1、 International Telecommunication Union ITU-T Y.2017TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (09/2009) SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Next Generation Networks Frameworks and functional architecture models Multicast functions
2、in next generation networks Recommendation ITU-T Y.2017 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.2017 (09/2009) i Recommendation ITU-T Y.2017 Multicast functions in next generation networks Summary The objective of Recommendation ITU-T Y.2017 is to describe the multicast functions in next generation networks (NGN), taking into account the capabilities and functional requirement
8、s provided in Recommendation ITU-T Y.2236 (Framework for NGN support of multicast-based services). Source Recommendation ITU-T Y.2017 was approved on 12 September 2009 by ITU-T Study Group 13 (2009-2012) under Recommendation ITU-T A.8 procedures. Keywords Multicast, multicast functions, NGN multicas
9、t-based services. ii Rec. ITU-T Y.2017 (09/2009) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a perm
10、anent 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 years, establi
11、shes 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 necessary stand
12、ards 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. However, the Reco
13、mmendation 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 equivalents a
14、re 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 claimed In
15、tellectual 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 had not rec
16、eived 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 http:/www.itu.int/ITU-T/i
17、pr/. ITU 2010 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T Y.2017 (09/2009) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Definitions 1 3.1 Terms defined elsewhere 1 3.2 Terms defined in this Reco
18、mmendation . 2 4 Abbreviations 2 5 Conventions 3 6 Overview of the NGN multicast . 4 7 Multicast functions in the NGN architecture 5 7.1 Service stratum . 5 7.2 Transport stratum 6 7.3 Management functions for multicast-based services 7 7.4 Multicast-capable end-user functions . 8 8 Description of f
19、unctional entities for multicast 8 8.1 Multicast functional entities in transport stratum . 8 8.2 Multicast functional entities in service stratum 9 8.3 Multicast application support functions and service support functions . 10 9 Security . 10 Appendix I NGN multicast-based service scenarios . 11 I.
20、1 NACF based access control 11 I.2 RACF-based admission control 12 I.3 Multicast-based service session management 14 I.4 Media adaptation service scenario 16 Appendix II Multiple multicast streaming 18 II.1 Multiple multicast streams . 18 II.2 Multiple multicast streaming function 18 II.3 Multiple m
21、ulticast streaming service scenario . 19 Bibliography. 20 Rec. ITU-T Y.2017 (09/2009) 1 Recommendation ITU-T Y.2017 Multicast functions in next generation networks 1 Scope The objective of this Recommendation is to describe the multicast functions in next generation networks (NGN), taking into accou
22、nt the service requirements, capabilities and functional requirements provided in ITU-T Y.2236. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, th
23、e 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 edition of the Recommendations and other references listed below. A list of the currentl
24、y 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 X.6 Recommendation ITU-T X.6 (1997), Multicast service definition. ITU-T X.603 Recommendation ITU-T X.603 (2
25、004) | ISO/IEC 16512-1:2005, Information technology Relayed multicast protocol: Framework. ITU-T Y.2001 Recommendation ITU-T Y.2001 (2004), General overview of NGN. ITU-T Y.2011 Recommendation ITU-T Y.2011 (2004), General principles and general reference model for Next Generation Networks. ITU-T Y.2
26、012 Recommendation ITU-T Y.2012 (2006), Functional requirements and architecture of the NGN Release 1. ITU-T Y.2014 Recommendation ITU-T Y.2014 (2008), Network attachment control functions in next generation networks. ITU-T Y.2021 Recommendation ITU-T Y.2021 (2006), IMS for Next Generation Networks.
27、 ITU-T Y.2091 Recommendation ITU-T Y.2091 (2008), Terms and definitions for Next Generation Networks. ITU-T Y.2111 Recommendation ITU-T Y.2111 (2008), Resource and admission control functions in next generation networks. ITU-T Y.2201 Recommendation ITU-T Y.2201 (2007), NGN release 1 requirements. IT
28、U-T Y.2236 Recommendation ITU-T Y.2236 (2009), Framework for NGN support of multicast-based services. 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 terms defined elsewhere: 3.
29、1.1 multicast ITU-T X.603: Data delivery scheme where the same data unit is transmitted from a single source to multiple destinations in a single invocation of service. 2 Rec. ITU-T Y.2017 (09/2009) 3.1.2 multicast server ITU-T X.6: A logical entity which provides the packet multicast service to the
30、 members. 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 multicast capable: Capabilities that provide multicast-based services. 3.2.2 multicast identifier: An identifier (e.g., multicast address) used between correspondent multicast entities. 3.2.3 mu
31、lticast stream: A multicast stream is a stream identified by the combination of unicast source address, (unicast source) port number, multicast destination address, and (multicast destination) port number. 3.2.4 single frequency network: A broadcast network where several transmitters simultaneously
32、send the same signal over the same frequency channel. 4 Abbreviations This Recommendation uses the following abbreviations: 2G Second Generation 3G Third Generation ABG-FE Access Border Gateway Functional Entity AN-FE Access Node Functional Entity ANI Application Network Interface AS Application Ser
33、ver AS-FE Application Support Functional Entity ASF b) multicast-capable application support functions and service support functions. 7.1.1 Multicast-capable service control functions The multicast-capable service control functions provide control functions such as session control functions, service
34、 user profile function, service authentication and authorization functions for multicast. 6 Rec. ITU-T Y.2017 (09/2009) In addition, they provide the following functions: 7.1.1.1 Reliable multicast data delivery function The reliable multicast data delivery function can optionally support the reliab
35、ility of end-to-end data delivery for multicast-based services from multicast source to multiple users at the service level. Some services such as file distribution, software-updates and application-sharing need reliable data delivery support. The multicast server re-transmits the lost and erroneous
36、 parts when users request re-transmission of lost and erroneous parts of multicast data (e.g., NACK). 7.1.1.2 Multicast server load sharing function The multicast server load sharing function is recommended to support the resilience for multicast-based services by sharing their multicast server load
37、. This function is capable of constructing multiple multicast trees from the multicast servers to receivers based on load balancing (i.e., each multicast server has similar level of load). The allocation of multicast servers can be determined based on its multicast load. 7.1.1.3 Service announcement
38、 function The service announcement function is required to provide the information for all available multicast-based services to users. Each service provider and user may have standardized methods (e.g., SAP, HTTP, SDP, EPG, etc.) for providing information of multicast-based services. a) Multicast s
39、ervice announcement based on standard protocols (e.g., SAP) using periodic advertisement; b) multicast service announcement based on servers (e.g., web servers, EPG servers). 7.1.2 Multicast-capable application support and service support functions The multicast-capable application support and servi
40、ce support functions include functions such as gateway, registration, authentication and authorization functions at the application level. These functions includes capabilities to support various NGN multicast-based services such as IPTV, DMB, e-learning, and hosting/executing multicast-based servic
41、es. The multicast-capable application support and service support functions work in conjunction with the multicast-capable service control functions to provide users with the NGN services they request. Through the UNI, the multicast-capable application support and service support functions provide a
42、 reference point to the multicast-capable end-user functions. Application interactions with the multicast-capable application support and service support functions are handled through the ANI reference point. 7.2 Transport stratum The transport stratum provides multicast-capable functions at the tra
43、nsport level, including the following parts: a) multicast-capable transport control functions; b) multicast-capable transport functions. 7.2.1 Multicast-capable transport control functions Multicast-capable transport control functions include multicast-capable resource and admission control function
44、s and multicast-capable network attachment control functions. Multicast-capable transport control functions are out of scope of this Recommendation and are detailed in ITU-T Y.2111 and ITU-T Y.2014. Rec. ITU-T Y.2017 (09/2009) 7 7.2.2 Multicast-capable transport functions Multicast-capable transport
45、 functions provide multicast transport mechanisms for the delivery of multicast-based services to users. These functions include access packet transport functions, core packet transport functions, edge node functional entity, access node functional entity, and media adaptation functions. The multica
46、st-capable transport functions can optionally support the multicast replication function and the media adaptation function. They can optionally support priority-based forwarding mechanisms, resource reservation mechanisms, and traffic control mechanisms. Multicast traffic is forwarded based on a mul
47、ticast identifier through multicast delivery paths. 7.2.2.1 Multicast replication function The multicast replication function is required to replicate multicast streams received from a multicast delivery function. An example of this is given in b-ITU-T Y.1910. This function can optionally be located
48、 in the access network functions, the edge functions, and the core transport functions (see ITU-T Y.2012). The multicast replication functions can optionally support priority-based forwarding mechanisms, resource reservation mechanisms, and traffic control mechanisms for multicast QoS. Multicast tra
49、ffic is forwarded by a multicast identifier through multicast delivery paths. 7.2.2.2 Multicast control point function The multicast control point function is required to select the individual multicast streams to be delivered over the access network to the end-user functions. The request for a multicast stream can optionally be authorized before it is accepted. This function can optionally be located in the access network functions, the edge functions, and the core transport functions (see I
