ITU-T H 248 12 AMD 1-2002 Gateway Control Protocol H 248 1 Packages for H 323 and H 324 Interworking Series H Audiovisual and Multimedia Systems Infrastructure of Audiovisual Serviw.pdf

1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T H.248.12TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 1(11/2002) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMSInfrastructure of audiovisual services Communication procedures Gateway control protocol: H.248.1 packages for H.323 and H.324 interwo

2、rking Amendment 1: New Annex A: Extended H.324, H.245 command and H.245 indication packages ITU-T Recommendation H.248.12 (2001) Amendment 1ITU-T H-SERIES RECOMMENDATIONS AUDIOVISUAL AND MULTIMEDIA SYSTEMS CHARACTERISTICS OF VISUAL TELEPHONE SYSTEMS H.100H.199 INFRASTRUCTURE OF AUDIOVISUAL SERVICES

3、General H.200H.219 Transmission multiplexing and synchronization H.220H.229 Systems aspects H.230H.239 Communication procedures H.240H.259 Coding of moving video H.260H.279 Related systems aspects H.280H.299 SYSTEMS AND TERMINAL EQUIPMENT FOR AUDIOVISUAL SERVICES H.300H.399 SUPPLEMENTARY SERVICES FO

4、R 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 applications and services H.520H.529 Security for mo

5、bile 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 For further details, please refer to the list of ITU-T Rec

6、ommendations. ITU-T Rec. H.248.12 (2001)/Amd.1 (11/2002) i ITU-T Recommendation H.248.12 Gateway control protocol: H.248.1 packages for H.323 and H.324 interworking Amendment 1 New Annex A: Extended H.324, H.245 command and H.245 indication packages Summary The new Annex A in this amendment defines

7、new H.248.1 packages, which extend the H.324, H.245 command and H.245 indication packages, defined in ITU-T Rec. H.248.12. The packages extend the existing packages by adding new properties. Source Amendment 1 to ITU-T Recommendation H.248.12 (2001) was prepared by ITU-T Study Group 16 (2001-2004) a

8、nd approved under the WTSA Resolution 1 procedure on 29 November 2002. ii ITU-T Rec. H.248.12 (2001)/Amd.1 (11/2002) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector

9、(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 Standardization Assembly (WTSA), which meets every fo

10、ur 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 information technology which fall within ITU-Ts purview, th

11、e 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. INTELLECTUAL PROPERTY RIGHTS ITU draws attention t

12、o 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 ITU members or others outsi

13、de 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, implementors are cautioned that this may not represent the lat

14、est information and are therefore strongly urged to consult the TSB patent database. ITU 2003 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. H.248.12 (2001)/Amd.1 (11/2002) iii CONTENTS Page A.1 Sco

15、pe 1 A.2 References 1 A.3 Definitions 1 A.4 Abbreviations . 2 A.5 Extended H.324 package 2 A.5.1 Properties 2 A.5.2 Events . 3 A.5.3 Signals 3 A.5.4 Statistics 3 A.5.5 Procedures 3 A.6 Extended H.245 Command Package 6 A.6.1 Properties 6 A.6.2 Events . 7 A.6.3 Signals 7 A.6.4 Statistics 7 A.6.5 Proce

16、dures 7 A.7 Extended H.245 Indication Package. 8 A.7.1 Properties 8 A.7.2 Events . 8 A.7.3 Signals 8 A.7.4 Statistics 8 A.7.5 Procedures 9 ITU-T Rec. H.248.12 (2001)/Amd.1 (11/2002) 1 ITU-T Recommendation H.248.12 Gateway control protocol: H.248.1 packages for H.323 and H.324 interworking Amendment

17、1 New Annex A: Extended H.324, H.245 command and H.245 indication packages A.1 Scope This annex defines properties for H.324 and H.323 interworking, which are needed together with the properties in the H.324 package, H.245 command package and H.245 indication package, for interworking with H.324 ter

18、minals having different H.324 capabilities, when the interworking function is handled by the MGC. A.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

19、, 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 applying the most recent edition of the Recommendations and other references listed below. A list of the curr

20、ently 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. ITU-T Recommendation H.223 (2001), Multiplexing protocol for low bit rate multimedia communication. ITU-T Reco

21、mmendation H.245 (2003), Control protocol for multimedia communications. ITU-T Recommendation H.248.1 (2002), Gateway control protocol: Version 2. ITU-T Recommendation H.248.12 (2001), Gateway control protocol H.248.1 packages for H.323 and H.324 interworking. ITU-T Recommendation H.248.15 (2002), G

22、ateway control protocol: SDP H.248 package attribute. ITU-T Recommendation H.324 (2002), Terminal for low bit-rate multimedia communication. ITU-T Recommendation X.691 (2002), Information technology ASN.1 encoding rules: Specification of Packed Encoding Rules (PER). IETF RFC 2327 (1998), SDP: Sessio

23、n Description Protocol. A.3 Definitions N/A 2 ITU-T Rec. H.248.12 (2001)/Amd.1 (11/2002) A.4 Abbreviations This annex uses the following abbreviations: LSB Least Significant Bit MGC Media Gateway Controller MSB Most Significant Bit MUX MUltipleX PDU Protocol Data Unit PER Packed Encoding Rules TCS T

24、erminal Capability Set A.5 Extended H.324 package PackageID: h324ext, (0x0063) Description: The Extended H.324 Package extends the H.324 Package defined in ITU-T Rec. H.248.12. The package defines new properties for H.324 and H.323 interworking, which are needed when the interworking function is han

25、dled by the MGC. Version: 1 Designed to be extended only: No Extends: h324 (0x002d) version 1 A.5.1 Properties A.5.1.1 Maximum H.223 MUX PDU size PropertyID: maxH223MUXPDUSize, (0x0007) Description: This property indicates the maximum size for H.223 MUX PDU in number of octets. Type: Integer Charact

26、eristics: Read/Write Defined in: LocalControl Possible values: Any positive integer A.5.1.2 Local H.223 capability PropertyID: h223capl, (0x0008) Description: This property indicates the local endpoints capabilities specific to the H.223 multiplex capability. Type: Octet String Characteristics: Read

27、/Write Defined in: LocalControl ITU-T Rec. H.248.12 (2001)/Amd.1 (11/2002) 3 Possible values: This property indicates the H.245 H223Capability structure encoded by applying the PER specified in ITU-T Rec. X.691. Binary encoding: Structure of the Octet String 8 7 6 5 4 3 2 1 MSB LSB Octe 1MSB LSB Oct

28、e nNOTE Octet 1 contains the most significant octet of data. Text encoding: Shall be encoded using the mechanism defined in B.3/H.248.1. A.5.1.3 H.223 Logical channel parameters PropertyID: h223lcparm, (0x0009) Description: This property is used to indicate parameters specific to using H.223. It ind

29、icates both adaptation layer and multiplex layer properties used for the logical channel. Type: Octet String Characteristics: Read/Write Defined in: Local and Remote descriptor Possible values: This property indicates the H.245 H223LogicalChannelsParameters structure encoded by applying the PER spec

30、ified in ITU-T Rec. X.691. Value encoded as per A.5.1.2. For text encoding the mechanism defined in ITU-T Rec. H.248.15 is used. A.5.2 Events None. A.5.3 Signals None. A.5.4 Statistics None. A.5.5 Procedures These procedures are related to the scenario in which MGC executes H.245 control itself as s

31、hown in Figures A.1 to A.3. 4 ITU-T Rec. H.248.12 (2001)/Amd.1 (11/2002) H.248.12ANN.A_F01H.324 terminal: MGC: H.323 terminal: MGAUDITAUDIT REPLYSERVICE CHANGE REQUESTSERVICE CHANGE REPLYTCSTCSTCSAckTCSTCSTCSAckTCSAckAudit MG for “Local H.223capability“ and “Maximum H.223MUX PDU size“ to be included

32、 inTCS and MiscCmdTDM, MUX and RTP terminations are added in MG by means of H.324 package.TCSAckMODIFYMODIFY_REPLYH.324 terminals H.223 capabilityis transferred to MG.MODIFY (MUX, S1 LocalControlh324/h223capr)NOTE Messages to H.323 and H.324 terminals show H.245 signalling. H.245 signalling between

33、MGCand H.324 terminal is transported via MG, but that is not shown in the sequence in order to simplify thefigure.MiscCmd:MaxMUXPDUFigure A.1/H.248.12 Sequence diagram terminal capability exchange at H.324 and H.323 interworking The MGC will participate in H.245 terminal capability exchange procedur

34、es after it has created an H324 termination in the MG as per Figure A.1. In order to know the H.223 multiplex capabilities to be provided to H.324 terminal, the MGC audits the MG for the “Local H.223 capability“ and “Maximum H.223 MUX PDU size“. ITU-T Rec. H.248.12 (2001)/Amd.1 (11/2002) 5 H.248.12A

35、NN.A_F02H.324 terminal: MGC: H.323 terminal: MGOLCOLCOLCAckMODIFYMODIFY_REPLYMODIFYMODIFY_REPLYReserve the stream and RTP-port.MODIFY(MUX: s3, LocalControl video codec LCN-in, h324ext/h223lcparm) MODIFY(RTP: s3, LocalControl inactive, LocalDescriptorvideo codec)OLCAckOLCOLCOLC ackOLC ackMODIFYMODIFY

36、_REPLYStream is opened in the direction H.324 to H.323.MODIFY(RTP: s3 Local Control send_only, RemoteDescriptorremoteAddress)Stream is opened in the direction H.323 to H.324.MODIFY(RTP: s3 LocalControl send receive)NOTE Messages to H.323 and H.324 terminals show H.245 signalling. H.245 signalling be

37、tween MGCand H.324 terminal is transported via MG, but that is not shown in the sequence in order to simplify thefigure.Figure A.2/H.248.12 Sequence diagram for opening the logical channel When logical channels are opened between terminals by the H.245 protocol, the MGC adds the streams between the

38、multiplex and RTP terminations in the MG as per Figure A.2. The streams are described by usual manner as described in 7.1/H.248.1. The H.223 Logical Channel Parameters define the H.223 multiplexing properties used for the stream towards the H.324 terminal, e.g. the adaptation layer to be used. When

39、textual encoding is used, the property is coded within SDP by using H.248.15. 6 ITU-T Rec. H.248.12 (2001)/Amd.1 (11/2002) H.248.12ANN.A_F03H.324 terminal: MGC: H.323 terminal: MGMODIFYMODIFY_REPLYMisc Cmd MaxMUXPDUMaximum MUX PDU size is forwarded to MG.MODIFY(MUX: S1: LocalControlh324ext/MaxH223MU

40、XPDUSize)NOTE Messages to H.323 and H.324 terminals show H.245 signalling. H.245 signalling between MGC andH.324 terminal is transported via MG, but that is not shown in the sequence in order to simplify the figure.Figure A.3/H.248.12 Sequence diagram for maximum PDU specification At any time when a

41、 remote H.324 terminal commands to restrict the size of the H.223 MUX-PDUs, the MGC shall order the MG to restrict the H.223 MUX PDU size that it transmits to a maximum of the specified number of octets as per Figure A.3. A.6 Extended H.245 Command Package PackageID: h245comext, (0x0064) Description

42、: The Extended H.245 Command Package extends the H.245 Command Package defined in ITU-T Rec. H.248.12. The package defines new properties for H.324 and H.323 interworking, which are needed when the interworking function is handled by the MGC. Version: 1 Designed to be extended only: No Extends: h245

43、com (0x002e) version 1 A.6.1 Properties A.6.1.1 H.245 Version PropertyID: h245version, (0x0005) Description: This property indicates the highest version of the H.245 protocol used. Type: Integer Characteristics: Read Only Defined in: LocalControl descriptor Possible values: Any positive integer as p

44、er the version from the H.245 protocolIdentifier structure. ITU-T Rec. H.248.12 (2001)/Amd.1 (11/2002) 7 A.6.1.2 Flow Control Command PropertyID: flowControlCom, (0x0006) Description: This property indicates the FlowControl to be used. Type: Octet String Characteristics: Read/Write Defined in: Local

45、Control descriptor Possible values: This property indicates the H.245 FlowControlCommand structure encoded by applying the PER specified in ITU-T Rec. X.691. Value encoded as per A.5.1.2. A.6.2 Events None. A.6.3 Signals None. A.6.4 Statistics None. A.6.5 Procedures These procedures are related to t

46、he scenario in which MGC executes H.245 control itself as shown in the Figure A.4 below. The MGC may audit the H.245 version, which the MG supports, after a service change. H.248.12ANN.A_F04H.324 terminal: MGC: H.323 terminal: MGFlowControlCommandMODIFYMODIFY_REPLYFlowControlIndicationNOTE Messages

47、to H.323 and H.324 terminals show H.245 signalling. H.245 signalling between MGCand H.324 terminal is transported via MG, but that is not shown in the sequence in order to simplify thefigure.Flow Control Command is forwarded to MG.MODIFY(MUX: S1:LocalControlh245comext/flowControlCmd)Figure A.4/H.248

48、.12 Sequence diagram for Flow Control Modification When a remote H.324 or H.323 terminal wants to restrict the bit rate of a channel, or whole multiplex, and the MGC accepts the request, the MGC orders the MG to restrict the bit rate of the stream(s) as per Figure A.4. 8 ITU-T Rec. H.248.12 (2001)/A

49、md.1 (11/2002) A.7 Extended H.245 Indication Package PackageID: h245indext, (0x0065) Description: The Extended H.245 Indication Package extends the H.245 Indication Package defined in ITU-T Rec. H.248.12. The package defines new properties for H.324 and H.323 interworking, which are needed when the interworking function is handled by the MGC. Version: 1 Designed to be extended only: No Extends: h245ind (0x002e) Version 1 A.7.1 Properties A.7.1.1 H.223 Skew Indication PropertyID: h223SkewInd, (0x0003) Descriptio