1、 InteITTELECOSTANDAOF ITU SERIINFRAND Next architFramIPv6RecornatiU-TMMUNICATRDIZATIONES Y: GASTRUNEXT-GGeneraecture mework-basedmmendonal ION SECTORLOBALCTUREENERAtion Netodelsof venext gation ITTelecINFOR, INTERTION works rtical meneraU-T Y.ommuMATIONET PNETWOFrameultihotion ne2056 nicatN ROTOCRKS
2、 works aming tworkion UY.2(OL ASPnd funcin s nion05608/2011ECTS tional ) 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 Netw
3、ork aspects 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,
4、access, 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 N
5、EXT GENERATION 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, nami
6、ng and addressing Y.2300Y.2399 Network management Y.2400Y.2499 Network control architectures and protocols Y.2500Y.2599 Smart ubiquitous networks Y.2600Y.2699 Security Y.2700Y.2799 Generalized mobility Y.2800Y.2899 Carrier grade open environment Y.2900Y.2999 Future networks Y.3000Y.3099 For further
7、details, please refer to the list of ITU-T Recommendations. Rec. ITU-T Y.2056 (08/2011) i Recommendation ITU-T Y.2056 Framework of vertical multihoming in IPv6-based next generation networks Summary Recommendation ITU-T Y.2056 describes a framework for vertical multihoming in IPv6-based next generat
8、ion networks (NGN). This Recommendation provides the definition, requirements, methods, functional architecture and applications of vertical multihoming in IPv6-based NGN. History Edition Recommendation Approval Study Group 1.0 ITU-T Y.2056 2011-08-06 13 Keywords IPv6, multihoming, NGN, vertical mul
9、tihoming. ii Rec. ITU-T Y.2056 (08/2011) 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 permanent or
10、gan 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, establishes the
11、 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 standards are
12、 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 Recommendati
13、on 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 are used
14、 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 Intellect
15、ual 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 received n
16、otice 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/ipr/. IT
17、U 2012 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.2056 (08/2011) iii Table of Contents Page 1 Scope 1 2 References. 1 3 Definitions 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this Re
18、commendation . 2 4 Abbreviations and acronyms 2 5 Conventions 3 6 Description of vertical multihoming in IPv6-based NGN 3 7 Requirements of vertical multihoming in IPv6-based NGN 4 7.1 Multihoming features and requirements of each layer . 4 7.2 Interaction across several layers . 5 7.3 Resource mana
19、gement of vertical multihoming . 5 7.4 Other requirements for vertical multihoming . 6 8 Methods of vertical multihoming . 6 8.1 Methods of vertical multihoming in terms of correspondence between IPv6 address and interface 6 8.2 Methods of vertical multihoming in terms of supporting layers 7 9 Funct
20、ional architecture of vertical multihoming 9 9.1 Functional architecture of vertical multihoming on the host side 9 9.2 Overall architecture of vertical multihoming on the network side . 10 10 Applications of vertical multihoming . 11 10.1 Use cases related to lower layer . 11 10.2 Use cases related
21、 to upper layer . 13 11 Security considerations . 14 Bibliography. 15 Rec. ITU-T Y.2056 (08/2011) 1 Recommendation ITU-T Y.2056 Framework of vertical multihoming in IPv6-based next generation networks 1 Scope As heterogeneous access technologies have been developed, network nodes have been given the
22、 ability to simultaneously connect multiple access networks to support reliability, load sharing and mobility. These simultaneous multiple connections are established through multiple accesses to next generation networks (NGNs) using multiple access technologies, multiple network interfaces, multipl
23、e Internet Protocol version 6 (IPv6) addresses and multiple transport sessions. To provide efficient simultaneous multiple connections, it is required to consider the impact from/on multiple access technologies, multiple network interfaces and multiple transport sessions. This Recommendation defines
24、 vertical multihoming as multihoming based on the characteristics of simultaneous multiple connections of several layers, which are managed vertically across several layers. This Recommendation describes a framework of vertical multihoming in IPv6-based NGN. This Recommendation describes or defines:
25、 vertical multihoming; requirements of vertical multihoming; methods of vertical multihoming; functional architecture of vertical multihoming; applications of vertical multihoming. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in th
26、is 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 applying the most recent edi
27、tion of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is published regularly. 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.2001 Recommendation I
28、TU-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.2051 Recommendation ITU-T Y.2051 (2008), General Overview of IPv6-based NGN. ITU-T Y.2052 Recommendation ITU-T Y.2052 (20
29、08), Framework of multi-homing in IPv6-based NGN. ITU-T Y.2701 Recommendation ITU-T Y.2701 (2007), Security requirements for NGN release 1. 2 Rec. ITU-T Y.2056 (08/2011) 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 IPv6-based NGN ITU
30、-T Y.2051: This refers to NGN that supports addressing, routing protocols and services associated with IPv6. An IPv6-based NGN shall recognize and process the IPv6 headers and options, operating over various underlying transport technologies in the transport stratum. 3.1.2 IPv6 multihoming ITU-T Y.2
31、052: A feature of an IPv6 host and/or IPv6 network that enables the host or network to be multihomed to networks through multiple network interfaces and multiple IPv6 addresses. 3.1.3 fault tolerance b-ITU-T E.800: The attribute of an item that makes it able to perform a required function in the pre
32、sence of certain given sub-item faults. 3.1.4 load balancing ITU-T Y.2052: A scheme by which the traffic load could be separated and balanced to effectively utilize the network resources (e.g., link bandwidth). 3.1.5 network interface ITU-T Y.2052: A device to be used by a node to connect to a netwo
33、rk. 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 multihoming: Multiple links between an end-point and one or more transport networks. Multihoming may be used, for example, for load balancing or protection via diverse routes. 3.2.2 vertical multihomi
34、ng: A feature of multihoming based on the characteristics of simultaneous multiple connections of several layers which are managed vertically across several layers. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: DCCP Datagram Congestion Control Protoc
35、ol IP Internet Protocol IPv4 Internet Protocol version 4 IPv6 Internet Protocol version 6 MAC Media Access Control NACF Network Attachment Control Functions NGN Next Generation Networks OS Operating System PHY PHYsical Layer QoS Quality of Service RACF Resource and Admission Control Functions SCTP S
36、tream Control Transmission Protocol TCP Transmission Control Protocol UDP User Datagram Protocol Rec. ITU-T Y.2056 (08/2011) 3 5 Conventions None. 6 Description of vertical multihoming in IPv6-based NGN IPv6-based NGN ITU-T Y.2051, as one example of NGN, consists of a core network and heterogeneous
37、access networks which allows flexible use of various interfaces. In addition, by using IPv6 multihoming capability ITU-T Y.2052, a network and/or a network node are able to have multiple network connections via multiple network interfaces with multiple IPv6 addresses. Although a network and/or a net
38、work node have multiple network connections with IPv6 multihoming, generally, it uses only one network connection at one time. Other network connections remain to prepare for a secondary (backup) connection and are used for special cases such as fault tolerance, providing higher bandwidth, load bala
39、ncing, and mobility. There is a difference between providing multiple network connections and providing simultaneous multiple network connections with respect to how many network connections are being utilized at a given moment. As heterogeneous access technologies are widely deployed in NGN, an NGN
40、 node can have the ability to connect various access networks simultaneously ITU-T Y.2001 and ITU-T Y.2011. In multiple network connections due to heterogeneous access networks, many layers are used to establish multiple network connections. From the point of view of the physical (PHY)/media access
41、control (MAC) layer, there may be multiple network interfaces/MAC protocols which are directly related to each access technology, and these multiple network interfaces/MAC protocols may be simultaneously used. So, in PHY/MAC layer, there are multiple link layer connections to communicate with other
42、nodes. From the network layers aspect, there may be multiple IPv6 addresses/IPv6 prefixes which are simultaneously used to establish multiple communication paths. So, in the network layer, there are multiple network layer connections to communicate with other nodes. From the transport layers aspect,
43、 there may be multiple transport layer sessions which are simultaneously used. When considering how multiple network connections are established, each layer has a specific role for multiple network connections. Multiple network connections are made with the help of each layer and there is no interac
44、tion or relationship between the layers. However, to make efficient multiple network connections and manage these connections, it is required to consider the interaction and the relationship between layers. To do this, the concept of vertical multihoming is used. In vertical multihoming, each layer
45、has its specific multihoming features, which should be harmonized between layers. Figure 1 shows the multihoming of each layer and vertical multihoming. This Recommendation defines vertical multihoming as multihoming based on the characteristics of simultaneous multiple connections of several layers
46、, which are managed vertically across several layers. 4 Rec. ITU-T Y.2056 (08/2011) Y.2056(11)_F01Application layermultihomingTransport layermultihomingNetwork layermultihomingMAC layermultihomingPhysical layermultihomingApplication layer Application layerTransport layer Transport layerNetwork layer
47、 Network layerMAC layer MAC layerPhysical layer Physical layerVertical multihoming Host 1IPv6-basedaccess network 1 IPv6-basedaccess networkIPv6-basedaccess networkIPv6-basedaccess network 2IPv6-basedaccess network 3IPv6-basedcore networkHost 2Figure 1 Concept of vertical multihoming In vertical mul
48、tihoming, each layer has multihoming features and many network resources are used to establish multiple network connections. In PHY/MAC layer, multiple access technologies, multiple network interfaces, and multiple radios are network resources. In the network layer, multiple IPv6 addresses and multi
49、ple IPv6 prefixes are network resources. In the transport layer, multiple transport sessions are network resources. To establish multiple network connections and manage network resources efficiently, an integrated and harmonized network management is needed. 7 Requirements of vertical multihoming in IPv6-based NGN With regard to the requirements of multihoming for IPv6-based NGN, the general, site specific, and host specific requirements are described in ITU-T Y.2052. As vertical multihoming is based on
