1、 ATIS-0800018.v002 IPTV LINEAR TV SERVICE ATIS is the leading technical planning and standards development organization committed to the rapid development of global, market-driven standards for the information, entertainment and communications industry. More than 200 companies actively formulate sta
2、ndards in ATIS Committees and Forums, covering issues including: IPTV, Cloud Services, Energy Efficiency, IP-Based and Wireless Technologies, Quality of Service, Billing and Operational Support, Emergency Services, Architectural Platforms and Emerging Networks. In addition, numerous Incubators, Focu
3、s and Exploratory Groups address evolving industry priorities including Smart Grid, Machine-to-Machine, Connected Vehicle, IP Downloadable Security, Policy Management and Network Optimization. ATIS is the North American Organizational Partner for the 3rd Generation Partnership Project (3GPP), a memb
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5、 Notice of Disclaimer updated several figures to accommodate other possible RACF reference points and added DTS-HD as an optional audio format. ATIS-0800018.v002 iii Table of Contents 1 INTRODUCTION 1 1.1 PURPOSE . 1 1.2 SCOPE 1 1.3 ORGANIZATION OF THE DOCUMENT . 2 2 REFERENCES . 2 3 DEFINITIONS, AC
6、RONYMS, it is temporally infinite in both directions. The TV service provides an essentially continuous stream flowing from the content provider to the terminal device in the home network. A key difference in the delivery of similar services via an IPTV platform is that the IP infrastructure uses a
7、packet network technology based on a multicast (rather than broadcast) data transfer mode. 1.1 Purpose The purpose of this document is to describe the use of the components identified in ATIS-0800007, IPTV High Level Architecture 2, for delivery of an IPTV service with a consumer experience similar
8、to that of a traditional television service. 1.2 Scope This specification defines the basic Linear TV service operation after the initialization, configuration, service provider discovery, and services discovery documented in ATIS-0800017, Network Attachment and Initialization of Devices and Client
9、Discovery of IPTV Services 5 and ATIS-0800009, Remote Management of Devices in the Consumer Domain for IPTV Services 3. Note that those specifications may enable an IPTV Terminal Function (ITF) to access additional IPTV services beyond the basic Linear TV service described in this specification. Thi
10、s specification defines the interfaces required between the Service Provider Domain to the Consumer Domain, as well as the essential Network Stratum interfaces. The Service Provider can provide additional processing of the video stream e.g., insertion of local content channels, advertising, etc. but
11、 such mechanisms are beyond the scope of this specification. Section 4 identifies the specific interfaces to be specified in this document in relation to the IPTV High Level Architecture components and interfaces. The scope of this specification ends with the delivery of the content to the ITF. Furt
12、her distribution beyond the ITF, user interface controls for presentation on a television set, etc., are beyond the scope of this specification. The Service Provider can replicate the content stream to multiple Delivery Networks, and the Delivery Networks can replicate the content stream for multipl
13、e home networks. This specification covers a client-server architecture (i.e., not peer-to-peer) with delivery via IP multicast (i.e., not unicast) techniques. This specification describes a basic acquisition mechanism for Linear TV content channels with options for various network resource allocati
14、on mechanisms. This specification can be used for low bandwidth and/or wireless infrastructures, but it is not optimized or explicitly addressed for those purposes. Content can be received by the service provider via satellite or other means, but hybrid delivery (i.e., via mechanisms other than an I
15、P network infrastructure) of content to the consumer domain is beyond the scope of this specification. ATIS-0800018.v002 2 The content delivered via the Linear TV service may be either secured or unsecured. Where content security is required to ensure confidentiality of the content and constrain its
16、 further distribution, appropriate Digital Rights Management mechanisms are used. These mechanisms are beyond the scope of this specification. This specification assumes the ITF is authorized to access one or more service packages. Mechanisms to restrict or modify the set of available authorized ser
17、vice packages are beyond the scope of this specification. 1.3 Organization of the Document Sections 2 and 3 address external references, acronyms, and defined terms. Sections 4 and 5 describe a functional architecture and overview for Linear TV from ATIS-0800007, IPTV High Level Architecture, as a r
18、eference for the specifications in the following sections. Section 6 defines the pre-conditions between the attachment state as defined in ATIS-0800017, Network Attachment and Initialization of Devices and Client Discovery of IPTV Services 5 and this document. Section 7 then addresses the initial re
19、source acquisition for both IMS and non-IMS service control. Sections 8 and 9 address the channel change resource management, and section 10 addresses release of resources being used for the Linear TV service. Section 11 addresses the media payload details (video, audio, etc). Section 12 defines num
20、erous system reference points. Informative Appendix A addresses non-IMS, decoupled service control. 2 References The following standards contain provisions which, through reference in this text, constitute provisions of this ATIS Standard. At the time of publication, the editions indicated were vali
21、d. All standards are subject to revision, and parties to agreements based on this Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. 1 ATIS-0800002, IPTV Architecture Requirements, 2006.12 ATIS-0800007, IPTV High Level Archit
22、ecture, 2007.13 ATIS-0800009.v002, Remote Management of Devices in the Consumer Domain for IPTV Services, 2009.14 ATIS-0800013.v002, Media Formats and Protocols Specification, 2012.15 ATIS-0800017.v003, Attachment and Initialization Specification for IPTV Services in the Consumer Domain, 2012.16 ATI
23、S-0800019, Multicast Network Service Specification, 2009.17 ATIS-0800020.v002, IPTV EPG Metadata Specification, 2011.18 ATIS-0800022.v002, IPTV Consumer Domain Configuration Metadata, 2011.19 ATIS-0800027.v002, IPTV Glossary, 2010.210 ITU-T Y.1910, IPTV Functional Architecture, 2008.211 ITU-T Y.2021
24、, IMS for Next Generation Networks, 2006.312 ITU-T Y.2111 Revision 1, Resource and Admission Control Functions in Next Generation Networks, 2008.313 UPnP-QoS Architecture:3 for UPnP Version 1.0, Standardized DCP, 2008.314 ITU-T Q.3301.1, Resource control protocol - Protocol at the Rs interface, 2007
25、.31This document is available from the Alliance for Telecommunications Industry Solutions, 1200 G Street N.W., Suite 500, Washington, DC 20005. 2These documents are available from the International Telecommunications Union. 3This document is available from the Universal Plug and Play Forum. ATIS-080
26、0018.v002 3 3 Definitions, Acronyms, the top-tier TRC is entitled to adjust the threshold of aggregate resources based on the resource utilization or upon the request of co-located TRC. The designating mode can only be performed at the aggregate level. The designating mode is used for adjustable res
27、ources between unicast and multicast (see section 8.2). For more information see ITU-T Y.2111 12. 4.3.5 Delivery Network Gateway Policy Enforcement Function The DNG Policy Enforcement Function enforces the network policy rules instructed by the RACF. It performs the following functions based on flow
28、 information such as classifier (e.g., IPv4 5-tuple) and flow direction, as well as transport interface identification information (e.g., VLAN) as needed: Enabling or disabling packet filtering for a media flow. Rate limiting and bandwidth allocation. Traffic classification and marking. Traffic poli
29、cing and shaping. Mapping of IP-layer QoS information onto link layer QoS information based on pre-defined static policy rules (e.g., setting 802.1p priority values). Collecting and reporting resource usage information (e.g., start-time, end-time, and octets of sent data). Use of the DNG Policy Enfo
30、rcement Function is for further study. For more information see ITU-T Y.2111 12. ATIS-0800018.v002 14 4.4 Geographically Distributed Functional Architecture Figure 5: Geographically Distributed Functional Architecture for Linear TV The functional elements of the network architecture can be mapped to
31、 the physical network as shown in Figure 5, which is a reformatted version of Figure 10 from ATIS-0800007, IPTV High Level Architecture 2. This figure includes a network hierarchy as media and control flows from the content provider to the consumer. This hierarchy is intended to be typical, with lar
32、ger networks having more levels and smaller networks having fewer. The content provider interfaces are included for context and are not specified here. Super Head End (SHE) network node(s) with the broadest content scope. The SHE sources content to an entire IPTV network. Intended uses include prima
33、ry storage for off-line content and transmission of region-independent off-air content e.g., premium and specialty programming. For the Linear TV service, the content is comprised of Virtual Channel Service Streams. Video Hub Office (VHO) network node(s) with a local/regional content scope. The VHO
34、sources region-dependent off-air content (e.g., local programming) and houses local off-line storage of content. Video Serving Office (VSO) network node(s) connect consumers (via access systems) to the IPTV network. The VSO (typically a Central Office) hosts or connects all access systems for interc
35、onnection to consumers. In addition, the VSO contains aggregation equipment to enable efficient interconnection of access systems to the IPTV network. The option to locate content interconnection and/or content processing equipment is shown, though perhaps not typical. ATIS-0800018.v002 15 5 Overvie
36、w Figure 6: Overview of Basic Linear TV Processes 5.1 Overview of Content Distribution and Control Paths through the Network The description of the protocols used in Linear TV is classified into two categories: content (Virtual Channel Service Stream) flow and control paths. All the major reference
37、points in Figure 3 and Figure 4 are described and specified. The following sections describe the flows taken through the network for the program content, its metadata attributions, and the control protocols used for controlling and monitoring those paths. The path descriptions and specifications are
38、 organized principally by reference points as being the major logical interconnections of interest. The following sections also cover the control flows between the various domains for Linear TV. These flows control the distribution of the Linear TV content including the selection of channel, mapping
39、 of logical channels to physical channels, resource allocation and monitoring, error recovery, and the connection with the end user. Prior to Linear TV Service attachment, an IPTV network may be engineered and deployed with a certain amount of network resources available for Linear TV service and ot
40、her services sharing the transport layer. The aggregate amount of network resources available for Linear TV (multicast) service and other (unicast) services may be static and determined by anticipated traffic patterns. The resource budget may be configured into transport nodes via network management
41、 mechanisms or pushed into transport nodes from the RACF. Alternatively, network resources may be dynamically allocated when the Linear TV Application session or Linear TV SIP session is established. The control of Linear TV service includes three distinct phases as shown in Figure 6. They are: ATIS
42、-0800018.v002 16 Linear TV Service Attachment and Initial Resource Acquisition: In this phase (Phase 1 of Figure 6) a Linear TV Application session or Linear TV SIP session is established, network resources may be allocated, and an initial Virtual Channel Service Stream is acquired. This phase may b
43、e triggered by the ITF being powered on or by the action of a user. Linear TV service attachment and initial resource allocation is performed differently for IMS and non-IMS networks. For non-IMS networks, the resources may have been statically allocated prior to service attachment or dynamically al
44、located when the Linear TV Application session is established. The Linear IPTV Application may use an admission control mechanism to prevent oversubscription. There are two dynamic resource allocation mechanisms: coupled and decoupled. In the coupled case, network resources are allocated at the requ
45、est of the application during the establishment of the Linear TV Application session e.g., when the ITF is powered on. In the decoupled case, network resources are allocated in response to a request for resources directly from the ITF when the resources are needed. For IMS networks, the Linear TV SI
46、P session establishment is decoupled from the Linear TV application and network resources are dynamically acquired when the Linear TV SIP session is established. Channel Change: This phase occurs when the user switches between two Linear TV programming sources, thus leaving one Virtual Channel Servi
47、ce Stream for another. Since Linear TV is a multicast service, channel changes may cause an increase, a decrease, or no change in the consumption of network resources on the edge, access, or consumer networks, depending on the particular channels being delivered to the various consumers of the Linea
48、r TV service. In order to reduce the channel change latency, most channel changes should not require a modification of the Linear TV Application session or Linear TV SIP session. Network resources for channel changes not requiring or following Linear TV session modification are managed by functions
49、exclusively in the transport layer (RACF and transport-node TRC). Network resource usage for these channel changes may be static or dynamic (Phase 2b of Figure 6). For the static case, an IPTV network can be engineered such that there are sufficient resources for the Linear TV service without network resource management during channel changes. For the dynamic case, there may be times when actual unicast and multicast traffic levels do not match what was anticipated and more efficient use of network resources can be achi
