1、 International Telecommunication Union ITU-T J.282TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (11/2006) SERIES J: CABLE NETWORKS AND TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS Digital transmission of television signals Architecture of multi-channel video signal dist
2、ribution over IP-based networks ITU-T Recommendation J.282 ITU-T Rec. J.282 (11/2006) i ITU-T Recommendation J.282 Architecture of multi-channel video signal distribution over IP-based networks Summary This Recommendation defines the architecture of IP-based video signal distribution systems. Becaus
3、e IP transmission technologies allow the use of various physical media due to their media-independent nature, this Recommendation describes some additional broadband access network technologies such as optical access network, xDSL and cable modem. Source ITU-T Recommendation J.282 was approved on 29
4、 November 2006 by ITU-T Study Group 9 (2005-2008) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. J.282 (11/2006) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardizatio
5、n 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 Standardization Assembly (WTSA), which meets
6、 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 technology which fall within ITU-Ts pu
7、rview, 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. Compliance with this Recommendation is vo
8、luntary. 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 obligatory language such as “must“ and t
9、he 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 RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involv
10、e 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 of the date of approval of this Recomm
11、endation, 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 to consult the TSB patent database at
12、http:/www.itu.int/ITU-T/ipr/. ITU 2007 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. J.282 (11/2006) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 2 4 Abbreviations and acronyms 2 5 Con
13、ventions 3 6 Architecture 3 6.1 Architectural framework 3 6.2 CDN 4 6.3 Internet protocol . 6 6.4 Service delivery model. 7 6.5 Channel switching 8 6.6 Services. 10 6.7 Service information 10 6.8 CPE. 11 6.9 Provisioning 11 6.10 Security. 12 Bibliography. 14 iv ITU-T Rec. J.282 (11/2006) Introductio
14、n This Recommendation defines the architecture of IP-based video signal distribution systems that satisfy the requirements defined in b-ITU-T J.281. Primary and secondary distribution of broadcasting programmes, the key services of CATV, are the goals of this architecture. Hence, some important issu
15、es, which are not derived from the requirements of generic video transmission service but are important in terms of broadcasting, such as area restriction and anonymous reception, are taken into account. Because IP transmission technologies can be used with various physical media due to their flexib
16、ility, this Recommendation also introduces some additional broadband access network technologies, which are not covered in b-ITU-T J.281, such as xDSL and cable modem. ITU-T Rec. J.282 (11/2006) 1 ITU-T Recommendation J.282 Architecture of multi-channel video signal distribution over IP-based networ
17、ks 1 Scope This Recommendation describes the architecture of IP-based video signal distribution systems that can provide functionalities and services equivalent to those of a conventional CATV system, including secondary distribution of broadcasts. High quality video distribution over the IP network
18、 requires broadband access network technologies such as optical access network, xDSL and cable modem. This Recommendation describes the functionalities of the CDN and access network required for multi-channel video services. The CDN is under the obvious control of network operator(s). Programme dist
19、ribution on a global basis is outside the scope of this Recommendation. The service configuration is roughly equivalent to conventional CATV. HDTV is available as one part of the video service. The two Internet protocols, IPv4 and IPv6, are basically the same with some differences such as the addres
20、s architecture and multicast management protocol. This Recommendation does not define which protocol should or should not be used. The choice of Internet protocol is left to the operator. IP technologies can be applied for contribution, primary and secondary distribution, and in-home transmission/di
21、stribution. This Recommendation focuses on primary and secondary distribution. The other usages, for example video on demand, may be added to the architecture of this Recommendation. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in
22、this text, constitute provisions of this Recommendation. 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 e
23、dition of the Recommendations and other references 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.222.0 ITU-T Recomme
24、ndation H.222.0 (2006) | ISO/IEC 13818-1 (2006), Information technology Generic coding of moving pictures and associated audio information: Systems. ITU-T J.94 ITU-T Recommendation J.94 (1998), Service information for digital broadcasting in cable television systems. ITU-T J.183 ITU-T Recommendation
25、 J.183 (2001), Time-division multiplexing of multiple MPEG-2 transport streams over cable television systems. ITU-T J.290 ITU-T Recommendation J.290 (2006), Next generation set-top box core architecture. ITU-T J.292 ITU-T Recommendation J.292 (2006), Next generation set-top box media-independent arc
26、hitecture. 2 ITU-T Rec. J.282 (11/2006) 3 Definitions This Recommendation defines the following terms: 3.1 IP stream (IPS): A flow of IP packets that is identified by destination/source IP address and port number. 3.2 network termination (NT): Generic term for equipment that terminates an access net
27、work at the user side. NT includes ONU, cable modem and xDSL modem. 3.3 transport stream (TS): A TS is a data structure defined in ITU-T H.222.0. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: CAS Conditional Access System CATV CAble TeleVision CDN Co
28、ntent Distribution Network CPE Customer Premises Equipment DHCP Dynamic Host Configuration Protocol ECM Entitlement Control Message EMM Entitlement Management Message EPG Electronic Programme Guide FEC Forward Error Correction FTTB Fibre To The Building FTTH Fibre To The Home HDTV High Definition Te
29、leVision IGMP Internet Group Management Protocol IP Internet Protocol IPS Internet Protocol Stream L2 Layer 2 MAC Media Access Control MLD Multicast Listener Discovery MPEG Moving Picture Experts Group NIT Network Information Table NT Network Termination ONU Optical Network Unit PC Personal Computer
30、 PES Packetized Elementary Stream PSI Programme Specific Information QoS Quality of Service RA Router Advertisement RTP Real-time Transport Protocol ITU-T Rec. J.282 (11/2006) 3 SI Service Information SLA Service Level Agreement STB Set-Top Box ToS Type of Service TS Transport Stream TSMF Transport
31、Streams Multiplexing Frame TTL Time To Live UDP User Datagram Protocol WWW World Wide Web xDSL x Digital Subscriber Line 5 Conventions Throughout this Recommendation words that are used to define the significance of particular requirements are capitalized. These words are: “MUST“ This word or the ad
32、jective “REQUIRED“ means that the item is an absolute requirement of this Recommendation. “MUST NOT“ This phrase means that the item is an absolute prohibition of this Recommendation. “SHOULD“ This word or the adjective “RECOMMENDED“ means that there may exist valid reasons in particular circumstanc
33、es to ignore this item, but the full implications should be understood and the case carefully weighed before choosing a different course. “SHOULD NOT“ This phrase means that there may exist valid reasons in particular circumstances when the listed behaviour is acceptable or even useful, but the full
34、 implications should be understood and the case carefully weighed before implementing any behaviour described with this label. “MAY“ This word or the adjective “OPTIONAL“ means that this item is truly optional. One vendor may choose to include the item because a particular marketplace requires it or
35、 because it enhances the product, for example; another vendor may omit the same item. 6 Architecture 6.1 Architectural framework A CATV service is a collective of service elements including video programmes, sound programmes, data broadcasts, EPGs and CASs that are produced on an MPEG-2 system. In o
36、rder to provide services equivalent to conventional CATV, the protocol stack of a CATV system above the MPEG-2 TS layer is applied with minimum modification as shown in Figure 6-1. CAS is also provided as part of the service functionalities that resides above the MPEG-2 TS layer. The transmission fu
37、nctionality that is defined in b-ITU-T J.83 for conventional CATV is replaced with IP and related functionalities. FEC functionalities, which enhance the transmission quality, reside on the MPEG-2 TS layer and/or the IP layer. 4 ITU-T Rec. J.282 (11/2006) Figure 6-1 Protocol stack The system physica
38、lly consists of a headend, CDN and CPE (customer premises equipment) as shown in Figure 6-2. Figure 6-2 System configuration A headend coordinates video programmes and ancillary information, produces transport streams and transmits into CDN, as does a conventional CATV headend. At least one headend
39、MUST be connected to the CDN. Two or more headends MAY be connected to the same CDN if necessary. In the case of multiple headends, CPE MAY be allowed to receive programmes generated from each headend. CDN delivers IP packets encapsulating MPEG-2 TS packets to CPE. Unlike conventional transmission t
40、echnology such as b-ITU-T J.83, designed for transmission over coaxial cable, IP technology allows the programmes to transit various physical media, and so is expected to ease the network design constraints. With regard to the access network, many access network technologies such as optical access n
41、etwork, xDSL and cable modem, if sufficient bandwidth is available, can be employed. Since the CDN is a closed network, the global reachability required for conventional Internet applications such as the WWW and e-mail is provided through connection through the Internet. CPE functionalities are equi
42、valent to those of CATV STBs except for the functionality of physical layer termination. 6.2 CDN CDN provides video distribution functionality from a headend to CPE. CDN may also provide connection with the Internet through interconnection with it. Also, bidirectional capability between a headend an
43、d CPE may be provided. The configuration of CDN is shown in Figure 6-3. ITU-T Rec. J.282 (11/2006) 5 Figure 6-3 Block diagram of video signal distribution CDN consists of a core network and an access network. Although CDN does not include the Internet, CDN can provide connectivity with the Internet
44、when CPE uses services that demand it. CDN needs to guarantee high transmission quality so as to meet the demands imposed by the video streams. Thus, the network operator responsible for CDN is required to maintain transmission quality. If several network operators are involved in the construction a
45、nd operation of CDN, an SLA SHOULD be made that defines the transmission quality of the network and the technology employed. 6.2.1 Core network The core network is responsible for distributing the injected IP packets to each access network with sufficient transmission quality. It has appropriate ban
46、dwidth, QoS functionality and/or network architecture so as to guarantee the quality needed for video transmission services, against the traffic generated by Internet applications such as the WWW and e-mail. The detailed functionality of the core network is outside the scope of this Recommendation.
47、6.2.2 Access network The access network connects the core network and the CPE or home network. The access network is required to provide sufficient bandwidth for video distribution. The access network MUST be able to deliver at least one IPS with sufficient quality. Also, it SHOULD be possible to de
48、liver multiple IPSs in order to take care of multiple CPEs connected to the same access network. This Recommendation applies to, including but not limited to, FTTH/FTTB, xDSL and cable modem as broadband access network technologies. The following are examples of appropriate access network technologi
49、es: b-ITU-T G.983.1; b-ITU-T G.983.3; b-ITU-T G.984.2; b-ITU-T G.993.2; b-ITU-T G.992.5; b-IEEE 802.3ah; b-ITU-T J.112; b-ITU-T J.122. 6 ITU-T Rec. J.282 (11/2006) 6.2.3 IP home network There may be network equipment between a NT and CPE in a customers home. This Recommendation refers to a set of network equipment of this kind as an “IP home network“. An IP home network delivers programmes from a NT to CPE as a part of a home network. A NT is allowed to transmit a programme to CPE. CPE MUST NOT be allowed to transmit a progr
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