1、INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU T.136 (05/99) SERIES T: TERMINALS FOR TELEMATIC SERVICES Remote device control application protocol ITU-T Recommendation T. 136 (Previously CCITT Recommendation) STDmITU-T RECMN TeL36-ENGL L999 m 4862591 O664
2、226 583 W ITU-T RECOMMENDATION T.136 REMOTE DEVICE CONTROL APPLICATION PROTOCOL Summary This Recommendation describes how remote device control may be performed using Recommendation T. 120 as the transport protocol. The core remote device control services and protocol are described in a separate Rec
3、ommendation H.282. This Recommendation explains how Recommendation H.282 may be used in a T. 120 environment. Source ITU-T Recommendation T.136 was prepared by ITU-T Study Group 16 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 27th of May 1999. Recommendation T.136 (0
4、999) 1 4862592 Obb4227 4LT - FOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in he field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, ope
5、rating and tariff questions and issuing Recommendations 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 thei
6、r turn, produce Recommendations 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. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborati
7、ve basis with IS0 and IEC. NOTE In this Recommendation the term recognized operating agency (ROA) includes any individual, company, corporation or governmental organization that operates a public correspondence service. The terms Administration, ROA and public correspondence are defined in the Const
8、itution of the ITU (Geneva, 1992). INTELLECTUAL PROPERTY RIGHTS The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicabi
9、lity of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by patents, which may be required to imple
10、ment this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. O ITU 1999 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means,
11、 electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. 11 Recommendation T.136 (05/99) - - . STD-ITU-T RECMN T-136-ENGL 1999 4862573 bb4228 35b m CONTENTS 1 2 3 4 5 5.1 5.2 5.3 6 6.1 Scope Normative references Definitions Abbreviations . The remo
12、te device control application . Nodes entering a conference 5.1.1 Enrolling in the standard base session 5.1.2 Capability distribution . Alternative node ID Conducted mode behaviour Use of MCS MCS channel usage Annex A . Object identifier assignments Recommendation T.136 (0999) Page 1 2 3 3 4 4 5 5
13、5 . 111 Recommendation T.136 REMOTE DEVICE CONTROL APPLICATION PROTOCOL (Geneva, 1999) 1 Scope Recommendation H.282 defines a set of functions and services for performing remote device control. This Recommendation defines how Recommendation H.282 may be applied in a T. 120 environment allowing these
14、 functions and services to be utilized in a multimedia conference. This Recommendation provides the standardized application protocol for remote device control in multipoint multimedia communication systems. It is therefore a GCC Client Application and relies on the services defined in companion Rec
15、ommendation T. 124 Generic Conference Control (GCC) and Recommendations T. 122 and T. 125 Multipoint Communication Service (MCS), which defines the multipoint delivery mechanism used in this Recommendation. 1 Recommendation T.136 (05/99) STD-ITU-T RECMN T.13b-ENGL 1999 = Y862591 OhhY23 TOY 9 .I Gene
16、ric Conference Control (GCC) T.124 A .I v v User Application(s) (sing both standard and non-standard Application Protocols) (Using standard Application Protocols) (Using non-standard Protocols) 4 c T.126 (SI) T.127 (MBFT I T.120 Application Protocol Recommendations t . L . - Non-standard Application
17、 Protocol Entity P I Network Specific Transport Protocols T.123 T1605640- Figure 1m.136 - T-120 infrastructure Recommendations 2 Normative references The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recom
18、mendation. 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 therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other re
19、ferences listed below. A list of the currently valid ITU-T Recommendations is regularly published. - ITU-T Recommendation H.243 (1 993), Procedures for establishing communication between three or more audiovisual terminals using channels up to 2 Mbit/,. - ITU-T Recommendation T. 120 (1 996), Data pr
20、otocols for multimedia conferencing. - ITU-T Recommendation T. 121 (1 996), Generic application template. 2 Recommendation T.136 (05/99) STDmITU-T RECMN T.13b-ENGL 1977 H 48b257L Obb423L 940 - ITU-T Recommendation T. 122 (1 998), Multipoint communication service - Service definition. ITU-T Recommend
21、ation T. 123 (1 996), Network spec data for multimedia conferencing. ITU-T Recommendation T. 124 (1 998), Generic Conference Control. specification. - - - ITU-T Recommendation T. 125 (1 998), Multipoint communication service protocol 3 Definitions This Recommendation defines the following terms: 3.1
22、 T. 120 services. 3.2 MCU . application protocol: Any standard or non-standard protocol specification that makes use of application protocol entity: The instantiation of an Application Protocol in a terminal or 3.3 application protocol session: A group of peer Application Protocol Entities communica
23、ting with each other. 3.4 controllable device: A device that has the capability to be controlled remotely in a conference environment. 3.5 device: An entity which provides a specific function, or set of functions, to the conference. Some devices such as cameras and microphones are capable of generat
24、ing a source to the conference. 3.6 multipoint control unit (MCU): A device used to interconnect multiple terminals andor further MCUs to allow multiple participants to be connected to single conference. Also known as a bridge. 3.7 node: Any entity that supports the T. 120 protocols. This includes b
25、oth terminal equipment and network elements such as routers and MCUs. 3.8 source: The origin of a real time media stream. 4 Abbreviations This Recommendation uses the following abbreviations: APE Application Protocol Entity GCC Generic Conference Control GCCSAP MCS Multipoint Communication Service M
26、CSAP MCU Multipoint Control Unit PDU Protocol Data Unit RDC Remote Device Control SAP Service Access Point Generic Conference Control Service Access Point Multipoint Communication Service Access Point Recommendation T.136 (05/99) 3 STDDITU-T RECMN T-13b-ENGL 1999 48b2591 Obb4232 887 I 5 Remote devic
27、e control may be performed in a multimedia environment using T. 120 by the use of the RDC Application Protocol Entity. This APE makes use of the services and the protocol that are defined by Recommendation H.282. The remote device control application 5.1 Nodes entering a conference In order to parti
28、cipate in a conference, an RDC APE shall establish an MCSAP and a GCCSAP. The method of creating SAPS is a local matter, outside the scope of this Recommendation. When a node joins a conference, its RDC APE shall wait until it receives a GCC-Application-Permission-To- Enroll indication. The RC APE s
29、hall then attempt to enrol in the RDC Registration Session as described in Recommendation T.121; it may optionally join the RDC Standard Base Session as described in 5.1.1. 5.1.1 An RDC APE at a Terminal shall follow the procedures defined in Recommendation T. 12 1 to enrol in the Standard Base Sess
30、ion. It shall join the RDC-CHANNEL-O channel. The RDC-CHANNEL-O * is used as Session ID. Once the User Application has received a GCC-Application-Roster-Report indication containing an entry in the Standard Base Session for its local RDC APE, it may start to use RDC functions. Enrolling in the stand
31、ard base session 5.1.2 Capability distribution Recommendation H.282 requires that any devices that are to be made available to the conference for remote control or selection are advertised as capabilities which are distributed to all nodes. The RDC APE shall advertise these in the GCC non-collapsing
32、 capability list, using the capability identifiers specified by Recommendation H.282. The application data associated with each non-collapsing capability should contain the device lists using the format specified by Recommendation H.282. The capabilities are passed to GCC on application enrolment. 5
33、.2 Alternative node ID When a terminal is joined to an H.243 multipoint conference, the terminal should use the Alternative Node ID member of the conference roster to advertise the H.243 site ID as described in Recommendation T.124. This will allow a terminal receiving an H.243 VIN or VIN2 symbol to
34、 associate the T. 136 node with the stream that is now being received. 5.3 Conducted mode behaviour RDC is a conductor aware application protocol in that it has two modes of operation: one for non-conducted mode and one for conducted mode, as described in this subclause. Applications become aware of
35、 a GCC Conference Conductor being assigned through receipt of a GCC-Conductor-Assign indication from its GCC provider. This includes the GCC User ID of the conducting node. Applications must determine the identity of the RDC application protocol which inherits the conductors role. When a conference
36、enters conducted mode the following operations require permission from the conference conductor: A node may not lock a new remote device without permission from the conference conductor but is free to unlock any device that it has previously locked without requiring permission. 4 Recommendation T.13
37、6 (0599) STD-ITU-T RECMN T.13b-ENGL 1999 4862593 0bb4233 713 - A node may not send control requests to a remote device without permission from the conference conductor. All other operations are unaffected by entering conducted mode. 6 Use of MCS The RDC APE shall use the PDUs described in Recommenda
38、tion H.282 to perform remote device control. An RDC PDU may be sent by issuing an MCS-Send-Data request, specijing the User ID of the destination node as the Channel ID and including the PDU in the Data field. Where Recommendation H.282 specifies the use of a medium priority data channel, the RDC AP
39、E shall specie the MCS-Send-Data request with medium priority. Where Recommendation H.282 specifies the use of a high priority data channel, the RDC APE shall specifj the MCS-Send-Data request with high priority. Where MCS offers the ability to send low latency unreliable data, the RDC APE may in tu
40、rn offer this option to a User Application as specified by Recommendation H.282. 6.1 MCS channel usage For a point-to-point or multipoint session, RDC utilizes 1 MCS static channel: 0 RDC-CHANNEL-O The RDC-CHANNEL-O is joined by all RDC APES. ANNEX A Object identifier assignments Table A. 1 lists th
41、e assignment of Object Identifiers defined for use by this Recommendation. Table A.lL.136 - T.136 object identifier assignment I Object Identifier value I Description I itu-t recommendation t136 version(0) 1) This Object Identifier is used to indicate the version of this Recommendation. At this time
42、 there is a single standardized version defined. Static Channel ID assignments Table A.2 lists the numerical assignment of static channel IDS for the static channels allocated for use by this Recommendation. Table A.2L.136 - Static Channel ID Assignments I Symbolicname 1 ChannelID 1 I RDC-CHANNEL-O
43、I 13 I Recommendation T.136 (05/99) 5 - leries A leries B ;eries C ;cries D ;cries E Series F Series G Series H Series I Series J Series K Series L Series M Series N Series O Series P Series Q Series R Series S Series T Series U Series V Series X Series Y Series Z ITU-T RECOMMENDATIONS SERIES Organi
44、zation of the work of the ITU-T Means of expression: definitions, symbols, classification General telecommunication statistics General tariff principles Overall network operation, telephone service, service operation and human factors Non-telephone telecommunication services Transmission systems and
45、 media, digital systems and networks Audiovisual and multimedia systems Integrated services digital network Transmission of television, sound programme and other multimedia signals Protection against interference Construction, installation and protection of cables and other elements of outside plant
46、 TMN and network maintenance: international transmission systems, telephone circuits telegraphy, facsimile and leased circuits Maintenance: international sound programme and television transmission circuits Specifications of measuring equipment Telephone transmission quality, telephone installations
47、, local line networks Switching and signalling Telegraph transmission Telegraph services terminal equipment Terminals for telematic services Telegraph switching Data communication over the telephone network Data networks and open system communications Global information infrastructure and Internet protocol aspects Languages and general software aspects for telecommunication systems Printed in Switzerland Geneva, 1999
