1、 International Telecommunication Union ITU-T J.291TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (11/2006) SERIES J: CABLE NETWORKS AND TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS Cable modems Next generation set-top-box cable architecture ITU-T Recommendation J.291 ITU
2、-T Rec. J.291 (11/2006) i ITU-T Recommendation J.291 Next generation set-top-box cable architecture Summary This Recommendation describes the cable network architecture component of the next-generation Set-Top-Box (STB). When combined with companion ITU-T Recs J.290 (J.stb-core-a) and J.292 (J.stb-m
3、i-a), the architecture defines a cost-efficient platform with capacity and flexibility to support growth of on-demand video, high definition digital TV, managed in-home networks connecting a wide range of consumer-provided devices, and future IP multimedia services including IP voice, video telephon
4、y, and multiplayer gaming. This Recommendation reflects key functional aspects of the next generation cable set-top-box, such as a common application platform and MPEG transport including advanced codecs. Source ITU-T Recommendation J.291 was approved on 29 November 2006 by ITU-T Study Group 9 (2005
5、-2008) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. J.291 (11/2006) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of IT
6、U. 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 every four years, establishes the topics f
7、or 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 purview, the necessary standards are prepared
8、 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 voluntary. However, the Recommendation may co
9、ntain 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 the negative equivalents are used to express
10、 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 involve the use of a claimed Intellectual Propert
11、y 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 Recommendation, ITU had not received notice of in
12、tellectual 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 http:/www.itu.int/ITU-T/ipr/. ITU 2007 All
13、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.291 (11/2006) iii CONTENTS Page 1 Scope 1 2 References. 1 2.1 Normative references 1 2.2 Informative references 1 3 Terms and definitions . 2 4 Abbreviat
14、ions and Acronyms . 3 5 Integrated multimedia architecture. 4 5.1 Reference architecture description . 4 5.2 Attributes of an integrated multimedia architecture. 4 5.3 Video services architecture. 6 5.4 DOCSIS signalling . 7 5.5 Use of coax for in-home networking 8 5.6 Telemetry services 9 6 Custome
15、r premises 9 6.1 Subscriber Video Devices (SVDs) . 10 7 Head-end network architecture. 10 7.1 Evolution of the DOCSIS CMTS and QAM modulators. 13 7.2 Session and resource management architecture . 15 Appendix I Business requirements for the cable network architecture 18 ITU-T Rec. J.291 (11/2006) 1
16、ITU-T Recommendation J.291 Next generation set-top-box cable architecture 1 Scope This Recommendation describes the cable network architecture component of the next-generation STB. When combined with companion ITU-T Recs J.290 and J.292, the architecture defines a cost-efficient platform with capaci
17、ty and flexibility to support growth of on-demand video, high definition digital TV, managed in-home networks connecting a wide range of consumer-provided devices, and future IP multimedia services including IP voice, video telephony, and multiplayer gaming. 2 References 2.1 Normative references Non
18、e. 2.2 Informative references ITU-T Recommendation J.83 (1997), Digital multi-programme systems for television, sound and data services for cable distribution. ITU-T Recommendation J.94 (1998), Service information for digital broadcasting in cable television systems. ITU-T Recommendation J.112 (1998
19、), Transmission systems for interactive cable television services. ITU-T Recommendation J.122 (2002), Second-generation transmission systems for interactive cable television services IP cable modems. ITU-T Recommendation J.125 (2004), Link privacy for cable modem implementations. ITU-T Recommendatio
20、n J.126 (2004), Embedded Cable Modem device specification. ITU-T Recommendation J.128 (2005), Set-top gateway specification for transmission systems for interactive cable television services. ITU-T Recommendation J.179 (2005), IPCablecom support for multimedia. ITU-T Recommendation J.197 (2005), Hig
21、h level requirements for a Digital Rights Management (DRM) bridge from a cable access network to a home network. ITU-T Recommendation J.200 (2001), Worldwide common core Application environment for digital interactive television services. ITU-T Recommendation J.201 (2004), Harmonization of declarati
22、ve content format for interactive television applications. ITU-T Recommendation J.202 (2005), Harmonization of procedural content formats for interactive TV applications. 2 ITU-T Rec. J.291 (11/2006) 3 Terms and definitions This Recommendation defines the following terms: 3.1 asynchronous time divis
23、ion multiple access (A-TDMA): A variant on the protocol for wireless communication, used in DOCSIS 2.0. 3.2 cable modem termination system (CMTS): Located at the cable television system headend or distribution hub, which provides complementary functionality to the cable modems to enable data connect
24、ivity to a wide-area network. 3.3 downloadable conditional access system (DCAS): A technology for downloading conditional access into software on a set-top box; this is an effort under way at CableLabs and due for publication in 2006. 3.4 DOCSIS signalling: DOCSIS signalling as defined in ITU-T Recs
25、 J.125 and J.126. DOCSIS is the term for a system or device compliant with any one of the Cable Television Laboratories, Inc. (“CableLabs“) series of specifications located at: http:/ 3.5 DSG: The DOCSIS Set-top Gateway is an interface defining signalling to and from a DOCSIS modem embedded in a cab
26、le set-top device. 3.6 Digital storage media command and control (DSM-CC): DSM-CC is for developing control channels associated with MPEG-2 streams. 3.7 Edge QAM: A device that provides QAM modulation to increase capacity in existing legacy cable networks. 3.8 IPCable2Home: The domain in MediaHomeNe
27、t that is well bounded and specified based on Internet Protocol Layer 3 interoperability, as opposed to other domains that can be independently, arbitrarily, or privately designed to an individual manufacturers specification. 3.9 IPCablecom: An ITU-T project that includes an architecture and a serie
28、s of Recommendations that enable the delivery of real-time services over the cable television networks using cable modems. 3.10 J.200 series: ITU-T Recommendation for Worldwide common core Application environment for digital interactive television services. J.200 is the common core underlying OpenCa
29、ble Applications Platform (OCAP) in the United States. 3.11 media gateway control protocol (MGCP): A protocol used within a Voice over IP system. 3.12 multi program transport stream (MPTS): A transport stream with multiple programs. 3.13 OpenCable Applications Platform (OCAP): The middleware standar
30、d for United States cable set-tops; J.200 Worldwide common core is a part of OCAP. 3.14 packet identifier (PID): Unique integer value used to identify elementary streams of a program in a single- or multi-program MPEG-2 stream. 3.15 real time transport protocol (RTP): A transport protocol for real-t
31、ime applications defined in ITU-T Rec. H.225.0. It is designed for real-time transmission of audio and video data. 3.16 Synchronous Code Division Multiple Access (S-CDMA): A variant of the protocol used for wireless communication, used in DOCSIS 2.0. 3.17 session initiation protocol (SIP): An applic
32、ation-layer control (signalling) protocol for creating, modifying, and terminating sessions with one or more participants. These sessions include Internet telephone calls, multimedia distribution, and multimedia conferences. ITU-T Rec. J.291 (11/2006) 3 3.18 simple object access protocol (SOAP): A l
33、ightweight, XML-based protocol for exchange of information in a decentralized, distributed environment. 3.19 single program transport stream (SPTS): A transport stream in which there is a single program. 3.20 telemetry service: Remote monitoring of data for purposes such as energy management or secu
34、rity in the home. 3.21 universal plug and play (UPnP): Set of standards for device and content discovery on home networks, promulgated by the UPnP Forum. 4 Abbreviations and Acronyms This Recommendation uses the following abbreviations: CMTS Cable Modem Termination System CPE Customer Premises Equip
35、ment DRM Digital Rights Management DSG DOCSIS Set-top Gateway DSM-CC Digital Storage Media Command and Control GigE Gigabit Ethernet HD High definition HDTV High definition TV IP Internet Protocol IPCMM IPCablecom Multimedia MAC Media Access Control MGCP Media Gateway Control Protocol MPEG Motion Pi
36、cture Experts Group MPTS Multiple Program Transport Stream NCS Network Call Signalling NGHE Next Generation Headend OCAP OpenCable Applications Platform PID Packet Identifier QAM Quadrature Amplitude Modulation QoS Quality of service RTP Real Time Protocol SCTE Society of Cable Television Engineers
37、SD Standard Definition SOAP Simple Object Access Protocol SPTS Single Program Transport Stream 4 ITU-T Rec. J.291 (11/2006) SVD Subscriber Video Device UPnP Universal Plug and Play USB Universal Serial Bus 5 Integrated multimedia architecture Note that the numbering of the clauses in this Recommenda
38、tion is intended to integrate with the clause numbering in ITU-T Rec. J.290. Also note that the requirements in this Recommendation are in addition to those in ITU-T Rec. J.290. 5.1 Reference architecture description The reference architecture is described in ITU-T Rec. J.290. 5.2 Attributes of an i
39、ntegrated multimedia architecture 5.2.1 Video services architecture At a minimum, cable-compliant CPE will have the following attributes. DOCSIS Signalling. All cable STB devices are two-way, using mature low cost DOCSIS 2.0 technology as foundation for two-way communications. See ITU-T Recs J.122,
40、J.125 and J.126. Cable Video Transport. Will use MPEG encapsulated inside IP over DOCSIS. 5.2.2 IP multimedia architecture Extension of established Recommendations. Sets directions to extend and adapt IPCable2Home, IPCablecom, and IPCablecom Multimedia to support NG-stb requirements, building on pre
41、vious investments in these programs. 5.2.3 Network segment: Customer premises Subscriber Video Devices (SVDs). SVDs are cable-compliant video devices that include a tuner, such as set-top or set-back units or standalone digital TV sets (DTVs). A baseline (low end) SVD is defined with minimum require
42、d cable network functionality. Higher-end SVDs include various step-up options at the discretion of suppliers, network operators, and retailers. Baseline SVD functions and examples of step-up options are listed in Table 1. ITU-T Rec. J.291 (11/2006) 5 Table 1/J.291 Baseline and extended SVD function
43、ality Baseline SVD functionality Optional step-up SVD functions (examples) Multiple tuners, capable of supporting any cable video transport mode or DOCSIS Two-way (reverse path) via DOCSIS 2.0 Support for multiple transport modes Support for decoding MPEG-2 (SD and HD) plus H.264 In-home networking
44、connectivity as a client Downloadable CA Capability for J.200-Series Recommendations including OCAP middleware Standard definition output High definition output Analog RF output interface with copy protection Digital output interfaces with copy protection; requirements as described in ITU-T Rec. J.1
45、97. OEM provided universal remote control capable of controlling the SVD and the legacy TV Supports J.83 QAM downstream modulation Includes general purpose USB-2 and/or Ethernet port for in-home networking connectivity and possible unspecified peripheral connection High definition output Copy-protec
46、ted digital interfaces (e.g., HDMI, DVI) Built-in gateway (client, server, and IP address management) function between access and in-home networks DVR baseline functionality IPCablecom telephony features Support for decoding SMPTE 421M (VC-1) Rights management. Cable CPE devices respect and protect
47、rights of content owners over the use of their high-value content. 5.2.4 Network segment: Outside plant Mid-split plan. Upstream bandwidth in most current cable systems is very limited. As a result, many operators have difficulty in accommodating the very rapidly growing demand for upstream services
48、 and consider an upward shift in the point of division between upstream and downstream bandwidth. It is thus important that CPE of the future be able to accommodate a change in the use of the frequency spectrum. 5.2.5 Network segment: Head-end Next generation head-end. Logical partitioning of the CM
49、TS to facilitate unbundling, providing more efficient use of network resources and flexibility to network operators to select the best subsystems from multiple suppliers. Definition of interfaces between CMTS components and integration of these components with other parts of the head-end. Includes unbundling of the data switching portions of the CMTS from the RF modulation portions, thereby allowing for sharing of the edge QAM resources among multiple services. Suppo
