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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。 相似文献
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移动Ad hoc网络路由协议标准 总被引:4,自引:0,他引:4
通过重点说明互联网工程任务组(IETF)已通过的两个移动Ad hoc网络路由协议标准,使得相关工程人员在对应用于此种网络的路由协议有一个整体认识基础之上,进一步加深对移动Ad hoc网络原理的理解. 相似文献
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通过对AODV路由协议进行改进,提出了基于AODV的能量有效的路由协议(EE—AODV)。新协议考虑了节点的剩余能量,根据节点的剩余能量调节RREQ延迟来平衡节点的能量消耗,利用节点最近一次传递过数据分组的时间作为约束条件来优化RREQ的洪泛广播,降低网络的能量消耗。仿真结果表明.和AODV路由协议相比,新协议降低了网络的能量消耗并减少了耗尽能量的节点数,延长了网络的生存时间。 相似文献
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一种基于缓存技术的改进型AODV路由协议 总被引:1,自引:1,他引:0
AODV路由协议是ad hoc网络中一种典型的按需路由协议,但是当网络节点具有高移动性,网络拓扑变化频繁使得路由链路断开频繁时,按需路由协议包括AODV算法都缺乏鲁棒性,各个移动节点在发送数据包时需要不断发起路由请求.文章对AODV算法进行了详细分析,并利用路由缓存技术对AODV算法进行了改进.在缓存中建立了两条备用路由,当活动路由链路断开时,选取一条较好的备用路由作为活动路由.NS2仿真结果表明,这种带缓存功能的AODV算法能降低丢包率、时延,提高路由的稳健性,从而适应网络拓扑结构的频繁变化. 相似文献
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NS2的Ad hoc网络AODV协议的仿真 总被引:2,自引:0,他引:2
无线Ad hoc网络作为一种典型的自组织网络,其路由协议一直是研究的重点。以仿真AODV(Adhocon.demand distancevector)协议为例介绍了NS2仿真路由协议的详细步骤,给出了仿真结果图和一些性能分析。结果表明,对路由协议性能影响最大的是数据源的发送频率。 相似文献
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基于移动性的AODV路由协议改进 总被引:2,自引:0,他引:2
介绍了Ad Hoc网络路由协议(Ad Hoc On-Demand Distance Vector Routing,AODV)的路由机制和特点,提出了一种基于AODV的改进协议V-AODV。V-AODV改进了AODV的路由测度,用量化的节点移动性代替跳数作为路由代价的度量,在动态网络中能够选取到更加稳定的路由。仿真表明,V-AODV比AODV在时延和重传次数等性能上都有一定程度的提升。 相似文献
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针对传统的AODV路由协议采用扩展环路由搜索算法导致的路由开销较大,没有考虑节点能量的问题,提出一种新的算法。此算法在路由请求过程中能够根据以前搜索中得到的信息,让多余的节点处于静默状态,不参与下一次的路由发现。并且综合考虑节点能量,尽可能地让低能量节点处于静默状态,从而达到均衡节点能量使用的目的。仿真结果表明改进算法有效延长了网络生存时间,提高了包投递率。 相似文献
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基于OPNET仿真平台的AODV协议的性能研究 总被引:4,自引:0,他引:4
AODV(Ad hoc On-demand Distance Vector Routing)路由协议是面向移动Adhoc网络的,在介绍了移动Ad hoc网络的特征、现有路由协议和AODV路由协议的发展过程之后,重点分析了AODV协议的特征、路由建立、维护过程,并基于OPNET平台仿真了AODV协议的性能(包括路由发现时间、协议效率、平均跳数、数据吞吐量),总结了目前AODV协议存在的问题及其改进的主要方法,最后对AODV协议改进的前景进行了预测。 相似文献
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基于当前使用非常广泛的随机早期检测(RED)拥塞控制机制,提出了一种改进方案:在AODV的路由发现阶段,根据当前平均队列长度来确定以不同的方式响应路由请求,从而使建立起来的路由比较可靠,使数据流可以绕过负担比较重的节点,实现一定程度的拥塞控制和流量均衡,最后对改进前后的协议进行了性能仿真和分析。结果表明,改进后的协议与原协议相比在复杂度没有明显增加的前提下,降低了平均延时和丢包率,提高了网络性能。 相似文献
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针对空基自组织网络的大容量通信需求,首先提出了基于频分复用的定向MAC协议,在邻居发现过程中将测距算法与多维尺度变换定位算法相结合得到每个节点的相对位置,并设计了双预约资源分配算法,完成定向数据传输;然后提出了定向路由协议,解决了次佳路由问题和路由应答风暴,并加入相邻搜索、链路质量评估和备用路由,降低了协议开销。空基自组网基于Ka/Ku相控阵天线的定向传播特性以及Ka/Ku频段频谱资源丰富的特点,使用频分复用、空分复用技术实现多个信道的高速并行传输,从而极大地提高网络的吞吐量。 相似文献
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移动自组网MANET是由许多移动节点组成的无中心的、多跳的自组织网络,网络中的节点由于移动和能量耗尽可能会使得路径失效,因此传统的单路径协议效率并不高。本文介绍了自组网中最常用的AODV协议,重点对AOMDV多路径路由协议的路由机制和维护管理进行了探讨。最后使用NS2仿真软件对两种协议进行了比较,结果表明,在分组投递率和端到端延时方面,AOMDV比AODV更具优势。 相似文献
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MERIT is a framework that can be used to assess routing protocols in mobile ad hoc networks (manets). It uses the novel concept of a shortest mobile path (SMP) in a mobile graph, a generalization of the shortest path problem for mobile environments. As a measure for routing protocol assessment, we propose the mean ratio of the cost of the route used by a protocol to the cost of the optimal mobile path for the same network history. The cost reflects that the route used in a session can change over time because of network dynamics such as topology changes. The aim is for the ratio to be an abstract, inherent measure of the protocol that is as implementation-independent as possible. The MERIT spectrum, which is the ratio expressed as the function of some parameters of interest, is a characterization of protocol effectiveness. MERIT, for MEan Real vs. Ideal cosT, provides a scalable assessment framework: rather than comparing performance measures of different protocols directly, we compare a protocol to the optimal solution. That is, rather than forcing the comparison to be in the same system, it is done once for each protocol in its own environment. Furthermore, we show that there is an efficient algorithm to solve the underlying SMP problem for important cases, making the approach practically feasible. We also investigate generalizations of and extensions within the MERIT framework. We show that the MERIT framework is rich, with much wider generality and potential applicability than assessing routing protocols. 相似文献
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ABRP: Anchor-based Routing Protocol for Mobile Ad Hoc Networks 总被引:2,自引:0,他引:2
Ad hoc networks, which do not rely on any infrastructure such as access points or base stations, can be deployed rapidly and
inexpensively even in situations with geographical or time constraints. Ad hoc networks are attractive in both military and
disaster situations and also in commercial uses like sensor networks or conferencing. In ad hoc networks, each node acts both
as a router and as a host. The topology of an ad hoc network may change dynamically, which makes it difficult to design an
efficient routing protocol. As more and more wireless devices connect to the network, it is important to design a scalable
routing protocol for ad hoc networks. In this paper, we present Anchor-based Routing Protocol (ABRP), a scalable routing protocol
for ad hoc networks. It is a hybrid routing protocol, which combines the table-based routing strategy with the geographic
routing strategy. However, GPS (Global Positioning System) (Kaplan, Understanding GPS principles and Applications, Boston:
Artech House publishers, 1996) support is not needed. ABRP consists of a location-based clustering protocol, an intra-cell
routing protocol and an inter-cell routing protocol. The location-based clustering protocol divides the network region into
different cells. The intra-cell routing protocol routes packets within one cell. The inter-cell routing protocol is used to
route packets between nodes in different cells. The combination of intra-cell and inter-cell routing protocol makes ABRP highly
scalable, since each node needs to only maintain routes within a cell. The inter-cell routing protocol establishes multiple
routes between different cells, which makes ABRP reliable and efficient. We evaluate the performance of ABRP using ns2 simulator.
We simulated different size of networks from 200 nodes to 1600 nodes. Simulation results show that ABRP is efficient and scales
well to large networks. ABRP combines the advantages of multi-path routing strategy and geographic routing strategy—efficiency
and scalability, and avoids the burden—GPS support. 相似文献
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对AODV路由协议中的断链问题进行了分析和仿真,提出了对其进行优化的方案并给出具体实现。优化方案使用了本地的反向路由重建方法,通过广播一个链路修复消息同时完成了路由查找和路由建立的任务。与传统的路由重建方式相比,可以节省在重建路由时引入的时延,并在一定程度上减少了路由重建的额外开销,以更好地适应自组网的应用环境。 相似文献