Performance analysis of mobile ad hoc networks under flooding attacks

Due to their characteristics of dynamic topology, wireless channels and limited resources, mobile ad hoc networks are particularly vulnerable to a denial of service (DoS) attacks launched by intruders. The effects of flooding attacks in network simulation 2 (NS2) and measured performance parameters are investigated, including packet loss ratio, average delay, throughput and average number of hops under different numbers of attack nodes, flooding frequency, network bandwidth and network size. Simulation results show that with the increase of the flooding frequency and the number of attack nodes, network performance sharply drops. But when the frequency of flooding attacks or the number of attack nodes is greater than a certain value, performance degradation tends to a stable value.     

TDMA体制下的移动自组织网时隙同步方法

在TDMA体制下的移动网状自组织网络中,为了解决网络时隙同步问题,提出了一种不依赖GPS授时的网络时隙互同步算法。各节点通过计算相邻节点的时隙偏差,通过加权计算并调整本节点的时隙位置,使网内各节点的时隙起始都调整到同一位置上,达到时隙的互同步。通过仿真和实验,分析并验证了移动自组织网络时隙互同步的收敛性能和抗干扰性能。     

一种基于辅助路由的拥塞自适应协议

针对现有多跳无线自组网路由协议以被动方式对拥塞进行处理,有可能导致更多的分组丢失、更长的时延和更大的网络开销问题,提出了一种基于辅助路由的拥塞自适应协议（congestion adaptive protocol based on aided-routing, CAPAR）。该协议以主动方式对拥塞进行处理,采取建立辅助路由的方法对发送给拥塞节点的业务流量进行分流,主动避免拥塞的发生,克服了以被动方式对拥塞进行处理所带来的不利影响。给出了CAPAR协议的建立过程,证明了CAPAR协议的正确性,并对其路由存储代价和路由更新代价进行了分析。结果表明,与其他按需路由协议相比,CAPAR减少了重新建立路由所带来的开销和时延,其路由更新代价明显降低。     

Distributed intrusion detection for mobile ad hoc networks

Mobile ad hoc networking(MANET)has become an exciting and important technology in recent years,because of the rapid proliferation of wireless devices.Mobile ad hoc networks is highly vulnerable to attacks due to the open medium,dynamically changing network topology,cooperative algorithms,and lack of centralized monitoring and management point.The traditional way of protecting networks with firewalls and encryption software is no longer sufficient and effective for those features.A distributed intrusion detection approach based on timed automata is given.A cluster-based detection scheme is presented,where periodically a node is elected as the monitor node for a cluster.These monitor nodes can not only make local intrusion detection decisions,but also cooperatively take part in global intrusion detection.And then the timed automata is constructed by the way of manually abstracting the correct behaviours of the node according to the routing protocol of dynamic source routing(DSR).The monitor nodes can verify the behaviour of every nodes by timed automata,and validly detect real-time attacks without signatures of intrusion or trained data.Compared with the architecture where each node is its own IDS agent,the approach is much more efficient while maintaining the same level of effectiveness.Finally,the intrusion detection method is evaluated through simulation experiments.     

基于双线性对的Ad hoc网络主动秘密共享方案

针对现有的基于双线性对的安全机制都假设在整个Ad hoc网络生存期内系统都是安全的,而基于该假设的Ad hoc网络并不安全的问题。重新定义了Ad hoc网络的攻击者模型,对传统的主动秘密共享方案进行了扩充,提出了基于双线性对的Ad hoc网络主动秘密共享方案,周期性地更新系统私钥的影子和网络节点的私钥,以提高网络安全机制的安全性和鲁棒性,并对其安全性和鲁棒性进行证明。结论表明,基于双线性对的密码体制非常适合建立实用的、轻量级的Ad hoc网络的安全机制。     

Reliable adaptive multicast protocol in wireless Ad hoc networks

1.INTRODUCTIONA wireless ad hoc networkis a multi-hop wireless net-workformed by a collection of mobile nodes withoutthe intervention of fixed infrastructure.Because awireless ad hoc networkis infrastructureless and self-organized,it is used to provide i mpromptu communi-cationfacilities in harsh environments.Typical appli-cation areas of wireless ad hoc networkinclude battle-fields,emergency search,rescue sites and data acqui-sitionin remote areas.A wireless ad-hoc network isalso useful …     

Ad hoc网络中继协作机制的博弈分析

针对Ad Hoc网络中的多跳通信需要自私节点间的数据分组中继,不使用协作的激励机制,提出了一种基于博弈论的解决方案。该方案通过建立节点间中继协作的无限次重复博弈模型,给出此博弈的纳什均衡中继策略TFT,并对其群体稳定性进行了分析。通过仿真表明,各节点根据网络拓扑结构变化速度的快慢调整TFT策略的宽容因子g,能够有效激励节点间的中继协作。     

Distributed intrusion detection for mobile ad hoc networks

Mobile ad hoc networking （MANET） has become an exciting and important technology in recent years, because of the rapid proliferation of wireless devices. Mobile ad hoc networks is highly vulnerable to attacks due to the open medium, dynamically changing network topology, cooperative algorithms, and lack of centralized monitoring and management point. The traditional way of protecting networks with firewalls and encryption software is no longer sufficient and effective for those features. A distributed intrusion detection approach based on timed automata is given. A cluster-based detection scheme is presented, where periodically a node is elected as the monitor node for a cluster. These monitor nodes can not only make local intrusion detection decisions, but also cooperatively take part in global intrusion detection. And then the timed automata is constructed by the way of manually abstracting the correct behaviours of the node according to the routing protocol of dynamic source routing （DSR）. The monitor nodes can verify the behaviour of every nodes by timed automata, and validly detect real-time attacks without signatures of intrusion or trained data. Compared with the architecture where each node is its own IDS agent, the approach is much more efficient while maintaining the same level of effectiveness. Finally, the intrusion detection method is evaluated through simulation experiments.     

QoS-aware multicast routing protocol for Ad hoc networks

1 .INTRODUCTIONA mobile ad hoc network ( MANET) is a multi-hopwireless network formed by a collection of mobilenodes without the intervention of fixedinfrastructure.Because an Ad hoc network is infrastructure-less andself-organized,it is used to provide i mpromptu com-munication facilities in harsh environments . Typicalapplication areas of mobile ad hoc networkinclude bat-tlefields ,emergency search,rescue sites and data ac-quisitionin remote areas . A mobile Ad hoc networkisalso usef…     

Distributed QoS multicast routing protocol in ad hoc networks

1 .INTRODUCTIONMobile ad hoc networks ( MANET) , also calledthe infrastructureless mobile network or self-or-ganized network,consists of a collection of mobilenodes sharing a wireless channel without any cen-tralized control or established communication back-bone .ad hoc networks have no fixed routers ;allnodes are capable of movement and can be connect-ed dynamically in an arbitrary manner . Usually ,these nodes act as both end systems and routers atthe same ti me . Nodes of these netwo…     

一种新型Ad hoc网络分簇路由协议

分簇路由协议能够提高系统性能,但也存在不足之处,维护簇结构需要复杂的簇选择算法,带来簇结构维护开销。提出了一种新的Ad hoc网络分簇路由协议,该协议利用簇的层次结构,并采用基于异常度的簇结构调整方案提高簇结构稳定性,减小路由协议开销。分析和仿真表明该协议具有控制开销小、网络性能高的特点。

Abstract：

The clustering hierarchical routing protocol have been developed to increase the system performance.Hierarchical structure has inevitably brought some drawbacks,maintaining the hierarchical structure needs more complicated cluster heads selection algorithm,which may result in the cost of maintaining cluster structure.A novel clustering structure based routing Protocol for ad hoc network was explored.It could reduce the route cost by adopting the hierarchical structure and could improve ad hoc network stability by introducing a configuration strategy based on ＂Exception Degree＂.Analysis and simulation show that the protocol is characterized with its low maintenance costs of routing and high network performance.     

战术移动Ad hoc网络仿真中移动模型研究

移动Ad hoc网络仿真中，节点移动模型的选取是否合适对于仿真非常重要，它直接影响到能否正确评价各层技术方案对动态拓扑的适应性。通过对现有移动Ad hoc网络移动模型的研究比较，针对战术移动Ad hoc网络结构特点，归纳出战术移动Ad hoc网络中节点移动特征，提出并建立了战术移动Ad hoc网络移动模型。通过仿真比较得出，建立的移动模型符合战术移动Ad hoc网络作战想定，适合战术移动Ad hoc网络仿真。     

无人飞行器Ad hoc网络中基于容错的中继节点配置

针对无人飞行器Ad hoc网络的容错设计需求,采用增加中继节点的方法实现。在二维平面同构网络中,将容错问题转化为边长受限条件下最少数量Steiner点的Steiner树问题。提出了两种基于最小成本子图的中继节点配置算法,以求解最少数量的中继节点及其位置,使改变后的网络拓扑图为顶点2-连通,实现容错。第一种为多项式时间的8-近似算法;第二种为随机近似算法,采用文化基因算法,搜索需要新增加的最小成本强化边组合。仿真结果表明了所提算法的有效性,当网络规模较小和中等时,随机近似算法得到的中继节点数量较少,平均情况下性能较优。     

Escape probability based routing for ad hoc networks

1. INTRODUCTION Mobile ad hoc networks are wireless multi-hop networks where mobile nodes are self-organized, have highly dynamic topology, limited bandwidth and no support of fixed infrastructure[1]. These characteristics often cause ad hoc networks to be viewed as quite different from traditional networks. Routing a packet from a source to a destination in an ad hoc network is a challenging problem. The main source of the challenge comes from the fact that there are no base stations in …     

Anonymous multipath routing protocol based on secret sharing in mobile ad hoc networks

Because the intrinsic characteristics of mobile ad hoc networks(MANETs) cause several vulnerabilities,anonymous routing protocols attract much more attention in secure mobile ad hoc networks for the purposes of security and privacy concerns.Until recently,lots of anonymous routing protocols have been proposed.However,most of them are single path or use one path at a time,and the multipath schemes can not thwart both the passive attacks and active attacks simultaneously.Thus an anonymous multipath routing protocol based on secret sharing is proposed.The protocol provides identity anonymity,location anonymity,data and traffic anonymity by employing cryptograph technology and secret sharing in MANET communication process.Meanwhile,a hash function is introduced to detect active attacks in the data transmission process.The protocol can effectively thwart various passive attacks and reduce the successful probability of active attacks(such as interception and physical destroy attacks).Simulation results show that the proposed scheme provides a reasonably good level of network security and performance.     

一种Ad Hoc网络信道接入排队退避公平算法

移动Ad hoc网络是一种特殊的无固定控制中心的多跳网络。由于其特殊性，传统的CSMA协议直接应用在Ad hoc网络中会带来隐终端、暴露终端和公平性问题。本文基于Ad hoc网络信道接入层已有退避算法，提出了一种新型排队退避公平算法。分析与仿真结果表明，与IEEE802．11标准的BEB算法和其它算法相比，本文算法更为简单实用，且对于合适的参数取值，本文算法能有效地改善信道接入的不公平性，并能在信道吞吐量的下降和信道接入公平性的改善之间达到一个较好的折衷。     

基于多串口卡的Ad hoc网络仿真系统的设计与实现

Ad hoc网络是一种无中心的自组织网络，其多跳性和移动性使得很难在传统的局域网或有中心的移动网络中仿真和调试其协议和算法。首先分析了在传统局域网和移动网进行Ad hoc网络仿真的难点和问题所在，接着提出了基于MOXA Smartio CP-168U／PCI多串口卡的Ad hoc网络仿真方案，然后详细介绍了仿真系统的功能和系统主要模块在VC 6．0环境下的实现，最后对系统作出分析和评价。     

无线自组织网中基于CSMA/CA的一种改进的功率控制算法

基于CSMA/CA机制,提出了一个改进的功率控制算法,用于解决传统的BASIC方案中,由于功率控制的引入而产生的非对称链路对节点传输的碰撞问题,它通过简单地修改802.11 MAC 层协议,采用变长的RTS/CTS来使载波侦听环中的节点荻得关于DATA/ACK传输的分组大小及功率强度信息,从而有效地避免碰撞与重传.仿真结果说明,该方法不仅可以节省能量,而且可以提高网络性能.     

Ad Hoc网络中一种基于邻节点活跃度的自适应退避算法

基于无线AdHoc网络中信道共享的特性,通常采用具有退避机制的MAC接入协议。由于网络节点的各邻居节点在前一段时间的活跃状态在一定程度上反映了网络的繁忙状况,活跃的邻居节点越多,表示信道竞争越激烈,网络越繁忙,反之网络比较空闲。据此,提出了一种基于邻居节点活跃状态的时延退避算法,根据邻居节点活跃数量自适应地调整时延退避窗口,从而提高了网络吞吐率。     

分层分布式Ad Hoc网络拓扑模型的研究

以战术互联网络应用环境为背景，对分层分布式Ad Hoe网络拓扑仿真模型进行了研究，提出了“分层分阶段拓扑生成算法”，拓扑仿真结果与实际网络拓扑特点相吻合。利用仿真平台Glomosim，将不同网络拓扑连接情况的组网性能参数相比较，发现分层分布式Ad Hoe网络拓扑对系统组网效率影响较大。