1、 International Telecommunication Union ITU-T Y.2080TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (06/2012) SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Next Generation Networks Frameworks and functional architecture models Functional architect
2、ure for distributed service networking Recommendation ITU-T Y.2080 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 as
3、pects Y.300Y.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
4、, network capabilities 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 GE
5、NERATION NETWORKS 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
6、 addressing Y.2300Y.2399 Network management Y.2400Y.2499 Network control architectures and protocols Y.2500Y.2599 Packet-based Networks Y.2600Y.2699 Security Y.2700Y.2799 Generalized mobility Y.2800Y.2899 Carrier grade open environment Y.2900Y.2999 FUTURE NETWORKS Y.3000Y.3499 CLOUD COMPUTING Y.3500
7、Y.3999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T Y.2080 (06/2012) i Recommendation ITU-T Y.2080 Functional architecture for distributed service networking Summary Recommendation ITU-T Y.2080 specifies the functional architecture for distributed service networ
8、king (DSN), taking into account the requirements and capabilities for DSN as described in Recommendation ITU-T Y.2206. The main objective of this Recommendation is to provide guidance regarding the design of networks, services and applications making use of DSN. History Edition Recommendation Approv
9、al Study Group 1.0 ITU-T Y.2080 2012-06-15 13 Keywords Distributed service networking, DSN, functional architecture, functions, reference points. ii Rec. ITU-T Y.2080 (06/2012) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommu
10、nications, 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 to standardizing telecommuni
11、cations 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 Recommendations is covered by the procedu
12、re 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 to indicate both a telecom
13、munication 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 is achieved when all of thes
14、e 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. INTELLECTUAL PROPERTY RIGHTS ITU
15、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, whether asserted by ITU member
16、s 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 cautioned that this may not
17、represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2013 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.2080 (
18、06/2012) iii Table of 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 3 5 Conventions 3 6 Characteristics of the DSN functional architecture 4 7 DSN functional architecture . 5 7.1 DSN arc
19、hitectural functions . 5 7.2 Reference points . 10 8 Security considerations . 25 Annex A Relationship between the DSN functional architecture and the NGN functional architecture 26 A.1 Functional mapping between DSN functions and NGN functions 26 A.2 Relationship between the DSN functional architec
20、ture and NGN functional architecture 27 Appendix I Information flows for DSN service 29 I.1 General information flows 29 I.2 Content delivery . 30 I.3 Information flows for MMTel 35 Appendix II DSN model . 39 Bibliography. 41 Rec. ITU-T Y.2080 (06/2012) 1 Recommendation ITU-T Y.2080 Functional archi
21、tecture for distributed service networking 1 Scope This Recommendation describes the functional architecture of distributed service networking (DSN) and its relationships with next generation networks (NGNs). This Recommendation provides a description of functions required for the support of the DSN
22、 and reference points between DSN functions. 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, the editions indicated were valid. All Recommendation
23、s 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 currently valid ITU-T Recommendations is regularly publishe
24、d. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T Y.2011 Recommendation ITU-T Y.2011 (2004), General principles and general reference model for Next Generation Networks. ITU-T Y.2012 Recommendation ITU-T Y.201
25、2 (2010), Functional requirements and architecture of next generation networks. ITU-T Y.2206 Recommendation ITU-T Y.2206 (2010), Requirements for distributed service networking capabilities. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1
26、.1 control plane ITU-T Y.2011: The set of functions that controls the operation of entities in the stratum or layer under consideration, plus the functions required to support this control. 3.1.2 distributed service networking ITU-T Y.2206: An overlay networking which provides distributed and manage
27、able capabilities to support various multimedia services and applications. 3.1.3 DSN node ITU-T Y.2206: A node used in DSN providing distributed functionalities, including distributed routing and distributed storage. 3.1.4 functional entity ITU-T Y.2012: An entity that comprises an indivisible set o
28、f specific functions. Functional entities are logical concepts, while groupings of functional entities are used to describe practical, physical implementations. 3.1.5 hash function b-ITU-T X.810: A (mathematical) function that maps values from a (possibly very) large set of values into a smaller ran
29、ge of values. 3.1.6 management plane ITU-T Y.2011: The set of functions used to manage entities in the stratum or layer under consideration, plus the functions required to support this management. 2 Rec. ITU-T Y.2080 (06/2012) 3.1.7 overlay network b-ITU-T Y-Sup.10: A network of nodes and logical li
30、nks that is built on top of the underlying, e.g., transport, network with the purpose of providing network service that is not available in the underlying network. 3.1.8 peer-to-peer (P2P) ITU-T Y.2206: A system is considered to be P2P if the nodes of the system share their resources in order to pro
31、vide the service the system supports. The nodes in the system both provide services to other nodes and request services from other nodes. NOTE Peer is the node in a P2P system. 3.1.9 reference point ITU-T Y.2012: A conceptual point at the conjunction of two non-overlapping functional entities that c
32、an be used to identify the type of information passing between these functional entities. 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 bootstrap node: The first node of the overlay network to which an enrolling node can connect. 3.2.2 buffer map: A
33、map indicating the availability of chunks in a DSN node, which can be shared between DSN nodes. 3.2.3 chunk: A basic unit of data resulting from partitioning content into defined component parts. NOTE A DSN node may use a chunk as a unit of storage, advertisement and exchange among peers. 3.2.4 cont
34、ent delivery: In the context of the DSN functional architecture, the operation of sending and receiving content between the requested peer and the requesting peer or client. NOTE A client is a service consumer external to DSN. A peer is a node within DSN. 3.2.5 content distribution: In the context o
35、f the DSN functional architecture, the whole process of content sending from one or more content sources, and sharing among DSN nodes. NOTE During the content distribution process, content is often sent to appropriate intermediate nodes to enable subsequent delivery. 3.2.6 content ID: In the context
36、 of the DSN functional architecture, a global unique content name for identifying the content. 3.2.7 content node: A DSN node which can be used for media content distribution, storage and/or caching. 3.2.8 control node: A DSN node which provides service control functionalities. 3.2.9 distributed has
37、h table (DHT): A hash table which is stored across a set of distributed peers. 3.2.10 hash table: A data structure that uses a hash function for mapping input values to their associated attributes. A hash function is applied to map the input values (typically a large range of them) to a smaller rang
38、e of index values that are spread in an equal probability distribution in its range statistically. The resulting index values point to the tables which manage the attributes associated to the original input values. NOTE In a common implementation, the first step (index calculation) is installed in a
39、ny nodes enquiring for the associated attributes and the second step (attribute table) is installed in a dedicated node. 3.2.11 overlay algorithm: An algorithm which forms and maintains a topology of interconnections among the peers, and determines the peers for storing a particular piece of data in
40、 the overlay (i.e., independent from the underlying network) and locates the peers in order to find a piece of data. Rec. ITU-T Y.2080 (06/2012) 3 3.2.12 relay node: A DSN node which relays data packets in order to improve node reachability and QoS by changing the original route of the packets. The
41、data can be voice data, video data, etc. 3.2.13 resource: In the context of the DSN functional architecture, data or an instance of service logic residing in DSN nodes. A resource in DSN is accessible by authorized DSN nodes only. NOTE 1 Examples of resource in DSN include user profile data, content
42、, relay, session control or other service capability. NOTE 2 In the DSN environment, resources can have multiple replicas residing in different DSN nodes. 3.2.14 user profile: In the context of the DSN functional architecture, a collection of information that specifies the subscribed services and ac
43、cess privileges related to a DSN service user. The data in the user profile is called user profile data. NOTE A user profile may include the following attributes: user ID and other data related to authentication and authorization, user preferences, service status, service class, usage and/or contrib
44、ution information, or subscriber accounting characteristics, etc. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: AF Application Function CDF Content Delivery Function CPU Central Processing Unit CSAF Content Service Application Function DHT Distribute
45、d Hash Table DSN Distributed Service Networking EF End-user Function ID Identifier MF Management Function NAT Network Address Translation NEF Node Enrolment Function NGN Next Generation Network P2P Peer-to-Peer PSTN Public Switched Telephone Network RF Relay Function RLF Resource Location Function S
46、CF Service Control Function TOCF Traffic Optimization Control Function UE User Equipment 5 Conventions The following conventions apply: 1) The meaning of functions is as follows. functions: In the context of the DSN functional architecture, “functions“ are defined as a functional group composed of f
47、unctional entities. It is represented by the following symbol: 4 Rec. ITU-T Y.2080 (06/2012) 2) In this Recommendation: The keywords “is required to“ and “is prohibited from“ indicate a requirement which must be strictly followed and from which no deviation is permitted if conformance to this docume
48、nt is to be claimed. The keywords “is recommended“ indicate a requirement which is recommended but which is not absolutely required. Thus adherence to this requirement need not be present to claim conformance. The keywords “can optionally“ indicate an optional requirement which is permissible, witho
49、ut implying any sense of being recommended. This term means the vendor may not choose to provide the feature (and an operator may choose not to offer it) but still claim conformance with the Recommendation. In the main body of this Recommendation and its annexes, the words “shall“, “shall not“, “should“, and “may“ sometimes appear, in which case they are to be interpreted, respectively, as “is required to“, “is prohibited from“, “is recommended“ and “can optionally“. The appearance of such phrases or
