ITU-T H 248 98-2016 Gateway control protocol Support of remote media pause and resume (Study Group 16)《网关控制协议 支持远程媒体暂停和恢复(研究组16)》.pdf

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.248.98 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (02/2016) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMS Infrastructure of audiovisual services Communication procedures Gateway control protocol: Support of remote med

2、ia pause and resume Recommendation ITU-T H.248.98 ITU-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 aspect

3、s 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.349 Directory services architecture for audiovisual and multimedia services H.350H.359 Quality of service architecture

4、for audiovisual and multimedia services H.360H.369 Telepresence 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 serv

5、ices H.510H.519 Mobile multimedia collaboration applications 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 collabor

6、ation inter-working procedures H.560H.569 BROADBAND, 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 SERVI

7、CES AND APPLICATIONS FOR IPTV General aspects H.700H.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 Signa

8、ge H.780H.789 E-HEALTH MULTIMEDIA SERVICES AND APPLICATIONS Personal health systems H.810H.819 Interoperability compliance testing of personal health systems (HRN, PAN, LAN, TAN and WAN) H.820H.859 Multimedia e-health data exchange services H.860H.869 For further details, please refer to the list of

9、 ITU-T Recommendations. Rec. ITU-T H.248.98 (02/2016) i Recommendation ITU-T H.248.98 Gateway control protocol: Support of remote media pause and resume Summary Recommendation ITU-T H.248.98 allows the real-time transport protocol (RTP) stream pause and resume functionality as defined by IETF RFC 77

10、28 to be supported on ITU-T H.248 controlled gateways. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T H.248.98 2016-02-29 16 11.1002/1000/12640 * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the Recom

11、mendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T H.248.98 (02/2016) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The

12、 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 Standar

13、dization 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 information t

14、echnology 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. Comp

15、liance 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 o

16、bligatory 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 RIGHTSITU draws attention to the possibility that the practice or implementa

17、tion 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. As

18、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 this may not represent the latest information and are therefore strongly urged

19、to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2016 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T H.248.98 (02/2016) iii Table of Contents Page 1 Scope . 1 2 References . 1

20、 3 Definitions 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 2 5 Conventions 2 6 Relationship to other Recommendations in the ITU-T H.248 sub-series . 3 7 Design considerations . 3 7.1 Real-time nature . 4 7.2 Message direction . 4 7.3 Appl

21、y to individual sources 4 7.4 Consensus . 5 7.5 Message acknowledgements 5 7.6 Retransmitting requests 5 7.7 Sequence numbering 5 8 RTP topology dependent RTCP handling 6 8.1 Introduction 6 8.2 Interactions with ITU-T H.248.88 6 8.3 Interactions with compound and reduced-size RTCP packets . 6 8.4 Ga

22、thering SSRC values, relevant for P/R-signalling, from the IP media path . 7 9 Remote pause and resume package 7 9.1 Properties 8 9.2 Events . 9 9.3 Signals 13 9.4 Statistics 17 9.5 Error codes 17 9.6 Procedures 17 10 Examples . 22 10.1 Initiation pause CCM config=1 . 22 10.2 Initiation pause CCM co

23、nfig=5 . 23 Appendix I Network use cases with ITU-T H.248 media gateways in the end-to-end RTP path with pause/resume signalling . 25 I.1 Introduction 25 I.2 Single RTP Termination . 25 I.3 Dual RTP Terminations 25 I.4 Multiple RTP Terminations 28 iv Rec. ITU-T H.248.98 (02/2016) Page Appendix II St

24、ate models for pause/resume signalling endpoints 31 II.1 Introduction 31 II.2 RTP pause state model at the RTP sender side 31 II.2 RTP pause state model at the RTP receiver side 31 Appendix III SSRC identifiers for pause/resume signalling endpoints 34 III.1 SSRC information in RTCP FB “pause/resume“

25、 messages . 34 III.2 Example use case 34 Bibliography. 36 Rec. ITU-T H.248.98 (02/2016) 1 Recommendation ITU-T H.248.98 Gateway control protocol: Support of remote media pause and resume 1 Scope This Recommendation describes the support of real-time transport protocol (RTP) stream pause and resume f

26、unctionality as defined by IETF RFC 7728 on ITU-T H.248 controlled gateways. It describes the mapping of call control session description protocol (SDP) related to pause/resume to ITU-T H.248 SDP and vice versa. It also contains a package that allows several different implementation types to be supp

27、orted. This allows the media gateway (MG) to operate in an autonomous manner by receiving, making pause/resume decisions and sending real-time control protocol (RTCP) level pause/resume messages with minimal media gateway controller (MGC) involvement. An MGC controlled configuration is also supporte

28、d whereby the reception of pause/request requests/responses is indicated to the MGC for it to make decisions and determine a response. It also allows the MGC to initiate pause/resume requests. The use of pause codec control messages (CCMs) as defined by IETF RFC 7728 and temporary maximum media stre

29、am bit rate requests (TMMBR) as defined by IETF RFC 5104 to pause and resume RTP media streams are both supported. It also contains considerations related to the support of RTP stream pause and resume in ITU-T H.248 controlled gateways. This Recommendation also details the relationship to other exis

30、ting ITU-T H.248.x sub-series Recommendations where pause/resume functions are supported. 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 edit

31、ions 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 currently vali

32、d 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 H.248.1 Recommendation ITU-T H.248.1 (2013), Gateway control protocol: Version 3. ITU-T H.248.9 Recommendation ITU

33、-T H.248.1 (2009), Gateway control protocol: Advanced media server packages. ITU-T H.248.71 Recommendation ITU-T H.248.71 (2010), Gateway control protocol: RTCP support packages. ITU-T H.248.88 Recommendation ITU-T H.248.88 (2014), Gateway control protocol: RTP topology dependent RTCP handling by IT

34、U-T H.248 media gateways with IP terminations. IETF RFC 3550 IETF RFC 3550 (2003), RTP: A Transport Protocol for Real-Time Applications. IETF RFC 5104 IETF RFC 5104 (2008), Codec Control Messages in the RTP Audio-Visual Profile with Feedback (AVPF). IETF RFC 5576 IETF RFC 5576 (2009), Source-Specifi

35、c Media Attributes in the Session Description Protocol (SDP). 2 Rec. ITU-T H.248.98 (02/2016) IETF RFC 7728 IETF RFC 7728 (2015), RTP Stream Pause and Resume. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 RTP stream b-IETF RFC 7656: A

36、 stream of RTP packets containing media data, source or redundant. The RTP stream is identified by an SSRC belonging to a particular RTP session. 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 P/R-signalling: The “RTP pause and resume“ signalling as d

37、efined by IETF RFC 7728. NOTE The signalling protocol syntax is based on dedicated RTCP “feedback“ packet types, the signalling protocol procedures use the associated bidirectional RTCP control flow and the signalling protocol semantics are that defined in sections 6 to 9 in IETF RFC 7728. 4 Abbrevi

38、ations and acronyms This Recommendation uses the following abbreviations and acronyms: AVPF Audio-Visual Profile with Feedback B2BRE Back-to-Back RTP End System CCM Codec Control Message CNAME Canonical NAME DTMF Dual Tone Multi Frequency FB Feedback IWF Interworking Function MG Media Gateway MGC Me

39、dia Gateway Controller P/R Pause and Resume RTCP Real-Time Control Protocol RTCP FB RTCP Feedback RTP Real-time Transport Protocol SDES Source Description SDP Session Description Protocol SSRC Synchronization Source Identifier TMMBN Temporary Maximum Media stream Bit rate Notification TMMBR Temporar

40、y Maximum Media stream Bit rate Request 5 Conventions Elements of the ITU-T H.248 protocol model, e.g., Context, Termination, Stream, Event are represented using the first letter capitalized. Property, Event, Signal and Parameter identities are given in italics. Rec. ITU-T H.248.98 (02/2016) 3 The s

41、uffix “.req“ added to an ITU-T H.248 command name stands for a command request, while the suffix “.rep“ stands for a command reply. For example, “Notify.req“ represents a Notify Request. Capitalized names PAUSE, RESUME, REFUSED, PAUSED refer abstractly to Codec Control Messages (CCM) defined in IETF

42、 RFC 7728 or to the CCMs temporary maximum media stream bit rate request (TMMBR) and temporary maximum media stream bit rate notification (TMMBN) IETF RFC 5104 when these are used to emulate specific pause/resume behaviour. 6 Relationship to other Recommendations in the ITU-T H.248 sub-series Gatewa

43、ys utilising ITU-T H.248 currently have several methods to pause the transmission of media. ITU-T H.248.1: Contains the Local Control Descriptor StreamMode property that allows the MGC to effectively stop sending an RTP media flow (i.e., change from send/receive to receive only) while still maintain

44、ing an RTCP control flow. To resume the flow of media the MGC can change the StreamMode back to send/receive. However, this is a local MG action rather than a request to a remote endpoint. The action is also triggered from a call control level stimulus. ITU-T H.248.1: The ITU-T H.248 connection mode

45、l (including the TopologyDescriptor) allows Terminations/Streams to be isolated from other Terminations/Streams in the Context. This allows an MGC to isolate an ITU-T H.248 media stream from other input streams effectively stopping the flow of RTP media. The MGC may then move the Termination/Stream

46、back into a Context to resume RTP media flow. ITU-T H.248.9: Contains the “Play collect“ package that enables a user to request (via a dual tone multi frequency (DTMF) digit) that the playout of media associated with a signal be paused. It also enables the user to resume the RTP media flow via a DTM

47、F digit. b-ITU-T H.248.66: Contains the “Signal pause” package which is a generic package that allows the MGC to request a pause in the playout of media and to later resume the RTP media flow. It is suited to scenarios where media playout has been initiated through the use of ITU-T H.248 Signals rat

48、her than real-time media flows. It again is a local MG action rather than a request to a remote endpoint and the action is also triggered from a call control level stimulus. ITU-T H.248.71: Contains the “RTCP source description” package which allows the MGC to request the MG to monitor, extract and

49、report synchronization source identifier (SSRC) values from RTP streams. Clause 8 describes how the package may be used together with RTP stream pause and resume services. ITU-T H.248.88: Describes RTCP handling by an ITU-T H.248 MG in association with a particular enforced local RTP topology. Clause 8 provides more detailed information on the subject. None of the above methods match the functionality supported by IETF RFC 7728. ITU-T H.248.1 and b-ITU-T H.248.66