MANET与Internet互联时的广播风暴抑制策略

Mobile Ad Hoc网络(MANET)与Internet互联时，如何使Internet网关适应MANET高度动态变化的网络条件与实际连接需求，以合理的开销向MANET通告可用网关信息是获取良好互联性能的关键。该文根据那些欲访问Internet的MANET节点距离Internet网关的实时位置及其访问需求自适应地设置网关通告报文之TTL值以实现最佳覆盖，同时采用基于计数的广播风暴抑制策略有效地抑制了洪泛网关通告报文所形成的广播风暴。用NS2进行的仿真说明该文提出的方法在将节点密度及规模变化的MANET接入Internet时能获取良好的连接性能而开销合理。     

MANET路由子层微移动管理

在采用无线自组网按需平面距离矢量(AODV)路由协议的移动自组网(MANET)网关设计中,针对MANET节点的微移动特性,提出应用于MANET路由子层的微移动管理策略,并在AODV路由协议中进行实现。在NS2平台上的仿真结果表明,采用微移动管理策略的MANET网关可有效降低MANET网络访问Internet的时延,并能减少MANET内控制报文的开销。     

基于负载均衡的移动自组网接入技术研究

在移动自组网（MANET）与Internet互联的网络结构中,针对传统单网关接入的不足,提出一种基于多网关负载均衡的非对称接入技术。该技术由网关发现、网关注册和数据传输三个步骤实现。进行了NS2软件仿真实验,结果表明,该接入算法在网络重负荷的情况下能有效地均衡网络中MANET节点与网关节点的负载,有效延长网络寿命。     

MANET中基于代理的Internet网关发现机制

针对大规模、高动态的移动Ad Hoc网络环境,提出一种基于代理的Internet网关发现机制（PGDIS）。PGDIS从移动节点中自动选举出代理网关,由Internet网关周期性地向代理网关发送网关公告消息。移动节点可以通过最近的代理网关建立通往Internet网关的路由。仿真结果表明,PGDIS在保持较高数据包投递率的前提下降低了传输延时。     

移动自组网与Internet互连的AODV协议扩展

针对移动自组网与Internet互连时网关带宽瓶颈问题,提出将域内有线节点视为移动自组网内部的互连节点的模型.从而把互连问题转化为含有有线节点的移动自组网路由协议的扩展问题,进而提出了支持与Internet互连的AODV扩展协议iAODV (Internet-AODV).通过结合多个互连节点和扩展AODV路由协议,iAODV把互连节点切换与移动节点之间的路由协议相统一,可以有效缓解互连节点的带宽瓶颈.NS2模拟实验表明,该协议可以为移动自组网提供比较稳定的Internet接入性能,且结合有线链路减小了互连延迟时间和系统开销、提高了包递交率,性能优于AODV.     

对移动自组网体系结构的再思考

移动自组网(MANET)是一组由路由和转发功能的移动节点组成的一个多跳、无中心的临时性自治系统.分析了MA-NET节点结构特点和常用的两种拓扑结构,即平面结构和分级结构.给出了网络体系结构定义,包括描述协议和通信机制的设计准则和实现网络体系结构的方法.报告了Internet体系结构发展过程现状,提出了MANET协议栈一般模型结构及基于MANET的管理平台,总结了对MANET体系结构发展建议,得到了网络体系结构中网络分层是典型的"结构决定功能"的系统科学的基本观点和网络体系结构与需求,技术相关的结论.     

MANET与Internet互联时的自适应增强机制

移动自组网(MANET)与Internet的互联能有效扩展Internet覆盖和MANET应用范围。针对既有互联协议无法适应MANET动态变化的网络条件,在网关发现过程中形成广播风暴以及将全局路由建立于单向链路上等原因所导致的互联性能恶化,提出了一种具有自适应增强机制的互联协议,该协议一方面依据实际网络条件与Internet访问需求自动调整网关通告分组在MANET中的覆盖范围;另一方面,基于网络条件自适应调整发送间隔的HELLO分组可同时避免全局路由计算过程引入单向链路以及形成广播风暴。仿真结果表明,此自适应增强协议能够以合理的开销,在复杂而多变的应用环境下为MANET提供优化的互联性能。     

无线自组网与Internet互联方案比较

通过无线自组网路由协议与Internet路由协议的协作,移动节点可经由多跳与网关节点通信,从而实现移动节点与Internet互联.首先分析了自组网与Internet互联所面临的困难,然后详细比较了多种已有的互联方案,从寻址、网关带宽瓶颈、路由复杂性及组播等方面进行了对比分析,最后总结了各种方案的性能特点和适用场景,并展望了该领域的进一步研究方向.     

无线移动网关配置协议研究

向移动领域扩展是下一代互联网的主要发展方向,移动互联网不仅能支持单个移动终端,而且需要支持中小规模的移动子网,其中移动网关的配置及服务策略是关键技术之一。为此提出了一个层次化的配置协议,利用移动自组网（MANET）分簇管理的思想,将移动终端进行适当分簇并选举簇首管理内部节点,集成移动网关将不同移动簇群的无线网络进行连接。在此基础上提出了三种移动网关的服务策略,对该配置协议进行了仿真试验,分析比较了在不同服务策略下移动网关的关键性能指标,验证了该协议能够较好地满足移动网络的需求。     

无线自组网簇间网关支配集优化策略

无线自组网的网关负责簇间信息的转发。逻辑上能和其他簇内节点通信的节点都可以做网关，这些节点相对于簇首节点称为网关支配集。为了减少网关支配集中的冗余网关，给出一种以节点唯一标识权值比较实现优化网关支配集的策略，可以消除簇间的冗余网关，使相交簇间仅存在一个网关，而相邻簇间仅存在一对网关。仿真结果表明，在保证网络连通的情况下，该策略可以有效地减少重播包的比率和广播延时。     

基于移动Ad Hoc路由技术的无线局域网

无线网关的覆盖范围受到衰减和干扰等因素的限制，因此部署无线网关的代价是比较高的。为了减少所需的网关数，同时又能保持相同的覆盖范围，可以将Adhoc路由协议集成到无线局域网的网络协议中，从而使不在网关直接传输范围内的结点也能够间接地获取Internet连接。详细讨论了这种无线局域网的地址配置和路由问题。仿真结果验证了该方法的有效性。     

基于拓扑的MANET路由协议性能与网络覆盖密度相关性的研究

结合实际的移动adhoc组网研究,针对以往MANET路由协议性能评价中没有考虑网络连通性的问题,引入了反映网络节点通信能力和网络连通性的网络覆盖密度概念,并进行了基于拓扑的MANET典型路由协议性能与网络覆盖密度相关性的研究.仿真结果分析表明,基于拓扑的adhoc路由协议包递送率随着网络密度的增加而增加,并与其构成S曲线.通过最低网络覆盖密度的定义,为实际的adhoc组网中各种路由协议的适用条件提供了明确的评判依据.     

Ad Hoc网络中改进的路由协议S-DSR的设计与分析

路由协议是移动AdHoc网络中的一个重要部分,很多研究表明,AdHoc网络的特性使得传统的路由协议不再有效。在简述动态源路由协议DSR,及其存在的问题后,着重介绍了具有安全路由发现、多路由的使用和提高路由缓存管理的S-DSB协议的设计,并对S-DSB与DSB就包传递率、包截获率等进行了性能仿真与分析比较。     

Ad hoc动态源路由协议的移动网关扩展

动态源路由协议（Dynamic Source Routing Protocol，DSR）是由移动节点组成的多跳无线AdHoc网络中一种简单和行之有效的路由协议。它使得一个Adhoc网内各个节点得以互联，但是却没有提供给它们必要的Internet接入方式。为这种封闭的Adhoc网络提供Intemet访问能力，将大大提高其应用价值。详细介绍了为引入移动网关（Mobile Gateway，MG）的概念对原始的DSR协议所进行的改进工作，从而使配有DSR协议的Adhoc网内节点可以通过移动网关访问Internet。同时还给出了我们在自行开发的DSR实验床上实现的移动网关及实际应用价值的评估实验。     

A MANET accessing Internet routing algorithm based on dynamic gateway adaptive selection

Based on the study on communication situation of mobile ad hoc network (MANET) accessing Internet and taking the gateway important function of accessing network into account, a MANET accessing Internet routing algorithm based on dynamic gateway adaptive selection (MRBDAS) is presented. It considers candidate gateways’ connecting degree, load degree, residual energy, and movement rate synthetically and uses the idea of group decision-making method for reference. The algorithm employs the methods of multipaths and query localization technique based on old path information to maintain routing adaptively. Compared with the existing accessing routing algorithm based on dynamic gateway, the algorithm demonstrates in its simulations that by bringing dynamic gateways colony function, the MRBDAS can improve network throughput, reduce average transmission delay of data packets and routing overhead, and prolong accessing network life. The validity of MRBDAS has been proven.     

Ad Hoc网络多路径需求路由及路径熵选择算法

无线移动Ad Hoc网络是一种不依赖任何固定基础设施的移动无线多跳网络.由于其动态性和资源的限制,在Ad Hoc网络中提供多路径路由是一个重要的研究课题.描述了一种Ad Hoc网络中基于信息熵选择的稳定多路径路由算法(stability multipath on-demand routing,简称SMDR),提出了路径熵的度量参数,并利用路径熵来选择稳定的、长寿命的多路径,减少了重构路由的次数,从而在网络拓扑频繁变化的Ad Hoc网络环境中较好地提供QoS保证和提高数据传输率.仿真结果表明,SMDR协议改进了分组传输率、端到端时延和路由负载率.SMDR协议为解决动态的Ad Hoc网络多路径传输提供了一种新的有效途径.     

A MANET accessing Internet routing algorithm based on dynamic gateway adaptive selection

Based on the study on communication situation of mobile ad hoc network (MANET) accessing Internet and taking the gateway important function of accessing network into account, a MANET accessing Internet routing algorithm based on dynamic gateway adaptive selection (MRBDAS) is presented. It considers candidate gateways’ connecting degree, load degree, residual energy, and movement rate synthetically and uses the idea of group decision-making method for reference. The algorithm employs the methods of multipaths and query localization technique based on old path information to maintain routing adaptively. Compared with the existing accessing routing algorithm based on dynamic gateway, the algorithm demonstrates in its simulations that by bringing dynamic gateways colony function, the MRBDAS can improve network throughput, reduce average transmission delay of data packets and routing overhead, and prolong accessing network life. The validity of MRBDAS has been proven.     

Anonymous Geo-Forwarding in MANETs through Location Cloaking

In this paper, we address the problem of destination anonymity for applications in mobile ad hoc networks where geographic information is ready for use in both ad hoc routing and Internet services. Geographic forwarding becomes a lightweight routing protocol in favor of the scenarios. Traditionally the anonymity of an entity of interest can be achieved by hiding it among a group of other entities with similar characteristics, i.e., an anonymity set. In mobile ad hoc networks, generating and maintaining an anonymity set for any ad hoc node is challenging because of the node mobility, consequently the dynamic network topology. We propose protocols that use the destination position to generate a geographic area called {em anonymity zone (AZ)}. A packet for a destination is delivered to all the nodes in the AZ, which make up the anonymity set. The size of the anonymity set may decrease because nodes are mobile, yet the corresponding anonymity set management is simple. We design techniques to further improve node anonymity and reduce communication overhead. We use analysis and extensive simulation to study the node anonymity and routing performance, and to determine the parameters that most impact the anonymity level that can be achieved by our protocol.     

A global security architecture for operated hybrid WLAN mesh networks

Hybrid Wireless Mesh Network (HWMN) is a new wireless networking paradigm. Unlike traditional wireless networks, in HWMNs, hosts may rely on each other to keep the network connected. Operators and wireless internet service providers are choosing HWMNs to offer Internet connectivity, as it allows fast, easy and affordable network deployments. One main challenge in design of these networks is their vulnerability to security attacks. In this paper, we investigate the main security issues focusing on the most vulnerable part of the hybrid WLAN mesh infrastructure which concerns the ad hoc network part. Through our proposed architecture, Security Architecture for Operator’s Hybrid WLAN Mesh Network (SATHAME), we identify the new challenges and opportunities posed by this emerging networking environment and explore approaches to secure users, data and communications. From the analysis of strengths and weaknesses of secured routing protocols, we designed a new robust routing structure called MacroGraph (MG). MG structure is extracted from the mesh ad hoc network for each communication to be established between a source and a destination. Especially, MG is a robust structure based on node-disjoint path routing scheme and dynamic trust management that can be adapted to respond to applications’ security requirements. We present a performance analysis of our efficient, robust and scalable multipath reactive secured routing protocol. We investigate the behavior of our proposed scheme under two attack scenarios: Packet Dropping and Route Error attacks in dense network configurations.     

移动Ad Hoc网络多播路由协议的研究进展

移动AdHoc网络是一个自组织、移动节点通过无线链路组成的动态拓扑变化的网络.由于网络规模小、无基础设施、构建迅速等特点,从而广泛用于紧急事件、军事和民用领域以及多媒体应用等.随着网络应用规模的增长,在移动AdHoc网络中支持多播路由成为网络领域中一类重要的研究课题.该文综述了移动AdHoc网络多播路由方面的一些最新工作,论述了设计移动AdHoc网络多播路由协议的特性、问题和技术,详细描述和比较了目前典型的移动AdHoc网络多播路由协议,为进一步的应用和研究提出了新的课题.