1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T H.420 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (10/2014) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMS Infrastructure of audiovisual services Telepresence Telepresence system architecture Recommendation ITU-T H.420 IT
2、U-T H-SERIES RECOMMENDATIONS AUDIOVISUAL AND MULTIMEDIA SYSTEMS CHARACTERISTICS OF VISUAL TELEPHONE SYSTEMS H.100H.199 INFRASTRUCTURE OF AUDIOVISUAL SERVICES General H.200H.219 Transmission multiplexing and synchronization H.220H.229 Systems aspects H.230H.239 Communication procedures H.240H.259 Cod
3、ing of moving video H.260H.279 Related systems aspects H.280H.299 Systems and terminal equipment for audiovisual services H.300H.349 Directory services architecture for audiovisual and multimedia services H.350H.359 Quality of service architecture for audiovisual and multimedia services H.360H.369 T
4、elepresence H.420H.429 Supplementary services for multimedia H.450H.499 MOBILITY AND COLLABORATION PROCEDURES Overview of Mobility and Collaboration, definitions, protocols and procedures H.500H.509 Mobility for H-Series multimedia systems and services H.510H.519 Mobile multimedia collaboration appl
5、ications and services H.520H.529 Security for mobile multimedia systems and services H.530H.539 Security for mobile multimedia collaboration applications and services H.540H.549 Mobility interworking procedures H.550H.559 Mobile multimedia collaboration inter-working procedures H.560H.569 BROADBAND,
6、 TRIPLE-PLAY AND ADVANCED MULTIMEDIA SERVICES Broadband multimedia services over VDSL H.610H.619 Advanced multimedia services and applications H.620H.629 Ubiquitous sensor network applications and Internet of Things H.640H.649 IPTV MULTIMEDIA SERVICES AND APPLICATIONS FOR IPTV General aspects H.700H
7、.719 IPTV terminal devices H.720H.729 IPTV middleware H.730H.739 IPTV application event handling H.740H.749 IPTV metadata H.750H.759 IPTV multimedia application frameworks H.760H.769 IPTV service discovery up to consumption H.770H.779 Digital Signage H.780H.789 E-HEALTH MULTIMEDIA SERVICES AND APPLI
8、CATIONS Interoperability compliance testing of personal health systems (HRN, PAN, LAN and WAN) H.820H.859 Multimedia ehealth data exchange services H.860H.869 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T H.420 (10/2014) i Recommendation ITU-T H.420 Telepresence
9、system architecture Summary Recommendation ITU-T H.420 describes a high-level telepresence system architecture. It describes subsystem components: telepresence endpoints, multipoint control units, call and resource controllers, gateways, management systems and how these are used in a communication s
10、ession to provide telepresence. It also provides guidance on telepresence room design in terms of room layout and room characteristics. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T H.420 2014-10-14 16 11.1002/1000/12245 _ * To access the Recommendation, type the URL http:
11、/handle.itu.int/ in the address field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T H.420 (10/2014) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field
12、of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing
13、 telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by
14、 the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate bo
15、th a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when
16、 all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY
17、 RIGHTSITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by
18、 ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that th
19、is may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2015 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU
20、-T H.420 (10/2014) iii Table of Contents Page 1 Scope . 1 2 References . 1 3 Definitions 1 3.1 Terms defined elsewhere 1 3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 2 5 Conventions 3 5.1 Requirement terminology . 3 5.2 Icons used . 4 6 High level architecture 5 6.1 Desc
21、ription of subsystem components . 6 7 Conference control functions 9 7.1 Media control functions 10 7.2 Meeting arrangement 12 7.3 Endpoint management 12 8 Subsystem architectures 13 8.1 Endpoint architecture 13 8.2 Multipoint control unit . 18 8.3 Call and resource controller 19 8.4 Gateway 19 9 IT
22、U-T H.323 architecture . 19 9.1 Mapping telepresence to ITU-T H.323 architecture . 19 9.2 Call process 22 10 Telepresence room design 23 10.1 Room layouts 23 10.2 Room characteristics 28 Rec. ITU-T H.420 (10/2014) 1 Recommendation ITU-T H.420 Telepresence system architecture 1 Scope This Recommendat
23、ion first describes a telepresence system in a high-level technology agnostic manner taking into consideration the use cases and requirements defined in ITU-T F.734. This is then followed by a more in depth description of the components. The latter parts of this Recommendation then describe how ITU-
24、T H.323 relates to a telepresence system. It then details aspects regarding the telepresence room design. Unless explicitly stated in the text, the interfaces depicted in the figures and functions in this Recommendation are logical and thus do not necessarily represent a particular physical implemen
25、tation. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to
26、 revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within
27、 this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T F.734 Recommendation ITU-T F.734 (2014), Definitions, requirements and use cases for telepresence systems. ITU-T H.243 Recommendation ITU-T H.243 (2005), Procedures for establishing communication
28、between three or more audiovisual terminals using digital channels up to 1920 kbit/s. ITU-T H.245 Recommendation ITU-T H.245 (2011), Control protocol for multimedia communication. ITU-T H.320 Recommendation ITU-T H.320 (2004), Narrow-band visual telephone systems and terminal equipment. ITU-T H.323
29、Recommendation ITU-T H.323 (2009), Packet-based multimedia communications systems. ISO 8995-1 ISO 8995-1 (2002), Lighting of work places Part 1: Indoor, including its Technical Corrigendum 1(2005). 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhe
30、re: 3.1.1 audio mixing b-IETF RFC 7262: Refers to the accumulation of scaled audio signals to produce a single audio stream. See b-IETF RFC 5117. 3.1.2 layout b-IETF RFC 7262: How rendered media streams are spatially arranged with respect to each other on a telepresence endpoint with a single screen
31、 and a single loudspeaker, and how rendered media streams are arranged with respect to each other on a telepresence endpoint with multiple screens or loudspeakers. 2 Rec. ITU-T H.420 (10/2014) NOTE Audio as well as video is encompassed by the term layout in other words, included is the placement of
32、audio streams on speakers as well as video streams on video screens. 3.1.3 remote b-IETF RFC 7262: Sender and/or receiver on the other side of the communication channel (depending on context); i.e., not local. A remote can be an endpoint or an MCU. 3.1.4 render b-IETF RFC 7262: The process of genera
33、ting a representation from a media, such as displayed motion video or sound emitted from loudspeakers. 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 endpoint: For the purposes of this Recommendation, an endpoint is a device representing the logical p
34、oint of final termination through receiving, decoding and rendering and/or point of origin through capturing, encoding and sending of media streams, e.g., an ITU-T H.323 terminal. 3.2.2 telepresence media codec: This term (and function) is used to describe any media (i.e., audio or video) codec that
35、 would be applicable for use in a telepresence system. 3.2.3 telepresence system: A set of functions, devices and network elements which are able to capture, deliver, manage and render multiple high quality interactive audio and video signals in a telepresence conference. An appropriate number of de
36、vices (e.g., cameras, screens, loudspeakers, microphones, codecs, multipoint control units (MCUs), personal computers (PCs) and environmental characteristics are used to establish telepresence. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: ACU Audio
37、Capture Unit ARU Audio Render Unit CCA Chair-control Command Acquire CCD Chair-control Command Disconnect CCK Chair-control Command Kill CCR Chair-control Command Release/Refuse CRC Call and Resource Controller GK Gatekeeper GW Gateway HDTV High Definition Television HVAC Heating, Ventilation and Ai
38、r Conditioning IP Internet Protocol ISDN Integrated Services Digital Network IU Interactive Unit LAN Local Area Network LCD Liquid Crystal Display MCU Multipoint Control Unit MCV Multipoint Command Visualization-forcing NAT Network Address Translation Rec. ITU-T H.420 (10/2014) 3 NU Network Unit PC
39、Personal Computer PDP Plasma Display Panel PLMN Public Land Mobile Network PSTN Public Switched Telephone Network QoE Quality of Experience QoS Quality of Service RAS Registration, Admission and Status RTCP RTP Control Protocol RTP Real-Time Protocol SIP Session Initiation Protocol TCU Telepresence
40、Control Unit TMC Telepresence Media Codec TMIO Telepresence Media Input/Output TMP Telepresence Media Processor VCB Video Command Broadcast VCU Video Capture Unit VRU Video Render Unit WAN Wide Area Network 5 Conventions 5.1 Requirement terminology In this Recommendation, the following conventions a
41、re used: “Shall“ indicates a mandatory requirement. “Should“ indicates a suggested but optional course of action. “May“ indicates an optional course of action rather than a recommendation that something takes place. 4 Rec. ITU-T H.420 (10/2014) 5.2 Icons used Figure 1 shows the meaning of icons used
42、 in this Recommendation. Figure 1 Icons used in this Recommendation Rec. ITU-T H.420 (10/2014) 5 6 High level architecture Figure 2 High-level telepresence architecture network model Figure 2 shows a high-level telepresence architecture including: telepresence endpoints, legacy video conferencing en
43、dpoints, legacy audio endpoints, legacy non-ITU-T H.323 endpoints including ITU-T H.320 and session initiation protocol (SIP) endpoints, multipoint control units (MCUs), call and resource controllers (CRCs), gateways (GWs), the management system, etc. There may be multiple forms of telepresence endp
44、oints, such as three-screen endpoints and single-screen endpoints. The architecture supports inter-operation of heterogeneous telepresence endpoints and inter-operation between telepresence endpoints and legacy video conferencing and audio endpoints. There may be multiple MCUs and CRCs in the archit
45、ecture. The architecture may have multiple GWs that connect to other types of networks, such as fixed and mobile telephone networks. 6 Rec. ITU-T H.420 (10/2014) 6.1 Description of subsystem components A telepresence system is made up of several functional components. These components are illustrate
46、d in Figure 3. Figure 3 Telepresence system functional components Figure 3 shows telepresence system functional components and the call control and media interfaces between them. All interfaces are assumed to be bidirectional. There may be multiple instantiations of the components. In this case, the
47、re may also be additional call control or media interfaces between them. For example, there may be a call control interface between call and resource controllers. The exception is the management system. Whilst there may be multiple systems, this is treated as a monolithic system in this architecture
48、. The interfaces are numbered according to Tables 1 to 3. The possible call control interfaces are illustrated in Table 1. The possible management interfaces are illustrated in Table 2. The possible media interfaces are illustrated in Table 3. Table 1 Telepresence system call control interfaces Inte
49、rface Interface defined between Component at one side Component at the other side C1 Telepresence endpoint Call and resource controller C2 Telepresence endpoint MCU C3 Telepresence endpoint Gateway C4 Telepresence endpoint Legacy endpoint C5 Telepresence endpoint Telepresence endpoint C6 Legacy endpoint Call and resource controller C7 Legacy endpoint MCU C8 Legacy endpoint Gateway C9 Legacy endpoint Legacy endpoint C10 Call and resource controller MCU Rec. ITU-T H.420
