1、 International Telecommunication Union ITU-T J.128TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (11/2005) SERIES J: CABLE NETWORKS AND TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS Interactive systems for digital television distribution Set-top gateway specification for
2、transmission systems for interactive cable television servicesITU-T Recommendation J.128 ITU-T Rec. J.128 (11/2005) i ITU-T Recommendation J.128 Set-top gateway specification for transmission systems for interactive cable television services Summary The DOCSIS Set-top Gateway (DSG) specification int
3、roduces additional requirements on a DOCSIS Cable Modem Termination System and DOCSIS Cable Modem (Annex B/J.112 and ITU-T Rec. J.122) to support the configuration and transport of a class of service known as “Out-Of-Band (OOB) messaging“ between a Set-top Controller (or application server) and the
4、customer premises equipment (CPE). In general, the CPE is intended to be a digital set-top device, but may include other CPE devices, such as residential gateways or other electronic equipment. Source ITU-T Recommendation J.128 was approved on 29 November 2005 by ITU-T Study Group 9 (2005-2008) unde
5、r the ITU-T Recommendation A.8 procedure. Keywords DOCSIS Set-top Gateway (DSG). ii ITU-T Rec. J.128 (11/2005) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T
6、) 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 every four yea
7、rs, 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 purview, the nece
8、ssary 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 voluntary. Howeve
9、r, 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 the negative equ
10、ivalents 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 involve the use of a
11、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 Recommendation, ITU h
12、ad/had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. ITU 2006 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.128 (11/2005) iii CONTENTS Page 1 Scope 1 1.1 Introduction and Overview. 1 1.2 Purpose of the Recommendation 1 2 References. 2 2.1 Normative references 2
14、 2.2 Informative references 2 3 Definitions, Abbreviations, and Conventions. 4 3.1 Definitions 4 3.2 Abbreviations . 6 3.3 Conventions 7 4 Reference Architecture . 7 4.1 DSG basic mode. 9 4.2 DSG advanced mode 10 4.3 DSG and IP multicast . 10 5 DOCSIS set-top gateway 10 5.1 Assumptions and Constrain
15、ts . 10 5.2 Requirements General . 11 5.3 Requirements DSG tunnel definition 15 5.4 DSG eCM operation. 24 5.5 Security considerations. 38 5.6 Interoperability . 39 5.7 DSG operation 40 Annex A DOCSIS set-top gateway agent MIB definition 47 Annex B DOCSIS set-top gateway set-top device MIB definition
16、 63 Annex C Format and content for DSG eCM event, SYSLOG, and SNMP trap extensions . 71 C.1 DSG eCM event extensions description. 71 C.2 DSG DOCSIS events extensions 73 Annex D Delivery of MPEG-2 sections in the broadcast tunnel 75 D.1 MPEG-2 section encapsulation 75 D.2 Layer 4 multiplexing 76 Appe
17、ndix I Parsing the MIB in the DSG agent 77 BIBLIOGRAPHY 90 ITU-T Rec. J.128 (11/2005) 1 ITU-T Recommendation J.128 Set-top gateway specification for transmission systems for interactive cable television services 1 Scope 1.1 Introduction and Overview The DOCSIS Set-top Gateway (DSG) Recommendation de
18、fines an interface and associated protocol that introduces additional requirements on a DOCSIS CMTS and DOCSIS CM to support the configuration and transport of a class of service known as “Out-Of-Band (OOB) messaging“ between a Set-top Controller (or application servers) and the customer premises eq
19、uipment (CPE). In general, the CPE is intended to be a digital Set-top Device, but may include other CPE devices, such as Residential Gateways or other electronic equipment. Figure 1-1 provides the context for this Recommendation in relation to the data-over-cable reference architecture and the othe
20、r interface specifications in the DOCSIS Cable Modem series. Traditionally, the physical transport of this Out-Of-Band messaging has been carried over a variety of mechanisms, including ITU-T J.184. This Recommendation defines the applicable communications standards and protocols needed to implement
21、 an Out-Of-Band messaging interface to the Set-top Device using DOCSIS as a transport. It applies to cable systems employing HFC and coaxial architectures. Specifically, the scope of this Recommendation is to: Describe the communications protocols and standards to be employed. Specify the data commu
22、nication requirements and parameters that will be common to all units. The intent of this Recommendation is to specify open protocols, with a preference for existing, well-known and well-accepted standards. This interface Recommendation is written to provide the minimal set of requirements for satis
23、factory communication between the Set-top Controller and the Set-top Device over the DOCSIS transport. “DOCSIS Set-top Gateway“ (DSG) shall be the general term used to describe this interface. 1.2 Purpose of the Recommendation Cable operators have deployed millions of digital set-top boxes enabling
24、broadcast and interactive services. They have also deployed millions of DOCSIS cable modems with the associated infrastructure, CMTS, routers, and network connectivity. There is significant interest in enabling digital set-top boxes to leverage the existing infrastructure of digital video and DOCSIS
25、 networks. This Recommendation is one of a series of interface specifications that will permit the early definition, design, development and deployment of digital cable systems on a uniform, consistent, open, non-proprietary, multi-vendor interoperable basis. The intended service will allow transpar
26、ent unidirectional and bidirectional transport of Out-Of-Band messaging over Internet Protocol (IP), between the cable system headend and customer locations, over an all-coaxial or hybrid-fibre/coax (HFC) cable network. This is shown in simplified form in Figure 1-1. 2 ITU-T Rec. J.128 (11/2005) Fig
27、ure 1-1/J.128 Transparent out-of-band messaging via DOCSIS The transmission path over the cable system is realized at the headend by a Set-top Controller that is responsible for managing the Set-top Devices, a regional or wide area IP network connecting the Set-top Controller to the Cable Modem Term
28、ination System (CMTS), and, at each customer location, a Set-top Device with an embedded Cable Modem. At the headend (or hub), the interface to the data-over-cable system is called the Cable Modem Termination System Network-Side Interface. The intent is for the cable operators to transparently trans
29、port OOB messaging traffic between these interfaces, including but not limited to UDP over IP datagrams in either unicast, broadcast, or multicast forms. DSG addresses several issues. DSG allows the DOCSIS downstream transport to be used for Out-of-Band signalling. DSG allows delivery of Out-of-Band
30、 messages through the DOCSIS downstream without requiring return path functionality between the Set-top Devices and the CMTS. DSG allows legacy non-IP addressing of Set-top Devices by a Set-top Controller to be transported over a tunnel on an IP network. 2 References 2.1 Normative references The fol
31、lowing ITU-T Recommendations and other references contain provisions which, through reference in 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 Rec
32、ommendation are therefore encouraged to investigate the possibility of applying the most recent edition 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 no
33、t give it, as a stand-alone document, the status of a Recommendation. J.112-B ITU-T Recommendation J.112 Annex B (2004), Data-over-cable service interface specifications: Radio-frequency interface specification. J.122 ITU-T Recommendation J.122 (2002), Second-generation transmission systems for inte
34、ractive cable television services IP cable modems. DOCSIS-RFI Refers to both J.112-B and J.122. 2.2 Informative references CAS ID Conditional Access System Identifier, CA_system_ID, administered by DVB, www.dvb.org. Table at http:/www.dvb.org/index.php?id=174 ANSI/SCTE 23-3 ANSI/SCTE 23-3 (2003), DO
35、CSIS 1.1 Part 3: Operations Support System Interface. ANSI/SCTE 79-2 ANSI/SCTE 79-2 (2002), DOCSIS 2.0 Operations Support System Interface. ITU-T Rec. J.128 (11/2005) 3 eDOCSIS ITU-T Recommendation J.126 (2004), Embedded Cable Modem device specification. IANA IANA (2006), Internet Multicast Addresse
36、s. http:/www.iana.org/assignments/multicast-addresses IEEE 802.3 IEEE 802.3 (2005), Local and metropolitan area networks Specific requirements Part 3: Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Access Method and Physical Layer Specifications. ITU-T J.94 ITU-T Recommendation J.9
37、4 (1998), Service information for digital broadcasting in cable television systems. ITU-T J.184 ITU-T Recommendation J.184 (2001), Digital broadband delivery system: Out-of-band transport. GRE 1 IETF RFC 1701 (1994), Generic Routing Encapsulation (GRE). http:/www.ietf.org/rfc/rfc1701.txt GRE 2 IETF
38、RFC 2784 (2000), Generic Routing Encapsulation (GRE). http:/www.ietf.org/rfc/rfc2784.txt MPEG-SI ITU-T Recommendation H.222.0 (2000) | ISO/IEC 13818-1: 2000, Information technology Generic coding of moving pictures and associated audio information: Systems. OUI Organizationally Unique Identifier, ht
39、tp:/standards.ieee.org/regauth/oui RFC 1112 IETF RFC 1112 (1989), Host Extensions for IP Multicasting, http:/www.ietf.org/rfc/rfc1112.txt RFC 2669 IETF RFC 2669 (1999), DOCSIS Cable Device MIB Cable Device Management Information Base for DOCSIS Compliant Cable Modems and Cable Modem Termination Syst
40、ems. http:/www.ietf.org/rfc/rfc2669.txt RFC 3171 IETF RFC 3171 (2001), IANA Guidelines for IPv4 Multicast Address Assignments. http:/www.ietf.org/rfc/rfc3171.txt RFC 3569 IETF RFC 3569 (2003), An Overview of Source-Specific Multicast (SSM). http:/www.ietf.org/rfc/rfc3569.txt OC-SP-CD-IF OpenCable TM
41、 Common Download Specification I08, 040831, http:/ OC-SP-OCAP1.0 OpenCable TM OC-SP-OCAP1.0-I16-050803 for OCAP, http:/ SCTE-18 SCTE 18 (2002), Emergency Alert Message for Cable, http:/www.scte.org 4 ITU-T Rec. J.128 (11/2005) 3 Definitions, Abbreviations, and Conventions 3.1 Definitions Figure 3-1/
42、J.128 DSG terminology This Recommendation defines the following terms: 3.1.1 Application ID: This is a 16-bit field indicating a numeric ID for an application running on the Set-top Device. The Application ID is typically assigned through a Source Name Sub-table (SNS) from ITU-T J.94 carried in the
43、Broadcast DSG Tunnel. 3.1.2 CA_system_ID: This is a 16-bit field indicating the type of CA system applicable for either the associated ECM and/or EMM streams. The CA_system_ID may be used as a DSG Client ID in DSG Advanced Mode. 3.1.3 DOCSIS Set-Top Gateway (DSG): The DOCSIS Set-top Gateway (DSG) de
44、fines functionality on a DOCSIS CMTS and DOCSIS CM to support the configuration and transport of a class of service known as “Out-Of-Band (OOB) messaging“ between a Set-top Controller (or application servers) and the customer premises equipment (CPE). The DSG is not intended for the delivery of prog
45、ramming content. 3.1.4 DSG address table: The collection of DSG Rules and DSG Classifiers contained within the DCD message. The DSG Client uses its DSG Client ID as an index into the DSG Address Table to determine what DSG Tunnel Address to receive. 3.1.5 DSG advanced mode: Operation with the DCD me
46、ssage. Address assignment is dynamic. The DSG Tunnel Address is determined by the DSG Agent and learned by the DSG Client through the DSG Address Table in the DCD message. 3.1.6 DSG agent: The DSG Agent is the implementation of the DSG protocol within the CMTS. The DSG Agent creates the DSG Tunnel,
47、places content from the DSG Server into the DSG Tunnel, and sends the DSG Tunnel to the DSG Client. 3.1.7 DSG basic mode: Operation without the DCD message. Address assignment is static. The DSG Tunnel Address is determined by the DSG Client and learned by the DSG Agent through configuration. This m
48、ode provides backwards compatibility with earlier versions of the DSG specification. 3.1.8 DSG channel: Any DOCSIS downstream channel that contains one or more DSG Tunnels. 3.1.9 DSG classifier: A description of layer 3 and layer 4 filtering applied to DSG Tunnel traffic. DSG Classifiers may be spec
49、ified in the DSG Agent and sent as a component of the DSG Address Table in the DCD Message. 3.1.10 DSG client: The DSG Client terminates the DSG Tunnel and receives content from the DSG Server. There may be more than one DSG Client within a Set-top Device. ITU-T Rec. J.128 (11/2005) 5 3.1.11 DSG client controller: The portion of the Set-top Device that handles the processing of DCD messages and makes decisions regarding the forwarding of DSG
