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 Series Y TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Supplement 43 (02/2017) SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS, NEXT-GENERATION NETWORKS, INTERNET OF THINGS AND SMART CITIES ITU-T Y.
2、1900-series Deployment models of N-screen services ITU-T Y-series Recommendations Supplement 43 ITU-T Y-SERIES RECOMMENDATIONS GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS, NEXT-GENERATION NETWORKS, INTERNET OF THINGS AND SMART CITIES GLOBAL INFORMATION INFRASTRUCTURE General Y.100Y.
3、199 Services, applications and middleware Y.200Y.299 Network aspects Y.300Y.399 Interfaces and protocols Y.400Y.499 Numbering, addressing and naming Y.500Y.599 Operation, administration and maintenance Y.600Y.699 Security Y.700Y.799 Performances Y.800Y.899 INTERNET PROTOCOL ASPECTS General Y.1000Y.1
4、099 Services and applications Y.1100Y.1199 Architecture, access, network capabilities and resource management Y.1200Y.1299 Transport Y.1300Y.1399 Interworking Y.1400Y.1499 Quality of service and network performance Y.1500Y.1599 Signalling Y.1600Y.1699 Operation, administration and maintenance Y.1700
5、Y.1799 Charging Y.1800Y.1899 IPTV over NGN Y.1900Y.1999 NEXT GENERATION NETWORKS Frameworks and functional architecture models Y.2000Y.2099 Quality of Service and performance Y.2100Y.2199 Service aspects: Service capabilities and service architecture Y.2200Y.2249 Service aspects: Interoperability of
6、 services and networks in NGN Y.2250Y.2299 Enhancements to NGN Y.2300Y.2399 Network management Y.2400Y.2499 Network control architectures and protocols Y.2500Y.2599 Packet-based Networks Y.2600Y.2699 Security Y.2700Y.2799 Generalized mobility Y.2800Y.2899 Carrier grade open environment Y.2900Y.2999
7、FUTURE NETWORKS Y.3000Y.3499 CLOUD COMPUTING Y.3500Y.3999 INTERNET OF THINGS AND SMART CITIES AND COMMUNITIES General Y.4000Y.4049 Definitions and terminologies Y.4050Y.4099 Requirements and use cases Y.4100Y.4249 Infrastructure, connectivity and networks Y.4250Y.4399 Frameworks, architectures and p
8、rotocols Y.4400Y.4549 Services, applications, computation and data processing Y.4550Y.4699 Management, control and performance Y.4700Y.4799 Identification and security Y.4800Y.4899 Evaluation and assessment Y.4900Y.4999 For further details, please refer to the list of ITU-T Recommendations. Y series
9、 Supplement 43 (02/2017) i Supplement 43 to ITU-T Y-series Recommendations ITU-T Y.1900-series Deployment models of N-screen services Summary N-screen services are about enabling a user to view same media content on multiple user devices. The translation and adjustment of content formats is necessar
10、y when the formats used in each user device are different. In order to address the challenge, Supplement 43 to ITU-T Y-series Recommendations describes three kinds of deployment model of N-screen services when user devices use the different protocols, metadata and stream formats. The service require
11、ments are also specified when the deployment model is applied for the support of N-screen services. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T Y Suppl. 43 2017-02-17 13 11.1002/1000/13244 Keywords Deployment model, metadata, N-screen service, stream format. * To access
12、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 Y series Supplement 43 (02/2017) FOREWORD The International Telecommunication Union (ITU) is the Uni
13、ted 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 and tariff questions and issuing Recommen
14、dations 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 app
15、roval 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 publication, the expression “Administratio
16、n“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this publication is voluntary. However, the publication may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with
17、the publication 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 publication is required of any
18、 party. INTELLECTUAL PROPERTY RIGHTSITU draws attention to the possibility that the practice or implementation of this publication may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property R
19、ights, whether asserted by ITU members or others outside of the publication development process. As of the date of approval of this publication, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this publication. However, implementers are
20、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 2017 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission
21、 of ITU. Y series Supplement 43 (02/2017) iii Table of Contents Page 1 Scope . 1 2 References . 1 3 Definitions 1 3.1 Terms defined elsewhere 1 3.2 Terms defined in this Supplement 1 4 Abbreviations and acronyms 2 5 Conventions 2 6 Overview . 3 7 Deployment models 3 8 Service requirements 5 9 Securi
22、ty considerations . 6 Appendix I Content formats and delivery protocols . 7 I.1 Media delivery protocol . 7 I.2 Metadata . 9 I.3 Stream format . 9 Bibliography. 10 Y series Supplement 43 (02/2017) 1 Supplement 43 to ITU-T Y-series Recommendations ITU-T Y.1900-series Deployment models of N-screen ser
23、vices 1 Scope This Supplement describes three kinds of deployment model of N-screen services when user devices use the different protocols, metadata and stream formats. The service requirements are also specified when the deployment model is applied for the support of N-screen services. This Supplem
24、ent specifies: deployment models of N-screen services; service requirements of N-screen services. 2 References ITU-T Y.1911 Recommendation ITU-T Y.1911 (2010), IPTV services and nomadism: Scenarios and functional architecture for unicast delivery. ITU-T Y.2701 Recommendation ITU-T Y.2701 (2007), Sec
25、urity requirements for NGN release 1. ITU-T Y-Sup.24 ITU-T Y-series Recommendations Supplement 24 (2013), ITU-T Y.2000-series Supplement on N-screen service scenarios for fixed mobile convergence. 3 Definitions 3.1 Terms defined elsewhere This Supplement uses the following terms defined elsewhere: 3
26、.1.1 media b-ITU-T H.324: One or more of audio, video or data. 3.1.2 Internet Protocol Television (IPTV) b-ITU-T Y.1901: Multimedia services such as television/video/audio/text/graphics/ data delivered over IP-based networks managed to support the required level of QoS/QoE, security, interactivity a
27、nd reliability. 3.1.3 N-screen service ITU-T Y-Sup.24: An information sharing and content providing service on all network enabled devices (TV, mobile phone, tablet, PC, home appliances and cars) that has a seamless and convenient manner. 3.1.4 video on demand (VoD) b-ITU-T Y.1910: A service in whic
28、h the end user can, on demand, select and view video content and where the end user can control the temporal order in which the video content is viewed (e.g., the ability to start the viewing, pause, fast forward, rewind, etc.). 3.2 Terms defined in this Supplement This Supplement defines the follow
29、ing terms: 3.2.1 media content: Set of media components (e.g., audio, video, timed text) that have a common timeline as well as relationships on how they may be presented (for example individually, jointly, or mutually exclusive) with an example being a program or a movie. 3.2.2 media presentation:
30、Structured collection of data that establishes a bounded or unbounded presentation of media content composed of components of continuous media. 3.2.3 media presentation description: Formalized description for a media presentation. 2 Y series Supplement 43 (02/2017) 3.2.4 segment: A resource that can
31、 be identified by an HTTP-URL and possibly a byte-range, included in the media presentation description (MPD), which when this entire resource thus identified is requested through HTTP/1.1 GET method (or partial GET with the indicated byte range) as defined in b-IETF RFC 2616 the segment is the enti
32、ty body of the request response. 3.2.5 streaming service: A service that the stream is constantly received by and presented to an end-user while being delivered by a provider. An end-user can begin playing the content (such as a movie) before the entire content has been transmitted. 4 Abbreviations
33、and acronyms This Supplement uses the following abbreviations and acronyms: 3GP 3GPP file format 3GPP third Generation Partnership Project DASH Dynamic Adaptive Streaming over HTTP HAS HTTP Adaptive Streaming HDS HTTP Dynamic Streaming HLS HTTP Live Streaming HTTP Hypertext Transfer Protocol IP Inte
34、rnet Protocol IPTV Internet Protocol Television MPD Media Presentation Description MPEG Moving Picture Experts Group OIPF Open IPTV Forum OTT Over-The-Top content PSS Packet-switched Streaming Service QoS Quality of Service RTCP Real-time Transport Control Protocol RTP Real-Time Transport Protocol R
35、TSP Real-Time Streaming Protocol RTT Round-Trip Time SDP Session Description Protocol UAProf User Agent Profile UDP User Datagram Protocol VoD Video on Demand XML extensible Markup Language 5 Conventions In this Recommendation: The keywords “is required to“ indicate a requirement which must be stric
36、tly followed and from which no deviation is permitted, if conformance to this Recommendation is to be claimed. Y series Supplement 43 (02/2017) 3 The keywords “is recommended to“ indicate a requirement which is recommended but which is not absolutely required. Thus, this requirement need not be pres
37、ent to claim conformance. 6 Overview Traditional linear TV services, broadcasting TV programmes at the offered time whoever is watching or not, were initially dominant, but other streaming services, e.g., video on demand (VoD), Internet protocol television (IPTV) or Internet streaming services, are
38、becoming more prevalent in a more flexible way, such as anytime, anywhere ITU-T Y.1911. The growth of Internet content (e.g., video) as well as the rapid proliferation of a variety of devices, tend to increase network traffic more and more. Due to viewer demand for personalization and flexibility, a
39、 variety of content types with different formats are accordingly also increasing. In addition, a variety of user devices (e.g., TVs, PCs, tablets, smart phones) and access networks (e.g., fixed broadband, WiFi, 4G, 5G) are driving the widespread consumption of video content. Therefore efficient deli
40、very methods should be devised in order to enable customers to access all types of content on any device and at any time, so called N-screen services. ITU-T Y-Sup.24 also describes a kind of N-screen service scenario. Consumers are today increasingly using multiple devices at the same time. To meet
41、demand, multi-device platforms enable users to enjoy the same content or services seamlessly, irrespective of which device or medium is being used. The N-screen service, which has recently been gaining attention, falls into the broader concept of a multi-device service. The N-screen service is about
42、 enabling the user to use multiple devices, which means that it should be made up of integrated platforms for multi-devices. The core element of the N-screen service is a platform that mediates the use of content or services on multiple devices. The ability to deliver content to multiple screens is
43、rapidly becoming a compulsory requirement for providers of such services as over-the-top content (OTT) and IPTV, as their aim is to meet customer needs for personalization and flexibility to earn revenue through such new business models. In general, a video-streaming service is served in a clientser
44、ver model and in a centralized architecture. It means that a user device in end user side and a media server in network side are tightly coupled as a pair and dependent on each other. Therefore a media server is really allowed to deliver all kinds of content to relevant user devices due to the diffe
45、rence in protocols and formats, especially for the support of N-screen services. The dedicated systems in each difference may lead to duplicated investments in deployment as well as operations. This Supplement aims to address these challenges. In this regard, this Supplement describes deployment mod
46、els of N-screen services. The service requirements are also specified for the support of N-screen services. 7 Deployment models Many types of device with different capabilities (e.g., screen size, resolution) are available on the user side and furthermore different players (e.g., HTTP live streaming
47、 (HLS), HTTP dynamic streaming (HDS) run on them. They are implemented on vendor specific and even standards (e.g., Moving Picture Experts Group (MPEG), Third Generation Partnership Project (3GPP), Open IPTV Forum (OIPF) that are fragmented in terms of protocols, metadata and stream formats. Each us
48、er device can handle a limited set of metadata and stream formats, and it may not properly display media content on the screen if a certain format is not supported. In this regard, three different deployment models possibly occur for the support of N-screen services: 1) coupling each user device wit
49、h a particular media server individually according to media delivery capabilities; 2) consolidating all media delivery capabilities on one server; or 3) converting an unsupported format to a supported format on each user device. 4 Y series Supplement 43 (02/2017) It is assumed that the content source is encoded in ITU-T H.264 codec and carried in a MPEG-TS container to each media server. The silo model means that each device is connected to the respective media
