SIPPING J. Rosenberg
Internet-Draft Cisco Systems
Expires: September 26, 2005 H. Schulzrinne
Columbia University
O. Levin, Ed.
Microsoft Corporation
March 25, 2005
A Session Initiation Protocol (SIP) Event Package for Conference
State
draft-ietf-sipping-conference-package-10
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Copyright Notice
Copyright (C) The Internet Society (2005).
Abstract
This document defines a conference event package for the Session
Initiation Protocol (SIP) Events framework, along with a data format
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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 and
optionally about changes in the state of additional conference
components.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Conference Event Package . . . . . . . . . . . . . . . . . . . 4
3.1 Event Package Name . . . . . . . . . . . . . . . . . . . . 4
3.2 SUBSCRIBE Bodies . . . . . . . . . . . . . . . . . . . . . 5
3.3 Subscription Duration . . . . . . . . . . . . . . . . . . 5
3.4 NOTIFY Bodies . . . . . . . . . . . . . . . . . . . . . . 5
3.5 Notifier Processing of SUBSCRIBE Requests . . . . . . . . 6
3.6 Notifier Generation of NOTIFY Requests . . . . . . . . . . 6
3.7 Subscriber Processing of NOTIFY Requests . . . . . . . . . 6
3.8 Handling of Forked Requests . . . . . . . . . . . . . . . 7
3.9 Rate of Notifications . . . . . . . . . . . . . . . . . . 7
3.10 State Agents . . . . . . . . . . . . . . . . . . . . . . . 7
4. Conference Document . . . . . . . . . . . . . . . . . . . . . 7
4.1 Format . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.2 Namespace . . . . . . . . . . . . . . . . . . . . . . . . 7
4.3 Versioning . . . . . . . . . . . . . . . . . . . . . . . . 7
4.4 Partial Notifications Mechanism . . . . . . . . . . . . . 8
4.5 Element Keys . . . . . . . . . . . . . . . . . . . . . . . 9
4.6 Constructing Coherent State Procedure . . . . . . . . . . 9
5. Conference Data . . . . . . . . . . . . . . . . . . . . . . . 10
5.1 <conference-info> . . . . . . . . . . . . . . . . . . . . 11
5.2 <conference-description> . . . . . . . . . . . . . . . . . 11
5.2.1 <conf-uris> . . . . . . . . . . . . . . . . . . . . . 12
5.2.2 <service-uris> . . . . . . . . . . . . . . . . . . . . 13
5.2.3 <maximum-user-count> . . . . . . . . . . . . . . . . . 13
5.2.4 <available-media> . . . . . . . . . . . . . . . . . . 13
5.3 <host-info> . . . . . . . . . . . . . . . . . . . . . . . 14
5.3.1 <display-text> . . . . . . . . . . . . . . . . . . . . 14
5.3.2 <web-page> . . . . . . . . . . . . . . . . . . . . . . 14
5.3.3 <uris> . . . . . . . . . . . . . . . . . . . . . . . . 14
5.4 <conference-state> . . . . . . . . . . . . . . . . . . . . 14
5.4.1 <user-count> . . . . . . . . . . . . . . . . . . . . . 14
5.4.2 <active> . . . . . . . . . . . . . . . . . . . . . . . 15
5.4.3 <locked> . . . . . . . . . . . . . . . . . . . . . . . 15
5.5 <users> of <user> . . . . . . . . . . . . . . . . . . . . 15
5.5.1 <display-text> . . . . . . . . . . . . . . . . . . . . 16
5.5.2 <associated-aors> . . . . . . . . . . . . . . . . . . 16
5.5.3 <roles> . . . . . . . . . . . . . . . . . . . . . . . 16
5.5.4 <language> . . . . . . . . . . . . . . . . . . . . . . 16
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5.5.5 <cascaded-focus> . . . . . . . . . . . . . . . . . . . 16
5.5.6 <endpoint> . . . . . . . . . . . . . . . . . . . . . . 16
5.6 <endpoint> . . . . . . . . . . . . . . . . . . . . . . . . 17
5.6.1 <display-text> . . . . . . . . . . . . . . . . . . . . 17
5.6.2 <referred> . . . . . . . . . . . . . . . . . . . . . . 17
5.6.3 <status> . . . . . . . . . . . . . . . . . . . . . . . 18
5.6.4 <joining-method> . . . . . . . . . . . . . . . . . . . 19
5.6.5 <joining-info> . . . . . . . . . . . . . . . . . . . . 19
5.6.6 <disconnection-method> . . . . . . . . . . . . . . . . 19
5.6.7 <disconnection-info> . . . . . . . . . . . . . . . . . 20
5.6.8 <media> . . . . . . . . . . . . . . . . . . . . . . . 20
5.6.9 <call-info> . . . . . . . . . . . . . . . . . . . . . 20
5.7 <media> . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.7.1 <display-text> . . . . . . . . . . . . . . . . . . . . 21
5.7.2 <type> . . . . . . . . . . . . . . . . . . . . . . . . 21
5.7.3 <label> . . . . . . . . . . . . . . . . . . . . . . . 21
5.7.4 <src-id> . . . . . . . . . . . . . . . . . . . . . . . 21
5.7.5 <status> . . . . . . . . . . . . . . . . . . . . . . . 22
5.8 <sidebars-by-ref> . . . . . . . . . . . . . . . . . . . . 22
5.9 <sidebar-by-val> . . . . . . . . . . . . . . . . . . . . . 22
6. XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . . 22
7. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
7.1 Basic Example . . . . . . . . . . . . . . . . . . . . . . 30
7.2 Rich Example . . . . . . . . . . . . . . . . . . . . . . . 32
8. Security Considerations . . . . . . . . . . . . . . . . . . . 35
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 36
9.1 conference Event Package Registration . . . . . . . . . . 36
9.2 application/conference-info+xml MIME Registration . . . . 36
9.3 URN Sub-Namespace Registration for
urn:ietf:params:xml:ns:conference-info . . . . . . . . . . 37
9.4 XML Schema Registration . . . . . . . . . . . . . . . . . 38
9.5 URI Purposes Sub-registry Establishment . . . . . . . . . 38
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 39
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 39
11.1 Normative References . . . . . . . . . . . . . . . . . . . 39
11.2 Informative References . . . . . . . . . . . . . . . . . . 40
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 41
Intellectual Property and Copyright Statements . . . . . . . . 43
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1. Introduction
The Session Initiation Protocol (SIP) Events Framework [9] 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
[19]. As described there, subscriptions to a conference URI are
routed to the focus that is handling the conference. It acts as the
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 description), conference sidebars, conference
service URIs, etc.
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 [1] 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, as described in Conferencing Framework [19]. The focus has
sufficient information about the state of the conference to inform
subscribers about it.
It is possible that 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 use of the
<cascaded-focus> element as specified by this package.
This section provides the details for defining a SIP-specific event
notification package, as specified by RFC 3265 [9].
3.1 Event Package Name
The name of this event package is "conference". This package name is
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carried in the Event and Allow-Events header, as defined in RFC 3265
[9].
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" as defined
in RFC 3265 [9].
3.4 NOTIFY Bodies
As described in RFC 3265 [9], 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 5.
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.
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.
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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 event package.
3.6 Notifier Generation of NOTIFY Requests
Notifications SHOULD be generated for the conference state when a new
participant joins (i.e. gets "connected" to) or a participant leaves
(i.e. gets "disconnected" from) the conference.
Subject to a local focus policy, additional changes in participants'
status, changes in their media types, and other optional information
MAY be reported by the focus.
Changes in sidebar rosters SHOULD be reported by the focus to their
participants and MAY be reported to others, subject to local policy.
Changes in conference identifiers and service URIs SHOULD be reported
by the focus to the Conference package subscribers.
Changes in other conference state information MAY be reported by the
focus to the Conference package subscribers.
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 construct 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
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particular document type. See Section 4.6 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 doesn't 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 Document
4.1 Format
Conference information is an XML document that MUST be well-formed
and valid. It MUST be based on Extensible Markup Language (XML) 1.0
and MUST be encoded using UTF-8 [12].
4.2 Namespace
This specification makes use of XML namespaces for identifying
conference information documents and document fragments. The
namespace URI for elements defined by this specification is a URN
[2], using the namespace identifier 'ietf' defined by [6] and
extended by RFC 3688 [13]. This URN is:
urn:ietf:params:xml:ns:conference-info
4.3 Versioning
The conference information is described by a hierarchal XML structure
with the root element <conference-info>. The root element is the
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only element in the schema that carries meaningful version number for
all the elements in the document. The whole conference information
is associated with this version number.
The 'version' attribute MUST be included in the root
<conference-info> element.
4.4 Partial Notifications Mechanism
This specification defines a basic partial notifications mechanism by
using a 'state' attribute as described below. This mechanism MUST be
supported by all subscribing clients. Additional general partial
notifications mechanisms can be defined and applied to this package
in the future.
All sub-elements in the <conference-info> hierarchal XML structure
can be classified in two groups: permissible for partial
notifications or not. Elements that carry a substantial amount of
data that is subject to frequent changes are permissible for partial
notifications and have a 'state' attribute attached to them. All
future extensions to this schema MUST define which extension elements
can also use this mechanism. All other elements can be updated as
atomic pieces of data only.
Below is the complete list of elements permissible to use the partial
notifications mechanism defined in this specification. (Note that
future partial notifications mechanisms can potentially be applicable
to additional elements.)
o Element <conference-info>
o Element <users>
o Element <user>
o Element <endpoint>
o Element <sidebars-by-val>
o Element <sidebars-by-ref>
The 'state' attribute value indicates whether the reported
information about the element is "full", "partial" or the element is
"deleted" from the conference state document. The default value of
any 'state' attribute is "full".
A 'state' attribute of a child element in the document MUST adhere to
its parent 'state'. It means that if the parent's 'state' is "full",
the state of its children MUST be "full". If the parent's 'state' is
"partial", the state of its children MAY be either "partial", "full",
or "deleted".
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4.5 Element Keys
The defined XML schema has a property of unique identification among
sub-elements of a common parent, which makes it possible to use the
partial notifications mechanism defined in this document. This
property is achieved by defining a key to each sub-element that can
appear multiple times under the common parent.
In the context of this specification, the element key is the set of
mandatory attributes or sub-elements of an element. The key value
MUST be unique for the element among its siblings of the same type.
In the context of this specification, the comparison rules for keys
of type xs:anyURI are byte-by-byte (including all URI parameters that
can be included with the URI).
Below is the list of elements (subject to partial notifications of
their parent elements) with their keys as defined by this
specification:
o Element <user> uses as the key 'entity'
o Element <endpoint> uses as the key 'entity'
o Element <media> uses as the key 'id'
o Element <entry> (child to <sidebars-by-val>) uses as the key
'entity'
o Element <sidebars-by-ref> uses as the key <uri>
4.6 Constructing Coherent State Procedure
A conference package subscriber maintains a local version number, a
local element for each element in the schema, and a table for each
element with its key as defined above.
The first time a NOTIFY with a "full" document is received (as
indicated by the value of the 'state' attribute in the
<conference-info> element), the conference package subscriber MUST
set the local 'version' number to the value of the 'version'
attribute from the received <conference-info> and populate local data
with the received information.
Each time a new NOTIFY is received, the value of the local version
number and the value of the 'version' attribute in the new received
document are compared. If the value in the document is equal or less
than the local version, the document is discarded without processing.
Otherwise, if the received NOTIFY contains a "full" or "deleted"
state, the conference package subscriber MUST set the local 'version'
number to the value of the 'version' attribute from the received
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<conference-info> and replace the local information with the received
document. Receiving "deleted" state means that the conference ceased
to exist and the subscriber SHOULD terminate the subscription by
sending the SUBSCRIBE with Expires = 0.
Otherwise (i.e. if the received NOTIFY contains "partial" state), if
the 'version' number in the received document is more than one number
higher than the previous local version number, the subscriber MUST
generate a subscription refresh request to trigger a full state
notification. If the 'version' number in the document is one higher
than the local version number, the local version number is updated
accordingly and the document is used to update the local content as
described below.
For each sub-element of the <conference-info> element in the received
document,
1. If the element contains "full" state, the whole local element
content is flushed and repopulated from the document.
2. Otherwise, if the element contains "deleted" state, the whole
element MUST be removed from the local content.
3. Otherwise, if the element contains "partial" state:
3.1 For elements with keys, the subscriber compares the keys received
in the update with the keys in the local tables.
3.1.1 If a key does not exist in the local table, a row is added, and
its content is set to the element information from the update.
3.1.2 Otherwise, if a key of the same value does exist, for each
sub-element in the row the algorithm is applied from step 3.2.
3.2 For each atomic element received in the schema, the element is
replaced with the new information as a whole. Also, for each
non-atomic element received in the schema with either no 'state'
attribute included or the state attribute is set to "full", the
element is replaced with the new information as a whole.
3.3 For each non-atomic element with the state attribute set to
"partial", the algorithm is applied recursively starting from step
3.1.
5. Conference Data
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5.1 <conference-info>
A conference information document begins with the root element tag
<conference-info> of conference-type.
The following attributes are defined for <conference-info>:
entity: This attribute contains the conference URI that identifies
the conference being described in the document.
state: This attribute indicates whether the document contains the
whole conference information ("full"), only the information that
has changed since the previous document ("partial"), or the
conference ceased to exist ("deleted"). For more detail see
Section 4.
version: This attribute allows the recipient of conference
information documents to properly order them and it MUST be
included when used in the root <conference-info> element. Version
number is a 32 bit monotonically increasing integer scoped within
a subscription. A server MUST increment the version number by one
for each new partial notification being sent to a subscriber.
The <conference-info> element is comprised of
<conference-description>, <host-info>, <conference-state>, <users>,
<sidebar-by-ref> and <sidebars-by-val> child elements. A "full"
conference document MUST at least include the
<conference-description> and <users> child elements.
Following sections describe these elements in detail. The full XML
schema is provided in Section 6.
5.2 <conference-description>
The <conference-description> element describes the conference as a
whole.
The child elements <display-text>, <subject>, <free-text>, and
<keywords> are used to describe the conference content:
<display-text>: Contains a text suitable for human consumption and
directory listing
<subject>: Contains the subject of the conference
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<free-text>: Contains an additional longer description of the
conference
<keywords>: Contains a list of comma-separated keywords that can be
used by search engines to better classify the conference
Additional child elements <conf-uris> and <service-uris> are used to
describe the conference-related URIs; <maximum-user-count> and
<available-media> are used to describe the overall characteristics.
This information is typically derived from the system conference
policies, is set before the conference activation, and is rarely
changed during the conference lifetime.
The following sections describe the remaining elements in more
detail. Other sub-elements can extend <conference-description> in
the future.
5.2.1 <conf-uris>
This element is a set of <entry> child elements - each containing the
URI to be used in order to access the conference by different
signaling means. The value of the URI MUST be unique in the
conference context and is included in the <uri> sub-element.
Each <entry> can contain additional optional information useful to
the participant when accessing the conference.
An <entry> element MAY contain the <display-text> sub-element that
provides a textual description meant for human consumption.
Each <entry> element SHOULD contain a <purpose> sub-element that
describes what happens when accessing the URI. The currently defined
<purpose> values to be used with the <conf-uris> are:
participation: Accessing a URI with this <purpose> will bring the
party into the conference
streaming: Accessing a URI with this <purpose> will commence
streaming the conference, but not allow active participation
Examples of suitable URI schemes include sip: and sips: [8], h323:
[18], and tel: [17] URIs. The rtsp [14] URI is suitable for
streaming.
Future extensions to this schema may define new values and register
them with IANA under the registry established by this specification.
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5.2.2 <service-uris>
This element describes auxiliary services available for the
conference. Like <conference-uris>, this element contains a set of
<entry> child elements - each containing the URI to be used in order
to access different services available for the particular conference.
The value of the URI MUST be unique in the conference context and is
included in the <uri> sub-element.
An <entry> element MAY contain the <display-text> sub-element that
provides a textual description meant for user consumption.
Each <entry> element SHOULD contain a <purpose> sub-element. The
currently defined <purpose> values to be used with the <service-uris>
are:
web-page: Indicates the web page containing the additional
information about the conference
recording: Indicates the link at which the recorded conference
context can be retrieved
event: Indicates the URI to which the subscription to the conference
event package needs to be performed. This would typically be the
conference URI of the main conference
Future extensions to this schema may define new values and register
them with IANA under the registry established by this specification.
5.2.3 <maximum-user-count>
This element, if used, specifies the maximum number of users
permitted in the conference.
5.2.4 <available-media>
This element contains a sequence of <entry> child elements of
conference-medium-type, each being indexed by the attribute 'label'.
The 'label' attribute is the media stream identifier being assigned
by the conferencing server such as its value is unique in the
<conference-info> context. The value of this attribute MAY
correspond to the SDP "label" media attribute defined in [22].
Each <entry> describes a single media stream available to the
participants in the conference and contains the following
information:
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<display-text> This element contains the display text for the media
stream.
<type> This element contains the media type of the media stream. The
value of this element MUST be one of the values registered for
"media" of SDP [3] and its later revision(s).
<status> This element indicates the status in both directions of the
media stream and has the values "sendrecv", "sendonly",
"recvonly", or "inactive" as defined in SDP [3] and its later
revision(s). Note that value specifies the direction from the
participant's point of view.
5.3 <host-info>
This element contains information about the entity hosting the
conference. This information is set before the conference
activation, and is rarely changed during the conference lifetime,
unless the whole conference is moved to be hosted by another entity.
The host information is comprised of the following elements:
5.3.1 <display-text>
This element contains display text describing the entity hosting the
conference.
5.3.2 <web-page>
This element contains a URI of a web page describing either the
conference service or the user hosting the conference.
5.3.3 <uris>
This element can contain additional (to the conference URI) URIs
pointing to the conference host.
5.4 <conference-state>
By including this element in the conference document, the server can
inform the subscribers about the changes in the overall conference
information. The <conference-state> child elements are described
below.
5.4.1 <user-count>
This element contains the current number of users in the conference.
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5.4.2 <active>
This Boolean element says whether the conference is currently active
or not. A conference is active if dialing into one of the
<conf-uris> results in successful establishment of a call signaling
session between the dialed user and the conference focus.
5.4.3 <locked>
This Boolean element says whether the conference is currently locked
or not. In this context, "locked" means that the conference roster
can not be added to (although participants may leave or be removed
from the conference).
5.5 <users> of <user>
The <users> element is a container of <user> child elements, each
describing a single participant in the conference.
The following attributes are defined for <user> element:
entity: This attribute contains the URI for the user in the
conference. This is a logical identifier, which corresponds to
the call signaling authenticated identity of the participant. The
'entity' value MUST be unique among all participants in the
conference. If for some participants, the focus decides to not
revealing this information (due to local policies or security
reasons, for example), the host portion of the user URI MUST use
the .invalid top level domain (TLD) according to definitions of
RFC 2606 [5]. The focus also MUST construct the user portion of
the URI such as the URI is unique among all participants of the
same domain. For example,
"Anonymous1" <sip:anonymous1@anonymous.invalid>
could be used for a participant requesting privacy in accordance
with the guidelines for generating anonymous URIs of RFC 3323
[15].
state: This attribute indicates whether the document contains the
whole user information ("full"), only the information that has
changed since the previous document ("partial"), or the user was
removed from the conference ("deleted").
The following child elements are defined for <user> element:
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5.5.1 <display-text>
This element is used to display the user friendly name in the
conference.
5.5.2 <associated-aors>
This element contains associated URIs of the user. Usually this
information will be manually provided by a system administrator
showing the logical association between signaling entities otherwise
independent.
5.5.3 <roles>
This element is used to display the roles of the user in the
conference.
5.5.4 <language>
This element contains the language preference of the user. This
information can be automatically learned via call signaling or be
manually set per participant.
5.5.5 <cascaded-focus>
This element 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 [19], this package allows for representation
of peer-to-peer (i.e. "flat") focus cascading only. The actual
cascading graph can not be deduced from the information provided in
the package alone. Advanced applications can construct the graph by
subscribing to both this package and the Dialog Package [20] of each
cascaded focus and correlating the relevant information.
5.5.6 <endpoint>
By including one or more <endpoint> elements under a parent <user>
element, the server can provide the desired level of details
(including the state, media streams, and access information) about
the user's devices and signaling sessions taking part in the
conference.
In a conferencing system where authentication is performed per
endpoint (rather than per user), the focus can be unaware of the
logical association of multiple endpoints under a common user. In
this case, each endpoint will appear as a separate <user> with its
own <endpoint> sub-element(s) in the conference document.
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In a different case, the focus may choose to shield the information
about the participant's multiple endpoints and signaling sessions
from other subscribers altogether (due to privacy policies, for
example). To do so, the focus MAY aggregate the multiple signaling
sessions' information under a single <endpoint> element. Note that
in this case, the detailed call signaling information (represented by
<call-info> sub-element) will not be included.
5.6 <endpoint>
This section describes the <endpoint> element in more detail.
The following attributes are defined for <endpoint> element:
entity: The server MUST generate the 'entity' key for each <endpoint>
element included under the parent <user>, such as its value is
unique in the user context. In SIP terms, this can be the Contact
URI, GRUU, etc.
state: This attribute indicates whether the element contains the
whole endpoint information ("full"), only the information that has
changed since the previous document ("partial"), or the endpoint
has been removed from the conference ("deleted").
The following child elements are defined for <endpoint> element:
5.6.1 <display-text>
This element contains the display text for the endpoint.
5.6.2 <referred>
This element contains information about the user who's action
resulted in this endpoint being brought into the conference (e.g.
the SIP user identified by this URI sent a REFER to the focus). It
can contain the following sub-elements:
when: This element contains the date and time that the endpoint was
referred to the conference and SHOULD be expressed in Coordinated
Universal Time (UTC) format.
reason: This element contains the reason the endpoint was referred to
the conference.
by: This element contains the URI of the entity who caused the
endpoint to be referred to the conference.
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5.6.3 <status>
This element contains the status of the endpoint, and can assume the
following values:
connected: The endpoint 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 endpoint is not a participant in the conference and
no active dialog exists between the endpoint and the focus.
on-hold: Active signaling dialog exists between an endpoint and a
focus, but endpoint 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 endpoint
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-via-focus: Active signaling dialog exists between an endpoint
and a focus and the endpoint can "listen" to the conference, but
endpoint's media is not being mixed into the conference. Note
that sometimes a subset of endpoint 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" endpoint connectivity <status> reflects the status of
the most active media.
pending: Endpoint is not yet in the session, but it is anticipated
that he/she will join in the near future.
alerting: A PSTN ALERTING or SIP 180 Ringing was returned for the
outbound call, endpoint is being alerted.
dialing-in: Endpoint is dialing into the conference, not yet in the
roster (probably being authenticated).
dialing-out: Focus has dialed out to connect the endpoint to the
conference, but the endpoint is not yet in the roster (probably
being authenticated).
disconnecting: Focus is in the process of disconnecting the endpoint
(e.g., in SIP a DISCONNECT or BYE was sent to the endpoint).
Note that the defined transient statuses (e.g., disconnecting,
alerting, etc.) could generate a lot of notifications.
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Implementations MAY choose not to generate notifications on these to
all participants if it will generate too much traffic.
5.6.4 <joining-method>
This element contains method by which the endpoint joined the
conference, and can assume the following values:
dialed-in: The endpoint dialed into the conference (e.g., in SIP sent
INVITE to the focus), which resulted in successful dialog
establishment.
dialed-out: The focus has brought the endpoint into the conference
(e.g., in SIP by sending a successful INVITE to the endpoint).
focus-owner: The endpoint is the focus for this conference. This
status is used only when a participant's UA acts as a conference
focus.
5.6.5 <joining-info>
This element contains information about how the endpoint joined and
can contain the following sub-elements:
when: This element contains the date and time that the endpoint
joined the conference and SHOULD be expressed in Coordinated
Universal Time (UTC).
reason: This element contains the reason the endpoint joined the
conference.
by: This element contains the URI of the entity who caused the
endpoint to join the conference.
5.6.6 <disconnection-method>
This element contains method by which the endpoint departed the
conference, and can assume the following values:
departed: In SIP, the endpoint sent a BYE, thus leaving the
conference.
booted: In SIP, the endpoint was sent a BYE by the focus, booting
him/her out of the conference. Alternatively, the endpoint tried
to dial into to conference but was rejected by the focus due to
local policy.
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failed: In SIP, the server tried to bring the endpoint into the
conference, but its attempt to contact the specific endpoint
resulted in a non-200 class final response. Alternatively, the
endpoint tried to dial into the conference without success due to
technical reasons.
5.6.7 <disconnection-info>
This element contains information about the endpoint's departure from
the conference and can contain the following sub-elements:
when: This element contains the date and time that the endpoint
departed the conference and SHOULD be expressed in Coordinated
Universal Time (UTC).
reason: This element contains the reason the endpoint departed the
conference. When known and meaningful, it is RECOMMENDED to
include the information as conveyed/reported by the call signaling
in the format defined by RFC 3326 [10]. For example,
<reason>Reason: SIP ;cause=415 ;text="Unsupported Media Type"</reason>
by: This element contains the URI of the entity who caused the
endpoint to depart the conference.
5.6.8 <media>
This element contains information about a single media stream and is
included for each media stream being established between the focus
and the <endpoint>.
Note that if the <call-info> sub-element of the endpoint is not
included in the document by the server, it is possible that the media
streams listed under the common <endpoint> were established by
separate signaling sessions.
5.6.9 <call-info>
The <call-info> element provides detailed call signaling information
for a call being maintained between the participant and the focus.
Privacy policies MUST be consulted before revealing this information
to other participants.
The <sip> sub-element contains the SIP dialog identifier of the
endpoint's dialog with the focus. The element includes sub-elements
<display-text>, <call-id>, <to-tag>, <from-tag>.
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In future, the <call-info> element can be expanded to include call
signaling protocol information for other protocols besides SIP.
5.7 <media>
This section describes the <media> element in more detail.
A single 'id' attribute is defined for this element. This is the
media stream identifier being generated by the server such as its
value is unique in the endpoint context. This attribute is the key
to refer to a particular media stream in the conference document.
The following child elements are defined for <media>:
5.7.1 <display-text>
This element contains the display text for the media stream.
5.7.2 <type>
This element contains the media type for the media stream. The value
of this element MUST be one of the values registered for "media" of
SDP [3] and its later revision(s).
5.7.3 <label>
The <label> element 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 SDP "label" media attribute
defined in [22].
5.7.4 <src-id>
The <src-id> element, if applicable, carries the information about
the actual source of the media. For example, for RTP/RTCP [11] media
streams, the value MUST contain the SSRC value generated by the
endpoint for the stream it sends.
When an RTP mixer generates a CSRC list according to RTP/RTCP [11],
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. A quote from RFC 3550: "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)."
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If an RTP mixer compliant to the above is used, participants can
perform an SSRC to user mapping and identify "a current speaker".
5.7.5 <status>
The element <status> indicates the status in both directions of the
media stream and has the values "sendrecv", "sendonly", "recvonly",
or "inactive" as defined in SDP [3] and its later revision(s). Note
that value specifies the direction from the participant's point of
view. For example, a muted participant's stream will have the value
of "recvonly".
5.8 <sidebars-by-ref>
This element contains a set of <entry> child elements each containing
a sidebar conference URI. The recipient of the information can then
subscribe to sidebar information independently from the main
conference package subscription.
5.9 <sidebar-by-val>
This element contains a set of <entry> child elements each containing
information about a single sidebar. By using this element of
conference-type, the server can include a full or a partial
description of each sidebar (as a sub-conference) in the body of the
main conference document.
6. XML 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" />
<!--
CONFERENCE ELEMENT
-->
<xs:element name="conference-info" type="conference-type"/>
<!--
CONFERENCE TYPE
-->
<xs:complexType name="conference-type">
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<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"/>
</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"/>
</xs:complexType>
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<!--
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"/>
</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"/>
</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"/>
</xs:complexType>
<!--
CONFERENCE MEDIUM TYPE
-->
<xs:complexType name="conference-medium-type">
<xs:sequence>
<xs:element name="display-text" type="xs:string"/>
<xs:element name="type" type="xs:string" minOccurs="0"/>
<xs:element name="status" type="media-status-type" minOccurs="0"/>
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<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"/>
</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"/>
</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"/>
</xs:complexType>
<!--
KEWORDS TYPE
-->
<xs:simpleType name="keywords-type">
<xs:list itemType="xs:string"/>
</xs:simpleType>
<!--
USERS TYPE
-->
<xs:complexType name="users-type">
<xs:sequence>
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<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"/>
</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="language" type="xs:language" 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"/>
</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"/>
</xs:complexType>
<!--
ENDPOINT TYPE
-->
<xs:complexType name="endpoint-type">
<xs:sequence>
<xs:element name="display-text" type="xs:string" minOccurs="0"/>
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<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"/>
</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>
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<!--
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: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"/>
</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"/>
</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>
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<xs:anyAttribute namespace="##other"/>
</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"/>
</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"/>
</xs:complexType>
</xs:schema>
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7. Examples
7.1 Basic Example
The following is an example conference information document:
<conference-info entity="sips:conf233@example.com" state="partial" version="5" >
<!--
CONFERENCE INFO
-->
<conference-description>
<subject>Agenda: This month's goals</subject>
<service-uris>
<entry>
<uri> http://sharepoint/salesgroup/</uri>
<purpose>web-page</purpose>
</entry>
</service-uris>
</conference-description>
<!--
CONFERENCE STATE
-->
<conference-state>
<user-count>33</user-count>
</conference-state>
<users>
<!--
USER
-->
<user entity="sip:bob@example.com" state="full">
<display-text>Bob Hoskins</display-text>
<!--
ENDPOINTS
-->
<endpoint entity="sip:bob@pc33.example.com">
<display-text>Bob's Laptop</display-text>
<status>disconnected</status>
<disconnection-method>departed</disconnection-method>
<disconnection-info>
<when>2005-03-04T20:00:00Z</when>
<reason>bad voice quality</reason>
<by>sip:mike@example.com</by>
</disconnection-info>
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<!--
MEDIA
-->
<media id="1">
<display-text>main audio</display-text>
<type>audio</type>
<label>34567</label>
<src-id>432424</src-id>
<status>sendrecv</status>
</media>
</endpoint>
</user>
<!--
USER
-->
<user entity="sip:alice@example.net" state="full">
<display-text>Alice</display-text>
<!--
ENDPOINTS
-->
<endpoint entity="sip:4kfk4j392jsu@example.net;grid=433kj4j3u" call="1">
<status>connected</status>
<joining-method>dialed-out</joining-method>
<joining-info>
<when>2005-03-04T20:00:00Z</when>
<by>sip:mike@example.com</by>
</joining-info>
<!--
MEDIA
-->
<media id="1">
<display-text>main audio</display-text>
<type>audio</type>
<label>34567</label>
<src-id>534232</src-id>
<status>sendrecv</status>
</media>
</endpoint>
</user>
</users>
</conference-info>
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7.2 Rich Example
The following is an example conference information document. In this
example of a partial state notification, there are 32 participants in
a voice conference. The user Bob has been booted from the conference
by Mike due to bad voice quality. Note that there are three sidebars
in the conference, two are referenced just by their sidebar URIs and
information about the third sidebar is included in this notification.
Also note that while this conference offers both audio and video
capabilities, only audio is currently in use.
<conference-info entity="sips:conf233@example.com" state="partial" version="5" >
<!--
CONFERENCE INFO
-->
<conference-description>
<display-text>Weekly Sales Meeting</display-text>
<subject>Agenda: This month's goals</subject>
<free-text>We will start strict on time</free-text>
<keywords>sales, meeting, weekly</keywords>
<conf-uris>
<entry>
<uri>tel:+18005671234</uri>
<display-text>TTI Bridge</display-text>
<purpose>participation</purpose>
</entry>
<entry>
<uri>h323:conf545@h323.example.com</uri>
<purpose>participation</purpose>
</entry>
<entry>
<uri>http://real.streaming.com/54634/live.ram</uri>
<purpose>streaming</purpose>
</entry>
</conf-uris>
<service-uris>
<entry>
<uri>http://sharepoint/salesgroup/</uri>
<purpose>web-page</purpose>
</entry>
<entry>
<uri>http://quicktime.com/54634/recording.mov</uri>
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<display-text>Quicktime</display-text>
<purpose>recording</purpose>
</entry>
</service-uris>
<maximum-user-count>100</maximum-user-count>
<available-media>
<entry label="34567">
<display-text>main audio</display-text>
<type>audio</type>
<status>sendrecv</status>
</entry>
<entry label="34569">
<display-text>main video</display-text>
<type>video</type>
<status>inactive</status>
</entry>
</available-media>
</conference-description>
<!--
HOST INFO
-->
<host-info>
<display-text>Sales Host</display-text>
<web-page>http://sharepoint/salesgroup/hosts/</web-page>
<uris>
<entry>
<uri>sip:sales@example.com</uri>
</entry>
</uris>
</host-info>
<!--
CONFERENCE STATE
-->
<conference-state>
<user-count>32</user-count>
<active>true</active>
<locked>false</locked>
</conference-state>
<!--
USERS
-->
<users>
<user entity="sip:bob@example.com">
<display-text>Bob Hoskins</display-text>
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<associated-aors>
<entry>
<uri>mailto:bob@example.com</uri>
<display-text>email</display-text>
</entry>
</associated-aors>
<roles>
<entry>participant</entry>
</roles>
<language>en</language>
<!--
ENDPOINTS
-->
<endpoint entity="sip:bob@pc33.example.com">
<display-text>Bob's Laptop</display-text>
<referred>
<when>2005-03-04T20:00:00Z</when>
<reason>expert required</reason>
<by>sip:mike@example.com</by>
</referred>
<status>disconnecting</status>
<joining-method>dialed-out</joining-method>
<joining-info>
<when>2005-03-04T20:00:00Z</when>
<reason>invitation</reason>
<by>sip:mike@example.com</by>
</joining-info>
<disconnection-method>booted</disconnection-method>
<disconnection-info>
<when>2005-03-04T20:00:00Z</when>
<reason>bad voice quality</reason>
<by>sip:mike@example.com</by>
</disconnection-info>
<!--
CALL INFO
-->
<call-info>
<sip>
<display-text>full info</display-text>
<call-id>hsjh8980vhsb78</call-id>
<from-tag>vav738dvbs</from-tag>
<to-tag>8954jgjg8432</to-tag>
</sip>
</call-info>
<!--
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MEDIA
-->
<media id="1">
<display-text>main audio</display-text>
<type>audio</type>
<label>34567</label>
<src-id>432424</src-id>
<status>sendrecv</status>
</media>
</endpoint>
</user>
</users>
<!--
SIDEBARS BY REFERENCE
-->
<sidebars-by-ref state="partial">
<entry>
<uri>sips:conf233@example.com; grid=45</uri>
<display-text>sidebar with Carol</display-text>
</entry>
<entry>
<uri>sips:conf233@example.com; grid=21</uri>
<display-text>private sidebar with Peter</display-text>
</entry>
</sidebars-by-ref>
<!--
SIDEBARS BY VALUE
-->
<sidebars-by-val state="partial">
<entry entity="sips:conf233@example.com; grid=77" state="partial">
<users>
<user entity="sip:bob@example.com"></user>
<user entity="sip:mark@example.com"></user>
<user entity="sip:dan@example.com"></user>
</users>
</entry>
</sidebars-by-val>
</conference-info>
8. Security Considerations
Subscriptions to conference state can reveal very sensitive
information. For this reason, the document recommends authentication
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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 participant 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 [15]. 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 Section 5.5
of this document MUST be followed.
9. IANA Considerations
This document registers a SIP event package, a new MIME type,
application/conference-info+xml, a new XML namespace, a new XML
schema, and creates a sub-registry "URI purposes" under the
existing registry: http://www.iana.org/assignments/sip-parameters.
9.1 conference Event Package Registration
This specification registers an event package, based on the
registration procedures defined in RFC 3265 [9]. 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, jdrosen@jdrosen.net.
9.2 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 [7]
Encoding considerations: Same as encoding considerations of
application/xml as specified in RFC 3023 [7]
Security considerations: See Section 10 of RFC 3023 [7] and Section 8
of this specification
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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, <jdrosen@jdrosen.net>
Intended usage: COMMON
Author/Change controller: The IETF
9.3 URN Sub-Namespace Registration for
urn:ietf:params:xml:ns:conference-info
This section registers a new XML namespace, as per the guidelines in
RFC 3688 [13].
URI: The URI for this namespace is
urn:ietf:params:xml:ns:conference-info
Registrant Contact: IETF, SIPPING working group, <sipping@ietf.org>,
Jonathan Rosenberg <jdrosen@jdrosen.net>
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
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9.4 XML Schema Registration
This specification registers a schema, as per the guidelines in RFC
3688 [13].
URI: please assign
Registrant Contact: IETF, SIPPING Working Group
(sipping@ietf.org), Jonathan Rosenberg (jdrosen@jdrosen.net)
XML: The XML can be found as the sole content of Section 6
9.5 URI Purposes Sub-registry Establishment
This document instructs the IANA to create a new sub-registry "URI
purposes" under the already existing registry:
http://www.iana.org/assignments/sip-parameters.
The purpose of a URI is an XML element, encoded in the conference
event package [RFC XXXX - substitute with the number assigned to this
draft]. The value of the <purpose> element indicates the intended
usage of the URI in the context of the conference event package and
is defined in sections Section 5.2.1 and Section 5.2.2 of this
specification.
This sub-registry is defined as a table that contains the following
three columns:
Value: The token under registration
Description: A descriptive text defining the intended usage of the
URI
Document: A reference to the document defining the registration
This specification instructs IANA to create the table with the
initial content as defined below:
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Value Description Document
------- ---------------------------------- ----------
participation The URI can be used to join the [RFC XXXX]
conference
streaming The URI can be used to access the [RFC XXXX]
streamed conference data
event The URI can be used to subscribe [RFC XXXX]
to the conference event package
recording The URI can be used to access the [RFC XXXX]
recorded conference data
web-page The URI can be used to access a [RFC XXXX]
web page that contains additional
information of the conference
New values of the "URI purposes" are registered by the IANA when a
specification becomes available and according to the definition of
RFC 2434 [4]. The IANA Considerations section of the specification
MUST include the following information:
Value: The value of the <purpose> element to be registered
Description: A short description of the intended usage of the URI
10. Acknowledgements
The authors would like to thank Dan Petrie, Sean Olson, Alan
Johnston, Rohan Mahy, Cullen Jennings, Brian Rosen, Roni Even, and
Miguel Garcia for their comments and inputs.
11. References
11.1 Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[2] Moats, R., "URN Syntax", RFC 2141, May 1997.
[3] Handley, M. and V. Jacobson, "SDP: Session Description
Protocol", RFC 2327, April 1998.
[4] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA
Considerations Section in RFCs", BCP 26, RFC 2434, October
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1998.
[5] Eastlake, D. and A. Panitz, "Reserved Top Level DNS Names",
BCP 32, RFC 2606, June 1999.
[6] Moats, R., "A URN Namespace for IETF Documents", RFC 2648,
August 1999.
[7] Murata, M., St. Laurent, S. and D. Kohn, "XML Media Types",
RFC 3023, January 2001.
[8] 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.
[9] Roach, A., "Session Initiation Protocol (SIP)-Specific Event
Notification", RFC 3265, June 2002.
[10] Schulzrinne, H., Oran, D. and G. Camarillo, "The Reason Header
Field for the Session Initiation Protocol (SIP)", RFC 3326,
December 2002.
[11] Schulzrinne, H., Casner, S., Frederick, R. and V. Jacobson,
"RTP: A Transport Protocol for Real-Time Applications", STD 64,
RFC 3550, July 2003.
[12] Yergeau, F., "UTF-8, a transformation format of ISO 10646",
STD 63, RFC 3629, November 2003.
[13] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
January 2004.
11.2 Informative References
[14] Schulzrinne, H., Rao, A. and R. Lanphier, "Real Time Streaming
Protocol (RTSP)", RFC 2326, April 1998.
[15] Peterson, J., "A Privacy Mechanism for the Session Initiation
Protocol (SIP)", RFC 3323, November 2002.
[16] Camarillo, G., Eriksson, G., Holler, J. and H. Schulzrinne,
"Grouping of Media Lines in the Session Description Protocol
(SDP)", RFC 3388, December 2002.
[17] Schulzrinne, H., "The tel URI for Telephone Numbers", RFC 3966,
December 2004.
[18] Levin, O., "H.323 Uniform Resource Locator (URL) Scheme
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Registration", RFC 3508, April 2003.
[19] Rosenberg, J., "A Framework for Conferencing with the Session
Initiation Protocol",
Internet-Draft draft-ietf-sipping-conferencing-framework-04,
February 2005.
[20] Rosenberg, J., "An INVITE Inititiated Dialog Event Package for
the Session Initiation Protocol (SIP)",
Internet-Draft draft-ietf-sipping-dialog-package-05, November
2004.
[21] Rosenberg, J., "Obtaining and Using Globally Routable User
Agent (UA) URIs (GRUU) in the Session Initiation Protocol
(SIP)", Internet-Draft draft-ietf-sip-gruu-03, February 2005.
[22] Levin, O. and G. Camarillo, "The SDP (Session Description
Protocol) Label Attribute",
Internet-Draft draft-ietf-mmusic-sdp-media-label-01, January
2005.
Authors' Addresses
Jonathan Rosenberg
Cisco Systems
600 Lanidex Plaza
Parsippany, NJ 07054
US
Phone: +1 973 952-5000
Email: jdrosen@cisco.com
URI: http://www.jdrosen.net
Henning Schulzrinne
Columbia University
M/S 0401
1214 Amsterdam Ave.
New York, NY 10027
US
Email: schulzrinne@cs.columbia.edu
URI: http://www.cs.columbia.edu/~hgs
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Orit Levin (editor)
Microsoft Corporation
One Microsoft Way
Redmond, WA 98052
US
Email: oritl@microsoft.com
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Acknowledgment
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