1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T F.743.4 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (03/2017) SERIES F: NON-TELEPHONE TELECOMMUNICATION SERVICES Multimedia services Functional requirements for virtual content delivery networks Recommendation ITU-T F.7
2、43.4 ITU-T F-SERIES RECOMMENDATIONS NON-TELEPHONE TELECOMMUNICATION SERVICES TELEGRAPH SERVICE Operating methods for the international public telegram service F.1F.19 The gentex network F.20F.29 Message switching F.30F.39 The international telemessage service F.40F.58 The international telex service
3、 F.59F.89 Statistics and publications on international telegraph services F.90F.99 Scheduled and leased communication services F.100F.104 Phototelegraph service F.105F.109 MOBILE SERVICE Mobile services and multidestination satellite services F.110F.159 TELEMATIC SERVICES Public facsimile service F.
4、160F.199 Teletex service F.200F.299 Videotex service F.300F.349 General provisions for telematic services F.350F.399 MESSAGE HANDLING SERVICES F.400F.499 DIRECTORY SERVICES F.500F.549 DOCUMENT COMMUNICATION Document communication F.550F.579 Programming communication interfaces F.580F.599 DATA TRANSM
5、ISSION SERVICES F.600F.699 MULTIMEDIA SERVICES F.700F.799 ISDN SERVICES F.800F.849 UNIVERSAL PERSONAL TELECOMMUNICATION F.850F.899 ACCESSIBILITY AND HUMAN FACTORS F.900F.999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T F.743.4 (03/2017) i Recommendation ITU-T F.
6、743.4 Functional requirements for virtual content delivery networks Summary Recommendation ITU-T F.743.4 gives an overview and the requirements for a virtual content delivery network (VCDN). Appendix I provides two use cases to show how to apply VCDN scenario. Compared with the traditional content d
7、elivery network (CDN) service provisioning defined in Recommendations ITU-T Y.1901 and ITU-T Y.2019, VCDN is a new paradigm using cloud computing, network virtualization and software defined networking (SDN) technology for content delivery for various multimedia services, providing a CDN infrastruct
8、ure according to vendors needs. This Recommendation specifies the requirements for VCDN, including requirements on service provision, physical resource management, virtual resource management, VCDN logically isolated network partition (LINP) management, service management, backbone network and secur
9、ity consideration. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T F.743.4 2017-03-01 16 11.1002/1000/13178 Keywords Cloud computing, content delivery network, SDN, streaming service, virtualisation. * To access the Recommendation, type the URL http:/handle.itu.int/ in the a
10、ddress field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T F.743.4 (03/2017) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications,
11、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 telecommunications on
12、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 procedure laid dow
13、n 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 telecommunication
14、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 these mandatory
15、 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 RIGHTSITU draws attent
16、ion 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 members or others
17、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 represent th
18、e latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2017 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 F.743.4 (03/2017) ii
19、i Table of Contents Page 1 Scope . 1 2 References . 1 3 Definitions 1 3.1 Terms defined elsewhere 1 3.2 Terms defined within this Recommendation 2 4 Abbreviations and acronyms 2 5 Conventions 2 6 Background . 2 7 Overview of VCDN 3 8 Objectives . 4 9 Requirements 4 9.1 Service provision requirements
20、 4 9.2 Physical resource management requirements . 5 9.3 Virtual resource requirements 5 9.4 VCDN LINP requirements . 7 9.5 Service management requirements . 8 10 Backbone network requirements 9 11 Security considerations . 9 Appendix I Use cases for VCDN 11 I.1 Use case 1: the number of users is ra
21、pidly rising in one area . 11 I.2 Use case 2: one node is broken . 12 Bibliography. 14 Rec. ITU-T F.743.4 (03/2017) 1 Recommendation ITU-T F.743.4 Functional requirements for virtual content delivery networks 1 Scope This Recommendation describes the functional requirements for a virtual content del
22、ivery network (VCDN). The scope of this Recommendation covers: An overview of VCDN concept and the objectives of VCDN. The requirements for applying VCDN on service provision, all kinds of resources of VCDN, and security considerations. 2 References The following ITU-T Recommendations and other refe
23、rences 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 Recommendation are therefore encouraged to inv
24、estigate 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 not give it, as a stand-alone document, the s
25、tatus of a Recommendation. ITU-T Y.1901 Recommendation ITU-T Y.1901 (2009), Requirements for the support of IPTV services. ITU-T Y.2019 Recommendation ITU-T Y.2019 (2010), Content delivery functional architecture in NGN. ITU-T Y.3011 Recommendation ITU-T Y.3011 (2012), Framework of network virtualiz
26、ation for future networks. ITU-T Y.3300 Recommendation ITU-T Y.3300 (2014), Framework of software-defined networking. ITU-T Y.3500 Recommendation ITU-T Y.3500 (2014) Information technology Cloud computing Overview and vocabulary. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the
27、 following terms defined elsewhere: 3.1.1 logically isolated network partition (LINP) ITU-T Y.3011: A network that is composed of multiple virtual resources which is isolated from other LINPs. 3.1.2 network virtualization ITU-T Y.3011: A technology that enables the creation of logically isolated net
28、work partitions over shared physical networks so that heterogeneous collection of multiple virtual networks can simultaneously coexist over the shared networks. This includes the aggregation of multiple resources in a provider and appearing as a single resource. 3.1.3 virtual resource ITU-T Y.3011:
29、An abstraction of physical or logical resource, which may have different characteristics from the physical or logical resource and whose capability may be not bound to the capability of the physical or logical resource. 2 Rec. ITU-T F.743.4 (03/2017) 3.1.4 software-defined networking ITU-T Y.3300: A
30、 set of techniques that enables to directly program, orchestrate, control and manage network resources, which facilitates the design, delivery and operation of network services in a dynamic and scalable manner. 3.1.5 cloud computing ITU-T Y.3500: Paradigm for enabling network access to a scalable an
31、d elastic pool of shareable physical or virtual resources with self-service provisioning and administration on-demand. 3.2 Terms defined within this Recommendation This Recommendation defines the following term: 3.2.1 virtual content delivery network: A content delivery network using virtualisation
32、technology that enables the allocation of virtual storage, virtual machines, and network resources according to vendors requirements in a dynamic and scalable manner. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: AAA Authentication, Authorization, an
33、d Accounting ACL Access Control List CPU Central Processing Unit I/O Input/Output LINP Logically Isolated Network Partition OS Operating System QoS Quality of Service SDN Software Defined Networking SLA Service Level Agreement VCDN Virtual Content Delivery Network VLAN Virtual Local Area Network 5 C
34、onventions In this Recommendation, the following conventions are used: The keywords “is required“ indicate a requirement which must be strictly followed and from which no deviation is permitted, if conformance to this Recommendation is to be claimed. The keywords “is recommended“ indicate a requirem
35、ent which is recommended but which is not absolutely required. Thus this requirement need not be present to claim conformance. The keywords “can optionally“ indicate an optional requirement which is permissible, without implying any sense of being recommended. This term is not intended to imply that
36、 the vendors implementation must provide the option and the feature can be optionally enabled by the network operator/service provider. Rather, it means the vendor may optionally provide the feature and still claim conformance with the specification. 6 Background With the development of Internet tec
37、hnology, the network traffic resulting from audio and video services grows exponentially. In the future Internet, video services will be mainstream. A content delivery network (CDN) is technically a comprehensive solution to handle the increased demand for Rec. ITU-T F.743.4 (03/2017) 3 services. Ex
38、isting CDN architectures face the challenges of a dramatic increase in video service traffic, as well as additional construction and maintenance costs provided to various multi-vendor services. How to sufficiently take advantage of the resource of CDN to provide flexible and superior service is an i
39、mportant issue to be resolved. The essential character of virtualisation technology is the elastic allocation of resources. A virtual content distribution network (VCDN) uses virtualization technology to make a unified resource pool, to provide the infrastructure of CDN according to the vendors need
40、. VCDN uses the management interface to monitor CDNs load. VCDN can realize accurate infrastructure distribution and elastic resource scheduling. VCDN can integrate the resources of CDN, reduce construction cost and improve the scalability. 7 Overview of VCDN Virtual CDN provides content delivery se
41、rvice to multiple vendors. VCDN utilizes a set of techniques including cloud computing, network virtualization and software defined networking (SDN) to dynamically control and manage the computing and network resources, which improves scalability, flexibility and availability. Figure 1 illustrates t
42、he basic concept of VCDN. Figure 1 VCDN concept A typical CDN providing good performance content delivery service generally consists of many nodes which are located in different areas close to the end user. The nodes are deployed as physical resources such as servers, storage and switches. The physi
43、cal resources are converted into virtual 4 Rec. ITU-T F.743.4 (03/2017) resources such as virtual machines, virtual storage and virtual switches, which form a virtual resources pool utilizing virtualization technology. In order to provide service to multiple vendors in a single physical CDN, virtual
44、 resources are aggregated and isolated according to vendors service requirements. Every logically isolated network partition allocated to a specific customer is called a logically isolated network partition (LINP). A VCDN LINP is an aggregation of virtual resources in all the nodes. The LINP is mana
45、ged by LINP management which controls and configures the LINP in terms of VCDN vendors requirement. The virtual resources and physical resources are managed by resources management. When the requirements of a LINP are changing, the LINP management requires resource management to perform functions su
46、ch as adding or diminishing the virtual resources to the LINP, moving virtual resources from one node to the other node. When resource management is required to adjust backbone network performance, the resource management requires that network controller performs functions such as optimize routing,
47、expanding bandwidth, etc. Note that the backbone network may support software defined networking (SDN) functions. 8 Objectives Virtual CDN is a paradigm using cloud computing, network virtualization and SDN technology for content delivery for various multimedia services. VCDN provides a scalable and
48、 elastic CDN function pool of shareable physical or virtual resources to multiple vendors with self-service provisioning and administration on demand. See b-ETSI-GS-NFV001. The following are the advantages of applying VCDN: Suitable for providing service to multiple vendors. VCDN provides on-demand
49、CDN resource provisioning, which dynamically provides resources according to VCDN vendors needs. So it is more suitable for providing service multiple vendors. Rapid and flexible adaptation to the requirement of vendors. VCDN provides rapid provisioning of service to adapt to vendors demands by dynamically changing its configurations and re-allocating virtual resources. Increased availability and usage efficiency. VCDN increases the availability and efficiency in the usage of resources by assigning
