1、 International Telecommunication Union ITU-T F.742TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (09/2005) SERIES F: NON-TELEPHONE TELECOMMUNICATION SERVICES Audiovisual services Service description and requirements for distance learning services ITU-T Recommendation F.742 ITU-T F-SERIES RECOMMENDA
2、TIONS NON-TELEPHONE TELECOMMUNICATION SERVICES TELEGRAPH SERVICE Operating methods for the international public telegram service F.1F.19 The gentex network F.20F.29 Message switching F.30F.39 The international telemessage service F.40F.58 The international telex service F.59F.89 Statistics and publi
3、cations on international telegraph services F.90F.99 Scheduled and leased communication services F.100F.104 Phototelegraph service F.105F.109 MOBILE SERVICE Mobile services and multidestination satellite services F.110F.159 TELEMATIC SERVICES Public facsimile service F.160F.199 Teletex service F.200
4、F.299 Videotex service F.300F.349 General provisions for telematic services F.350F.399 MESSAGE HANDLING SERVICES F.400F.499DIRECTORY SERVICES F.500F.549 DOCUMENT COMMUNICATION Document communication F.550F.579 Programming communication interfaces F.580F.599 DATA TRANSMISSION SERVICES F.600F.699 AUDI
5、OVISUAL SERVICES F.700F.799 ISDN SERVICES F.800F.849 UNIVERSAL PERSONAL TELECOMMUNICATION F.850F.899 HUMAN FACTORS F.900F.999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. F.742 (09/2005) i ITU-T Recommendation F.742 Service description and requirements for dista
6、nce learning services Summary Following the methodology defined in ITU-T Rec. F.701, this Recommendation provides the service description and requirements for distance learning services. This Recommendation is intended to support the multimedia framework for distance learning services. Source ITU-T
7、Recommendation F.742 was approved on 13 September 2005 by ITU-T Study Group 16 (2005-2008) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. F.742 (09/2005) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications.
8、 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 telecommunications on a worldwide basis. The World Telecommunication Sta
9、ndardization 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 the procedure laid down in WTSA Resolution 1. In some areas of informati
10、on 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 both a telecommunication administration and a recognized operating agency.
11、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 all of these mandatory provisions are met. The words “shall“ or some other
12、 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 RIGHTS ITU draws attention to the possibility that the practice or impleme
13、ntation 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 ITU members or others outside of the Recommendation development process.
14、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, implementors are cautioned that this may not represent the latest information and are therefore strongly urg
15、ed to consult the TSB patent database. ITU 2005 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. F.742 (09/2005) iii CONTENTS Page 1 Scope 1 2 References. 1 2.1 Normative references 1 2.2 Informative
16、references 1 3 Definitions 1 4 Abbreviations 3 5 Conventions 4 6 Prose description. 4 7 The functional model of distance learning services . 4 8 Applications 5 8.1 Consumer/residential applications 5 8.2 Business/institutional applications . 6 9 Application scenarios 7 9.1 Real-time distance learnin
17、g applications 7 9.2 Non-real-time distance learning applications. 9 10 Requirements 9 10.1 General requirements 9 10.2 Requirements of users 10 10.3 Naming-related requirements . 11 10.4 Navigation-related requirements 11 10.5 Synchronization/display-related requirements . 11 10.6 Security authenti
18、cation-related requirements . 11 10.7 DRM-related requirements. 11 10.8 Accounting-related requirements . 11 10.9 QoS-related requirements. 11 11 Implementation notes . 11 ITU-T Rec. F.742 (09/2005) 1 ITU-T Recommendation F.742 Service description and requirements for distance learning services 1 Sc
19、ope This Recommendation provides the service description and the requirements for distance learning services. This Recommendation is intended to support the multimedia framework for distance learning services. 2 References The following ITU-T Recommendations and other references contain provisions w
20、hich, 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; users of this Recommendation are therefore encouraged to investigate the possibility of
21、 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 this Recommendation does not give it, as a stand-alone document, the status of a Recommendation.
22、2.1 Normative references None. 2.2 Informative references ITU-T Recommendation F.700 (2000), Framework Recommendation for multimedia services. ITU-T Recommendation F.701 (2000), Guideline Recommendation for identifying multimedia service requirements. ITU-T Recommendation F.702 (1996), Multimedia co
23、nference services. ITU-T Recommendation F.740 (1993), Audiovisual interactive services. ITU-T Recommendation F.750 (2005), Metadata framework. ITU-T H-series Recommendations Supplement 1 (1999), Application profile Sign language and lip-reading real-time conversation using low bit-rate video communi
24、cation. IEEE 1484.1 (2003), Learning Technology Systems Architecture (LTSA) Architecture and Reference Model. 3 Definitions This Recommendation defines the following terms: Terms defined in ITU-T Recs F.700, F.701 and H.323 are used in this Recommendation and listed in this clause for the readers co
25、nvenience. 3.1 ad hoc multipoint conference: An ad hoc multipoint conference is a point-to-point conference that is expanded into a multipoint conference at some time during the call. This can be done if one or more of the terminals in the initial point-to-point conference contain a Multipoint Contr
26、oller (MC), if the call is made using a Gatekeeper that includes MC functionality, or if the initial call is made through an MCU as a multipoint call between only two terminals. 3.2 audiovisual multicasting: When users request the same content at the same time, the audiovisual on-demand services pla
27、tform list them in the same multicasting group. The system 2 ITU-T Rec. F.742 (09/2005) sends the requested content media streaming to that multicasting group address, then the users within the same group may receive the same requested content. 3.3 audiovisual on-demand: A kind of network-delivered
28、service that offers the functionality of the home VCR (as play only) without having to get a copy of the chosen material. 3.4 broadcast conference: A broadcast conference is one in which there is one transmitter of media streams and many receivers. There is no bidirectional transmission of control o
29、r media streams. Such conferences may be implemented using network transport multicast facilities, if available. 3.5 broadcast panel conference: A broadcast panel conference is a combination of a multipoint conference and a broadcast conference. In this conference, several terminals are engaged in a
30、 multipoint conference, while many other terminals are only receiving the media streams. There is bidirectional transmission between the terminals in the multipoint portion of the conference and no bidirectional transmission between them and the listening terminals. 3.6 centralized multipoint confer
31、ence: A centralized multipoint conference is one in which all participating terminals communicate in a point-to-point fashion with an MCU. The terminals transmit their control, audio, video, and/or data streams to the MCU. The MC within the MCU centrally manages the conference. The Multipoint Proces
32、sor (MP) within the MCU processes the audio, video, and/or data streams and returns the processed streams to each terminal. 3.7 decentralized multipoint conference: A decentralized multipoint conference is one in which the participating terminals multicast their audio and video to all other particip
33、ating terminals without using an MCU. The terminals are responsible for: a) Summing the received audio streams; and b) Selecting one or more of the received video streams for display. No audio or video MP is required in this case. The terminals communicate on their H.245 Control Channels with an MC
34、that manages the conference. The data stream is still centrally processed by the Multipoint Communication System (MCS)-MCU that may be within an MP. 3.8 distance learning: Learning experiences and environments distributed over space and time (asynchronous learning). In this Recommendation, it refers
35、 to distance learning using telecommunication services over telecommunication networks. 3.9 distance learning services platform (DLSP): A collection of multimedia service systems with an integrated management system, an integrated authentication, authorization and accounting system to support part o
36、r all kinds of distance learning services. 3.10 hybrid multipoint conference centralized audio: A hybrid multipoint centralized audio conference is one in which terminals multicast their video to other participating terminals and unicast their audio to the MP for mixing. The MP returns a mixed audio
37、 stream to each terminal. 3.11 hybrid multipoint conference centralized video: A hybrid multipoint centralized videoconference is one in which terminals multicast their audio to other participating terminals and unicast their video to the MP for switching or mixing. The MP returns a video stream to
38、each terminal. 3.12 individual instruction: A form of distance learning in which a teacher (or another learner) explains or answers the questions asked by a learner located at a different place through telecommunication networks. 3.13 mixed multipoint conference: A mixed multipoint conference (see F
39、igure 1) has some terminals (D, E and F) participating in a centralized mode while other terminals (A, B and C) are participating in a decentralized mode. A terminal is not aware of the mixed nature of the ITU-T Rec. F.742 (09/2005) 3 conference, only of the type of conference it is participating in
40、. The MCU provides the bridge between the two types of conferences. Figure 1/F.742 Mixed multipoint conference 3.14 multimedia services: Multimedia services are telecommunication services that handle two or more types of media in a synchronized way from the users point of view. A multimedia service
41、may involve multiple parties, multiple connections, and the addition or deletion of resources and users within a single communication session. 3.15 multi-role learning/team learning: Learners (of the collective learner entity) operating as a team in which learners have different roles. 3.16 self-pac
42、ing learning: A form of distance learning in which learners find a solution to a question given by a teacher, or others, by searching information related to the question from learning resources, analysing the information and giving solutions to the question with or without the help of others. 3.17 t
43、eaching-centred: A form of distance learning in which the main role is a teacher. Learners located at separate places learn by listening to or watching the courses given by the teacher with or without interaction between the learners and the teacher during the course. 3.18 videoconference service: A
44、n audiovisual conference service providing bidirectional real-time transfer of voice, motion video and real-time text between groups of users in two or more separate locations. Although the audio and motion video information are the essential part of the service, other types of information, such as
45、high resolution still pictures or graphics may also be exchanged. 3.19 videophone service: An audiovisual conversational service providing bidirectional symmetric real-time transfer of voice, motion video and real-time text between two locations. The minimum requirement is that, under normal conditi
46、ons, the picture information transmitted is sufficient for the adequate representation of fluid movement of a person displayed in head and shoulder view. 4 Abbreviations This Recommendation uses the following abbreviations: AVoD Audiovisual on-Demand BBS Bulletin Board System DL Distance Learning DL
47、SP Distance Learning Services Platform 4 ITU-T Rec. F.742 (09/2005) DRM Digital Right Management MCU Multipoint Control Unit PC Personal Computer PDA Personal Digital Assistance PSTN Public Switched Telephone Network STU Set Top Unit TV Television 5 Conventions In this Recommendation, the following
48、conventions are 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 take place. 6 Prose description Distance learning involves interactive and non-inter
49、active multimedia communications between learners and learning resources located at two or more separate locations. The aims of learners who use distance learning services may be to get some degree certificates based on the degree standards, to get training given by employers, or to learn special knowledge independently. The distance learning services may be teaching-centred learning services that are similar to traditional face-to-face classroom learning, individual instruction, self-pacing learning, multi-role learning/team learn
