1、 International Telecommunication Union ITU-T Y.2019TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (09/2010) SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Next Generation Networks Frameworks and functional architecture models Content delivery fun
2、ctional architecture in NGN Recommendation ITU-T Y.2019 ITU-T Y-SERIES RECOMMENDATIONS GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS GLOBAL INFORMATION INFRASTRUCTURE General Y.100Y.199 Services, applications and middleware Y.200Y.299 Network aspects Y.300
3、Y.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.1099 Services and applications Y.1100Y.1199 Architecture, access, network c
4、apabilities 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.1700Y.1799 Charging Y.1800Y.1899 IPTV over NGN Y.1900Y.1999 NEXT GENERATION NE
5、TWORKS Frameworks and functional architecture models Y.2000Y.2099Quality of Service and performance Y.2100Y.2199 Service aspects: Service capabilities and service architecture Y.2200Y.2249 Service aspects: Interoperability of services and networks in NGN Y.2250Y.2299 Numbering, naming and addressing
6、 Y.2300Y.2399 Network management Y.2400Y.2499 Network control architectures and protocols Y.2500Y.2599 Future networks Y.2600Y.2699 Security Y.2700Y.2799 Generalized mobility Y.2800Y.2899 Carrier grade open environment Y.2900Y.2999 For further details, please refer to the list of ITU-T Recommendatio
7、ns. Rec. ITU-T Y.2019 (09/2010) i Recommendation ITU-T Y.2019 Content delivery functional architecture in NGN Summary Recommendation ITU-T Y.2019 describes the content delivery functional architecture in NGN. This detailed architecture is based on the IPTV functional architecture described in Recomm
8、endation ITU-T Y.1910. Only the NGN architecture options (IMS and non-IMS) are addressed. History Edition Recommendation Approval Study Group 1.0 ITU-T Y.2019 2010-09-06 13 ii Rec. ITU-T Y.2019 (09/2010) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agenc
9、y 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 Recommendations on them with a view t
10、o 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 approval of ITU-T Recommendation
11、s 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 Recommendation, the expression “Administration“ is used for conciseness
12、 to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation i
13、s 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 Recommendation is required of any party. INTELL
14、ECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whe
15、ther 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 intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are c
16、autioned 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 2011 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission
17、of ITU. Rec. ITU-T Y.2019 (09/2010) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 1 3.1 Terms defined elsewhere 1 3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 2 5 Conventions 3 6 Content delivery overview 3 6.1 Introduction 3 6.2 Content ingestion 5 6.3 Conte
18、nt dispatching 5 6.4 Content delivery . 5 7 Content delivery functions 6 7.1 Content delivery functions in the IPTV architecture 6 7.2 Hierarchical content delivery architecture 8 8 Content delivery requirements 9 8.1 Mandatory requirements . 9 8.2 Optional requirements 10 9 Reference points . 10 9.
19、1 Reference point D1 between CD a hierarchical architecture of content delivery functions and related reference points; requirements for content delivery; procedures related to content delivery functions. 2 References The following ITU-T Recommendations and other references contain provisions which,
20、 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 Recommendation are therefore encouraged to investigate the possibility of appl
21、ying 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 not give it, as a stand-alone document, the status of a Recommendation. ITU-T
22、 Y.1910 Recommendation ITU-T Y.1910 (2008), IPTV functional architecture. ITU-T Y.2012 Recommendation ITU-T Y.2012 (2010), Functional requirements and architecture of next generation networks. ITU-T Y.2014 Recommendation ITU-T Y.2014 (2010), Network attachment control functions in next generation ne
23、tworks. ITU-T Y.2111 Recommendation ITU-T Y.2111 (2008), Resource and admission control functions in next generation networks. ITU-T Y.2701 Recommendation ITU-T Y.2701 (2007), Security requirements for NGN release 1. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following te
24、rms defined elsewhere: 3.1.1 functional architecture ITU-T Y.2012: A set of functional entities and the reference points between them used to describe the structure of an NGN. These functional entities are separated by reference points, and thus, they define the distribution of functions. NOTE The f
25、unctional entities can be used to describe a set of reference configurations. These reference configurations identify which reference points are visible at the boundaries of equipment implementations and between administrative domains. 3.1.2 linear TV ITU-T Y.1910: A television service in which a co
26、ntinuous stream flows in real time from the service provider to the terminal device and where the user cannot control the temporal order in which contents are viewed. 2 Rec. ITU-T Y.2019 (09/2010) 3.1.3 reference point ITU-T Y.2012: A conceptual point at the conjunction of two non-overlapping functi
27、onal entities that can be used to identify the type of information passing between these functional entities. NOTE A reference point may correspond to one or more physical interfaces between pieces of equipment. 3.2 Terms defined in this Recommendation This Recommendation defines the following terms
28、: 3.2.1 cluster: Cluster is a grouping of content delivery processing entities with their related control entity. Such grouping allows the sharing of resources (e.g., storage capacity) based on providers policy (e.g., taking into account parameters such as user location). 3.2.2 content aging: The pr
29、ocess to delete a content and related metadata from the content delivery functions. 3.2.3 content dispatching: The process to distribute a content and related metadata within different instances of content delivery functions. 3.2.4 content ingestion: The process of acquiring a content and related me
30、tadata by content delivery functions from content preparation functions. 3.2.5 content segment: To improve the efficiency of content dispatching, a complete media content is needed to be divided into several serial media content. One piece of the divided media content is called a content segment. NO
31、TE The term content segment in this Recommendation includes non-continuous portion of content as well as continuous portion of content. 3.2.6 linear TV relay: Entity which receives stream from a linear TV source and delivers it to the end-user using multicast or unicast. 3.2.7 pull mode: A content d
32、elivery mode which provides delivery of content at the request of the end-user. 3.2.8 push mode: A content delivery mode which provides delivery of content at the request of the service provider. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: AF Appli
33、cation Functions CCF Cluster Control Functions CDCF Content Delivery Control Functions CDC-FE Content Delivery Control Functional Entity CDF Content Delivery Functions CDPF Content Delivery Processing Functions CDP-FE Content Delivery Processing Functional Entity CD metadata processing functional bl
34、ock; content processing control functional block; content pre-processing functional block. Content delivery functions (CDF): content distribution and location control functions; content delivery and storage functions. In ITU-T Y.1910, the functions involved in content delivery are in relationship wi
35、th the management functions and the content provider functions. Note that in some cases the SCP functions are involved in the content delivery process (e.g., for content encryption). Content delivery includes the following: content ingestion: this process loads content received from CPRF for immedia
36、te or delayed delivery; content dispatching: this process distributes content within different instances of content delivery functions; content delivery: this process supplies content to the end-user. 6.2 Content ingestion Content ingestion handles content and related metadata received from CPRF. CP
37、RF control the preparation and aggregation of content received from the content provider functions. The ingestion process can optionally be based on: push mechanism: once prepared, the content is sent by CPRF to the content delivery functions; pull mechanism: the content is fetched from CPRF only wh
38、en needed by the content delivery functions. The ingestion process can optionally include recording content. In this case, the content delivery functions perform functions that record linear content, either on demand or systematically depending on the end-user and/or service needs. This recording is
39、 for immediate or delayed delivery. 6.3 Content dispatching After ingestion, content can optionally be duplicated through the content delivery functions depending on a predefined policy. For example, popular content can optionally be duplicated on all content delivery functions, local content can op
40、tionally reside only in certain targeted areas and rare contents are less duplicated than the latter two. The policy for duplication can optionally be defined on a static basis or dynamically updated, e.g., based on usage statistics. 6.4 Content delivery Content delivery supplies content to the end-
41、user under the control of the application functions. The related procedures are detailed in Appendix I of ITU-T Y.1910. 6 Rec. ITU-T Y.2019 (09/2010) 7 Content delivery functions Content delivery capabilities allow IPTV end-users to select, watch and/or listen to video or audio content. Content deli
42、very capabilities either stream content through end-user functions, allowing viewing in real time, or download it to end-user functions with storage ability (e.g., personal computer, digital video recorder or portable media player) for viewing at any time. By using the content delivery capabilities,
43、 a service provider delivers linear TV content to the IPTV terminal device with the optional capability to record, rewind, and pause, over the network. The content delivery capabilities allow the delivery of IPTV content to IPTV end-users by responding dynamically to IPTV users requests. The content
44、 delivery capabilities can optionally support two delivery modes towards IPTV end-users: multicast delivery and unicast delivery. In the content delivery architecture, either download of the content from a single storage instance or download of the content in segments from multiple storage instances
45、 is supported. 7.1 Content delivery functions in the IPTV architecture Figure 7-1 shows the content delivery functions in the IPTV architecture and the corresponding reference points (refer to ITU-T Y.1910 for further details). Content delivery and storage functionsContent distribution and location
46、control functionsDistribution controlfunctional blockLocation controlfunctional blockMulticast deliveryfunctional blockCache/storagefunctional blockDistributionfunctional blockContent delivery controlfunctional blockError recoveryfunctional blockUnicast deliveryfunctional blockD1Content processingfu
47、nctional blockC1S1E4Uc MdE6McS5C2A2Figure 7-1 Content delivery functions in ITU-T Y.1910 In ITU-T Y.1910, the content delivery functions consist of two groups of functions: content distribution content delivery content delivery processing functions (CDPF) including the following functional blocks: c
48、ache/storage; distribution; content processing; unicast delivery; error recovery; multicast delivery. NOTE Error recovery and multicast delivery functional blocks are optional. A new reference point, i.e., the D2 reference point, is added between CDCF and CDPF. Such functional split allows the suppo
49、rt of the deployment scenarios described in this Recommendation. The functional architecture shown in Figure 7-2 is compatible with the NGN functional architecture, as described in clause 9.3.4 of ITU-T Y.2012. More specifically: The CD The CDCF correspond to the CDC-FE as per clause 9.3.4.2 of ITU-T Y.2012; The CDPF correspond to the CDP-FE as per clause 9.3.4.3 of ITU-T Y.2012. Content distribution and location control functionsContent delivery con
