1、 International Telecommunication Union ITU-T Y.2251TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (03/2011) SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Next Generation Networks Service aspects: Interoperability of services and networks in NGN
2、Multi-connection requirements Recommendation ITU-T Y.2251 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.3
3、00Y.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
4、 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 GENERATION
5、NETWORKS Frameworks and functional architecture models Y.2000Y.2099 Quality 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.2299Numbering, naming and addressi
6、ng 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 details, please
7、 refer to the list of ITU-T Recommendations. Rec. ITU-T Y.2251 (03/2011) i Recommendation ITU-T Y.2251 Multi-connection requirements Summary In order to support multi-connection capability, new functions are required in the user equipment (UE) and network, such as connection management and coordinat
8、ion, QoS policy control, and access network selection. Recommendation ITU-T Y.2251 describes the requirements to support multi-connection. History Edition Recommendation Approval Study Group 1.0 ITU-T Y.2251 2011-03-16 13 Keywords Access network connection, coordination, management, multi-connection
9、, policy. ii Rec. ITU-T Y.2251 (03/2011) 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 received notic
16、e 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/. ITU 20
17、12 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.2251 (03/2011) 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 Recomm
18、endation . 2 4 Abbreviations and acronyms 3 5 Conventions 4 6 Multi-connection requirements . 4 6.1 Connection management 6 6.2 Multi-connection registration . 6 6.3 Multi-connection coordination . 6 6.4 Service transfer . 6 6.5 Service decomposition and composition 7 6.6 Multi-connection related po
19、licies . 7 6.7 QoS requirements in multi-connection . 8 6.8 QoS mapping among different access networks 8 6.9 Access network selection . 8 6.10 Access network monitoring 8 6.11 Identifying and binding of IP flows 9 6.12 Charging and accounting in multi-connection . 9 6.13 UE function in multi-connec
20、tion 9 6.14 IPv4/6 consideration . 10 6.15 Energy efficiency and energy/power management in multi-connection 10 6.16 Backward compatibility 10 6.17 Security requirement 10 7 Security considerations . 10 Appendix I QoS mapping among different access networks 11 Appendix II Generic scenarios of multi-
21、connection . 12 Appendix III Policy required for different scenarios 14 Bibliography. 15 Rec. ITU-T Y.2251 (03/2011) 1 Recommendation ITU-T Y.2251 Multi-connection requirements 1 Scope Multi-connection is the functionality which provides capability to the user equipment (UE) and network to maintain
22、more than one access network connection simultaneously. Furthermore, multi-connection controls and coordinates the media sessions and components across such access network connections. Different types of access network connections provide users with different user experiences, such as high throughpu
23、t, low delay, and high security. Multi-connection enables users to utilize any or all of the available access network connections in support of new service scenarios. It is recognized that operators and users will benefit from harmonization of multiple connections, such as efficient utilization of n
24、etwork resources, load balancing, reliability of connection and continuity of services. This Recommendation describes the requirements of multi-connection and provides a high-level overview of the functionality to be addressed. The descriptions cover aspects related to service requirements, capabili
25、ties requirements, functional requirements, and other technology requirements. 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 indica
26、ted 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 currently valid ITU-T Rec
27、ommendations 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 Q.1706 Recommendation ITU-T Q.1706/Y.2801 (2006), Mobility management requirements for NGN. ITU-T Q.2981 Recommendation ITU-T
28、 Q.2981 (1999), Broadband integrated services digital network (B-ISDN) and broadband private integrated services network (B-PISN) Call control protocol. ITU-T T.140 Recommendation ITU-T T.140 (1998), Protocol for multimedia application text conversation. ITU-T X.200 Recommendation ITU-T X.200 (1994)
29、 | ISO/IEC 7498-1:1994, Information technology Open Systems Interconnection Basic Reference Model: The basic model. ITU-T Y.1221 Recommendation ITU-T Y.1221 (2010), Traffic control and congestion control in IP-based networks. ITU-T Y.2011 Recommendation ITU-T Y.2011 (2004), General principles and ge
30、neral reference model for Next Generation Networks. ITU-T Y.2012 Recommendation ITU-T Y.2012 (2010), Functional requirements and architecture of next generation networks. ITU-T Y.2051 Recommendation ITU-T Y.2051 (2008), General overview of IPv6-based NGN. 2 Rec. ITU-T Y.2251 (03/2011) ITU-T Y.2052 R
31、ecommendation ITU-T Y.2052 (2008), Framework of multi-homing in IPv6-based NGN. ITU-T Y.2091 Recommendation ITU-T Y.2091 (2007), Terms and definitions for Next Generation Networks. ITU-T Y.2233 Recommendation ITU-T Y.2233 (2010), Requirements and framework allowing accounting and charging capabiliti
32、es in NGN. ITU-T Y.2261 Recommendation ITU-T Y.2261 (2006), PSTN/ISDN evolution to NGN. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 application ITU-T Y.2261: A structured set of capabilities, which provide value-added functionality
33、supported by one or more services, which may be supported by an API interface. 3.1.2 call ITU-T Q.2981: An association between two or more users using a telecommunication service to communicate through one or more networks. 3.1.3 connection ITU-T X.200: A connection is an association established for
34、 the transfer of data between two or more peer-(N)-entities. This association binds the peer-(N)-entities together with the (N1)-entities in the next lower layer. 3.1.4 handover ITU-T Q.1706: The ability to provide services with some impact on their service level agreements to a moving object during
35、 and after movement. 3.1.5 IP flow ITU-T Y.1221: An IP flow at a given interface is defined as the occurrence at that interface of the set of IP packets which match a given classification. An IP flow may consist of packets from a single application session, or it may be an aggregation comprising the
36、 combined traffic from a number of application sessions. When a classification may be subdivided into different sub-classifications (separate or overlapping), different IP subflows may be recognized in the corresponding IP flow. 3.1.6 service continuity ITU-T Q.1706: The ability for a moving object
37、to maintain ongoing service over including current states, such as users network environment and session for a service. 3.1.7 session ITU-T T.140: A logical connection between two or more user terminals for the purpose of exchanging information in text format on a real-time basis. 3.2 Terms defined
38、in this Recommendation This Recommendation defines the following terms: 3.2.1 multi-connection: The functionality which provides capability to the user equipment (UE) and network to maintain more than one access network connection simultaneously. NOTE 1 All connections are coordinated to provide ser
39、vice to higher layer entities. NOTE 2 In a multi-connection communications at least one UE is required to be a multi-connection UE. 3.2.2 service component: Part of a service which cannot be further decomposed. 3.2.3 service decomposition: Act of decomposing a service into several service components
40、. NOTE The original service logic can be restructured transparently to the end user and application. 3.2.4 service transfer: Act of moving, one or more services or service components belonging to a single multi-connection UE, from one access network associated with one interface of the multi-connect
41、ion UE to another access network(s) associated with other interface(s) of the multi-connection UE. Rec. ITU-T Y.2251 (03/2011) 3 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: 2G Second Generation wireless telephone technology 3G Third Generation wire
42、less telephone technology 3GPP 3rd Generation Partnership Project AP Access Point API Application Programming Interface BSS Base Station Subsystem CPU Central Processing Unit CS Circuit Switched DHCP Dynamic Host Configuration Protocol DNS Domain Name System FTP File Transfer Protocol GPRS General P
43、acket Radio Service GSM Global System for Mobile communications IP Internet Protocol LTE 3GPP Long Term Evolution MCS Modulation and Coding Scheme MPLS MultiProtocol Label Switching NGN Next Generation Network PC Personal Computer PPP Pont-to-Point Protocol PS Packet Switched QoS Quality of Service
44、RED Random Early Detection RSS Received Signal Strength RTP Real-time Transport Protocol SP Strict Priority UE User Equipment UMTS Universal Mobile Telecommunications System VoD Video on Demand VoIP Voice over IP VPN Virtual Private Network WFQ Weighted Fair Queue WiMax Worldwide Interoperability fo
45、r Microwave Access WLAN Wireless Local Area Network WRR Weighted Round Robin 4 Rec. ITU-T Y.2251 (03/2011) 5 Conventions In this Recommendation: The keywords “is required to“ indicate a requirement which must be strictly followed and from which no deviation is permitted if conformance with this Reco
46、mmendation is to be claimed. The keywords “is prohibited from“ indicate a requirement which must be strictly followed and from which no deviation is permitted if conformance with this Recommendation is to be claimed. The keywords “is recommended“ indicate a requirement which is recommended but which
47、 is not absolutely required. Thus this requirement need not be present to claim conformance. The keywords “is not recommended“ indicate a requirement which is not recommended but which is not specifically prohibited. Thus, conformance with this Recommendation can still be claimed even if this requir
48、ement is present. 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 the vendors implementation must provide the option and the feature can be optionally enabled by the network
49、operator/service provider. Rather, it means the vendor may optionally provide the feature and still claim conformance with this Recommendation. 6 Multi-connection requirements The multi-connection capability facilitates realization of the use cases described in b-ITU-T Y-Sup.9, such as balancing network load, higher throughput via connection aggregation or service transfer across connections. Take video conferencing as an example, the voice may be carried by a 2G or 3G netw
