user is "on-hold" for this conference, i.e. neither he/she is "hearing" the conference mix, nor is his/her media being mixed in the conference. As an example, the user has asked to join the conference using SIP, but his/her participation is pending based on moderator approval. In the meantime he/she is hearing music-on-hold or some other kind of related content. muted-by-focus: Active SIP dialog exists between a user and a focus and the user can "listen" to the conference, but user's media is not being mixed into the conference. Note that sometimes a subset of user media streams can be muted by focus (such as poor quality video) while others (such as voice or IM) can still be active. In this case, it is RECOMMENDED that the "aggregated" user connectivity "status" reflects the status of the active media. The following statuses are defined for the "joining-mode" element: dialed-in: The user dialed into the conference, i.e. sent INVITE to the focus, which resulted in successful dialog establishment. dialed-out: The focus has brought the user into the conference by sending a successful INVITE to the user. focus-owner: The user is the focus itselffor this conference. This status is used only when a participant UA acts as a conference focus being identified by its own AOR or GRUU. The following statuses are defined for the disconnection-reason element: departed: The user sent a BYE, thus leaving the conference. booted: The user was sent a BYE by the focus, booting him/her out of the conference. Alternatively, the user tried to dial into to conference without success because was rejected by the focus according to local policy decisions. failed: The server tried to bring the user into the conference, but its attempt to contact the specific user resulted in a non-200 class final response. Alternatively, the user tried to dial into the conference without success due to technical reasons. 18.104.22.168.1.1.3 Media Stream Information Each user has zero or more "media-stream" sub-elements. Each "media-stream" element indicates the media stream that the user is currently connected to. Here, "connected to" implies that a user has a media line in theirhis/her SDP . document(s). With this definition, a user is connected to a media stream even if they arehe/she is not sending any media. The "media-stream" element has a mandatory "media-type" attribute which identifies the media type (e.g. audio, video, message and application) and MUST have one of the values registered for "media" of SDP .. The "media-stream" element has also an optional "proto" sub-element, which MUST has the value registered for "proto" of SDP ).. An optional "ssrc" sub-element, if present, carries the value of SSRC (RTP/RTCP )(defined in RTP/RTCP ) as generated by the user for the stream it sends. When an RTP mixer generates a CSRC list according to RTP/RTCP ,, it inserts a list of the SSRC identifiers of the sources that contributed to the generation of a particular packet into the RTP header of that packet. "An example application is audio conferencing where a mixer indicates all the talkers whose speech was combined to produce the outgoing packet, allowing the receiver to indicate the current talker, even though all the audio packets contain the same SSRC identifier (that of the mixer)." An optional "info" sub-element, if present, carries a human readable description for this stream populated by the focus. The value of this element corresponds to the information media attribute "i" in SDP . An optional "label" sub-element, if present, carries a unique identifier for this stream among all streams in the conference and is assigned by the focus. The value of this element corresponds to the "label" media attribute in SDP  and defined in . An optional "dialog-id" sub-element, if present, carries a URI, which MUST uniquely identify the signaling dialog being used for establishing of this media stream. In SIP, for example, values of Contact URI or GRUU  can be used for this purpose. It is RECOMMENDED to include the "dialog-id" information for every user that has more than a single dialog associated with the conference. This element SHOULD NOT be included for an anonymous participant. 4.1.2 Sidebar Element The sidebar element has one attribute - "entity" that indicates"entity", which carries the URI which identifiersidentifying the sidebar. This URI MUST be unique among the sidebar identifiers of the same conference. Attribute "entity" is used as the key in partial notifications about sidebars of a conference. A sidebar has zero or more users that are of type "user-type" as the usersof the main conference are."user-type". 4.1.3 Additional Conference Identifiers In addition to the Conference URI present in the "entity" attribute, a conference MAY have additional URIs of various types. Connecting to these URIs will result in joining to the same conference. 4.1.4 Policy URIs A policy URI specifies where and how a certain policy pertaining to the conference can be accessed. The actual policy name and usage is deduced from the URI schema name. An example for the "policy-uri" usage is inclusion of the URI of the CPCP .. A subscriber to the Conference package can use the Policy URI to access and modify the conference policy. 4.2 Constructing Coherent State The conferenceConference information subscriber maintains a table for the list of users in the conference. The table contains a row for each user. Each row is indexed by a URI, present in the "uri" attribute of the "user" element. The contents of each row contain the state of that user as conveyed in the document. The tableis associated with a version number. The version number MUST be initialized with the value of the "version" attribute from the "conference-info" element in the first document received. Each time a new document is received, the value of the local version number, and the "version" attribute in the new document, are compared. If the value in the new document is one higher than the local version number, the local version number is increased by one, and the document is processed. If the value in the document is more than one higher than the local version number, the local version number is set to the value in the new document, the document is processed, and the subscriber SHOULD generate a refresh request to trigger a full state notification. If the value in the document is less than the local version, the document is discarded without processing. TheFurther processing of the conference information document depends on whether it contains full or partial state. If it contains full state, indicated by the value of the "state" attribute in the "conference-info" element, the contents of the table is flushed. Itwhole local content is flushed and repopulated from the document. A new row in the user table is created for each "user" element.If the document contains partial state, as indicated by the value of the "state" attribute in the "conference-info" element, the document is used to update the table. For each "user" element inlocal content as described below. The conference information is described by a means of a root element: "conference-info", which can be comprised of elements of four main types: "user-type", "sidebar-type", "conf-ids-type", and "policy-ids-type". Updates from partial notifications MUST be implemented as a set of atomic operations on elements of these types only. 4.2.1 User and Sidebar Updates The conference package subscriber maintains two tables: one for the document,list of users and another for the subscriber checks to see whetherlist of sidebars in the conference. Each table contains a row existsfor that user in theeach user table. This checkor each sidebar correspondingly. Each row is doneindexed by comparing thea URI key, present in the "uri" attribute of the "user" element withor in the URI associated with"entity" attribute of the row. If"sidebar" element correspondingly. The contents of each row contain the state of that user or a sidebar as conveyed in the document. If the document is an update (i.e. contains partial state), for each table and for each element (i.e. "user" or "sidebar") the subscriber compares the keys received in the update with the keys in the local tables. If a key doesn't exist in the local table, a row is added, and its statecontent is set to the element information from that "user" element.the update. If a key of the usersame value does exist, its statethe row content is updated to bereplaced with the information from that "user" element.received information. If a row is updated or created,created such that itsuser's state becomes "disconnected", that entry MAY be removed from the table at any time. If a row is now disconnected, booted, failedupdated or departed,created such that entrya sidebar element doesn't contain any users, that sidebar element MAY be removed from the table at any time. 4.2.2 Conference and Policy Identifiers Updates In order to support additional conference features, the conference package subscriber SHOULD locally maintain two additional informational elements: "conf-ids" and "policy-ids". The content of each contains a list of URIs for additional conference identifiers or for policy protocols (correspondingly) applicable to this conference. If the document is an update (i.e. contains partial state), and one or both of the elements exist in the update, the element(s) is/are replaced with the new information as a whole. If the element is updated or created, such that it is empty, that element MAY be removed from the local content at any time. 4.3 Schema <?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"> <!-- This import brings in the XML language attribute xml:lang --> <xs:import namespace="http://www.w3.org/XML/1998/namespace" schemaLocation="http://www.w3.org/2001/03/xml.xsd" /> <xs:element name="conference-info"> <xs:complexType> <xs:sequence> <xs:element name="user" type="user-type" minOccurs="0" maxOccurs="unbounded" /> <xs:element name="sidebar" type="sidebar-type" minOccurs="0" maxOccurs="unbounded" /> <xs:element name="conf-uri" type="xs:anyURI"name="conf-ids" type="conf-ids-type" minOccurs="0" maxOccurs="unbounded"maxOccurs="1" /> <xs:element name="policy-uri" type="xs:anyURI"name="policy-ids" type="policy-ids-type" minOccurs="0" maxOccurs="unbounded"maxOccurs="1" /> <xs:any processContents="lax" minOccurs="0" maxOccurs="unbounded" /> </xs:sequence> <xs:attribute name="version" type="xs:nonNegativeInteger" use="required" /> <xs:attribute name="state" use="required"> <xs:simpleType> <xs:restriction base="xs:string"> <xs:enumeration value="full" /> <xs:enumeration value="partial" /> </xs:restriction> </xs:simpleType> </xs:attribute> <xs:attribute name="entity" type="xs:anyURI" use="required" /> <xs:attribute name="recording" type="tns:recording-type" use="optional" /> <xs:anyAttribute /> </xs:complexType> </xs:element> <xs:complexType name="user-type"> <xs:sequence> <xs:element name="status" type="tns:status-type" minOccurs="0" /> <xs:element name="joining-mode" type="tns:joining-mode-type" minOccurs="0" /> <xs:element name="disconnection-reason" type="tns:disconnection-reason-type" minOccurs="0" /> <xs:element name="media-stream" type="tns:media-stream-type" minOccurs="0" maxOccurs="unbounded" /> <xs:any processContents="lax" minOccurs="0" maxOccurs="unbounded" /> </xs:sequence> <xs:attribute name="uri" type="xs:anyURI" use="required" /> <xs:attribute name="display-name" type="xs:string" use="optional" /> <xs:attribute ref="xml:lang" use="optional" /> <xs:attribute name="cascaded-focus" type="xs:anyURI" use="optional" /> <xs:anyAttribute /> </xs:complexType> <xs:complexType name="sidebar-type"> <xs:sequence> <xs:element name="user" type="user-type" minOccurs="0" maxOccurs="unbounded" /> <xs:any processContents="lax" minOccurs="0" maxOccurs="unbounded" /> </xs:sequence> <xs:attribute name="entity" type="xs:anyURI" use="required" /> </xs:complexType> <xs:complexType name="conf-ids-type"> <xs:sequence> <xs:element name="conf-uri" type="xs:anyURI" minOccurs="0" maxOccurs="unbounded" /> <xs:any processContents="lax" minOccurs="0" maxOccurs="unbounded" /> </xs:sequence> <xs:anyAttribute /> </xs:complexType> <xs:complexType name="policy-ids-type"> <xs:sequence> <xs:element name="policy-uri" type="xs:anyURI" minOccurs="0" maxOccurs="unbounded" /> <xs:any processContents="lax" minOccurs="0" maxOccurs="unbounded" /> </xs:sequence> <xs:anyAttribute /> </xs:complexType> <xs:complexType name="media-stream-type"> <xs:sequence> <xs:element name="proto" type="xs:string" minOccurs="0" /> <xs:element name="ssrc" type="xs:nonNegativeInteger" minOccurs="0" /> <xs:element name="info" type="xs:string" minOccurs="0" /> <xs:element name="label" type="xs:string" minOccurs="0" /> <xs:element name="dialog-id" type="xs:anyURI" minOccurs="0" /> <xs:any processContents="lax" minOccurs="0" maxOccurs="unbounded" /> </xs:sequence> <xs:attribute name="media" type="xs:string" use="required" /> </xs:complexType> <xs:simpleType name="status-type"> <xs:restriction base="xs:string"> <xs:enumeration value="connected" /> <xs:enumeration value="disconnected" /> <xs:enumeration value="on-hold" /> <xs:enumeration value="muted-by-focus" /> </xs:restriction> </xs:simpleType> <xs:simpleType name="joining-mode-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> <xs:simpleType name="disconnection-reason-type"> <xs:restriction base="xs:string"> <xs:enumeration value="departed" /> <xs:enumeration value="booted" /> <xs:enumeration value="failed" /> </xs:restriction> </xs:simpleType> <xs:simpleType name="recording-type"> <xs:restriction base="xs:string"> <xs:enumeration value="on" /> <xs:enumeration value="off" /> </xs:restriction> </xs:simpleType> </xs:schema> 4.4 Example The following is an example conference information document: <conference-info version="0" state="full" entity="sip:firstname.lastname@example.org" recording="on"> <user uri="sip:email@example.com" display-name="Bob Jones"> <status>connected</status> <joining-mode>dialed-in</joining-mode> <media-stream media-type="audio"> <proto> RTP/AVP </proto> <ssrc> 583398 </ssrc> </media-stream> </user> <user uri="sip:firstname.lastname@example.org" display-name="Barbara Jones"> <status>on-hold</status> </user> <user uri="sip:email@example.com" display-name="Bill Minelli"> <status>on-hold</status> </user> <sidebar entity="sip:firstname.lastname@example.org"> <user uri="sip:email@example.com"> <user uri="sip:firstname.lastname@example.org"> </sidebar> <conf-ids> <conf-uri>tel:+18005671234</conf-uri> <conf-uri>h323:email@example.com</conf-uri> </conf-ids> </conference-info> This conference currently has three users, two of which are in a sidebar conversation. The conference is being recorded. There are additional means to join the conference either by phone using tel URI  or by H.323 protocol using h323H.323 URL .. 5. Security Considerations Subscriptions to conference state can reveal very sensitive information. For this reason, the document recommends authentication and authorization, and provides guidelines on sensible authorization policies. Since the data in notifications is sensitive as well, end-to-end SIP encryption mechanisms using S/MIME SHOULD be used to protect it. Since a focus provides participants identity information using this event package, participant privacy needs to be taken into account. A focus MUST support requests by participants for privacy. Privacy can be indicated by the conference policy - for every participant or select participants. It can also be indicated in the session signaling. In SIP this can be done using the Privacy header field described in RFC 3323 . For a participant requesting privacy, no identity information SHOULD be revealed by the focus such as a URI (e.g. the Address of Record, Contact, or GRUU). For these cases, the anonymous URI generation method outlined in section "User Element" of this document MUST be followed. 6. IANA Considerations This document registers a SIP event package, a new MIME type, application/conference-info+xml, a new XML namespace, and a new XML schema. 6.1 conference Event Package Registration This specification registers an event package, based on the registration procedures defined in RFC 3265 .. The following is the information required for such a registration: Package Name: conference Package or Template-Package: This is a package. Published Document: RFC XXXX (Note to RFC Editor: Please fill in XXXX with the RFC number of this specification). Person to Contact: Jonathan Rosenberg, firstname.lastname@example.org. 6.2 application/conference-info+xml MIME Registration MIME media type name: application MIME subtype name: conference-info+xml Mandatory parameters: none Optional parameters: Same as charset parameter application/xml as specified in RFC 3023 .. Encoding considerations: Same as encoding considerations of application/xml as specified in RFC 3023 .. Security considerations: See Section 10 of RFC 3023  and Section 5 of this specification. Interoperability considerations: none. Published specification: This document. Applications which use this media type: This document type has been used to support SIP conferencing applications. Additional Information: Magic Number: None File Extension: .cif or .xml Macintosh file type code: "TEXT" Personal and email address for further information: Jonathan Rosenberg, <email@example.com> Intended usage: COMMON Author/Change controller: The IETF. 6.3 URN Sub-Namespace Registration for urn:ietf:params:xml:ns:conference-info This section registers a new XML namespace, as per the guidelines in .. URI: The URI for this namespace is urn:ietf:params:xml:ns:conference-info. Registrant Contact: IETF, SIPPING working group, <firstname.lastname@example.org>, Jonathan Rosenberg <email@example.com>. XML: BEGIN <?xml version="1.0"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML Basic 1.0//EN" "http://www.w3.org/TR/xhtml-basic/xhtml-basic10.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="content-type" content="text/html;charset=iso-8859-1"/> <title>Conference Information Namespace</title> </head <body> <h1>Namespace for Conference Information</h1> <h2>urn:ietf:params:xml:ns:conference-info</h2> <p>See <a href="[[[URL of published RFC]]]">RFCXXXX</a>.</p> </body> </html> END 6.4 XML Schema Registration This specification registers a schema, as per the guidelines in in .. URI: please assign. Registrant Contact: IETF, SIPPING Working Group (firstname.lastname@example.org), Jonathan Rosenberg (email@example.com). XML: The XML can be found as the sole content of Section 4.3. 7. Acknowledgements The authors would like to thank Dan Petrie, Sean Olson, and Alan Johnston for their comments. 8.Alan Johnston for their comments and inputs. 8. Changes History 8.1 Changes since -03 o "Constructing Coherent State" section has been updated. o In order to support partial notifications, two placeholders "conference-ids" and "policy-ids" (for "conf-uri" and "policy-uri" elements, correspondingly) are created. o Discussion and security considerations regarding anonymous participation have been added. o Optional elements "dialog-uri", "info" and "label" per media stream are added. 8.2 Changes since -02 o State "muted-by-focus" is added to user's status. o Optional conference attribute "recording" is added. o Policy URI placeholder (i.e. element "policy-uri") is created. o ExampleĂsExample's syntax is corrected. o Optional attribute "cascaded-focus" URI per user is added. o Optional additional conference identifiers (i.e. element "conf-uri") are added. o In order to cover all possible cases, participant's status is expressed using three optional statuses: "status", "joining-mode" and "disconnection-reason". That is instead of "activity-status", "history-status" and "is-on-dial-out-list". 9.8.3 Changes since -01 o Package parameters are removed. Decision about performing "recursive" membership algorithm is perceived as a focus local policy. o General information (i.e. pointers to additional available services) is removed. The defined XML schema can be extended in future to include those when XCON work matures. o Dialog information is removed. It can be obtained by direct subscription to a dialog package of a participant. o Media stream information is aligned with SDP definitions (media and proto) and SSRC attribute is added. o Participant's status is expressed using two optional statuses: "activity" and "history". Optional "is-on-a-dial-out-list" indication is added. o Normative references to XCON work are removed. o Optional sidebar rosters are added. 9. References 9.1 Normative References  Mealling, M., "The IETF XML Registry", draft-mealling-iana-xmlns-registry-05 (work in progress), June 2003.  Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997.  Roach, A., "Session Initiation Protocol (SIP)-Specific Event Notification", RFC 3265, June 2002. 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. Moats, R., "URN Syntax", RFC 2141, May 1997.  Moats, R., "A URN Namespace for IETF Documents", RFC 2648, August 1999.  Mealling, M., "The IETF XML Registry", draft-mealling-iana-xmlns-registry-05 (work in progress), June 2003.  Murata, M., St. Laurent, S. and D. Kohn, "XML Media Types", RFC 3023, January 2001.  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.  Roach, A., "Session Initiation Protocol (SIP)-Specific Event Notification", RFC 3265, June 2002.  Peterson, J., "A Privacy Mechanism for the Session Initiation Protocol (SIP)", RFC 3323, November 2002.  Camarillo, G., Eriksson, G., Holler, J. and H. Schulzrinne, "Grouping of Media Lines in the Session Description Protocol (SDP)", RFC 3388, December 2002.  Schulzrinne, H., Casner, S., Frederick, R. and V. Jacobson, "RTP: A Transport Protocol for Real-Time Applications", RFC 3550, July 2003. 9.2 Informative References  Handley, M. and V. Jacobson, "SDP: Session Description Protocol", RFC 2327, April 1998.  Levin, O., "H.323 Uniform Resource Locator (URL) Scheme Registration", RFC 3508, April 2003.  Rosenberg, J., "A Framework for Conferencing with the Session Initiation Protocol", draft-ietf-sipping-conferencing-framework-01 (work in progress), October 2003.  Rosenberg, J. and H. Schulzrinne, "An INVITE Inititiated Dialog Event Package for the Session Initiation Protocol (SIP)", draft-ietf-sipping-dialog-package-03draft-ietf-sipping-dialog-package-04 (work in progress), October 2003. February 2004.  Koskelainen, P.,P. and H. Khartabil, "Requirements for Conference Policy Control Protocol", draft-ietf-xcon-cpcp-reqs-02draft-ietf-xcon-cpcp-reqs-03 (work in progress), FebruaryApril 2004.  Handley, M. Rosenberg, J., "Obtaining and V. Jacobson, "SDP:Using Globally Routable User Agent (UA) URIs (GRUU) in the Session Description Protocol", RFC 2327, April 1998.  Levin, O., "H.323 Uniform Resource Locator (URL) Scheme Registration", RFC 3508, April 2003.  Schulzrinne, H., "The tel URI for Telephone Numbers", draft-ietf-iptel-tel-rfc2806bis-03Initiation Protocol (SIP)", draft-ietf-sip-gruu-01 (work in progress), February 2004.  Levin, O. and G. Camarillo, "SDP Media Label", draft-levin-mmusic-sdp-media-label-00 (work in progress), May 2004. Authors' Addresses Jonathan Rosenberg dynamicsoft 600 Lanidex Plaza Parsippany, NJ 07054 US Phone: +1 973 952-5000 EMail: firstname.lastname@example.org URI: http://www.jdrosen.net Henning Schulzrinne Columbia University M/S 0401 1214 Amsterdam Ave. New York, NY 10027 US EMail: email@example.com URI: http://www.cs.columbia.edu/~hgs Orit Levin (editor) Microsoft Corporation One Microsoft Way Redmond, WA 98052 USA EMail: firstname.lastname@example.org Intellectual Property Statement The IETF takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. 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