1、 STDDITU-T RECMN F.702-ENGL 199b = Li8b259L Ob25911 713 I NTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU F.702 (07196) SERIES F: NON-TELEPHONE TELECOMMUNICATION SERVICES Audiovisual services Multimedia conference services ITU-T Recommendation E702 (Previou
2、sly “CCITT Recommendation”) ITU-T F-SERIES RECOMMENDATIONS NON-TELEPHONE TELECOMMUNICATION SERVICES TELEGRAPH SERVICE Operating methods for the international public telegram service The gentex network Message switching The international telemessage service The international telex service Statistics
3、and publications on international telegraph services Scheduled and leased communication services Phototelegraph service Mobile services and multidestination satellite services MOBILE SERVICE TELEMATIC SERVICES Public facsimile service Teletex service Videotex service General provisions for telematic
4、 services MESSAGE HANDLING SERVICES DIRECTORY SERVICES DOCUMENT COMMUNICATION Document communication Programming communication interfaces DATA TRANSMISSION SERVICES F.1-F.109 F. l-F. 19 F.20-F.29 F.30-F.39 F.40-F.58 F.59-F.89 F.90-F.99 F. 1 OO-F. 104 F.105-F.109 F. 1 10-F. 159 F.110-F.159 F. 160-F.3
5、99 F. 160-F. 199 F.200-F.299 F.300-F.349 F.350-F.399 F.400-F.499 F.500-F.549 F.550-F.599 F.550-F.579 F.580-F.599 F.600-F.699 AUDIOVISUAL SERVICES F.700-F.799 ISDN SERVICES F.800-F.849 UNIVERSAL PERSONAL TELECOMMUNICATION HUMAN FACTORS F.850-F.899 F.900-F.999 For further details, please refer to ITU-
6、T List of Recommendations. - STD*ITU-T RECMN F-702-ENGL L77b 48b2571 Ob25713 59b FOREWORD The ITU-T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (ITLJ). The ITU-T is responsible for studying technical, operating and tariff questions and
7、 issuing Recommen- dations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendatio
8、ns on these topics. The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12, 1993). IT-T Recommendation F.702 was prepared by ITU-T Study Group 1 (1993-1996) and was approved under the WTSC Resolution No. 1 proc
9、edure on the 19th of July 1996. NOTE In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. O ITU 1997 All rights reserved. No part of this publication may be reproduced or utilized in any
10、 form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing fi-om the ITU. Recommendation F.702 (07/96) i 1 2 3 4 5 6 7 11 CONTENTS Introduction Definition . References and terminology . 3.1 References . 3.2 Terminology . Description . 4.1 Gen
11、eral description . 4.3 Configuration Roles of the participants 4.5 Terminal aspects . 4.6 Applications 4.7 Supplementary services Static aspects General aspects of the service . 4.2 Functional model 4.4 5.1 Service level 5.1.1 5.1.2 Quality of service 5.1.3 Security aspects . 5.1.4 General charging
12、principles 5.2 Communication task level . 5.2.1 Communication tasks used for the service 5.2.2 Quality of service 5.3 Media component level . 5.3.1 5.3.2 Quality of service Dynamic aspects . 6.1 Activation phase . 6.1.1 Provision, withdrawal . 6.1.2 Call establishment . 6.1.3 Reservation 6.1.4 On de
13、mand 6.2 Communication phase . Media components used for the service 6.2.1 Call Set-up . Addition of another party during the call 6.2.3 Conference splitting Call prolongation in the case of reservation 6.2.2 6.2.4 Change of communication mode 6.2.5 6.2.6 Terminal disconnection . 6.2.7 Conference ma
14、nagement procedures 6.3 Termination phase . 6.3.1 Call termination . Service profiles . 7.1 7.2 List of service profiles Different types of multimedia conference services . Recommendation F.702 (0796) Page 1 1 1 1 2 2 2 3 4 5 7 8 8 8 8 8 8 10 10 10 10 10 11 11 11 12 12 12 12 12 13 13 13 13 14 14 14
15、15 15 16 16 17 17 17 . 8 Interworking and intercommunication . Interworkingintercommunication between two terminals . Different types of audiographic conference terminals Audiographic conference and videoconference terminals 8.1 General 8.2 8.2.1 8.2.2 8.2.3 8.2.4 Different types of videoconference
16、terminals . CDH and other types of terminals . 8.3 Interworkingintercommunication between several terminals 8.3.1 8.3.2 8.3.3 8.3.4 Different types of multimedia conference terminals . Videophone and other multimedia conference terminals, multimedia conference and Addition of a telephone terminal .
17、Communication with a facsimile terminal videophone terminals Annex A . Multipoint Conference Units (MCUs) A.l General A.2 Call control functions A.3 Conference control functions A.4 Handling the various media components AS Distributed MCU functions . A.6 Ports and interfaces . A.7 Interworkinginterc
18、ommunication Appendix I - Control of multiple windows . 1.1 General 1.2 Starting, stopping and organizing multiple windowing 1.3 Selection of the windows contents Page 19 19 19 19 19 19 19 19 19 20 20 20 20 20 22 22 23 23 25 25 25 25 25 25 . Recommendation F.702 (07196) 111 Recommendation F.702 MULT
19、IMEDIA CONFERENCE SERVICES (Geneva, 1996) 1 Introduction The purpose of this Recommendation is to define the generic multimedia conference service and to describe their general features, regardless of the network environment in which these services are provided. These services allow conversational c
20、ommunication between several users in two or more locations, The generic multimedia conference service is one of the generic service types identified in Recommendation F.700, and its description follows the methodology described therein. The user requirements for the various applications supported b
21、y the service are translated into generic service specifications, independent of the constraints of specific implementations. Thus this Recommendation sets out the requirements that will satis the users needs and allow proper intercommunication on an international basis of services offered by differ
22、ent providers and of equipment from different manufacturers. Various instances (profiles) of this generic service are considered here with a network independent view. Specific service descriptions for each network will be issued in other Recommendations. The detailed technical specifications of the
23、terminal, network and protocol aspects for each of them are described in dedicated Recommendations of the H.200-, H.300-, H.400-Series, and of the T. 120-Series for specific multipoint protocols. Along with the F.700 methodology, the description relies on the media components and the communication t
24、asks described respectively in Annex AF.700 and Annex BF.700. These are service independent modular communication capabilities. 2 Definition The multimedia conference services provide real-time transmission of voice together with motion video andor various types of multimedia information between gro
25、ups of users in two or more locations. The documents exchanged may contain all information types. When moving pictures are present, their quality must be at least sufficient for the adequate representation of the fluid movements of a small group of participants. The media components used are describ
26、ed in Annex AF.700 on audiovisualmultimedia services. Media component audio (A.lm.700) is mandatory, and one or more of the media components video (A.2.700), text (A.3/F.700), graphics (A.4F.700) and still pictures (A.YF.700) should be present. 3 References and terminology The following Recommendati
27、ons 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 revision: all users of this Recommendation are there
28、fore 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. 3.1 References - ITU-T Recommendation F.700 (1996), Framework Recommendation for au
29、diovisual/multimedia services. - ITU-T Recommendation G.114 (1996), One-way transmission time. - CCITT Recommendation G.711 (1988), Pulse Code Modulation (PCM) of voicefrequencies. - CCITT Recommendation G.722. (1988), 7 kHz audio-coding within 64 kbit/s. - ITU-T Recommendation T. 120 (1 996), Data
30、protocols for multimedia conferencing. Recommendation F.702 (07/96) 1 3.2 Terminology For the purposes of this Recommendation, the following definitions apply. 3.2.1 audiographic conference service: An international service, offered by Administrations, enabling participants to conduct a real-time mu
31、ltimedia conference in which audio signals are exchanged together with non-voice graphics information, without motion video. 3.2.2 chairman: The user who chairs the meeting and manages the conference. 3.2.3 collaborative document handling service (CDH): A service that provides bidirectional transfer
32、 of data between two or more locations so that users are able to work on a common document, for drafting or amending it collectively. 3.2.4 communication modes: A communication mode is defined by the various channels supporting the media used for the conference. Changes in communication mode may occ
33、ur during the course of the conference, in order to set up or eliminate one of the media, or to change its quality level and thus the bit-rate allocation. It may be used for instance to temporarily add a channel for transmitting still pictures. 3.2.5 conference controller: The user who manages the c
34、all during the conference. 3.2.6 conference convener: The user who has organized the conference. 3.2.7 conference room: In this Recommendation, the expression, conference room, refers to any location where a multimedia conference terminal is located. This may be a specially prepared group conference
35、 facility or an individual desktop terminal. 3.2.8 conference rooms. multipoint conference unit (MCU): Equipment that provides multipoint connections among three or more 3.2.9 muting: Preventing sound to be transmitted from a terminal equipment. 3.2.10 presenter: The participant in a conference who
36、controls the visual information being actively discussed. 3.2.1 1 videoconference service: An audiovisual conversational conference service providing bidirectional real-time transfer of voice and motion video between groups of users in two or more separate locations. Although the audio and motion vi
37、deo information are the essential part of the service, other types of information, such as high resolution still pictures, text or graphics may also be exchanged. 3.2.12 videophone service: An audiovisual conversational service providing bidirectional symmetric real-time transfer of voice and motion
38、 video between two locations. The minimum requirement is that under normal conditions the picture information transmitted is sufficient for the adequate representation of fluid movements of a person displayed in head and shoulders view. 4 Description 4.1 General description A multimedia conference s
39、ervice provides real-time communication between several users in different locations, combining a good audio facility with motion video of participants and/or transmission of multimedia information. The service is applicable to companies private conference rooms as well as to public-access conferenc
40、e rooms for hire on an occasional basis. It is applicable to a variety of types of multimedia conference terminals such as: - - - dedicated studios equipped for multimedia conferences; multipurpose meeting rooms used only part-time for teleconferencing; portable or roll-about equipment which can be
41、moved fi-om one room to another to provide temporary service; terminal equipment for individual participants, e.g. microcomputer based terminals. - 2 Recommendation F.702 (07/96) The service is bidirectional via telecommunication networks, and provides for interconnection of two or more multimedia c
42、onference terminals on an equal basis. Other types of terminals may be added to the conference, such as videotelephones or even plain telephones; although they will usually have some limitations on the capability to send and receive all the different types of information used in a multimedia confere
43、nce call, they will at least be able to exchange speech allowing their users to take part in the discussion; this is described in clause 8 on intercommunication. When the conference includes more than two terminals, a Multipoint Conference Unit (MCU) is usually required. Ali locations are connected
44、individually to an MCU which elaborates a selection or the appropriate combination of these signals for each of the locations, and manages the signalling and the optional channels. Multimedia conference services are essentially built around the communication task conferencing described in B.2E.700.
45、Other communication tasks (receiving and sending) are optional. 4.2 Functional model In a multimedia conference, two or more terminals exchange multimedia information through an interconnection system, under the control of a control unit (Figure 1). The interconnection system includes equipment for
46、switching andor combining the information from the different terminals and one or several networks. User information Control signals (call control and conference control) - NOTE - The physical boundaries of equipment are independent from the functional boundaries shown on the figure. For instance an
47、 MCU usually includes a control unit and other units, dedicated to the various media components, which perform switching andor combining actions and functionally belong to the interconnection system. In the special case where there are only two terminals, they are connected point-to-point and a cont
48、rol unit is not needed. FIGURE 1E.702 Functional model Recommendation F.702 (07/96) 3 4.3 Configuration The configuration may be point-to-point between two multimedia conference rooms, or multipoint-to-multipoint between several. In the latter case the terminals are usually connected through one or
49、more Multipoint Conference Units (MCUs). The MCUs have to fulfill three functions: a) b) c) managing the call, setting up and closing the connections; managing the conference, through control and indication signals exchanged with the terminals; handling the signals received and sent on each connection, switching, distributing, multiplexing and when necessary adapting and combining them as appropriate. Types of configurations The multipoint configurations can be subdivided into: - multichannel multipoint; - shared channel multipoint; - switched multipoint. I
