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.248.97 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (11/2015) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMS Infrastructure of audiovisual services Communication procedures Gateway control protocol: ITU-T H.248 support f
2、or control of SCTP bearer connections Recommendation ITU-T H.248.97 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.
3、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 multimedia services H.350H.359 Quality of ser
4、vice 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.509 Mobility for H-Series multimedi
5、a 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 interworking procedures H.550H.559 Mobile m
6、ultimedia 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 and Internet of Things H.640H.649 IPT
7、V 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 service discovery up to consumption H.770H
8、.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.860H.869 For further details, please re
9、fer to the list of ITU-T Recommendations. Rec. ITU-T H.248.97 (11/2015) i Recommendation ITU-T H.248.97 Gateway control protocol: ITU-T H.248 support for control of SCTP bearer connections Summary Recommendation ITU-T H.248.97 introduces support for stream control transmission protocol (SCTP) bearer
10、s in IP media gateways (MGs). It defines ITU-T H.248 packages that allow a media gateway controller (MGC) to control the establishment and the release of SCTP Associations with one of multiple SCTP Streams as well as SCTP reconfiguration procedures. This Recommendation defines a grouping semantics w
11、ith a deaggregation stream that allows the partition of the protocol stack in two segments: on one side the SCTP Association and layers below, on the other side the individual SCTP Streams. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T H.248.97 2015-11-29 16 11.1002/1000/1
12、2639 Keywords GCP, SCTP, WebRTC. * To access the 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.248.97 (11/2015) FOREWORD The Internationa
13、l Telecommunication Union (ITU) is the United Nations 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
14、 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 four years, establishes the topics for study by the ITU-T study groups which, in turn, produc
15、e 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, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this
16、Recommendation, the expression “Administration“ is 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., inte
17、roperability or applicability) and compliance with 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 t
18、hat compliance with the Recommendation is required 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,
19、validity or applicability 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, ITU had not received notice of intellectual property, protected by patents, which may be
20、required to implement this Recommendation. However, 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 repr
21、oduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T H.248.97 (11/2015) iii Table of Contents Page 1 Scope . 1 1.1 Applicability statements . 1 2 References . 2 3 Definitions 3 3.1 Terms defined elsewhere 3 3.2 Terms defined in this Recommendation . 3 4 Abbreviati
22、ons and acronyms 4 5 Conventions 5 5.1 Naming of Stream endpoints and Terminations . 5 5.2 Conventions used in signalling flows . 5 5.3 SCTP bearer connection . 5 5.4 SCTP bearer control . 5 5.5 SCTP endpoint notations 6 5.6 Protocol stack notation . 6 6 Use case descriptions 7 6.1 Use cases related
23、 to SCTP transport modes . 7 6.2 Bearer connection network use cases with ITU-T H.248 IP-IP gateways . 8 6.3 Bearer connection network use cases with ITU-T H.248 “SCTP to non-SCTP“ gateways . 10 6.4 Supported use cases by this Recommendation . 10 7 Models 10 7.1 Network model from ITU-T H.248 entity
24、 point of view 10 7.2 ITU-T H.248 model for SCTP multi-Stream . 11 7.3 Bearer connection model 12 7.4 Protocol stack model for mapping of SCTP Streams to applications 13 8 SCTP basic connection control package(s) 14 8.1 Properties 14 8.2 Events . 16 8.3 Signals 17 8.4 Statistics 18 8.5 Error codes 1
25、8 8.6 Procedures 18 9 SCTP Reconfiguration Stream Reset Package . 21 9.1 Properties 21 9.2 Events . 21 9.3 Signals 23 9.4 Statistics 24 iv Rec. ITU-T H.248.97 (11/2015) Page 9.5 Error codes 24 9.6 Procedures 24 10 Package-less SCTP control . 26 11 SCTP grouping semantic 26 11.1 Introduction 26 11.2
26、Grouping of ITU-T H.248 Streams representing individual SCTP Streams 27 11.3 Isolation of DTLS in case of SCTP over DTLS . 28 11.4 Separation of DTLS connection and underlying multiple L4 connectivity . 29 Annex A State modelling for SCTP bearer connection endpoints 30 A.1 Introduction and purpose 3
27、0 A.2 Original state model for SCTP bearer connection endpoints . 30 A.3 Simplified state model for ITU-T H.248-based SCTP basic connection control . 32 A.4 ITU-T H.248 state model for tunnelled SCTP via DTLS/UDP . 34 Appendix I SDP for gateway control - IANA considerations 35 I.1 Purpose . 35 I.2 S
28、DP codepoints related to SDP “m=“ line element 35 I.3 SDP codepoints related to SDP attributes 35 Appendix II Example signalling scenarios for tunnelled SCTP via DTLS/UDP and interworking to non-SCTP based data transport . 36 II.1 Example application for tunnelled SCTP via DTLS/UDP: generic data cha
29、nnel 36 II.2 Example application for tunnelled SCTP via DTLS/UDP: application-aware data channel service for WebRTC . 39 II.3 Example application for tunnelled SCTP via DTLS/UDP: application-aware data channel service for telepresence . 47 Bibliography. 48 Rec. ITU-T H.248.97 (11/2015) 1 Recommendat
30、ion ITU-T H.248.97 Gateway control protocol: ITU-T H.248 support for control of SCTP bearer connections 1 Scope This Recommendation details stream control transmission protocol (SCTP)-based bearer interfaces on ITU-T H.248 IP media gateways (MGs) . Such an ITU-T H.248 MG provides various functions f
31、or processing of SCTP packets, SCTP packet payload data (so-called SCTP DATA chunks) and functions related to SCTP protocol control information (based on called SCTP control chunks). This Recommendation focuses primarily on the aspect of SCTP Association control, which comprises the establishment an
32、d release of SCTP Associations, and the control, configuration and reconfiguration of SCTP Streams. The Recommendation considers: SCTP transport modes, i.e., the multiple protocol stack options with an SCTP layer; connection and interworking models with a single or multiple SCTP Association endpoint
33、(s) within an ITU T H.248 Context; SCTP Stream models concerning the mapping of multi-SCTP Stream structures on ITU-T H.248 Terminations; usage of ITU-T H.248 Stream grouping concept for SCTP; and new ITU-T H.248 packages for control of SCTP bearer connections. Further, this Recommendation provides
34、information on state modelling for MG-located connection endpoints related to SCTP Associations. 1.1 Applicability statements Table 1 summarizes all possible SCTP-based interfaces of ITU-T H.248 entities, under the assumption of an underlying IP network, and their relevance for this Recommendation.
35、Table 1 Main SCTP-based interfaces of ITU-T H.248 entities and their relevance for this Recommendation SCTP-based transport H.248 entity Relevance Call control interface (e.g., SIP-over-SCTP) MGC Out of scope of this Recommendation. Gateway control interface (ITU-T H.248) MGC, MG Out of scope of thi
36、s Recommendation. Possible ITU-T H.248 transport modes are indicated by ITU-T H.248.67. Usage of an SCTP-based ITU-T H.248 transport mode would be typically specified by an ITU-T H.248 profile as part of clause 6.12 in the profile definition template (see Appendix III in ITU-T H.248.1) and should be
37、 done in accordance with ITU-T H.248.4. Bearer interface MG Within the scope of this Recommendation. 2 Rec. ITU-T H.248.97 (11/2015) 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommend
38、ation. 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 references
39、 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:
40、Version 3. ITU-T H.248.4 Recommendation ITU-T H.248.4 (2009), Gateway control protocol: Transport over Stream Control Transmission Protocol (SCTP). ITU-T H.248.67 Recommendation ITU-T H.248.67 (2009), Gateway control protocol: Transport mode indication package. ITU-T H.248.88 Recommendation ITU-T H.
41、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 Recommendation ITU-T H.248.89 (2014), Gateway control protocol: TCP support packages. ITU-T H.248.92 Recommendation ITU-T H.248.92 (2014), Gateway control
42、protocol: Stream endpoint interlinkage package. ITU-T H.248.93 Recommendation ITU-T H.248.93 (2014), Gateway control protocol: ITU-T H.248 support for control of transport security using the datagram transport layer (DTLS) protocol. ITU-T H.248.94 Recommendation ITU-T H.248.94 (2015), Gateway contro
43、l protocol: Web-based real-time communication services H.248 protocol support and profile guidelines. ITU-T H.248.96 Recommendation ITU-T H.248.96 (2015), Gateway control protocol: H.248 Stream grouping and aggregation. ITU-T Q.1950 Recommendation ITU-T Q.1950 (2002), Bearer independent call bearer
44、control protocol. ITU-T X.200 Recommendation ITU-T X.200 (1994), Information technology Open Systems Interconnection Basic Reference Model: The basic model. IETF RFC 4571 IETF RFC 4571 (2006), Framing Real-time Transport Protocol (RTP) and RTP Control Protocol (RTCP) Packets over Connection-Oriented
45、 Transport. IETF RFC 4960 IETF RFC 4960 (2007), Stream Control Transmission Protocol. IETF RFC 5061 IETF RFC 5061 (2007), Stream Control Transmission Protocol (SCTP) Dynamic Address Reconfiguration. IETF RFC 6525 IETF RFC 6525 (2012), Stream Control Transmission Protocol (SCTP) Stream Reconfiguratio
46、n. Rec. ITU-T H.248.97 (11/2015) 3 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 SCTP association IETF RFC 4960: A protocol relationship between SCTP endpoints, composed of the two SCTP endpoints and protocol state information includi
47、ng Verification Tags and the currently active set of Transmission Sequence Numbers (TSNs), etc. An Association can be uniquely identified by the transport addresses used by the endpoints in the Association. Two SCTP endpoints MUST NOT have more than one SCTP Association between them at any given tim
48、e. 3.1.2 SCTP chunk IETF RFC 4960: A unit of information within an SCTP packet, consisting of a chunk header and chunk-specific content. 3.1.3 SCTP endpoint IETF RFC 4960: The logical sender/receiver of SCTP packets. On a multi-homed host, an SCTP endpoint is represented to its peers as a combinatio
49、n of a set of eligible destination transport addresses to which SCTP packets can be sent and a set of eligible source transport addresses from which SCTP packets can be received. All transport addresses used by an SCTP endpoint must use the same port number, but can use multiple IP addresses. A transport address used by an SCTP endpoint must not be used by another SCTP endpoint. In other words, a transport address is unique to an SCTP endpoint. 3.1.4 SCTP
