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 Y.2029 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (06/2015) SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS AND NEXT-GENERATION NETWORKS Next Generation Networks Frameworks and functional archite
2、cture models A multi-path transmission control in multi-connection Recommendation ITU-T Y.2029 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 midd
3、leware Y.200Y.299 Network 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.110
4、0Y.1199 Architecture, 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 o
5、ver NGN Y.1900Y.1999 NEXT GENERATION 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.225
6、0Y.2299 Enhancements to NGN 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
7、COMPUTING Y.3500Y.3999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T Y.2029 (06/2015) i Recommendation ITU-T Y.2029 A multi-path transmission control in multi-connection Summary The objective of Recommendation ITU-T Y.2029 is to describe the multi-path transmissi
8、on control in multi-connection. This Recommendation also covers scenarios, requirements, mechanisms, information flows, and provides consideration to topics on security. Multi-path transmission control is a mechanism in the multi-connection network, which is provided based on requirements, such as c
9、ongestion control and traffic transmission adjustment, retransmission scheme, service flow separation, energy efficiency and management. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T Y.2029 2015-06-29 13 11.1002/1000/12510 Keywords Multi-connection, multi-path, transmissio
10、n control. _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address 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 Y.2029 (06/2015) FOREWORD The International Telecommunication Un
11、ion (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 organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions
12、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 topics for study by the ITU-T study groups which, in turn, produce Recommendations on t
13、hese 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 prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the ex
14、pression “Administration“ is used for conciseness to indicate both a telecommunication 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 applic
15、ability) 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 to express requirements. The use of such words does not suggest that compliance with th
16、e Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTSITU 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 applicabil
17、ity 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 notice of intellectual property, protected by patents, which may be required to implement
18、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 2015 All rights reserved. No part of this publication may be reproduced, by any means w
19、hatsoever, without the prior written permission of ITU. Rec. ITU-T Y.2029 (06/2015) 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 2 5 Conventions 3 6 Scenarios and requir
20、ements 3 6.1 Scenarios . 3 6.2 Requirements 4 7 A multi-path transmission mechanism . 5 7.1 Overview 5 7.2 Initialization of the mechanism 6 7.3 Description of the mechanism 7 8 Capability requirements 10 8.1 MPT-enhanced MUE requirements in the sending side . 10 8.2 MPT-enhanced MUE requirements in
21、 the receiving side 11 8.3 MPT-enhanced MPC-FE requirements 11 8.4 MPT-enhanced SCF requirements . 11 9 Information flow . 12 9.1 Path selection mechanism . 12 9.2 Traffic adjustment mechanism . 15 10 Security considerations . 18 10.1 Security requirement 18 10.2 Attack defence 19 Bibliography. 22 R
22、ec. ITU-T Y.2029 (06/2015) 1 Recommendation ITU-T Y.2029 A multi-path transmission control in multi-connection 1 Scope This Recommendation describes the scenarios and requirements of multi-path transmission control in multi-connection and provides the mechanisms of multi-path transmission control. T
23、he descriptions cover aspects related to capability requirements, information flows and security. 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,
24、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 edition of the Recommendations and other references listed below. A list of the curren
25、tly 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 Q.1706 Recommendation ITU-T Q.1706/Y.2801 (2006), Mobility management requirements for NGN. ITU-T X.200 Re
26、commendation ITU-T X.200 (1994) | ISO/IEC 7498-1:1994, Information technology Open Systems Interconnection. ITU-T X.800 Recommendation ITU-T X.800 (1991), Security architecture for Open Systems Interconnection for CCITT applications. ITU-T Y.2001 Recommendation ITU-T Y.2001 (2004), General overview
27、of NGN. ITU-T Y.2027 Recommendation ITU-T Y.2027 (2012), Functional architecture of Multi-connection Requirements. ITU-T Y.2091 Recommendation ITU-T Y.2091 (2011), Terms and definitions for next generation networks. ITU-T Y.2201 Recommendation ITU-T Y.2201 (2009), Requirements and Capabilities for I
28、TU-T NGN. ITU-T Y.2233 Recommendation ITU-T Y.2233 (2008), Requirements and framework allowing accounting and charging capabilities in NGN. ITU-T Y.2251 Recommendation ITU-T Y.2251 (2011), Multi-connection requirements. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following
29、 terms defined elsewhere: 3.1.1 multi-connection ITU-T Y.2251: The functionality which provides capability to the user equipment (UE) and network to maintain more than one access network connection simultaneously. 3.1.2 multi-connection user equipment ITU-T Y.2027: A user equipment which can support
30、 two or more network connections simultaneously under the control of a network enhanced for multi-connection capability. 2 Rec. ITU-T Y.2029 (06/2015) 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 multi-path connection: A set of one or more sub-trans
31、mission flows, over which the application in a multi-path transmission enhanced multi-connection user equipment can communicate with the corresponding application. 3.2.2 multi-path transmission enhanced multi-connection policy control function entity: A multi-connection policy control function entit
32、y ITU-T Y.2027 with enhanced capabilities of multi-path transmission control within the transport layer. 3.2.3 multi-path transmission enhanced multi-connection user equipment: A multi-connection user equipment ITU-T Y.2027 with enhanced capabilities of multi-path transmission control within the tra
33、nsport layer. 3.2.4 multi-path transmission enhanced service control function: A service control function ITU-T Y.2027 with enhanced capabilities of multi-path transmission control within the transport layer. 3.2.5 path: The route taken by the multi-path transmission packets between two associated m
34、ulti-path transmissions enhanced multi-connection user equipment. If the user equipment is not enhanced with multi-path transmission capability, the multi-path transmission enhanced service control function can be used as a proxy. A path can be uniquely identified by the associated IP addresses and
35、port number pairs. 3.2.6 sub-transmission flow: A unidirectional logical channel established from one multi-path transmission enhanced multi-connection user equipment to another, which forms part of a larger multi-path connection. 4 Abbreviations and acronyms This Recommendation uses the following a
36、bbreviations and acronyms: ACK Acknowledgement Cwnd Congestion Window ICV Integrity Check Value MPC-FE Multi-connection Policy Control Function Entity MPTCP Multi-Path TCP MPT-enhanced MPC-FE Multi-Path Transmission enhanced Multi-connection Policy Control Function Entity MPT-enhanced MUE Multi-Path
37、 Transmission enhanced Multi-connection User Equipment MPT-enhanced SCF Multi-Path Transmission enhanced Service Control Function MUE Multi-connection User Equipment PLR Packet Loss Rate QoS Quality of Service RTO Retransmission Timeout RTT Round-Trip Time SCF Service Control Function SCTP Stream Co
38、ntrol Transmission Protocol SCTP-CMT Stream Control Transmission Protocol-Concurrent Multi-path Transfer Rec. ITU-T Y.2029 (06/2015) 3 SSThresh Slow Start Threshold UE User Equipment WLAN Wireless Local Area Network 5 Conventions In this Recommendation: The keyword “is required to“ indicate a requir
39、ement which must be strictly followed and from which no deviation is permitted if conformance to this document is to be claimed. The keyword “is prohibited from“ indicate a requirement which must be strictly followed and from which no deviation is permitted if conformance to this document is to be c
40、laimed. The keyword “is recommended“ indicate a requirement which is recommended but which is not absolutely required. Thus this requirement is not present to claim conformance. The keyword “is not recommended“ indicate a requirement which is not recommended but which is not specifically prohibited.
41、 Thus, conformance with this specification can still be claimed even if this requirement is present. The keyword “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
42、 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 Scenarios and requirements 6.1 Scenarios The general scenarios in b-ITU-T
43、Y Suppl.9 are required to be taken into consideration in multi-path transmission control. Typical scenarios are derived based on scenario C of b-ITU T Y Suppl.9 where a multi-connection user equipment (MUE) can establish multiple connections to heterogeneous access networks controlled by different a
44、ccess control functions, but the same service control function for a specific service. According to the relationship among the multiple service flows, these scenarios can be further classified into: 1) Scenario I In scenario I, an MUE establishes multiple connections to heterogeneous access networks
45、, for example, in a video conference: voice is transmitted by 2G, 3G or long term evolution (LTE) to assure real-time service, and video is transmitted by wireless local area network (WLAN) which has higher bandwidth and may be cost efficient for a large number of network flows. In the transport lay
46、er, the flows can be transported in multiple paths. In this scenario, the multiple service data flows may have a native coupled relationship, but some mechanisms are required to guarantee the aggregation of the service. Cache and synchronization are the necessary mechanisms for service aggregation.
47、2) Scenario II In scenario II, an MUE is required for access to heterogeneous access networks simultaneously, such as 2G, 3G or WLAN. For example, to achieve greater bandwidth when downloading a multimedia file with a large volume of data, the MUE chooses a WLAN connection for download. When time is
48、 limited, to achieve a higher transmission rate, the multimedia file will be split and transferred to both the WLAN and 3G paths in the transport layer. 4 Rec. ITU-T Y.2029 (06/2015) In this scenario, the multiple data flows are split and aggregation is simply based on the service separation policy
49、and data scheduling mechanism. 6.2 Requirements In ITU-T Y.2251 IP flows are identified and bound to the proper connections. Because the connection status and service flows change dynamically, some connections may become overloaded and the lost data packets will be retransmitted frequently, thus reducing data transmission efficiency. Occasionally, data transmission through a single path cannot meet a users service requirements such as real-time demand for large amounts of data. In m
