CLUE Working Group R. Presta
Internet-Draft S. Romano
Intended status: Standards Track University of Napoli
Expires: April 21, 2016 October 19, 2015
CLUE protocol
draft-ietf-clue-protocol-06
Abstract
The CLUE protocol is an application protocol conceived for the
description and negotiation of a CLUE telepresence session. The
design of the CLUE protocol takes into account the requirements and
the framework defined, respectively, in [I-D.ietf-clue-framework] and
[RFC7262]. The companion document [I-D.ietf-clue-signaling] delves
into CLUE signaling details, as well as on the SIP/SDP session
establishment phase. CLUE messages flow upon the CLUE data channel,
based on reliable and ordered SCTP over DTLS transport, as described
in [I-D.ietf-clue-datachannel]. Message details, together with the
behavior of CLUE Participants acting as Media Providers and/or Media
Consumers, are herein discussed.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 21, 2016.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
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publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Overview of the CLUE protocol . . . . . . . . . . . . . . . . 5
4. Protocol messages . . . . . . . . . . . . . . . . . . . . . . 7
4.1. OPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.2. OPTIONS RESPONSE . . . . . . . . . . . . . . . . . . . . . 11
4.3. ADVERTISEMENT . . . . . . . . . . . . . . . . . . . . . . 12
4.4. ADVERTISEMENT ACKNOWLEDGEMENT . . . . . . . . . . . . . . 13
4.5. CONFIGURE . . . . . . . . . . . . . . . . . . . . . . . . 14
4.6. CONFIGURE RESPONSE . . . . . . . . . . . . . . . . . . . . 14
4.7. Response codes and reason strings . . . . . . . . . . . . 15
5. Protocol state machines . . . . . . . . . . . . . . . . . . . 17
6. CLUE Participant's state machine . . . . . . . . . . . . . . . 17
6.1. Media Provider's state machine . . . . . . . . . . . . . . 19
6.2. Media Consumer's state machine . . . . . . . . . . . . . . 22
7. Versioning . . . . . . . . . . . . . . . . . . . . . . . . . . 25
8. Extensions and options . . . . . . . . . . . . . . . . . . . . 26
9. XML Schema . . . . . . . . . . . . . . . . . . . . . . . . . . 27
10. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
10.1. Simple ADV . . . . . . . . . . . . . . . . . . . . . . . . 31
10.2. ADV with MCCs . . . . . . . . . . . . . . . . . . . . . . 37
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 44
11.1. URN Sub-Namespace Registration . . . . . . . . . . . . . . 44
11.2. XML Schema registration . . . . . . . . . . . . . . . . . 45
11.3. MIME Media Type Registration for 'application/clue+xml' . 45
11.4. DNS Registrations . . . . . . . . . . . . . . . . . . . . 46
11.4.1. Application Service tag . . . . . . . . . . . . . . . 46
11.4.2. Application Protocol tag . . . . . . . . . . . . . . 46
11.5. CLUE Protocol Registry . . . . . . . . . . . . . . . . . . 47
11.5.1. CLUE Message Types . . . . . . . . . . . . . . . . . 47
11.5.2. CLUE Response Codes . . . . . . . . . . . . . . . . . 48
12. Diff with draft-ietf-clue-protocol-05 . . . . . . . . . . . . 49
13. Diff with draft-ietf-clue-protocol-04 . . . . . . . . . . . . 49
14. Diff with draft-ietf-clue-protocol-03 . . . . . . . . . . . . 49
15. Diff with draft-ietf-clue-protocol-02 . . . . . . . . . . . . 50
16. Diff with draft-ietf-clue-protocol-01 . . . . . . . . . . . . 50
17. Diff with draft-ietf-clue-protocol-00 . . . . . . . . . . . . 50
18. Diff with draft-presta-clue-protocol-04 . . . . . . . . . . . 51
19. Diff with draft-presta-clue-protocol-03 . . . . . . . . . . . 51
20. Diff with draft-presta-clue-protocol-02 . . . . . . . . . . . 51
21. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 51
22. References . . . . . . . . . . . . . . . . . . . . . . . . . . 52
22.1. Normative References . . . . . . . . . . . . . . . . . . . 52
22.2. Informative References . . . . . . . . . . . . . . . . . . 53
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1. Introduction
The CLUE protocol is an application protocol used by two CLUE
Participants to enhance the experience of a multimedia telepresence
session. The main goals of the CLUE protocol are:
1. enabling a Media Provider (MP) to properly announce its current
telepresence capabilities to a Media Consumer (MC) in terms of
available media captures, groups of encodings, simultaneity
constraints and other information envisioned in
[I-D.ietf-clue-framework];
2. enabling an MC to request the desired multimedia streams from the
offering MP.
CLUE-capable endpoints are connected by means of the CLUE data
channel, an SCTP over DTLS channel which is opened and established as
described in [I-D.ietf-clue-signaling] and
[I-D.ietf-clue-datachannel]. CLUE protocol messages flowing upon
such a channel are detailed in this document, both syntactically and
semantically.
In Section 3 we provide a general overview of the CLUE protocol.
CLUE protocol messages are detailed in Section 4. The CLUE
Participant state machine is introduced in Section 5. Versioning and
extensions are discussed in Section 7 and Section 8, respectively.
The XML schema defining the CLUE messages is reported in Section 9.
2. Terminology
This document refers to the same terminology used in
[I-D.ietf-clue-framework] and in [RFC7262]. We briefly recall herein
some of the main terms used in the document. The definition of "CLUE
Participant" herein proposed is not imported from any of the above
documents.
CLUE Participant (CP): An entity able to use the CLUE protocol
within a telepresence session. It can be an endpoint or an MCU
able to use the CLUE protocol.
CLUE-capable device: A device that supports the CLUE data channel
[I-D.ietf-clue-datachannel], the CLUE protocol and the principles
of CLUE negotiation, and seeks CLUE-enabled calls.
Endpoint: The logical point of final termination through receiving,
decoding and rendering, and/or initiation through capturing,
encoding, and sending of media streams. An endpoint consists of
one or more physical devices which source and sink media streams,
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and exactly one [RFC4353] Participant (which, in turn, includes
exactly one SIP User Agent). Endpoints can be anything from
multiscreen/multicamera room controllers to handheld devices.
MCU: Multipoint Control Unit (MCU) - a device that connects two or
more endpoints together into one single multimedia conference
[RFC5117]. An MCU may include a Mixer [RFC4353].
Media: Any data that, after suitable encoding, can be conveyed over
RTP, including audio, video or timed text.
Media Capture: A "Media Capture", or simply "Capture", is a source
of Media.
Media Consumer (MC): A CLUE Participant (i.e., an Endpoint or an
MCU) able to receive Media Streams.
Capture Encoding: A specific encoding of a Media Capture, to be sent
via RTP [RFC3550].
Media Provider (MP): A CLUE Participant (i.e., an Endpoint or an
MCU) able to send Media Streams.
Media Stream: The term "Media Stream", or simply "Stream", is used
as a synonym of Capture Encoding.
3. Overview of the CLUE protocol
The CLUE protocol is conceived to enable CLUE telepresence sessions.
It is designed in order to address SDP limitations in terms of the
description of some information about the multimedia streams that are
involved in a real-time multimedia conference. Indeed, by simply
using SDP we are not able to convey information about the features of
the flowing multimedia streams that are needed to enable a "being
there" rendering experience. Such information is designed in the
CLUE framework document and formally defined and described in the
CLUE data model document. The CLUE protocol represents the mechanism
for the exchange of CLUE information between CLUE Participants. It
mainly provides the messages to enable a Media Provider to advertise
its telepresence capabilities and to enable a Media Consumer to
select the desired telepresence options.
The CLUE protocol, as defined in the following, is a stateful,
client-server, XML-based application protocol. CLUE protocol
messages flow on a reliable and ordered SCTP over DTLS transport
channel connecting two CLUE Participants. Messages carry information
taken from the XML-based CLUE data model
([I-D.ietf-clue-data-model-schema]). Three main communication layers
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can be identified:
1. Establishment of the CLUE data channel: in this phase, the CLUE
data channel setup takes place. If it completes successfully,
the CPs are able to communicate and start the initiation phase.
2. Negotiation of the CLUE protocol version and options (initiation
phase): the CPs connected via the CLUE data channel agree on the
version and on the options to be used during the telepresence
session. Special CLUE messages are used for such a task (OPTIONS
and OPTIONS RESPONSE). The version and options negotiation can
be performed once and only at this stage. At the end of that
basic negotiation, each CP starts its activity as a CLUE MP
and/or CLUE MC.
3. CLUE telepresence capabilities description and negotiation: in
this phase, the MP-MC dialogues take place on the data channel by
means of the CLUE protocol messages.
As soon as the channel is ready, the CLUE Participants must agree on
the protocol version and extensions to be used within the
telepresence session. CLUE protocol version numbers are
characterized by a major version number and a minor version number,
both unsigned integers, separated by a dot. While minor version
numbers denote backward compatible changes in the context of a given
major version, different major version numbers generally indicate a
lack of interoperability between the protocol implementations. In
order to correctly establish a CLUE dialogue, the involved CPs MUST
have in common a major version number (see Section 7 for further
details). The subset of the protocol options and extensions that are
allowed within the CLUE session is also determined in the initiation
phase, such subset being the one including only the options that are
supported by both parties. A mechanism for the negotiation of the
CLUE protocol version and extensions is is part of the initial phase.
According to such a solution, the CP which is the CLUE Channel
initiator (CI) issues a proper CLUE message (OPTIONS) to the CP which
is the Channel Receiver (CR) specifying the supported version and
extensions. The CR then answers by selecting the subset of the CI
extensions that it is able to support and determines the protocol
version to be used.
After that negotiation phase is completed, CLUE Participants describe
and agree on the media flows to be exchanged. In many cases CPs will
seek to both transmit and receive media. Hence in a call between two
CPs, A and B, there would be two seperate dialogs, as follows:
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1. the one needed to describe and set up the media streams sent from
A to B, i.e., the dialogue between A's Media Provider side and
B's Media Consumer side
2. the one needed to describe and set up the media streams sent from
B to A, i.e., the dialogue between B's Media Provider side and
A's Media Consumer side
CLUE messages for the media session description and negotiation are
designed by considering the MP side as the server side of the
protocol, since it produces and provides media streams, and the MC
side as the client side of the protocol, since it requests and
receives media streams. The messages that are exchanged to set up
the telepresence media session are described by focusing on a single
MP-MC dialogue.
The MP first advertises its available media captures and encoding
capabilities to the MC, as well as its simultaneity constraints,
according to the information model defined in
[I-D.ietf-clue-framework]. The CLUE message conveying the MP's
multimedia offer is the ADVERTISEMENT message. Such message
leverages the XML data model definitions provided in
[I-D.ietf-clue-data-model-schema].
The MC selects the desired streams of the MP by using the CONFIGURE
message, which makes reference to the information carried in the
previously received ADVERTISEMENT.
Besides ADVERTISEMENT and CONFIGURE, other messages have been
conceived in order to provide all the needed mechanisms and
operations. Such messages will be detailed in the following
sections.
4. Protocol messages
CLUE protocol messages are textual, XML-based messages that enable
the configuration of the telepresence session. The formal definition
of such messages is provided in the XML Schema provided at the end of
this document (Section 9).
The XML definitions of the CLUE information provided in
[I-D.ietf-clue-data-model-schema] are included within some CLUE
protocol messages (namely the ADVERTISEMENT and the CONFIGURE
messages), in order to use the concepts defined in
[I-D.ietf-clue-framework].
The CLUE protocol messages are the following:
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o OPTIONS
o OPTIONS RESPONSE
o ADVERTISEMENT (ADV)
o ADVERTISEMENT ACKNOWLEDGEMENT (ACK)
o CONFIGURE (CONF)
o CONFIGURE RESPONSE (CONF RESPONSE)
While the OPTIONS and OPTIONS RESPONSE messages are exchanged in the
initiation phase between the CPs, the other messages are involved in
MP-MC dialogues.
Each CLUE message inherits a basic structure depicted in the
following excerpt:
<!-- CLUE MESSAGE TYPE -->
<xs:complexType name="clueMessageType" abstract="true">
<xs:sequence>
<xs:element name="clueId" type="xs:string"/>
<xs:element name="sequenceNr" type="xs:positiveInteger"/>
</xs:sequence>
<xs:attribute name="protocol" type="xs:string" fixed="CLUE" use="required"/>
<xs:attribute name="v" type="versionType" use="required"/>
</xs:complexType>
<!-- VERSION TYPE -->
<xs:simpleType name="versionType">
<xs:restriction base="xs:string">
<xs:pattern value="([0-9])+\.([0-9]+)"></xs:pattern>
</xs:restriction>
</xs:simpleType>
The basic structure determines the mandatory information that is
carried within each CLUE message. Such an information is made by:
o clueId: an XML element containing the identifier (in the form of a
generic string) of the CP within the telepresence system;
o sequenceNr: an XML element containing the local message sequence
number. The sender must increment the sequence numbers by one for
each new message sent, the receiver must remember the most recent
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sequence number received and send back a 401 error if it receives
a message with an unexpected sequence number;
o protocol: a mandatory attribute set to "CLUE", identifying the
procotol the messages refer to;
o v: a mandatory attribute carrying the version of the protocol.
The content of the "v" attribute is composed by the major version
number followed by a dot and then by the minor version number of
the CLUE protocol in use. Allowed values are of this kind: "1.3",
"2.45", etc.
Each CP should manage up to three (independent) streams of sequence
numbers: (i) one for the messages exchanged in the initiation phase,
(ii) one for the messages exchanged as MP, and (iii) one for the
messages exchanged as MC.
4.1. OPTIONS
The OPTIONS message is sent by the CP which is the CI to the CP which
is the CR as soon as the CLUE data channel is ready. Besides the
information envisioned in the basic structure, it specifies:
o mediaProvider: a mandatory boolean field set to "true" if the CP
is able to act as a MP
o mediaConsumer: a mandatory boolean field set to "true" if the CP
is able to act as a MC
o supportedVersions: the list of the supported versions
o supportedOptions: the list of the supported options
The XML Schema of such a message is reported below:
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<!-- CLUE OPTIONS -->
<xs:complexType name="optionsMessageType">
<xs:complexContent>
<xs:extension base="clueMessageType">
<xs:sequence>
<xs:element name="mediaProvider" type="xs:boolean"/>
<xs:element name="mediaConsumer" type="xs:boolean"/>
<xs:element name="supportedVersions" type="versionsListType" minOccurs="0"/>
<xs:element name="supportedOptions" type="optionsListType" minOccurs="0"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<!-- VERSIONS LIST TYPE -->
<xs:complexType name="versionsListType">
<xs:sequence>
<xs:element name="version" type="versionType" minOccurs="1"
maxOccurs="unbounded"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>
<!-- OPTIONS LIST TYPE -->
<xs:complexType name="optionsListType">
<xs:sequence>
<xs:element name="option" type="optionType" minOccurs="1"
maxOccurs="unbounded"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>
<!-- OPTION TYPE -->
<xs:complexType name="optionType">
<xs:sequence>
<xs:element name="name" type="xs:string" />
<xs:element name="schemaRef" type="xs:anyURI" minOccurs="0"/>
<xs:element name="version" type="versionType" minOccurs="0"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>
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<supportedVersions> contains the list of the versions that are
supported by the CI, each one represented in a child <version>
element. The content of each <version> element is a string made by
the major version number followed by a dot and then by the minor
version number (e.g., 1.3 or 2.43). Only one <version> element MUST
be provided for each major version supported, containing the maximum
minor version number of such a version, since all minor versions are
backward compatible. If no <supportedVersions> is carried within the
OPTIONS message, the CI supports only the version declared in the "v"
attribute and all the versions having the same major version number
and lower minor version number. For example, if the "v" attribute
has a value of "3.4" and there is no <supportedVersions> tag in the
OPTIONS message, it means the CI supports only major version 3 with
all the minor versions comprised between 3.0 and 3.4, with version
3.4 included. If a <supportedVersion> is provided, at least one
<version> tag MUST be included.
The <supportedOptions> element specifies the list of options
supported by the CI. If there is no <supportedOptions> in the
OPTIONS message, the CI does not support anything other than what is
envisioned in the versions it supports. For each option, an <option>
element is provided. An option is characterized by a name, an XML
schema of reference where the option is defined, and the version of
the protocol which the option refers to.
4.2. OPTIONS RESPONSE
The OPTIONS RESPONSE is sent by a CR to a CI as a reply to the
OPTIONS message. As depicted in the figure below, the OPTIONS
RESPONSE contains mandatorily a response code and a reason string
indicating the processing result of the OPTIONS message. If the
responseCode is of the type 2xx the response MUST also include
<mediaProvider>, <mediaConsumer>, <version> and <commonOptions>
elements; it MAY include them for any other response code.
<mediaProvider> and <mediaConsumer> elements are associated with the
supported roles (in terms of, respectively MP and MC), similarly to
what the CI does in the OPTIONS message. The <version> field
indicates the highest commonly supported version number. The content
of the <version> element MUST be a string made of the major version
number followed by a dot and then by the minor version number (e.g.,
1.3 or 2.43). Finally, the commonly supported options are copied in
the the <commonOptions> field.
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<!-- CLUE OPTIONS RESPONSE -->
<xs:complexType name="optionsResponseMessageType">
<xs:complexContent>
<xs:extension base="clueMessageType">
<xs:sequence>
<xs:element name="responseCode" type="xs:short"/>
<xs:element name="reasonString" type="xs:string"/>
<xs:element name="mediaProvider" type="xs:boolean" minOccurs="0"/>
<xs:element name="mediaConsumer" type="xs:boolean" minOccurs="0"/>
<xs:element name="version" type="versionType" minOccurs="0"/>
<xs:element name="commonOptions" type="optionsListType" minOccurs="0"/>
<xs:any namespace="##other"
processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
After the reception of such a message, the version to be used is
determined by each part of the conversation. Indeed, it is the one
provided in the <version> tag of the OPTIONS RESPONSE message. The
following CLUE messages MUST use such a version number in the "v"
attribute. The allowed options in the CLUE dialogue will be those
indicated in the <commonOptions> of the OPTIONS RESPONSE message.
4.3. ADVERTISEMENT
The ADVERTISEMENT message (ADV) is used by the MP to advertise the
available media captures and related information to the MC. The MP
sends to the MC an ADV as soon as it is ready after the successful
completion of the initiation phase, i.e., as soon as the version and
the options of the CLUE protocol are agreed between the CPs. During
a single CLUE session, an MP may send new ADV messages to replace the
previously advertised options, if, for instance, its media CLUE
telepresence capabilities change mid-call. A new ADV completely
invalidates the previous ADV.
The ADV structure is defined in the picture below. The ADV contains
elements compliant with the CLUE data model that characterize the
MP's telepresence offer. Namely, such elements are: the list of the
media captures (<mediaCaptures>), of the encoding groups
(<encodingGroups>), of the capture scenes (<captureScenes>), of the
simultaneous sets (<simultaneousSets>), of the global views
(<globalViews>), and of the represented participants (<people>).
Each of them is fully described in the CLUE framework document and
formally defined in the CLUE data model document.
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<!-- CLUE ADVERTISEMENT MESSAGE TYPE -->
<xs:complexType name="advertisementMessageType">
<xs:complexContent>
<xs:extension base="clueMessageType">
<xs:sequence>
<!-- mandatory -->
<xs:element name="mediaCaptures" type="dm:mediaCapturesType"/>
<xs:element name="encodingGroups" type="dm:encodingGroupsType"/>
<xs:element name="captureScenes" type="dm:captureScenesType"/>
<!-- optional -->
<xs:element name="simultaneousSets" type="dm:simultaneousSetsType"
minOccurs="0"/>
<xs:element name="globalViews" type="dm:globalViewsType"
minOccurs="0"/>
<xs:element name="people" type="dm:peopleType" minOccurs="0"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
4.4. ADVERTISEMENT ACKNOWLEDGEMENT
The ADVERTISEMENT ACKNOWLEDGEMENT message (ACK) is sent by a MC to a
MP to acknowledge an ADV message. As it can be seen from the message
schema provided in the following, the ACK contains a response code
and a reason string for describing the processing result of the ADV.
The <advSequenceNr> carries the sequence number of the ADV the ACK
refers to.
<!-- ADV ACK MESSAGE TYPE -->
<xs:complexType name="advAcknowledgementMessageType">
<xs:complexContent>
<xs:extension base="clueMessageType">
<xs:sequence>
<xs:element name="responseCode" type="xs:short"/>
<xs:element name="reasonString" type="xs:string"/>
<xs:element name="advSequenceNr" type="xs:positiveInteger"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
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4.5. CONFIGURE
The CONFIGURE message (CONF) is sent from a MC to a MP to list the
advertised captures the MC wants to receive. The MC can send a CONF
after the reception of an ADV or each time it wants to request other
captures that have been previously advertised by the MP. The content
of the CONF message is shown below.
<!-- CLUE CONFIGURE MESSAGE TYPE -->
<xs:complexType name="configureMessageType">
<xs:complexContent>
<xs:extension base="clueMessageType">
<xs:sequence>
<!-- mandatory fields -->
<xs:element name="advSequenceNr" type="xs:positiveInteger"/>
<xs:element name="ack" type="xs:boolean" minOccurs="0" fixed="true"/>
<xs:element name="captureEncodings" type="dm:captureEncodingsType"
minOccurs="0"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
The <advSequenceNr> element contains the sequence number of the ADV
message the CONF refers to.
The optional boolean <ack> element, set to "true", if present,
indicates that the CONF message also acknowledges the referred
advertisement, by applying in that way a piggybacking mechanism for
simultaneously acknowledging and replying to the ADV message. In the
above case, the CONF message MUST carry a 200 (Success) response
code. The <ack> element MUST not be present if an ACK message has
been already sent back to the MP.
The most important content of the CONFIGURE message is the list of
the capture encodings provided in the <captureEncodings> element.
Such an element contains a sequence of capture encodings,
representing the streams to be instantiated.
4.6. CONFIGURE RESPONSE
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<!-- CONFIGURE RESPONSE MESSAGE TYPE -->
<xs:complexType name="configureResponseMessageType">
<xs:complexContent>
<xs:extension base="clueMessageType">
<xs:sequence>
<xs:element name="responseCode" type="xs:short"/>
<xs:element name="reasonString" type="xs:string"/>
<xs:element name="confSequenceNr" type="xs:positiveInteger"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
The CONFIGURE RESPONSE message (CONF RESPONSE) is sent from the MP to
the MC to communicate the processing result of requests carried in
the previously received CONF message. It contains a response code
with a reason string indicating either the success or the failure
(along with failure details) of a CONF request processing.
Following, the <confSequenceNr> field contains the sequence number of
the CONF message the response refers to.
4.7. Response codes and reason strings
The response codes and strings defined for use with CLUE are as
follows:
+-----------------+----------------------+--------------------------+
| | | |
| Response code | Reason string | Description |
| | | |
+-----------------+----------------------+--------------------------+
| | | |
| 200 | Success | The request has been |
| | | successfully processed. |
| | | |
+-----------------+----------------------+--------------------------+
| | | |
| 300 | Bad syntax | The XML syntax of the |
| | | message is not |
| | | correct. |
+-----------------+----------------------+--------------------------+
| | | |
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| 301 | Invalid value | The message |
| | | contains an invalid |
| | | parameter value. |
+-----------------+----------------------+--------------------------+
| | | |
| 302 | Conflicting values | The message |
| | | contains values that |
| | | cannot be used together.|
+-----------------+----------------------+--------------------------+
| | | |
| 400 | Version not supported| The protocol version |
| | | used in the message |
| | | is not supported. |
| | | |
+-----------------+----------------------+--------------------------+
| | | |
| 401 | Invalid sequencing | The sequence number of |
| | | the message is out |
| | | of date. |
+-----------------+----------------------+--------------------------+
| | | |
| 402 | Invalid identifier | The identifier used in |
| | | the message is |
| | | not valid or unknown. |
+-----------------+----------------------+--------------------------+
| | | |
| 403 | ADV Expired | The number of the ADV |
| | | the CONF refers to is |
| | | out of date. |
+-----------------+----------------------+--------------------------+
| | | |
| 404 | Subset choice not | The subset choice is not|
| | allowed | allowed for the specified|
| | | MCC |
+-----------------+----------------------+--------------------------+
Response codes are defined as a sequence of three digits. A well-
defined meaning is associated with the first digit. Response codes
beginning with "2" are associated with successful responses.
Response codes beginning with "1" will represent a delayed or
incomplete response. Response codes that do not begin with either
"2" or "1" indicate an error response, i.e., that an error occurred
while processing a CLUE request. In particular, response codes
beginning with "3" indicate problems with the XML content of the
message ("Bad syntax", "Invalid value", etc.), while response codes
beginning with "4" refer to problems related to CLUE protocol
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semantics ("Invalid sequencing", "Version not supported", etc.).
Further response codes can be designed in future versions of the
protocol, provided they do not overwrite the ones here defined and
they respect the semantics of the first code digit.
5. Protocol state machines
The CLUE protocol is an application protocol used between two CPs in
order to properly configure a multimedia telepresence session. CLUE
protocol messages flow upon the CLUE Data Channel, a DTLS/SCTP
channel established as depicted in [I-D.ietf-clue-datachannel]. We
herein discuss the state machines associated, respectively, with the
CLUE Participant, with the MC process and with the MP process.
Endpoints often wish to both send a receive media, i.e., act as both
MP and MC. As such there will often be two sets of messages flowing
in opposite directions; the state machines of these two flows do not
interact with each other. Only the CLUE application logic is
considered. The interaction of CLUE protocol and SDP negotiations
for the media streams exchanged is treated in
[I-D.ietf-clue-signaling].
6. CLUE Participant's state machine
The main state machines focus on the behavior of the CLUE Participant
(CP) acting as a CLUE channel initiator/receiver (CI/CR).
The initial state is the IDLE one. When in the IDLE state, the CLUE
data channel is not established and no CLUE-controlled media are
exchanged between the two considered CLUE-capable devices (if there
is an ongoing exchange of media streams, such media streams are not
currently CLUE-controlled).
When the CLUE data channel set up starts ("start channel"), the CP
moves from the IDLE state to the CHANNEL SETUP state.
If the CLUE data channel is successfully set up ("channel
established"), the CP moves from the CHANNEL SETUP state to the
OPTIONS state. Otherwise ("channel error"), it moves back to the
IDLE state. The same transition happens if the CLUE-enabled
telepresence session ends ("session ends"), i.e., when an SDP
negotiation for removing the CLUE channel is performed.
When in the OPTIONS state, the CP addresses the initiation phase
where both parts agree on the version and on the options to be used
in the subsequent CLUE messages exchange phase. If the CP is the
Channel Initiator (CI), it sends an OPTIONS message and waits for the
OPTIONS RESPONSE message. If the CP is the Channel Receiver (CR), it
waits for the OPTIONS message and, as soon as it arrives, replies
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with the OPTIONS RESPONSE message. If the negotiation is
successfully completed ("OPTIONS phase success"), the CP moves from
the OPTIONS state to the ACTIVE state. If the initiation phase fails
("OPTIONS phase failure"), the CP moves from the OPTIONS state to the
IDLE state. The initiation phase might fail because of one of the
following reasons:
1. the CI receives an OPTIONS RESPONSE with an error response code
2. the CI does not receive any OPTIONS RESPONSE and a timeout error
is raised
3. the CR does not receive any OPTIONS and a timeout error is raised
When in the ACTIVE state, the CP starts the envisioned sub-state
machines (i.e., the MP state machine and the MC state machine)
according to the roles it plays in the telepresence sessions. Such
roles have been previously declared in the OPTIONS and OPTIONS
RESPONSE messages involved in the initiation phase (see OPTIONS
sections Section 4.1 and Section 4.2 for the details). When in the
ACTIVE state, the CP delegates the sending and the processing of the
CLUE messages to the appropriate MP/MC sub-state machines. If the CP
receives a further OPTIONS/OPTIONS RESPONSE message, it MUST ignore
the message and stay in the ACTIVE state.
The CP moves from the ACTIVE state to the IDLE one when the sub-state
machines that have been activated are (both) in the relative
TERMINATED state (see sections Section 6.1 and Section 6.2).
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+----+
+---------------------->|IDLE|<----------------------------+
| +-+--+ |
| | |
| | start |
| | channel |
| v |
| channel error/ +--------+ |
| session ends | CHANNEL| |
+----------------------+ SETUP | |
| +--+-----+ |
| | |
| | channel |
| | established |
| channel error/ v OPTIONS phase |
| session ends +-------+ failure |
+-----------------------+OPTIONS+--------------------------+
| +-+-----+ |
| | |
| | OPTIONS phase |
| | success |
| v |
| channel error/ +---------+ |
| session ends | ACTIVE | |
+----------------------+ | |
| +----+ +------------------+ |
| | MP | | send/receive | |
| +----+ | CLUE messages | |
| |<-----------------+ |
| +----+ | |
| | MC | |both sub state machines |
| +----+ |terminated |
| | |
+---------+-------------------------+
6.1. Media Provider's state machine
As soon as the sub-state machine of the MP is activated, it is in the
ADV state. In the ADV state, the MP is preparing the ADV message
reflecting its actual telepresence capabilities.
After the ADV has been sent ("ADV sent"), the MP moves from the ADV
state to the WAIT FOR ACK state. If an ACK message with a successful
response code arrives ("ACK received"), the MP moves to the WAIT FOR
CONF state. If a NACK arrives (i.e., an ACK message with an error
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response code), and the number of NACKs for the issued ADV is under
the retry threshold ("NACK received && retry not expired"), the MP
moves back to the ADV state for preparing a new ADV. If a NACK
arrives and the number of received NACKs for that ADV overcomes the
threshold ("NACK received and && retry expired"), the MP goes to the
MP-TERMINATED state. The same happens if the waiting time for the
ACK is fired a number of times under the retry threshold ("timeout &&
retry not expired"): also in this case, the MP goes back to the ADV
state to send a new copy of the ADV. If the number of retries
overcomes the threshold ("timeout && retry expired"), the MP moves
from the WAIT FOR ACK state to the MP-TERMINATED state. When in the
WAIT FOR ACK state, if a CONFIGURE message with the <ack> element set
to TRUE arrives ("CONF+ACK received"), the MP goes directly to the
CONF RESPONSE state. CONF+ACK messages referring to out-of-date
(i.e., having a sequence number equal to or less than the highest
seen so far) ADVs MUST be ignored, i.e., they do not trigger any
state transition. If the telepresence settings of the MP change
while in the WAIT FOR ACK state ("changed telepresence settings"),
the MP switches from the WAIT FOR ACK state to the ADV state to
create a new ADV.
When in the WAIT FOR CONF state, the MP listens to the channel for a
CONF request coming from the MC. If a CONF arrives ("CONF
received"), the MP switches to the CONF RESPONSE state. If the CONF
does not arrive within the timeout interval and the retry threshold
has not been overcome ("timeout && retry not expired"), the MP moves
back to the ADV state. When the retry expires ("timeout && retry
expired") the MP moves to the MP TERMINATED state. If the
telepresence settings change in the meanwhile ("changed telepresence
settings"), the MP moves from the WAIT FOR CONF back to the ADV state
to create the new ADV to be sent to the MC.
The MP in the CONF RESPONSE state processes the received CONF in
order to produce a CONF RESPONSE message. If the MP successfully
processes the MC's configuration, then it sends a 200 CONF RESPONSE
("success CONF RESPONSE sent") and moves to the ESTABLISHED state.
If there are errors in the CONF processing, then the MP issues a CONF
RESPONSE carrying an error response code and, if under the retry
treshold ("error CONF RESPONSE sent && retry not expired"), it goes
back to the WAIT FOR CONF state to wait for a new configuration
request. If the number of trials exceeds the retry threshold ("error
CONF RESPONSE sent && retry expired"), the state MP TERMINATED is
reached. Finally, if there are changes in the MP's telepresence
settings ("changed telepresence settings"), the MP switches to the
ADV state.
The MP in the ESTABLISHED state has successfully negotiated the media
streams with the MC by means of the CLUE messages. If there are
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changes in the MP's telepresence settings ("changed telepresence
settings"), the MP moves back to the ADV state. In the ESTABLISHED
state, the CLUE-controlled media streams of the session are those
described in the last successfully processed CONF message.
+------------------------->+-----+<---------------------------+
| +------------>| ADV |<-------------------+ |
| | +-+---+ | |timeout
| | | NACK received | |&&
| | ADV sent| && | |retry
| | v retry not expired| |not
| changed| +--------+ | |expired
|telepresence+-------------+WAIT FOR+-----------------+ |
| settings| +---------+ ACK +-------------------------+
| | |CONF+ACK +-+------+------------------------------------+
| | |received | NACK received && |
| | | |ACK received retry expired,|
| | | v timeout && retry expired|
+------------|-------------+--------+ |
timeout +-------------+WAIT FOR| timeout && retry expired |
&& | | | CONF +------------------------------------+
retry | | +-+------+<-------------------------------+ |
not expired | | | | |
| | |CONF received | |
| | v error CONF RESPONSE sent| |
| +-------->+---------+ && retry not expired | |
+-------------+CONF |-------------------------------+ |
+--------------------->|RESPONSE +-----------------------------------+
| | +-+-------+ error CONF RESPONSE sent|
| | | && retry expired|
| | | success |
| | | CONF RESPONSE |
| | | sent |
| | | |
| | | |
|CONF | | |
|received| v |
| | +------------+ |
| +-------------+ESTABLISHED | |
+----------------------+------------+ |
|
|
|
+-----------+ |
! MP | |
|TERMINATED | |
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+-----------+<--------------------------------+
6.2. Media Consumer's state machine
As soon as the sub-state machine of the MC is activated, it is in the
WAIT FOR ADV state. An MC in the WAIT FOR ADV state is waiting for
an ADV coming from the MP. If the ADV arrives ("ADV received"), the
MC reaches the ADV PROCESSING state. Otherwise, the MC is stuck in
the WAIT FOR ADV state.
In the ADV PROCESSING state, the ADV is parsed by the MC. If the ADV
is successfully processed, there are two possibilities. According to
the first one, the MC issues a successful ACK message to the MP ("ACK
sent") and moves to the CONF state. In the second one, the MC
prepares and sends a CONF message with the <ack> field set to "true"
("CONF+ACK sent") and goes directly to the WAIT FOR CONF RESPONSE
state.
If the ADV elaboration is unsuccessful (bad syntax, missing XML
elements, etc.), and the number of times this has happened is under
the retry treshold, the MC sends a NACK message (i.e., an ACK with an
error response code) to the MP describing the problem via a proper
reason phrase. By this way ("NACK sent && retry not expired"), the
MC switches back to the WAIT FOR ADV state, waiting for a new ADV.
If the NACK retry expires ("NACK sent && retry expired"), the MC
moves to the MC TERMINATED state.
When in the CONF state, the MC is preparing the CONF request to be
issued to the MP on the basis of the previously ACK-ed ADV. When the
CONF has been sent ("CONF sent"), the MC moves to the WAIT FOR CONF
RESPONSE state. If a new ADV arrives in the meanwhile ("ADV
received"), the MC goes back to the ADV PROCESSING state.
In the WAIT FOR CONF RESPONSE state, the MC is waiting for the MP's
response to the issued CONF or CONF+ACK. If a 200 CONF RESPONSE
message is received ("successful CONF RESPONSE received"), it means
that the MP and the MC have successfully agreed on the media streams
to be shared. Then, the MC can move to the ESTABLISHED state. On
the other hand, if an error response is received and the associated
retry counter does not overcome the threshold ("error CONF RESPONSE
received && retry not expired"), the MC moves back to the CONF state
to prepare a new CONF request. In case of "error CONF RESPONSE
received && retry expired", the MC moves to the MC TERMINATED state.
If no CONF RESPONSE arrives and the number of timeouts is under the
threshold ("timeout && retry not expired"), the MC moves to the CONF
state and sends again the CONF message. If no CONF RESPONSE arrives
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and the number of timeouts is over the threshold ("timeout && retry
expired"), the MC moves to the MC TERMINATED state. If a new ADV is
received in the WAIT FOR CONF RESPONSE state, the MC switches to the
ADV PROCESSING state.
When the MC is in the ESTABLISHED state, the telepresence session
configuration has been set up at the CLUE application level according
to the MC's preferences. Both the MP and the MC have agreed on (and
are aware of) the CLUE-controlled media streams to be exchanged
within the call. While in the ESTABLISHED state, it might happen
that the MC decides to change something in the call settings. The MC
then issues a new CONF ("CONF sent") and goes to wait for the new
CONF RESPONSE in the WAIT FOR CONF RESPONSE state. On the other
hand, in the ESTABLISHED state, if a new ADV arrives from the MP
("ADV received"), it means that something has changed on the MP's
side. The MC then moves to the ADV PROCESSING state.
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+----------+
| WAIT FOR |
| ADV |
+----+-----+<--------+
| |
ADV | NACK sent|
received| && retry |
v not expired| NACK sent &&
+-----------+--------+ retry expired
| ADV +---------------------------+
| PROCESSING|<-----------------------+ |
+-+-----+---+ | |
| | | |
CONF+ACK | | ACK | |
sent | | sent | |
| v | |
| +-----+ | |
| |CONF | ADV received | |
+----------------------->| +-------------------------+ |
| | +--+--+ | |
|error CONF RESPONSE | | error CONF RESPONSE | |
|received && | | CONF received && | |
|retry not expired, | | sent retry expired | |
|timeout && | | +------------------------+
|retry not expired v v | | |
+------------------+---------------+ ADV received | |
+--------->| WAIT FOR +---------------------+ |
| | CONF RESPONSE+------------------------+
| +-------+-------+ timeout&& | |
| | retry expired | |
| | | |
| |successful | |
| |CONF RESPONSE | |
| |received | |
| v | |
|CONF sent +-----------+ ADV received| |
+------------+ESTABLISHED+-----------------------+ |
+-----------+ |
|
|
|
+-----------+ |
| MC |<------------------------+
|TERMINATED |
+-----------+
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7. Versioning
CLUE protocol messages are XML messages compliant to the CLUE
protocol XML schema [I-D.ietf-clue-data-model-schema]. The version
of the protocol corresponds to the version of the schema. Both
client and server have to test the compliance of the received
messages with the XML schema of the CLUE protocol. If the compliance
is not verified, the message cannot be processed further.
Obviously, client and server cannot communicate if they do not share
exactly the same XML schema. Such a schema associated with the CLUE
URN "urn:ietf:params:xml:ns:clue-protocol". If all CLUE-enabled
devices use that schema there will be no interoperability problems
due to schema issues.
The version of the XML schema contained in the standard document
deriving from this draft will be 1.0. The version usage is similar
in philosophy to XMPP ([RFC6120]). A version number has major and
minor components, each a non-negative integer. Major version changes
denote non-interoperable changes. Minor version changes denote
schema changes that are backward compatible by ignoring unknown XML
elements, or other backward compatible changes.
The minor versions of the XML schema MUST be backward compatible, not
only in terms of schema but also semantically and procedurally as
well. This means that they should define further features and
functionality besides those defined in the previous versions, in an
incremental way, without impacting the basic rules defined in the
previous version of the schema. In this way, if a MP is able to
speak, e.g., version 1.5 of the protocol while the MC only
understands version 1.4, the MP should have no problem in reverting
the dialogue back to version 1.4 without exploiting 1.5 features and
functionality.
It is expected that, before the CLUE protocol XML schema reaches a
steady state, prototypes developed by different organizations will
conduct interoperability testing. In that case, in order to
interoperate, they have to be compliant to the current version of the
XML schema, i.e., the one copied in the most up-to-date version of
the draft defining the CLUE protocol. The versions of the non-
standard XML schema will be numbered as 0.01, 0.02, and so on.
During the standard development phase, the versions of the XML schema
will probably not be backward compatible so it is left to prototype
implementers the responsibility of keeping their products up to date.
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8. Extensions and options
Although the standard version of the CLUE protocol XML schema is
designed to thoroughly cope with the requirements emerging from the
application domain, new needs might arise and extensions can be
designed. Extensions specify information and behaviors that are not
described in a certain version of the protocol. They can relate to:
1. new information, to be carried in the existing messages. For
example, we may want to add more fields within an existing
message;
2. new messages. This is the case if there is no proper message for
a certain task, so a brand new CLUE message needs to be defined.
As to the first type of extensions, it is possible to distinguish
between protocol-specific and data model information. Indeed, CLUE
messages are envelopes carrying both:
o (i) XML elements defined within the CLUE protocol XML schema
itself (protocol-specific information)
o (ii) other XML elements compliant to the CLUE data model schema
(data model information)
When new protocol-specific information is needed somewhere in the
protocol messages, it can be added in place of the <any> elements and
<anyAttribute> elements envisioned by the protocol schema. The
policy currently defined in the protocol schema for handling <any>
and <anyAttribute> elements is:
o elementFormDefault="qualified"
o attributeFormDefault="unqualified"
In that case, the new information must be qualified by namespaces
other than "urn:ietf:params:xml:ns:clue-protocol" (the protocol URN)
and "urn:ietf:params:xml:ns:clue-info" (the data model URN).
Elements or attributes from unknown namespaces MUST be ignored.
The other matter concerns data model information. Data model
information is defined by the XML schema associated with the URN
"urn:ietf:params:xml:ns:clue-info". Also for the XML elements
defined in such a schema there are extensibility issues. Those
issues are overcome by using <any> and <anyAttribute> placeholders.
Similarly to what said before, new information within data model
elements can be added in place of <any> and <anyAttribute> schema
elements, as long as they are properly namespace qualified.
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On the other hand (second type of extensions), "extra" CLUE protocol
messages, i.e., messages not envisioned in the latest standard
version of the schema, can be needed. In that case, the messages and
the associated behavior should be defined in external documents that
both communication parties must be aware of.
Both types of extensions, i.e., new information and new messages, can
be characterized by:
o a name;
o an external XML Schema defining the XML information and/or the XML
messages representing the extension;
o the standard version of the protocol the extension refers to.
For that reason, the extensions can be represented by means of the
<option> element as defined below, which is carried within the
OPTIONS and OPTIONS RESPONSE messages to represent the extensions
supported by the CI and by the CR.
<!-- OPTION TYPE -->
<xs:complexType name="optionType">
<xs:sequence>
<xs:element name="name" type="xs:string" />
<xs:element name="schemaRef" type="xs:anyURI" minOccurs="0"/>
<xs:element name="version" type="versionType" minOccurs="0"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>
9. XML Schema
In this section, the XML schema defining the CLUE messages is
provided.
<?xml version="1.0" encoding="UTF-8" ?>
<xs:schema
version="0.6"
targetNamespace="urn:ietf:params:xml:ns:clue-protocol"
xmlns:tns="urn:ietf:params:xml:ns:clue-protocol"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
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xmlns:dm="urn:ietf:params:xml:ns:clue-info"
xmlns="urn:ietf:params:xml:ns:clue-protocol"
elementFormDefault="qualified"
attributeFormDefault="unqualified">
<!-- Import data model schema -->
<xs:import namespace="urn:ietf:params:xml:ns:clue-info"
schemaLocation="data-model-schema-09.xsd"/>
<!-- ELEMENT DEFINITIONS -->
<xs:element name="options" type="optionsMessageType"/>
<xs:element name="optionsResponse" type="optionsResponseMessageType"/>
<xs:element name="advertisement" type="advertisementMessageType"/>
<xs:element name="ack" type="advAcknowledgementMessageType"/>
<xs:element name="configure" type="configureMessageType"/>
<xs:element name="configureResponse" type="configureResponseMessageType"/>
<!-- CLUE MESSAGE TYPE -->
<xs:complexType name="clueMessageType" abstract="true">
<xs:sequence>
<xs:element name="clueId" type="xs:string"/>
<xs:element name="sequenceNr" type="xs:positiveInteger"/>
</xs:sequence>
<xs:attribute name="protocol" type="xs:string" fixed="CLUE" use="required"/>
<xs:attribute name="v" type="versionType" use="required"/>
</xs:complexType>
<!-- VERSION TYPE -->
<xs:simpleType name="versionType">
<xs:restriction base="xs:string">
<xs:pattern value="([0-9])+\.([0-9]+)"></xs:pattern>
</xs:restriction>
</xs:simpleType>
<!-- RESPONSE CODE TYPE -->
<xs:simpleType name="responseCodeType">
<xs:restriction base="xs:integer">
<xs:pattern value="[1-9][0-9][0-9]"/>
</xs:restriction>
</xs:simpleType>
<!-- CLUE OPTIONS -->
<xs:complexType name="optionsMessageType">
<xs:complexContent>
<xs:extension base="clueMessageType">
<xs:sequence>
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<xs:element name="mediaProvider" type="xs:boolean"/>
<xs:element name="mediaConsumer" type="xs:boolean"/>
<xs:element name="supportedVersions" type="versionsListType" minOccurs="0"/>
<xs:element name="supportedOptions" type="optionsListType" minOccurs="0"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<!-- VERSIONS LIST TYPE -->
<xs:complexType name="versionsListType">
<xs:sequence>
<xs:element name="version" type="versionType" minOccurs="1"
maxOccurs="unbounded"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>
<!-- OPTIONS LIST TYPE -->
<xs:complexType name="optionsListType">
<xs:sequence>
<xs:element name="option" type="optionType" minOccurs="1"
maxOccurs="unbounded"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>
<!-- OPTION TYPE -->
<xs:complexType name="optionType">
<xs:sequence>
<xs:element name="name" type="xs:string" />
<xs:element name="schemaRef" type="xs:anyURI" minOccurs="0"/>
<xs:element name="version" type="versionType" minOccurs="0"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:complexType>
<!-- CLUE OPTIONS RESPONSE -->
<xs:complexType name="optionsResponseMessageType">
<xs:complexContent>
<xs:extension base="clueMessageType">
<xs:sequence>
<xs:element name="responseCode" type="responseCodeType"/>
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<xs:element name="reasonString" type="xs:string"/>
<xs:element name="mediaProvider" type="xs:boolean" minOccurs="0"/>
<xs:element name="mediaConsumer" type="xs:boolean" minOccurs="0"/>
<xs:element name="version" type="versionType" minOccurs="0"/>
<xs:element name="commonOptions" type="optionsListType" minOccurs="0"/>
<xs:any namespace="##other"
processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<!-- CLUE ADVERTISEMENT MESSAGE TYPE -->
<xs:complexType name="advertisementMessageType">
<xs:complexContent>
<xs:extension base="clueMessageType">
<xs:sequence>
<!-- mandatory -->
<xs:element name="mediaCaptures" type="dm:mediaCapturesType"/>
<xs:element name="encodingGroups" type="dm:encodingGroupsType"/>
<xs:element name="captureScenes" type="dm:captureScenesType"/>
<!-- optional -->
<xs:element name="simultaneousSets" type="dm:simultaneousSetsType"
minOccurs="0"/>
<xs:element name="globalViews" type="dm:globalViewsType"
minOccurs="0"/>
<xs:element name="people" type="dm:peopleType" minOccurs="0"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<!-- ACK MESSAGE TYPE -->
<xs:complexType name="advAcknowledgementMessageType">
<xs:complexContent>
<xs:extension base="clueMessageType">
<xs:sequence>
<xs:element name="responseCode" type="responseCodeType"/>
<xs:element name="reasonString" type="xs:string"/>
<xs:element name="advSequenceNr" type="xs:positiveInteger"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:extension>
</xs:complexContent>
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</xs:complexType>
<!-- CLUE CONFIGURE MESSAGE TYPE -->
<xs:complexType name="configureMessageType">
<xs:complexContent>
<xs:extension base="clueMessageType">
<xs:sequence>
<xs:element name="advSequenceNr" type="xs:positiveInteger"/>
<xs:element name="ack" type="xs:boolean"
minOccurs="0" fixed="true"/>
<xs:element name="captureEncodings" type="dm:captureEncodingsType"
minOccurs="0"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
<!-- CONFIGURE RESPONSE MESSAGE TYPE -->
<xs:complexType name="configureResponseMessageType">
<xs:complexContent>
<xs:extension base="clueMessageType">
<xs:sequence>
<xs:element name="responseCode" type="responseCodeType"/>
<xs:element name="reasonString" type="xs:string"/>
<xs:element name="confSequenceNr" type="xs:positiveInteger"/>
<xs:any namespace="##other" processContents="lax" minOccurs="0"/>
</xs:sequence>
<xs:anyAttribute namespace="##other" processContents="lax"/>
</xs:extension>
</xs:complexContent>
</xs:complexType>
</xs:schema>
10. Examples
In the following we provide an example of ADVERTISEMENT representing
the telepresence environment described in
[I-D.ietf-clue-data-model-schema], Section "Sample XML file" and
Section "MCC example" respectively.
10.1. Simple ADV
The associated Media Provider's telepresence capabilities are
described in [I-D.ietf-clue-data-model-schema], Section "Sample XML
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file".
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<advertisement xmlns="urn:ietf:params:xml:ns:clue-protocol"
xmlns:ns2="urn:ietf:params:xml:ns:clue-info"
xmlns:ns3="urn:ietf:params:xml:ns:vcard-4.0"
protocol="CLUE" v="0.4">
<clueId>Napoli</clueId>
<sequenceNr>45</sequenceNr>
<mediaCaptures>
<ns2:mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:type="ns2:videoCaptureType" captureID="AC0" mediaType="video">
<ns2:captureSceneIDREF>CS1</ns2:captureSceneIDREF>
<ns2:encGroupIDREF>EG1</ns2:encGroupIDREF>
<ns2:spatialInformation>
<ns2:capturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>1.0</ns2:y>
<ns2:z>0.5</ns2:z>
<ns2:lineOfCapturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>0.0</ns2:y>
<ns2:z>0.5</ns2:z>
</ns2:lineOfCapturePoint>
</ns2:capturePoint>
</ns2:spatialInformation>
<ns2:individual>true</ns2:individual>
<ns2:description lang="en">main audio from the room</ns2:description>
<ns2:priority>1</ns2:priority>
<ns2:lang>it</ns2:lang>
<ns2:mobility>static</ns2:mobility>
<ns2:view>room</ns2:view>
<ns2:capturedPeople>
<ns2:personIDREF>alice</ns2:personIDREF>
<ns2:personIDREF>bob</ns2:personIDREF>
<ns2:personIDREF>ciccio</ns2:personIDREF>
</ns2:capturedPeople>
</ns2:mediaCapture>
<ns2:mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:type="ns2:videoCaptureType" mediaType="video" captureID="VC0">
<ns2:captureSceneIDREF>CS1</ns2:captureSceneIDREF>
<ns2:encGroupIDREF>EG0</ns2:encGroupIDREF>
<ns2:spatialInformation>
<ns2:capturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>1.0</ns2:y>
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<ns2:z>0.5</ns2:z>
<ns2:lineOfCapturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>0.0</ns2:y>
<ns2:z>0.5</ns2:z>
</ns2:lineOfCapturePoint>
</ns2:capturePoint>
</ns2:spatialInformation>
<ns2:individual>true</ns2:individual>
<ns2:description lang="en">left camera video capture
</ns2:description>
<ns2:priority>1</ns2:priority>
<ns2:lang>it</ns2:lang>
<ns2:mobility>static</ns2:mobility>
<ns2:view>individual</ns2:view>
<ns2:capturedPeople>
<ns2:personIDREF>ciccio</ns2:personIDREF>
</ns2:capturedPeople>
</ns2:mediaCapture>
<ns2:mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:type="ns2:videoCaptureType" mediaType="video" captureID="VC1">
<ns2:captureSceneIDREF>CS1</ns2:captureSceneIDREF>
<ns2:encGroupIDREF>EG0</ns2:encGroupIDREF>
<ns2:spatialInformation>
<ns2:capturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>1.0</ns2:y>
<ns2:z>0.5</ns2:z>
<ns2:lineOfCapturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>0.0</ns2:y>
<ns2:z>0.5</ns2:z>
</ns2:lineOfCapturePoint>
</ns2:capturePoint>
</ns2:spatialInformation>
<ns2:individual>true</ns2:individual>
<ns2:description lang="en">central camera video capture
</ns2:description>
<ns2:priority>1</ns2:priority>
<ns2:lang>it</ns2:lang>
<ns2:mobility>static</ns2:mobility>
<ns2:view>individual</ns2:view>
<ns2:capturedPeople>
<ns2:personIDREF>alice</ns2:personIDREF>
</ns2:capturedPeople>
</ns2:mediaCapture>
<ns2:mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:type="ns2:videoCaptureType" mediaType="video" captureID="VC2">
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<ns2:captureSceneIDREF>CS1</ns2:captureSceneIDREF>
<ns2:encGroupIDREF>EG0</ns2:encGroupIDREF>
<ns2:spatialInformation>
<ns2:capturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>1.0</ns2:y>
<ns2:z>0.5</ns2:z>
<ns2:lineOfCapturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>0.0</ns2:y>
<ns2:z>0.5</ns2:z>
</ns2:lineOfCapturePoint>
</ns2:capturePoint>
</ns2:spatialInformation>
<ns2:individual>true</ns2:individual>
<ns2:description lang="en">right camera video capture
</ns2:description>
<ns2:priority>1</ns2:priority>
<ns2:lang>it</ns2:lang>
<ns2:mobility>static</ns2:mobility>
<ns2:view>individual</ns2:view>
<ns2:capturedPeople>
<ns2:personIDREF>bob</ns2:personIDREF>
</ns2:capturedPeople>
</ns2:mediaCapture>
<ns2:mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:type="ns2:videoCaptureType" mediaType="video" captureID="VC3">
<ns2:captureSceneIDREF>CS1</ns2:captureSceneIDREF>
<ns2:encGroupIDREF>EG0</ns2:encGroupIDREF>
<ns2:nonSpatiallyDefinable>true</ns2:nonSpatiallyDefinable>
<ns2:composed>false</ns2:composed>
<ns2:switched>true</ns2:switched>
<ns2:policy>Soundlevel:0</ns2:policy>
<ns2:maxCaptures>1</ns2:maxCaptures>
<ns2:description lang="en">loudest room segment</ns2:description>
<ns2:priority>1</ns2:priority>
<ns2:lang>it</ns2:lang>
<ns2:mobility>static</ns2:mobility>
<ns2:view>individual</ns2:view>
</ns2:mediaCapture>
<ns2:mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:type="ns2:videoCaptureType" mediaType="video" captureID="VC4">
<ns2:captureSceneIDREF>CS1</ns2:captureSceneIDREF>
<ns2:encGroupIDREF>EG0</ns2:encGroupIDREF>
<ns2:spatialInformation>
<ns2:capturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>1.0</ns2:y>
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<ns2:z>0.5</ns2:z>
<ns2:lineOfCapturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>0.0</ns2:y>
<ns2:z>0.5</ns2:z>
</ns2:lineOfCapturePoint>
</ns2:capturePoint>
</ns2:spatialInformation>
<ns2:individual>true</ns2:individual>
<ns2:description lang="en">zoomed out view of all people in
the room
</ns2:description>
<ns2:priority>1</ns2:priority>
<ns2:lang>it</ns2:lang>
<ns2:mobility>static</ns2:mobility>
<ns2:view>room</ns2:view>
<ns2:capturedPeople>
<ns2:personIDREF>alice</ns2:personIDREF>
<ns2:personIDREF>bob</ns2:personIDREF>
<ns2:personIDREF>ciccio</ns2:personIDREF>
</ns2:capturedPeople>
</ns2:mediaCapture>
</mediaCaptures>
<encodingGroups>
<ns2:encodingGroup encodingGroupID="EG0">
<ns2:maxGroupBandwidth>600000</ns2:maxGroupBandwidth>
<ns2:encodingIDList>
<ns2:encID>ENC1</ns2:encID>
<ns2:encID>ENC2</ns2:encID>
<ns2:encID>ENC3</ns2:encID>
</ns2:encodingIDList>
</ns2:encodingGroup>
<ns2:encodingGroup encodingGroupID="EG1">
<ns2:maxGroupBandwidth>300000</ns2:maxGroupBandwidth>
<ns2:encodingIDList>
<ns2:encID>ENC4</ns2:encID>
<ns2:encID>ENC5</ns2:encID>
</ns2:encodingIDList>
</ns2:encodingGroup>
</encodingGroups>
<captureScenes>
<ns2:captureScene scale="unknown" sceneID="CS1">
<ns2:sceneViews>
<ns2:sceneView sceneViewID="SE1">
<ns2:mediaCaptureIDs>
<ns2:captureIDREF>VC0</ns2:captureIDREF>
<ns2:captureIDREF>VC1</ns2:captureIDREF>
<ns2:captureIDREF>VC2</ns2:captureIDREF>
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</ns2:mediaCaptureIDs>
</ns2:sceneView>
<ns2:sceneView sceneViewID="SE2">
<ns2:mediaCaptureIDs>
<ns2:captureIDREF>VC3</ns2:captureIDREF>
</ns2:mediaCaptureIDs>
</ns2:sceneView>
<ns2:sceneView sceneViewID="SE3">
<ns2:mediaCaptureIDs>
<ns2:captureIDREF>VC4</ns2:captureIDREF>
</ns2:mediaCaptureIDs>
</ns2:sceneView>
<ns2:sceneView sceneViewID="SE4">
<ns2:mediaCaptureIDs>
<ns2:captureIDREF>VC4</ns2:captureIDREF>
</ns2:mediaCaptureIDs>
</ns2:sceneView>
</ns2:sceneViews>
</ns2:captureScene>
</captureScenes>
<simultaneousSets>
<ns2:simultaneousSet setID="SS1">
<ns2:mediaCaptureIDREF>VC3</ns2:mediaCaptureIDREF>
<ns2:sceneViewIDREF>SE1</ns2:sceneViewIDREF>
</ns2:simultaneousSet>
<ns2:simultaneousSet setID="SS2">
<ns2:mediaCaptureIDREF>VC0</ns2:mediaCaptureIDREF>
<ns2:mediaCaptureIDREF>VC2</ns2:mediaCaptureIDREF>
<ns2:mediaCaptureIDREF>VC4</ns2:mediaCaptureIDREF>
<ns2:mediaCaptureIDREF>VC3</ns2:mediaCaptureIDREF>
</ns2:simultaneousSet>
</simultaneousSets>
<people>
<ns2:person personID="bob">
<ns2:personInfo>
<ns3:fn>
<ns3:text>Bob</ns3:text>
</ns3:fn>
</ns2:personInfo>
<ns2:personType>minute taker</ns2:personType>
</ns2:person>
<ns2:person personID="alice">
<ns2:personInfo>
<ns3:fn>
<ns3:text>Alice</ns3:text>
</ns3:fn>
</ns2:personInfo>
<ns2:personType>presenter</ns2:personType>
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</ns2:person>
<ns2:person personID="ciccio">
<ns2:personInfo>
<ns3:fn>
<ns3:text>Ciccio</ns3:text>
</ns3:fn>
</ns2:personInfo>
<ns2:personType>chairman</ns2:personType>
<ns2:personType>timekeeper</ns2:personType>
</ns2:person>
</people>
</advertisement>
10.2. ADV with MCCs
The associated Media Provider's telepresence capabilities are
described in [I-D.ietf-clue-data-model-schema], Section "MCC
example".
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<advertisement xmlns="urn:ietf:params:xml:ns:clue-protocol"
xmlns:ns2="urn:ietf:params:xml:ns:clue-info"
xmlns:ns3="urn:ietf:params:xml:ns:vcard-4.0" protocol="CLUE" v="0.4">
<clueId>Napoli CLUE Endpoint</clueId>
<sequenceNr>34</sequenceNr>
<mediaCaptures>
<ns2:mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:type="ns2:videoCaptureType" mediaType="video" captureID="AC0">
<ns2:captureSceneIDREF>CS1</ns2:captureSceneIDREF>
<ns2:encGroupIDREF>EG1</ns2:encGroupIDREF>
<ns2:spatialInformation>
<ns2:capturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>1.0</ns2:y>
<ns2:z>0.5</ns2:z>
<ns2:lineOfCapturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>0.0</ns2:y>
<ns2:z>0.5</ns2:z>
</ns2:lineOfCapturePoint>
</ns2:capturePoint>
</ns2:spatialInformation>
<ns2:individual>true</ns2:individual>
<ns2:description lang="en">main audio from the room</ns2:description>
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<ns2:priority>1</ns2:priority>
<ns2:lang>it</ns2:lang>
<ns2:mobility>static</ns2:mobility>
<ns2:view>room</ns2:view>
<ns2:capturedPeople>
<ns2:personIDREF>alice</ns2:personIDREF>
<ns2:personIDREF>bob</ns2:personIDREF>
<ns2:personIDREF>ciccio</ns2:personIDREF>
</ns2:capturedPeople>
</ns2:mediaCapture>
<ns2:mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:type="ns2:videoCaptureType" captureID="VC0" mediaType="video" >
<ns2:captureSceneIDREF>CS1</ns2:captureSceneIDREF>
<ns2:encGroupIDREF>EG0</ns2:encGroupIDREF>
<ns2:spatialInformation>
<ns2:capturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>1.0</ns2:y>
<ns2:z>0.5</ns2:z>
<ns2:lineOfCapturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>0.0</ns2:y>
<ns2:z>0.5</ns2:z>
</ns2:lineOfCapturePoint>
</ns2:capturePoint>
</ns2:spatialInformation>
<ns2:individual>true</ns2:individual>
<ns2:description lang="en">left camera video capture</ns2:description>
<ns2:priority>1</ns2:priority>
<ns2:lang>it</ns2:lang>
<ns2:mobility>static</ns2:mobility>
<ns2:view>individual</ns2:view>
<ns2:capturedPeople>
<ns2:personIDREF>ciccio</ns2:personIDREF>
</ns2:capturedPeople>
</ns2:mediaCapture>
<ns2:mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:type="ns2:videoCaptureType" captureID="VC1" mediaType="video">
<ns2:captureSceneIDREF>CS1</ns2:captureSceneIDREF>
<ns2:encGroupIDREF>EG0</ns2:encGroupIDREF>
<ns2:spatialInformation>
<ns2:capturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>1.0</ns2:y>
<ns2:z>0.5</ns2:z>
<ns2:lineOfCapturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>0.0</ns2:y>
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<ns2:z>0.5</ns2:z>
</ns2:lineOfCapturePoint>
</ns2:capturePoint>
</ns2:spatialInformation>
<ns2:individual>true</ns2:individual>
<ns2:description lang="en">central camera video capture
</ns2:description>
<ns2:priority>1</ns2:priority>
<ns2:lang>it</ns2:lang>
<ns2:mobility>static</ns2:mobility>
<ns2:view>individual</ns2:view>
<ns2:capturedPeople>
<ns2:personIDREF>alice</ns2:personIDREF>
</ns2:capturedPeople>
</ns2:mediaCapture>
<ns2:mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:type="ns2:videoCaptureType" captureID="VC2" mediaType="video" >
<ns2:captureSceneIDREF>CS1</ns2:captureSceneIDREF>
<ns2:encGroupIDREF>EG0</ns2:encGroupIDREF>
<ns2:spatialInformation>
<ns2:capturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>1.0</ns2:y>
<ns2:z>0.5</ns2:z>
<ns2:lineOfCapturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>0.0</ns2:y>
<ns2:z>0.5</ns2:z>
</ns2:lineOfCapturePoint>
</ns2:capturePoint>
</ns2:spatialInformation>
<ns2:individual>true</ns2:individual>
<ns2:description lang="en">right camera video capture
</ns2:description>
<ns2:priority>1</ns2:priority>
<ns2:lang>it</ns2:lang>
<ns2:mobility>static</ns2:mobility>
<ns2:view>individual</ns2:view>
<ns2:capturedPeople>
<ns2:personIDREF>bob</ns2:personIDREF>
</ns2:capturedPeople>
</ns2:mediaCapture>
<ns2:mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:type="ns2:videoCaptureType" captureID="VC3" mediaType="video" >
<ns2:captureSceneIDREF>CS1</ns2:captureSceneIDREF>
<ns2:encGroupIDREF>EG0</ns2:encGroupIDREF>
<ns2:nonSpatiallyDefinable>true</ns2:nonSpatiallyDefinable>
<ns2:content>
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<ns2:sceneViewIDREF>SE1</ns2:sceneViewIDREF>
</ns2:content>
<ns2:policy>Soundlevel:0</ns2:policy>
<ns2:maxCaptures>1</ns2:maxCaptures>
<ns2:allowSubsetChoice>false</ns2:allowSubsetChoice>
<ns2:description lang="en">loudest room segment</ns2:description>
<ns2:priority>1</ns2:priority>
<ns2:lang>it</ns2:lang>
<ns2:mobility>static</ns2:mobility>
<ns2:view>individual</ns2:view>
</ns2:mediaCapture>
<ns2:mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:type="ns2:videoCaptureType" captureID="VC4" mediaType="video">
<ns2:captureSceneIDREF>CS1</ns2:captureSceneIDREF>
<ns2:encGroupIDREF>EG0</ns2:encGroupIDREF>
<ns2:spatialInformation>
<ns2:capturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>1.0</ns2:y>
<ns2:z>0.5</ns2:z>
<ns2:lineOfCapturePoint>
<ns2:x>0.5</ns2:x>
<ns2:y>0.0</ns2:y>
<ns2:z>0.5</ns2:z>
</ns2:lineOfCapturePoint>
</ns2:capturePoint>
</ns2:spatialInformation>
<ns2:individual>true</ns2:individual>
<ns2:description lang="en">zoomed out view of all people in the room
</ns2:description>
<ns2:priority>1</ns2:priority>
<ns2:lang>it</ns2:lang>
<ns2:mobility>static</ns2:mobility>
<ns2:view>room</ns2:view>
<ns2:capturedPeople>
<ns2:personIDREF>alice</ns2:personIDREF>
<ns2:personIDREF>bob</ns2:personIDREF>
<ns2:personIDREF>ciccio</ns2:personIDREF>
</ns2:capturedPeople>
</ns2:mediaCapture>
<ns2:mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:type="ns2:videoCaptureType" captureID="VC5" mediaType="video">
<ns2:captureSceneIDREF>CS1</ns2:captureSceneIDREF>
<ns2:nonSpatiallyDefinable>true</ns2:nonSpatiallyDefinable>
<ns2:content>
<ns2:sceneViewIDREF>SE1</ns2:sceneViewIDREF>
</ns2:content>
<ns2:policy>Soundlevel:1</ns2:policy>
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<ns2:maxCaptures>1</ns2:maxCaptures>
<ns2:allowSubsetChoice>false</ns2:allowSubsetChoice>
<ns2:description lang="en">penultimate loudest room segment
</ns2:description>
<ns2:priority>1</ns2:priority>
<ns2:lang>it</ns2:lang>
<ns2:mobility>static</ns2:mobility>
<ns2:view>individual</ns2:view>
</ns2:mediaCapture>
<ns2:mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:type="ns2:videoCaptureType" captureID="VC6" mediaType="video">
<ns2:captureSceneIDREF>CS1</ns2:captureSceneIDREF>
<ns2:nonSpatiallyDefinable>true</ns2:nonSpatiallyDefinable>
<ns2:content>
<ns2:sceneViewIDREF>SE1</ns2:sceneViewIDREF>
</ns2:content>
<ns2:composed>false</ns2:composed>
<ns2:switched>true</ns2:switched>
<ns2:policy>Soundlevel:2</ns2:policy>
<ns2:maxCaptures>1</ns2:maxCaptures>
<ns2:allowSubsetChoice>false</ns2:allowSubsetChoice>
<ns2:description lang="en">last but two loudest room segment
</ns2:description>
<ns2:priority>1</ns2:priority>
<ns2:lang>it</ns2:lang>
<ns2:mobility>static</ns2:mobility>
<ns2:view>individual</ns2:view>
</ns2:mediaCapture>
<ns2:mediaCapture xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:type="ns2:videoCaptureType" captureID="VC7" mediaType="video">
<ns2:captureSceneIDREF>CS1</ns2:captureSceneIDREF>
<ns2:nonSpatiallyDefinable>true</ns2:nonSpatiallyDefinable>
<ns2:content>
<ns2:captureIDREF>VC3</ns2:captureIDREF>
<ns2:captureIDREF>VC5</ns2:captureIDREF>
<ns2:captureIDREF>VC6</ns2:captureIDREF>
</ns2:content>
<ns2:composed>true</ns2:composed>
<ns2:switched>true</ns2:switched>
<ns2:maxCaptures>1</ns2:maxCaptures>
<ns2:allowSubsetChoice>false</ns2:allowSubsetChoice>
<ns2:description lang="en">big picture of the current speaker +
pips about previous speakers</ns2:description>
<ns2:priority>1</ns2:priority>
<ns2:lang>it</ns2:lang>
<ns2:mobility>static</ns2:mobility>
<ns2:view>individual</ns2:view>
</ns2:mediaCapture>
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</mediaCaptures>
<encodingGroups>
<ns2:encodingGroup encodingGroupID="EG0">
<ns2:maxGroupBandwidth>600000</ns2:maxGroupBandwidth>
<ns2:encodingIDList>
<ns2:encID>ENC1</ns2:encID>
<ns2:encID>ENC2</ns2:encID>
<ns2:encID>ENC3</ns2:encID>
</ns2:encodingIDList>
</ns2:encodingGroup>
<ns2:encodingGroup encodingGroupID="EG1">
<ns2:maxGroupBandwidth>300000</ns2:maxGroupBandwidth>
<ns2:encodingIDList>
<ns2:encID>ENC4</ns2:encID>
<ns2:encID>ENC5</ns2:encID>
</ns2:encodingIDList>
</ns2:encodingGroup>
</encodingGroups>
<captureScenes>
<ns2:captureScene scale="unknown" sceneID="CS1">
<ns2:sceneViews>
<ns2:sceneView sceneViewID="SE1">
<ns2:description lang="en">participants' individual videos
</ns2:description>
<ns2:mediaCaptureIDs>
<ns2:captureIDREF>VC0</ns2:captureIDREF>
<ns2:captureIDREF>VC1</ns2:captureIDREF>
<ns2:captureIDREF>VC2</ns2:captureIDREF>
</ns2:mediaCaptureIDs>
</ns2:sceneView>
<ns2:sceneView sceneViewID="SE2">
<ns2:description lang="en">loudest segment of the room
</ns2:description>
<ns2:mediaCaptureIDs>
<ns2:captureIDREF>VC3</ns2:captureIDREF>
</ns2:mediaCaptureIDs>
</ns2:sceneView>
<ns2:sceneView sceneViewID="SE5">
<ns2:description lang="en">loudest segment
of the room + pips</ns2:description>
<ns2:mediaCaptureIDs>
<ns2:captureIDREF>VC7</ns2:captureIDREF>
</ns2:mediaCaptureIDs>
</ns2:sceneView>
<ns2:sceneView sceneViewID="SE4">
<ns2:description lang="en">room audio</ns2:description>
<ns2:mediaCaptureIDs>
<ns2:captureIDREF>AC0</ns2:captureIDREF>
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</ns2:mediaCaptureIDs>
</ns2:sceneView>
<ns2:sceneView sceneViewID="SE3">
<ns2:description lang="en">room video</ns2:description>
<ns2:mediaCaptureIDs>
<ns2:captureIDREF>VC4</ns2:captureIDREF>
</ns2:mediaCaptureIDs>
</ns2:sceneView>
</ns2:sceneViews>
</ns2:captureScene>
</captureScenes>
<simultaneousSets>
<ns2:simultaneousSet setID="SS1">
<ns2:mediaCaptureIDREF>VC7</ns2:mediaCaptureIDREF>
<ns2:sceneViewIDREF>SE1</ns2:sceneViewIDREF>
</ns2:simultaneousSet>
<ns2:simultaneousSet setID="SS2">
<ns2:mediaCaptureIDREF>VC0</ns2:mediaCaptureIDREF>
<ns2:mediaCaptureIDREF>VC2</ns2:mediaCaptureIDREF>
<ns2:mediaCaptureIDREF>VC4</ns2:mediaCaptureIDREF>
<ns2:mediaCaptureIDREF>VC7</ns2:mediaCaptureIDREF>
</ns2:simultaneousSet>
</simultaneousSets>
<people>
<ns2:person personID="bob">
<ns2:personInfo>
<ns3:fn>
<ns3:text>Bob</ns3:text>
</ns3:fn>
</ns2:personInfo>
<ns2:personType>minute taker</ns2:personType>
</ns2:person>
<ns2:person personID="alice">
<ns2:personInfo>
<ns3:fn>
<ns3:text>Alice</ns3:text>
</ns3:fn>
</ns2:personInfo>
<ns2:personType>presenter</ns2:personType>
</ns2:person>
<ns2:person personID="ciccio">
<ns2:personInfo>
<ns3:fn>
<ns3:text>Ciccio</ns3:text>
</ns3:fn>
</ns2:personInfo>
<ns2:personType>chairman</ns2:personType>
<ns2:personType>timekeeper</ns2:personType>
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</ns2:person>
</people>
</advertisement>
11. IANA Considerations
This document registers a new XML namespace, a new XML schema and the
MIME type for the schema. This document also registers the "CLUE"
Application Service tag and the "CLUE" Application Protocol tag and
defines registries for the CLUE messages and response codes.
11.1. URN Sub-Namespace Registration
This section registers a new XML namespace,
""urn:ietf:params:xml:ns:clue-protocol"".
URI: urn:ietf:params:xml:ns:clue-protocol
Registrant Contact: IETF CLUE working group (clue@ietf.org), Simon
Pietro Romano (spromano@unina.it).
XML:
BEGIN
<?xml version="1.0"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<title>CLUE Messages</title>
</head>
<body>
<h1>Namespace for CLUE Messages</h1>
<h2>urn:ietf:params:xml:ns:clue-protocol</h2>
[[NOTE TO IANA/RFC-EDITOR: Please update RFC URL and replace XXXX
with the RFC number for this specification.]]
<p>See <a href="[[RFC URL]]">
RFCXXXX</a>.</p>
</body>
</html>
END
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11.2. XML Schema registration
This section registers an XML schema per the guidelines in [RFC3688].
URI: urn:ietf:params:xml:schema:clue-protocol
Registrant Contact: CLUE working group (clue@ietf.org), Simon Pietro
Romano (spromano@unina.it).
Schema: The XML for this schema can be found as the entirety of
Section 9 of this document.
11.3. MIME Media Type Registration for 'application/clue+xml'
This section registers the " "application/clue+xml"" MIME type.
To: ietf-types@iana.org
Subject: Registration of MIME media type application/clue+xml
MIME media type name: application
MIME subtype name: clue+xml
Required parameters: (none)
Optional parameters: charset
Same as the charset parameter of "application/xml" as specified in
[RFC3023], Section 3.2.
Encoding considerations: Same as the encoding considerations of
"application/xml" as specified in [RFC3023], Section 3.2.
Security considerations: This content type is designed to carry
protocol data related to telepresence session control. Some of the
data could be considered private. This media type does not provide
any protection and thus other mechanisms such as those described in
Section Security are required to protect the data. This media type
does not contain executable content.
Interoperability considerations: None.
Published specification: RFC XXXX [[NOTE TO IANA/RFC-EDITOR: Please
replace XXXX with the RFC number for this specification.]]
Applications that use this media type: CLUE participants.
Additional Information: Magic Number(s): (none),
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File extension(s): .clue,
Macintosh File Type Code(s): TEXT.
Person & email address to contact for further information: Simon
Pietro Romano (spromano@unina.it).
Intended usage: LIMITED USE
Author/Change controller: The IETF
Other information: This media type is a specialization of
application/xml [RFC3023], and many of the considerations described
there also apply to application/clue+xml.
11.4. DNS Registrations
Section 11.4.1 defines an Application Service tag of "CLUE", which is
used to identify the CLUE service. The Application Protocol tag
"CLUE", defined in Section 11.4.2, is used to identify a CLUE
Participant that understands CLUE.
11.4.1. Application Service tag
This section registers a new S-NAPTR/U-NAPTR Application Service tag
for CLUE, as mandated by [RFC3958].
Application Service Tag: CLUE
Intended usage: Identifies a server that supports CLUE telepresence
conferencing.
Defining publication: RFCXXXX [[NOTE TO IANA/RFC-EDITOR: Please
replace XXXX with the RFC number for this specification.]]
Contact information: The authors of this document
Author/Change controller: The IESG
11.4.2. Application Protocol tag
This section registers a new S-NAPTR/U-NAPTR Application Protocol tag
for CLUE, as mandated by [RFC3958].
Application Service Tag: CLUE
Intended Usage: Identifies the CLUE Protocol.
Applicable Service Tag(s): CLUE
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Terminal NAPTR Record Type(s): U
Defining Publication: RFC XXXX [[NOTE TO IANA/RFC-EDITOR: Please
replace XXXX with the RFC number for this specification.]]
Contact Information: The authors of this document
Author/Change Controller: The IESG
11.5. CLUE Protocol Registry
The document requests that the IANA creates new registries for CLUE
messages and response codes.
11.5.1. CLUE Message Types
The following summarizes the registry for CLUE messages:
Related Registry: CLUE Message Types Registry
Defining RFC: RFC XXXX [[NOTE TO IANA/RFC-EDITOR: Please replace XXXX
with the RFC number for this specification.]]
Registration/Assignment Procedures: Following the policies outlined
in [RFC5226], the IANA policy for assigning new values for the CLUE
message types for the CLUE protocol is Specification Required.
Registrant Contact: IETF CLUE working group (clue@ietf.org), Simon
Pietro Romano (spromano@unina.it).
The initial Message table is populated using the CLUE messages
described in Section 4 and defined in the XML schema in Section 9.
o OPTIONS
o OPTIONS RESPONSE
o ADVERTISEMENT (ADV)
o ADVERTISEMENT ACKNOWLEDGEMENT (ACK)
o CONFIGURE (CONF)
o CONFIGURE RESPONSE (CONF RESPONSE)
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11.5.2. CLUE Response Codes
The following summarizes the requested registry for CLUE response
codes:
Related Registry: CLUE Response Code Registry
Defining RFC: RFC XXXX [[NOTE TO IANA/RFC-EDITOR: Please replace XXXX
with the RFC number for this specification.]]
Registration/Assignment Procedures: Following the policies outlined
in [RFC5226], the IANA policy for assigning new values for the
Response codes for CLUE shall be Specification Required.
Registrant Contact: IETF CLUE working group (clue@ietf.org), Simon
Pietro Romano (spromano@unina.it).
The initial Response-code table is populated using the Response codes
defined in Section 4.7 as follows:
+-----------------+----------------------+--------------------------+
| | | |
| Response code | Response string | Description |
| | | |
+-----------------+----------------------+--------------------------+
| | | |
| 200 | Success | The request has been |
| | | successfully processed. |
| | | |
+-----------------+----------------------+--------------------------+
| | | |
| 300 | Bad syntax | The XML syntax of the |
| | | message is not |
| | | correct. |
+-----------------+----------------------+--------------------------+
| | | |
| 301 | Invalid value | The message |
| | | contains an invalid |
| | | parameter value. |
+-----------------+----------------------+--------------------------+
| | | |
| 302 | Conflicting values | The message |
| | | contains values that |
| | | cannot be used together.|
+-----------------+----------------------+--------------------------+
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| | | |
| 400 | Version not supported| The protocol version |
| | | used in the message |
| | | is not supported. |
| | | |
+-----------------+----------------------+--------------------------+
| | | |
| 401 | Invalid sequencing | The sequence number of |
| | | the message is out |
| | | of date. |
+-----------------+----------------------+--------------------------+
| | | |
| 402 | Invalid identifier | The identifier used in |
| | | the message is |
| | | not valid or unknown. |
+-----------------+----------------------+--------------------------+
| | | |
| 403 | ADV Expired | The number of the ADV |
| | | the CONF refers to is |
| | | out of date. |
+-----------------+----------------------+--------------------------+
| | | |
| 404 | Subset choice not | The subset choice is not|
| | allowed | allowed for the specified|
| | | MCC |
+-----------------+----------------------+--------------------------+
12. Diff with draft-ietf-clue-protocol-05
o This document corrects some versioning errors of
draft-ietf-clue-protocol-05.
13. Diff with draft-ietf-clue-protocol-04
o The document has been revised based on feedback recevied on the
ML. No major modification is included in this version.
14. Diff with draft-ietf-clue-protocol-03
o Response codes section updated.
o maxCaptureEncodings removed from examples, allowSubsetChoice
added.
o State machines descriptions aligned with pictures.
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o Applied recommended updates indicated in Christian's review (2015-
03-19).
15. Diff with draft-ietf-clue-protocol-02
o CLUE Participant state machine: TERMINATED state replaced with
IDLE.
o MP and MC state machines: SDP O/A state removed.
o Diff mechanism (and related example) removed.
o Schema updates: versionType used as the data type for all versions
fields, xs:unsignedInt used as the data type for all sequence
number fields, diff support removed from the ADV definition.
16. Diff with draft-ietf-clue-protocol-01
o The diff mechanism for the ADV message has been introduced.
o READV and READV RESPONSE message have been both removed.
o The state machines have been deeply reviewed and changed.
o References: references have been updated and splitted into
Informative references and Normative references as in framework
v17.
o Schema: <globalSceneEntries> changed in <globalViews>,
<participants> in <people>
o Terminology: many definitions added.
o Response codes updated.
17. Diff with draft-ietf-clue-protocol-00
1. The XML schema of the ADVERTISEMENT and of the READV have been
aligned with the current definitions in
[I-D.ietf-clue-data-model-schema] (example of updates:
<participants> --> <people>, <globalCaptureEntries> -->
<globalSceneEntries>)
2. Text has been added to clarify that, in the OPTIONS RESPONSE,
when the response code is not an error response code, both
<mediaProvider> and <mediaConsumer> are mandatory.
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3. The content of the "v" attribute and of the <version> elements
carried in the OPTIONS and OPTIONS RESPONSE messages has been
described more precisely.
4. Advertisement examples have been added.
18. Diff with draft-presta-clue-protocol-04
1. The response code type error in the OPTIONS response (and in
other parts) has been corrected.
19. Diff with draft-presta-clue-protocol-03
1. The XML Schema has been deeply revised and completed.
2. The descriptions of the CLUE messages have been added.
3. The distinction between major version numbers and minor version
numbers has been cut and pasted from [I-D.ietf-clue-signaling].
4. Besides the two way one, a three way mechanism for the options
negotiation has been proposed and provided to foster discussion.
20. Diff with draft-presta-clue-protocol-02
1. "Terminology" section added.
2. Introduced the concept of "CLUE Participant" - an Endpoint or a
MCU able to use the CLUE protocol within a telepresence session.
A CLUE Participant can act as a Media Provider and/or as a Media
Consumer.
3. Introduced the ACK/NACK mechanism for the ADVERTISEMENT.
4. MP and MC state machines have been updated. The CP state machine
has been added.
21. Acknowledgments
The authors thank all the CLUErs for their precious feedbacks and
support, in particular Paul Kyzivat, Christian Groves and Scarlett
Liuyan.
22. References
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22.1. Normative References
[I-D.ietf-clue-data-model-schema] Presta, R. and S. Romano, "An XML
Schema for the CLUE data model", d
raft-ietf-clue-data-model-schema-
10 (work in progress), June 2015.
[I-D.ietf-clue-datachannel] Holmberg, C., "CLUE Protocol data
channel",
draft-ietf-clue-datachannel-10
(work in progress),
September 2015.
[I-D.ietf-clue-framework] Duckworth, M., Pepperell, A., and
S. Wenger, "Framework for
Telepresence Multi-Streams",
draft-ietf-clue-framework-23 (work
in progress), September 2015.
[I-D.ietf-clue-signaling] Kyzivat, P., Xiao, L., Groves, C.,
and R. Hansen, "CLUE Signaling",
draft-ietf-clue-signaling-06 (work
in progress), August 2015.
[RFC3023] Murata, M., St. Laurent, S., and
D. Kohn, "XML Media Types",
RFC 3023, DOI 10.17487/RFC3023,
January 2001, <http://
www.rfc-editor.org/info/rfc3023>.
[RFC3550] Schulzrinne, H., Casner, S.,
Frederick, R., and V. Jacobson,
"RTP: A Transport Protocol for
Real-Time Applications", STD 64,
RFC 3550, DOI 10.17487/RFC3550,
July 2003, <http://
www.rfc-editor.org/info/rfc3550>.
[RFC3688] Mealling, M., "The IETF XML
Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688,
January 2004, <http://
www.rfc-editor.org/info/rfc3688>.
[RFC3958] Daigle, L. and A. Newton, "Domain-
Based Application Service Location
Using SRV RRs and the Dynamic
Delegation Discovery Service
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(DDDS)", RFC 3958, DOI 10.17487/
RFC3958, January 2005, <http://
www.rfc-editor.org/info/rfc3958>.
[RFC5226] Narten, T. and H. Alvestrand,
"Guidelines for Writing an IANA
Considerations Section in RFCs",
BCP 26, RFC 5226, DOI 10.17487/
RFC5226, May 2008, <http://
www.rfc-editor.org/info/rfc5226>.
22.2. Informative References
[RFC4353] Rosenberg, J., "A Framework for
Conferencing with the Session
Initiation Protocol (SIP)",
RFC 4353, DOI 10.17487/RFC4353,
February 2006, <http://
www.rfc-editor.org/info/rfc4353>.
[RFC5117] Westerlund, M. and S. Wenger, "RTP
Topologies", RFC 5117,
DOI 10.17487/RFC5117,
January 2008, <http://
www.rfc-editor.org/info/rfc5117>.
[RFC6120] Saint-Andre, P., "Extensible
Messaging and Presence Protocol
(XMPP): Core", RFC 6120,
DOI 10.17487/RFC6120, March 2011,
<http://www.rfc-editor.org/info/
rfc6120>.
[RFC6502] Camarillo, G., Srinivasan, S.,
Even, R., and J. Urpalainen,
"Conference Event Package Data
Format Extension for Centralized
Conferencing (XCON)", RFC 6502,
DOI 10.17487/RFC6502, March 2012,
<http://www.rfc-editor.org/info/
rfc6502>.
[RFC6503] Barnes, M., Boulton, C., Romano,
S., and H. Schulzrinne,
"Centralized Conferencing
Manipulation Protocol", RFC 6503,
DOI 10.17487/RFC6503, March 2012,
<http://www.rfc-editor.org/info/
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rfc6503>.
[RFC7262] Romanow, A., Botzko, S., and M.
Barnes, "Requirements for
Telepresence Multistreams",
RFC 7262, DOI 10.17487/RFC7262,
June 2014, <http://
www.rfc-editor.org/info/rfc7262>.
Authors' Addresses
Roberta Presta
University of Napoli
Via Claudio 21
Napoli 80125
Italy
EMail: roberta.presta@unina.it
Simon Pietro Romano
University of Napoli
Via Claudio 21
Napoli 80125
Italy
EMail: spromano@unina.it
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