【作者】 董德才；

【导师】 程时端；

【作者基本信息】 北京邮电大学 ， 计算机科学与技术， 2008， 硕士

【摘要】 随着无线通信技术的快速发展,通过多种无线接入技术接入因特网成为了未来网络发展的趋势。多路传输技术研究在源主机和目的主机之间,同时使用多条路径传输数据,其目的在于有效提高网络资源的利用效率,提高端到端的吞吐量。目前,网络层、传输层和应用层都有实现多路传输的技术方案。但是,现有的多路传输方案还处在实现或改进多路传输机制的阶段,很少关注和研究移动过程中路径管理和路径选择策略问题,缺乏对移动场景的支持。因此,移动环境中的多路传输技术是未来移动性管理中的重要研究点之一。在现有多路传输技术中,传输层的方案因其端到端控制、传输控制机制而备受关注,其关键在于将总体的流量控制与单个路径的拥塞控制解耦合。而在SCTP协议设计中,其最重要特性之一是多家乡性,允许终端携带多个网络接口,另外,IETF又为SCTP做了动态地址重配置扩展,形成移动SCTP协议(mSCTP),具有移动性支持能力。因此,很多研究中都选择SCTP实现多路传输。本文对移动场景中基于mSCTP的多路传输技术进行研究,分析了其中的关键技术问题:基本传输机制的改进,移动过程中路径管理、路径选择策略的制定。本文对以上三个问题进行了详细的分析研究,结合国内外对该问题的研究现状,提出和借鉴了相应的解决方案。同时,在NS-2仿真软件中实现了上述方案,设计开发仿真场景,使用吞吐量参数对仿真实验进行分析总结,从实验结果可以得出:终端根据移动过程中所处的实际网络环境选择合适的网络进行多路传输,提高关联间吞吐量,有效利用网络资源。本文最后对LKSCTP项目模块进行安装、测试,并对在Linux环境中实现基于mSCTP多路传输方案做需求分析和概要设计。更多还原

【Abstract】 With the development of wireless communication technology, it is an obvious trend that we can access to Internet using heterogeneous wireless access networks. The multi-path transmission technology use multiple paths to transmit data simultaneously. It aims at improving the network efficiency and end-to-end throughput. The existing multi-path transmission schemes are realized at network layer, transport layer or application layer. However, the existing schemes focus on basic transmission mechanism implementation, while paying little attention on path management and path selection strategies, i.e., lack of support for mobile environments. Therefore, the multi-path transmission technology in mobile environment is one of the important research issues in mobility management.Because of end-to-end control and transmission control mechanism, transport layer is suitable to implement concurrent multi-path transmission. And the key factor is to decouple the congestion control for the whole data transmission with the flow control for each path. In the design of SCTP (Stream Control Transmission protocol), multi-homing is one of the good features, which allowing for multi-interface terminals. In addition, IETF designed the DAR (Dynamic Address Reconfiguration) extension for SCTP, i.e., mobile SCTP(mSCTP), which has mobility supporting ability. Therefore, many schemes select SCTP to implement multi-path transmission.This dissertation mainly focused on the key problems to implement the multi-path transmission based on mSCTP protocol in mobile environments. Based on analysis to the existing schemes, the key problems are proposed: modification of the original transmission mechanisms, path management solution in mobile environment, path selection strategy. Corresponding solutions for these three problems are proposed. In addition, the proposed solutions are implemented in NS-2 network simulation software. Then the simulation scenarios are designed and developed. Simulation results show that this proposed solution can improve the end-to-end throughput of an association and the network efficiency in mobile environment. Finally, we installed and tested the LKSCTP module, and we proposed preliminary design for implementing multi-path transmission based on mSCTP in mobile environment in Linux OS.更多还原