Ad Hoc网络中一种基于自裁减的广播算法

为解决简单泛洪式广播算法所引起的AdHocN络的广播风暴问题,提出了一种基于自裁减的广播算法。算法根据自裁减广播策略,通过设定延时机制和优先转发机制对网络节点是否需要转发广播包进行判定。最后,将算法应用于AODV协议,并与标准AODV协议在不同节点最大移动速度的场景下进行了转发节点数、到达率、端到端平均时延和归一化路由开销等参数的比较,以验证提出算法的有效性。     

多跳无线网络中无需邻节点信息的空间覆盖广播算法

针对多跳无线网络中广播的转发冗余问题,该文提出了一种无需邻节点信息的空间覆盖广播(Space-Covered Broadcast,SCB)算法。SCB算法通过优化转发节点的空间分布达到利用最少数目的转发节点实现对网络空间的覆盖,从而在保证较高送达率的同时明显降低了广播的转发次数。由于无需邻节点信息和网络拓扑信息,SCB算法降低了带宽和存储计算等开销;并且,转发节点的选择由接收节点通过延时转发机制来完成,因而SCB算法能够自动适应信道状况,避免信道变化造成的传输错误。仿真结果表明:该算法在不同的节点密度和网络负载条件下能够明显提高广播的传输效率。     

一种多跳无线网络中的高效广播算法

广播是多跳无线网络中的一种基本操作。现有的广播算法中普遍存在转发冗余过多的问题。该文首先分析了覆盖网络所需的最少转发节点数目,然后以此为基础,提出了一种简单高效的广播算法。该算法中,每个节点最多只需选择3个转发节点,从而明显地减少了广播的转发次数,提高了节点能量和网络资源的利用率;同时,所有转发节点实现了对整个网络接近双重的覆盖,能够保证较高的传输可靠性;此外,对不同的网络规模和拓扑的动态变化,该算法具有较好的可扩展性。仿真结果显示,该算法在多种常见的网络环境下具有比现有方法更优越的性能。     

车载通信中增强型多跳广播算法研究

提出了一种高速公路场景下基于邻居信息的增强型多跳广播协议(enhanced neighbor information-based muti-hop broadcast protocol,ENIMBP),提出的协议利用车辆的邻居信息同时结合车辆的位置、行驶速度和方向来确定转发等待时间,以选择最优的转发车辆。根据车辆的位置,ENIMBP可以初步确定与广播车辆距离不同的车辆的转发等待时间。而在与广播车辆距离相同的情况下,ENIMBP则利用车辆速度和方向来区分转发等待时间。ENIMBP很好地解决了高速公路场景下的网络分割问题以及隐藏/暴露节点问题。仿真结果表明,在不同的车辆密度场景下,ENIMBP能显著地降低端到端时延,同时保持较好的分组到达率。     

ZigBee网络自剪裁路由算法

ZigBee网络中的AODVjr算法通过全网广播路由请求RREQ消息而获得分组发送的最短路径,但节点大量广播RREQ消息增加了网络控制开销,导致网络节点耗能剧增,同时网络堵塞的可能性也大大提升。针对AODVjr算法存在的网络节点耗能剧增问题,在AODVjr算法基础上,结合节点邻居表,提出筛选RREQ消息转发节点,从而限制RREQ消息转发次数的路由算法Zig Bee树节点自剪裁转发算法(ZigBee On-tree Self-pruning Rebroadcast Algorithm,ZOSR)和ZigBee转发节点选择算法(ZigBee On-tree Forwarding Node Selection Algorithm,ZOFNS)。仿真结果表明,算法能有效降低网络节点的转发次数,从而降低网络整体功耗,延长网络工作时间。     

基于极大独立集的最小连通支配集的分布式算法

全网范围的广播在无线传感器网络和移动自组织网络中有着广泛的应用.为节省网络资源,减少冗余转发节点成为广播中需解决的关键问题.广播过程中最小化参与转发节点数问题与图论中求解最小连通支配集问题等价,而在任意图中求解最小连通支配集是NP完全问题.本文基于极大独立集,提出了一种求解最小连通支配集的分布式算法(MISB),并证明了算法的正确性.仿真结果表明,使用该算法能得到较小的连通支配集,从而有效减少网络广播过程中的转发节点数,大大节省了网络资源.     

一种基于战术互联网的广播

战术互联网是AdHoc网络技术在军事领域的重要应用,广播是战术互联网中基本的信息发布方式,也是AdHoc网络技术研究的一个重要问题。首先把AdHoc网络广播算法分为邻居决定转发和自身决定转发,然后仿真分析几种典型的广播算法;最后根据战术互联网的特点,结合现有的AdHoc网络广播,提出一种新的战术互联网广播协议（TIBP）。仿真结果表明：TIBP在战术互联网环境下具有较高的效率。     

基于限制广播域和节点剩余能量的按需路由算法研究

按需路由协议AODV的路由发现使用洪泛方式的扩散法,导致网络超负荷运行和拥塞,而且在选择转发路由时,总是选择最少跳数的路由,造成无线传感网络中节点能量不均,减少网络寿命.本文提出了AODV-DE算法,该算法引入广播域的概念,限制RREQ分组的转发范围,同时避免使用剩余能量低的节点转发数据分组,选择路由路径时选择总剩余能量最多的路径进行信息的传送.仿真结果表明,AODV-DE协议在路由开销、网络寿命和端到端的延迟这三个方面表现出了优势.     

基于无线网络数据广播算法的多媒体信息传输技术与应用

随着无线网络的迅猛发展,传统声音、文字通讯模式已发生巨大的改变,本文以无线网络数据广播算法为基础,对多媒体信息传输技术进行了研究.通过分析TFB算法、节点选择、转发节点选择、相近转发节点的消除,建立了基于无线网络数据TFB三点转发广播算法的多媒体交互系统构架,采用UDP+ CDN传输协议中转模式,在Windows XP上,采用TFB三点转发广播算法,进行无线移动网络多媒体发包与丢包的测试,通过CDN服务器,连续发5 000个包,实验结果表明,两次发包间不延时,无线网络未出现丢包现象,丢包现象主要发生在发送节点侧与接受节点侧,丢包范围在0.3％ ～2.3％之间,这对用户体验不会造成影响.     

一种基于动态概率转发的AODV路由协议

在Ad hoc网络(自组织网络)的路由建立过程中,由于AODV(Ad hoc按需距离矢量)路由采用洪泛方式转发RREQ(路由请求)消息会产生很多不必要的重传,很可能引发广播风暴而影响网络性能。文章提出了一种基于动态概率转发RREQ消息的改进方案,该方案根据邻居节点的个数选择不同的概率转发RREQ消息。仿真结果表明,在网络节点较多且网络比较稠密的情况下,改进方案能有效减少网络端到端时延,提高网络吞吐量和分组投递率。     

A Hybrid Spanning Tree algorithm for efficient topology distribution in PNNI

The ATM Forum's PNNI standard specifies a flooding mechanism to distribute topological state information amongst nodes participating in a PNNI network. While the flooding mechanism provides robust topology distribution, we show by simulation that it can disproportionately overload lower-bandwidth links and, due to its inherent redundancy, can generate considerable computational overhead due to the processing of redundant topology updates. To address these issues, we introduce the Hybrid Spanning Tree algorithm, a spanning tree-based topology distribution mechanism that has low computational maintenance and can support policy that restricts topology distribution control traffic from being carried over lower-bandwidth links. Unlike other spanning tree proposals, the Hybrid Spanning Tree algorithm provides a simple and practical migration path to smoothly transition PNNI nodes executing the flooding algorithm to those of the Hybrid Spanning Tree algorithm. This revised version was published online in August 2006 with corrections to the Cover Date.     

Cooperative detection and protection for Interest flooding attacks in named data networking

Named data networking (NDN) is a new emerging architecture for future network, which may be a substitute of the current TCP/IP‐based network, for the content‐oriented data request mode becoming the future trend of development. The security of NDN has attracted much attention, as an implementation of next‐generation Internet architecture. Although NDN is immune to most current attack, it cannot resist the distributed denial of service like attack – Interest flooding attack (IFA) – effectively. IFA takes advantages of the forwarding mechanism of NDN, flooding a large number of malicious Interest packets at quite a high rate, and exploits the network resources, which may cause the paralysis of the network. Taking into account the severity of the destruction, we propose an algorithm to counter such new type of attack. We analyze three properties of IFA, and use them to judge and filter Interest packets. Vector space model and Markov model are used in our method to realize a cooperative detection. Meanwhile, we present the retransmission forwarding mechanism to ensure legitimate user request. The ndnSIM module of ns3 is used for the corresponding simulation, and results of the simulation will be given to show the effectiveness of our algorithm. Copyright © 2014 John Wiley & Sons, Ltd.     

基于改进型蚁群算法的P2P网络资源搜索的研究

目前P2P网络中的资源搜索算法以泛洪法为核心,产生的巨大网络流量加重了网络负载,只适合小型网络。蚁群优化算法具有较好的鲁棒性、并行性等优点,已有不少学者将其应用于P2P资源搜索。本文在分析蚁群算法应用于P2P网络中资源搜索面临的问题的基础上,给出一个适合蚁群算法的新型的P2P文件共享构架,以解决P2P路由的不一致性等问题。在P2P网络中应用能见度会带来3个缺点:容易导致局部极小解、容易导致流量集中、实际网络中的实现有较大难度,由此本文提出了去能见度蚁群算法。构建了开放式的网络仿真拓扑结构,通过一系列的实验结果验证了去能见度蚁群算法的全局能力更强。     

基于泛洪约束的MANET按需组播路由协议

降低路由控制开销是MANET网络组播路由协议节省节点能量,提高带宽利用率的关键因素之一。本文研究了组播路径近邻节点对路由维护的作用以及链路的连通性,分别提出了一个新的泛k-洪约束算法和一个混合泛洪模式。基于泛k-洪约束算法和混合泛洪模式,提出一个新的按需组播路由协议ODMRP-CF,ODMRP-CF协议通过选择k-路由近邻节点转发泛洪分组来提高泛洪效率。ODMRP-CF协议不仅保持了ODMRP协议所具有的简单,对节点移动鲁棒性好的优点,而且有效地降低了ODMRP-CF协议的控制开销。     

一种非结构化P2P网络的资源搜索算法

本文针对非结构F2P网络中利用洪泛搜索机制来进行资源搜索的盲目性问题，提出一种利用节点经验积累和cache技术相结合来指导资源搜索的算法。在访搜索算法中，节点记录收到的查询主题和满足该主题的邻居节点，建立主题与邻居节点的对应关系表，当再次收到该主题时，节点就利用该表来指导资源搜索。为了加快搜索速度，将常见查询主题的记录放到cache中。该算法利用一个相似度函数来判断本地文档是否满足查询主题。仿真实验表明，该算法有效地改进了资源搜索的盲目性。减少查询带来的网络流量，提高了查询成功率。     

A novel convex hull-based flooding scheme using 1-hop neighbor information for mobile ad hoc networks

Flooding is one of the most essential and commonly used operations in mobile ad hoc networks. Different sender-based and receiver-based flooding algorithms have been presented separately in the literature. To integrate the advantages of sender-based and receiver-based flooding algorithms, this paper proposes a novel joint 1-hop neighbor information-based flooding scheme that consists of two sub-algorithms: the sender-phase algorithm and the receiver-phase algorithm. The sender-phase algorithm of our flooding scheme helps a node select a subset of its 1-hop neighbors to forward the flooding message. Based on the convex-hull concept, this algorithm selects forwarding nodes with the highest contribution to flooding message dissemination. On the other hand, the receiver-phase algorithm complements the sender-phase algorithm, allowing our flooding scheme to guarantee full delivery. We prove that our flooding scheme requires lower time complexity O(n log h), where h is the number of forwarding nodes, than the best known 1-hop neighbor information-based flooding algorithms proposed by Liu et al. and Khabbazian et al. Additionally, to alleviate the local optimal problem caused by sender-based flooding algorithms, we relax the full delivery requirement and modify our flooding scheme to discard more redundant rebroadcasting operations. Simulation experiments are conducted to compare the performance of our flooding schemes with those of Liu et al.??s and Khabbazian et al.??s flooding algorithms. The simulation results show that our flooding schemes accomplish a lower ratio of broadcasting nodes and a higher message delivery ratio simultaneously under various network conditions. Moreover, since our flooding schemes have lower ratios of broadcasting nodes, they incur fewer packet collisions on the network. Consequently, message disseminations applying our flooding schemes have a smaller effect on other transmissions of different message types.     

无线传感器网络中一种高能效低延时的泛洪算法研究

提出了一种新的应用于无线传感器网络的泛洪传播算法——覆盖优先泛洪算法。算法采用覆盖优先策略为相邻节点分配不同的转发优先权，实现泛洪包快速覆盖整个网络；采用节点转发抑制策略和动态延时转发机制，尽可能抑制冗余包和减少冲突重传。仿真结果表明，该算法与同类算法相比，具有更高的能源有效性，更低的延时。     

Improving Resilience against DDoS Attack in Unstructured P2P Networks

In unstructured peer-to-peer （P2P） systems such as Gnutella, a general routing search algorithm is used to blindly flood a query through network among peers. But unfortunately, malicious nodes could easily make use of the search approach launching distributed denial of service （DDoS） attack which aims at the whole network. In order to alleviate or minimize the bad effect due to behavior of malicious nodes using the flooding search mechanism, the paper proposes a Markov-based evaluation model which exerts the trust and reputation mechanism to computing the level of trustworthy of nodes having the information requested by evaluation of the nodes＇ history behavior. Moreover, it can differentiate malicious nodes as early as possible for isolating and controlling the ones＇ message transmitted. The simulation results of the algorithm proposed show that it could effectively isolate malicious nodes, and hold back the transmission of vicious messages so that it could enhance tolerance of DDoS based on flooding in Guutella-like P2P network.     

低开销的MANET网络按需路由协议

针对简单泛洪效率低的问题,提出了一个限制洪泛的高效的路由广播算法,通过Euclidean距离来限制路由发现过程中请求分组被转发的次数;研究了减少路由维护开销,并降低路由发现的频率的方法,提出了一个基于节点高度的路由修复与优化算法,该算法使用节点监听来对链路断裂的路由进行修复与优化.基于限制泛洪的高效的路由广播算法和路由修复优化算法,提出了一种新的低开销的MANET网络按需路由协议LOOR(low overhead on-demand routing).仿真结果表明,新协议增强了路由的顽健性,减少了路由跳数,降低了路由发现的频率,提高了数据分组递送率,并显著地降低了路由控制开销.     

基于行为规律的搜索资源分配新算法

针对具有行为规律的目标搜索问题,提出一种搜索资源分配算法。该方法以目标在各搜索区域的概率分布为基础,利用最优搜索理论分配区域搜索时长;以目标在各搜索区域的行为规律为基础,利用包络检测等方法决定区域开始搜索的时刻。针对网站关键词搜索的实验显示,根据目标行为规律在时间上相关程度的不同,本算法相对于最优搜索算法的性能提升在15%~50%之间,在对大量信息源进行信息搜索时具有应用价值。