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.248.94 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (11/2015) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMS Infrastructure of audiovisual services Communication procedures Gateway control protocol: Web-based real-time c
2、ommunication services ITU-T H.248 protocol support and profile guidelines Recommendation ITU-T H.248.94 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 mult
3、iplexing 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.349 Directory services architecture for audiovisual and multimedi
4、a services H.350H.359 Quality of service architecture 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
5、.509 Mobility for H-Series multimedia systems and services 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 interwo
6、rking procedures H.550H.559 Mobile multimedia collaboration 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 a
7、nd Internet of Things H.640H.649 IPTV MULTIMEDIA SERVICES 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 servic
8、e discovery up to consumption H.770H.779 Digital Signage 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.860
9、H.869 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T H.248.94 (11/2015) i Recommendation ITU-T H.248.94 Gateway control protocol: Web-based real-time communication services ITU-T H.248 protocol support and profile guidelines Summary Recommendation ITU-T H.248.94 p
10、rovides guidelines on the use and configuration of ITU-T H.248 real-time communication in web-browsers (WebRTC) gateways via ITU-T H.248 profiles. These guidelines may be used by other standards developing organizations (SDOs) when defining their ITU-T H.248.1 profiles in support of WebRTC gateways.
11、 WebRTC represents an extensive real-time multimedia conversational service with a specific protocol stack in order to address network address translation (NAT) traversal as well as maximize multiplexing support. The WebRTC gateway consequently requires the support of user plane interworking functio
12、ns (IWFs) for connecting WebRTC clients to non-WebRTC networks. The Recommendation also defines a new package to support the data channel establishment protocol (DCEP). History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T H.248.94 2015-11-29 16 11.1002/1000/12636 * To access the
13、Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T H.248.94 (11/2015) FOREWORD The International Telecommunication Union (ITU) is the United Nat
14、ions specialized agency in the field of telecommunications, information and communication technologies (ICTs). 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
15、 on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization 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 o
16、f 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, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ i
17、s used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance wit
18、h the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other 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 require
19、d of any party. INTELLECTUAL PROPERTY RIGHTSITU draws attention to 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
20、 Property Rights, whether asserted by ITU members or others outside 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. Howeve
21、r, implementers are cautioned that this may not represent the latest information and are therefore strongly urged 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 prio
22、r written permission of ITU. Rec. ITU-T H.248.94 (11/2015) iii Table of Contents Page 1 Scope . 1 1.1 Applicability statements . 1 2 References . 2 3 Definitions 4 3.1 Terms defined elsewhere 4 3.2 Terms defined in this Recommendation . 4 4 Abbreviations and acronyms 5 5 Conventions 6 5.1 Acronym us
23、age . 6 5.2 Prescriptive language 7 5.3 ITU-T H.248 protocol element notation . 7 6 WebRTC core technology overview 7 6.1 WebRTC gateways . 7 6.2 Capabilities . 7 6.3 Transport of user plane WebRTC traffic 8 7 ITU-T H.248 WebRTC gateways: example use cases . 9 7.1 Point-to-point communication 9 7.2
24、Multipoint communication . 11 8 Functional requirements for ITU-T H.248 WebRTC gateways . 11 8.1 Requirements related to NAT traversal support . 11 8.2 Requirements related to communication topologies 13 8.3 Requirements related to bearer traffic multiplexing . 13 8.4 Requirements related to RTP-to-
25、RTP type interworking . 13 8.5 Requirements related to TCP-based media transport . 15 8.6 Requirements related to media-aware type of interworking 16 8.7 Requirements related to bearer security . 18 8.8 Requirements related to WebRTC emergency and priority services . 19 8.9 Requirements related to Q
26、oS support . 19 8.10 Requirements related to bearer-path coupled congestion controls . 20 8.11 Requirements related to performance monitoring 21 8.12 Requirements related to SDP-based description, declaration and negotiation of WebRTC media configurations . 22 8.13 Requirements related to ITU-T H.24
27、8 signalling . 29 9 Data channel establishment protocol support package . 29 9.1 Properties 29 9.2 Events . 29 9.3 Signals 32 9.4 Statistics 35 iv Rec. ITU-T H.248.94 (11/2015) Page 9.5 Error codes 35 9.6 Procedures 35 10 Out-of-band WebRTC data channel negotiation 39 11 ITU-T H.248 profile specific
28、ation guidelines 40 11.1 Profile identification . 40 11.2 Summary . 40 11.3 Gateway control protocol version 40 11.4 Connection model . 40 11.5 Context attributes 40 11.6 Terminations . 40 11.7 Descriptors 40 11.8 Command API 44 11.9 Generic command syntax and encoding . 44 11.10 Transactions 44 11.
29、11 Messages . 44 11.12 Transport . 45 11.13 Security . 45 11.14 Packages . 45 11.15 Mandatory support of SDP and ITU-T H.248.1 Annex C information elements 65 11.16 Optional support of SDP and ITU-T H.248.1 Annex C information elements 66 11.17 Procedures 67 Appendix I Use case specific capability s
30、ets Examples . 88 I.1 Overview 88 Appendix II Distributed text-over-IP endpoints for WebRTC data text . 90 II.1 Purpose . 90 II.2 Problem statement 90 II.3 Solution Guidelines for the WebRTC MG (ITU-T T.140)-IWF . 95 Bibliography. 96 Rec. ITU-T H.248.94 (11/2015) 1 Recommendation ITU-T H.248.94 Gate
31、way control protocol: Web-based real-time communication services ITU-T H.248 protocol support and profile guidelines 1 Scope Web-based real-time communication is a service standardized by the IETF and World Wide Web Consortium (W3C) (called real-time communication in web-browsers (WebRTC) or RTCWeb
32、service) and defines a particular protocol suite for IP-based communication in web browser environments. This application is related to multimedia conversational services which cover typical service components such as: telephony, conferencing, instant messaging. The native IETF/W3C WebRTC service (a
33、s defined for the public Internet by the IETF) will be embedded in other IP communication infrastructures such as next generation network (NGN)/ IP multimedia subsystem (IMS). This Recommendation: describes example use cases with ITU-T H.248 WebRTC gateway involvement; identifies ITU-T H.248 capabil
34、ities for such gateways; introduces a new ITU-T H.248 package for the support of WebRTC data channel protocol procedures; and provides guidelines for the specification of ITU-T H.248 profiles for dedicated ITU-T H.248 WebRTC gateway types. It is expected that the WebRTC communication service will ev
35、olve and be enhanced and/or extended in the future. The next clause provides information about the specific scope of Release 1 of this Recommendation. 1.1 Applicability statements 1.1.1 Release 1 Release 1 provides a basic WebRTC service, but has some limitations due to dependencies on other standar
36、ds, which are still in progress. Release 1 supports: WebRTC calls with audio and video, the two WebRTC media components are either unbundled or bundled, i.e., using ITU-T H.248 Stream grouping or not; WebRTC calls with additional data, but limited to WebRTC-embedded instant messaging (based on messa
37、ge session relay protocol (MSRP) only. Release 1 does not yet support: WebRTC calls with data applications related to WebRTC conferencing control (based on binary floor control protocol (BFCP) and WebRTC text conversation (based on ITU-T T.140); full support of datagram transport layer security (DTL
38、S) for WebRTC data: basic establishment and release procedures are supported via ITU-T H.248. However, the ability to influence the DTLS negotiation process and other DTLS capabilities is not supported; interactive connectivity establishment (ICE)-based NAT traversal: current ITU-T H.248 WebRTC gate
39、way capabilities support an asymmetric network access model. Additional extensions cannot be excluded for other network configurations, e.g., additional ICE aspects; 2 Rec. ITU-T H.248.94 (11/2015) secure RTP (SRTP) key management schemes: the single “DTLS-SRTP“-related key management schemes, as su
40、bject of WebRTC, is implicity supported. Additional SRTP key management schemes demand the explicit support of revised ITU-T H.248.77. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recomme
41、ndation. 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 applying the most recent edition of the Recommendations and other referenc
42、es 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. ITU-T H.248.1 Recommendation ITU-T H.248.1 (2013), Gateway control protocol
43、: Version 3. ITU-T H.248.37 Recommendation ITU-T H.248.37 (2008), Gateway control protocol: IP NAPT traversal package. ITU-T H.248.39 Recommendation ITU-T H.248.39 (2014), Gateway control protocol: H.248 SDP parameter identification and wildcarding. ITU-T H.248.48 Recommendation ITU-T H.248.48 (2012
44、), Gateway control protocol: RTCP XR block reporting package. ITU-T H.248.50 Recommendation ITU-T H.248.50 (2010), Gateway control protocol: NAT traversal toolkit packages. ITU-T H.248.52 Recommendation ITU-T H.248.52 (2008), Gateway control protocol: QoS support packages. ITU-T H.248.53 Recommendat
45、ion ITU-T H.248.53 (2009), Gateway control protocol: Traffic management packages. ITU-T H.248.57 Recommendation ITU-T H.248.57 (2014), Gateway control protocol: RTP control protocol package. ITU-T H.248.71 Recommendation ITU-T H.248.71 (2010), Gateway control protocol: RTCP support packages. ITU-T H
46、.248.77 Recommendation ITU-T H.248.77 (2010), Gateway control protocol: Secure real-time transport protocol (SRTP) package and procedures. ITU-T H.248.78 Recommendation ITU-T H.248.78 (2013), Gateway control protocol: Bearer-level application level gateway. ITU-T H.248.80 Recommendation ITU-T H.248.
47、80 (2014), Gateway control protocol: Usage of the revised SDP offer/answer model with ITU-T H.248. ITU-T H.248.84 Recommendation ITU-T H.248.84 (2012), Gateway control protocol: NAT traversal for peer-to-peer services. ITU-T H.248.87 Recommendation ITU-T H.248.87 (2014), Gateway control protocol: Gu
48、idelines on the use of ITU-T H.248 capabilities for performance monitoring in RTP networks in ITU-T H.248 profiles. ITU-T H.248.88 Recommendation ITU-T H.248.88 (2014), Gateway control protocol: RTP topology dependent RTCP handling by ITU-T H.248 media gateways with IP terminations. ITU-T H.248.89 R
49、ecommendation ITU-T H.248.89 (2014), Gateway control protocol: TCP support packages. Rec. ITU-T H.248.94 (11/2015) 3 ITU-T H.248.90 Recommendation ITU-T H.248.90 (2014), Gateway control protocol: ITU-T H.248 packages for control of transport security using transport layer security (TLS). ITU-T H.248.92 Recommendation ITU-T H.248.92 (2014), Gateway control protocol: Stream endpoint interlinkage package. ITU-T H.248.93 Recommendation ITU-T H.248.93
