用于降低网络开销的改进ODMRP算法研究

ODMRP组播路由协议适用于带宽窄、移动性强和节点分散的移动自组织网络(Mobile AdHoc Network,MANET)。为了进一步提高该协议的性能,设计了一种改进方案,首次提出"备用转发节点"的概念,将其应用于原协议中,以降低网络的负载。理论分析表明,改进方案通过控制备用转发节点能动态的控制路由数量,进而控制转发分组节点数据,从而降低网络负载。所以,该改进方案有效地提高了ODMRP协议的性能,使之更加适用于大规模的MANET网络。     

基于ODMRP的贪婪稳定路由协议

针对ODMRP协议在拓扑频繁变化的移动自组网中存在的不足,提出一种贪婪稳定路由协议GS-ODMRP,通过贪婪转发机制建立主路径,每条链路的备用路径基于链路保持连接时间建立,从而提高协议的鲁棒性.仿真结果表明,相比ODMRP协议,GS-ODMRP协议提高了分组传输成功率,并且降低了网络开销和传输时延.     

无线Mesh网络中基于链路状态的组播路由算法研究

参考移动AdHoc网络的MAODV的组播路由协议,结合无线Mesh网络的特性,及其对路由的影响,提出了一种基于链路稳定性的路由选择和基于链路可持续时间预测的组播路由改进算法MAODV-PPS,该算法是在选择路径时选取相对稳定的路径转发数据;并在维护路径的过程中,在预测可持续连接时间小于算法所规定的阀值时,主动激活路由修复。基于NS2对改进算法进行仿真,仿真结果证明了改进算法的有效性。     

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。     

一种基于带宽和时延约束的分布式组播路由算法

针对已有分布式组播路由算法在寻找QoS路由时的低成功率问题,本文提出了一种新的基于带宽和时延约束的分布式组播路由算法-QDMR(QoS-based Distributed Multicast Routing).在为新组播成员搜索连接到组播树的可行路径时,QDMR算法使用RBMF(Reverse Best Metric Forwarding)转发算法代替RPF(Reverse Path Forwarding)转发算法,从而优先搜索满足带宽和时延约束要求的路径,然后才考虑代价的优化.模拟分析表明,QDMR提高了路由搜索的成功率,并且降低了协议开销.     

无线Mesh网中灵活冗余路径的ODMRP协议

提出了一种灵活冗余路径的ODMRP协议(FRP-ODMRP),能在节点故障或网络链路失败时,为接收节点提供不间断的传送数据服务.FRP-ODMRP协议利用积极非转发节点上本采无用的复制包,根据被动转发概率提供一条灵活的冗余转发路径把数据转发到目的节点,不需要进行路由更新,不增加网络重建和修复开销、提高网络的可靠性.仿真...     

Ad Hoc网络组播路由ODMRP协议的改进

ODMRP组播协议非常适合于带宽限制大、移动性强和节点能量受限的Ad hoc网络.为了进一步提高该协议的性能,文中提出一种新的技术来增强其功效.增强ODMRP的主要目标有:(1)改进节点移动模式的适应性;(2)消除路由获得时延.最后仿真结果显示该改进协议比原协议在数据分发率和网络有效性等性能方面有很大改善.     

IP Multicast组播技术——网络广播的基石(二)

２几种主要的路由协议２ １ＩＰ组播路由的两种模式———密集模式 ,稀疏模式由一个特定的“源 ,宿组”对表示的ＩＰ组播 ,是指通过一个将该组中所有的主机联结在一起的一个生成树 (ｓｐａｎｎｉｎｇｔｒｅｅ) ,将信息从源端分发到所有接收者的传输。不同的ＩＰ组播路由协议采用不同的技巧构造生成树 ,一旦构造了一个树 ,所有的组播流就通过它进行分发。ＩＰ组播路由选择主要有两种方法。ＩＰ组播路由协议一般根据组播组的成员在整个网络上的预期分布 ,在两种方法中选择其中之一来构造生成树。第一种方法假定组播组成员密集地分布在整个网络…     

链路可靠的无线传感器网络组播路由协议

在无线传感器网络实际应用中,组播正在发挥着越来越重要的作用.但由于能量等多方面的因素,使得为无线传感器网络设计一个有效的组播路由是非常困难的.针对无线传感器网络中节点的能量限制,通过寻求节点间最短路径,提出一种能量有效的链路可靠组播路由协议(RLMR).该协议充分考虑到网络中节点的能耗因素和两节点间的链路可靠性等,通过对这两个因素的综合考虑,让能量较多并且以发送节点更靠近的节点承担更多传输任务的方式,为数据流优化路由选择,均衡无线传感器网络节点的能量消耗,以延长网络的生存时间.仿真结果证明了RLMR的有效性和可靠性.     

基于ODMRP的稳定路由协议LB-ODMRP

针对Ad Hoc网络拓扑变化频繁及节点能量有限的问题,提出了基于ODMRP的稳定路由协议LBODMRP,通过贪婪转发机制建立主路径,在综合考虑路径保持连接时间和节点负载及节点剩余能量的基础上,引入路径质量模型建立路径,提高了协议的鲁棒性,根据负载情况实现节点能量的均衡消耗,延长了网络的生存时间.仿真结果验证了该协议的有效性.     

High-throughput multicast routing metrics in wireless mesh networks

The stationary nature of nodes in a mesh network has shifted the main design goal of routing protocols from maintaining connectivity between source and destination nodes to finding high-throughput paths between them. Numerous link-quality-based routing metrics have been proposed for choosing high-throughput routing paths in recent years. In this paper, we study routing metrics for high-throughput tree or mesh construction in multicast protocols. We show that there is a fundamental difference between unicast and multicast routing in how data packets are transmitted at the link layer, and accordingly how the routing metrics for unicast routing should be adapted for high-throughput multicast routing. We propose a low-overhead adaptive online algorithm to incorporate link-quality metrics to a representative multicast routing protocol. We then study the performance improvement achieved by using different link-quality-based routing metrics via extensive simulation and experiments on a mesh-network testbed, using ODMRP as a representative multicast protocol.Our extensive simulation studies show that: (1) ODMRP equipped with any of the link-quality-based routing metrics can achieve higher throughput than the original ODMRP. In particular, under a tree topology, on average, ODMRP enhanced with link-quality routing metrics achieve up to 34% higher throughput than the original ODMRP under low multicast sending rate; (2) the improvement reduces to 21% under high multicast sending rate due to higher interference experienced by the data packets from the probe packets; (3) heavily penalizing lossy links is an effective way in the link-quality metric design to avoid low-throughput paths; and (4) the path redundancy from a mesh data dissemination topology in mesh-based multicast protocols provides another degree of robustness to link characteristics and reduces the additional throughput gain achieved by using link-quality-based routing metrics. Finally, our experiments on an eight-node testbed show that on average, ODMRP using SPP and PP achieves 14% and 17% higher throughput over ODMRP, respectively, validating the simulation results.     

Wireless Ad Hoc Multicast Routing with Mobility Prediction

An ad hoc wireless network is an infrastructureless network composed of mobile hosts. The primary concerns in ad hoc networks are bandwidth limitations and unpredictable topology changes. Thus, efficient utilization of routing packets and immediate recovery of route breaks are critical in routing and multicasting protocols. A multicast scheme, On-Demand Multicast Routing Protocol (ODMRP), has been recently proposed for mobile ad hoc networks. ODMRP is a reactive (on-demand) protocol that delivers packets to destination(s) on a mesh topology using scoped flooding of data. We can apply a number of enhancements to improve the performance of ODMRP. In this paper, we propose a mobility prediction scheme to help select stable routes and to perform rerouting in anticipation of topology changes. We also introduce techniques to improve transmission reliability and eliminate route acquisition latency. The impact of our improvements is evaluated via simulation.     

Multicast Routing in Mobile Ad Hoc Networks

We focus on one critical issue in mobile ad hoc networks that is multicast routing. Advantages and limitations of existing routing protocols are illustrated. Optimal routes, stable links, power conservation, loop freedom, and reduced channel overhead are the main features to be addressed in a more efficient mechanism. In this paper, we propose a new on-demand multicast routing protocol, named Source Routing-based Multicast Protocol (SRMP). Our proposition addresses two important issues in solving routing problems: (i) path availability concept, and (ii) higher battery life paths. SRMP applies a source routing mechanism, and constructs a mesh to connect group members. It provides stable paths based on links' availability according to future prediction of links' states, and higher battery life paths. This protocol succeeded to minimize network load via designing optimal routes that guarantee reliable transmission and active adaptability. A performance comparison study with On-demand Multicast Routing Protocol (ODMRP) and Adaptive Demand-driven Multicast Routing (ADMR) protocol is undertaken. Analysis results show the strength of the SRMP nodes' selection criteria and its efficient energy consumption compared to the other two protocols.     

Way-Point Multicast Routing Framework for improving QoS in hybrid wireless mesh networks

Since internet access is used by billions of people worldwide and the number of internet user is also increasing every day, a new technology called as wireless mesh network (WMN) is becoming popular. This is because it has some desirable characteristic, but it has some limitation for multi-hop routing, bandwidth, and many more. In order to overcome these issues, we proposed Way-Point Multicast Routing Framework (WPMRF) for improving the quality of service (QoS) in Hybrid WMN. Initially, the multicast framework is established based on the minimum load factor. The route established with least load factor is considered, as it avoids any kind of congestion in the network. After that, segmentation of route is done, and the way-point nodes are selected to join the multicast session. After that, the transmission is performed using MAODV and ODMRP protocol. In addition, an estimated route disconnection parameter is used for fast route recovery process and helps to select more reliable route path. The advantage of the proposed work is that it provides more reliable routing path to increase the quality of service (QoS) with fast route recovery process.     

Protocol-independent multicast packet delivery improvement service for mobile Ad hoc networks

This paper addresses the issue of improving multicast packet delivery in mobile ad hoc networks and proposes an adaptive mechanism called Protocol-Independent Packet Delivery Improvement Service (PIDIS) to recover lost multicast packets. PIDIS provides its packet-delivery improvement services to any multicast routing protocol for mobile ad hoc networks by exploiting the mechanism of swarm intelligence to make intelligent decisions about where to fetch the lost multicast packets from. PIDIS is a gossip protocol, and nodes using PIDIS are only concerned with which neighbor nodes to gossip with to recover the most lost packets, rather than which member nodes to gossip with. Thus, it does not rely on membership information in a multicast scenario, which is often difficult to get. PIDIS employs the beneficial aspects of probabilistic routing and adapts well to mobility. PIDIS achieves probabilistic improvement in multicast packet delivery and, unlike other gossip-based schemes, does not need to maintain information about group members from which lost multicast packets are retrieved. Further, the operations of PIDIS do not rely on any underlying routing protocol or primitive, and can be incorporated into any ad hoc multicast routing protocol. We incorporated PIDIS over ODMRP [On-Demand Multicast Routing Protocol in Multihop Wireless Mobile Networks, Kluwer Mobile Networks and Applications, 2000], and compared it against Anonymous Gossip (AG) [International Conference on Distributed Computing Systems (ICDCS 2001) Phoenix, Arizona, April 2001] implemented over ODMRP, and ODMRP itself. Our simulation results show that ODMRP + PIDIS is more efficient and performs better than ODMRP + AG and ODMRP in terms of multicast packet delivery, end-to-end delay, and MAC layer overheads. We attribute the better performance and lower MAC overheads of ODMRP + PIDIS to the efficient gossiping made possible by using the swarm intelligence techniques.     

能量感知和链路稳定度的多径MANET路由

在移动自组织网络中,相对于单路径路由算法而言,多路径路由算法可以均衡网络负载、提高路由的可靠性。通过对AOMDV路由协议进行改进,提出了基于能量感知和链路稳定度的多径MANET路由协议ELMRP。ELMRP协议综合考虑了节点的剩余能量和链路稳定度,根据路径的剩余能量和稳定度计算代价值,按照代价值在多条节点不相交路径上分配数据流量。仿真结果表明,和AOMDV路由协议相比,ELMRP协议延长了网络的生存时间,提高了数据分组递送率,降低了路由发现频度。     

基于可靠路径稳定性估计的MANET路由发现算法研究

提出一种基于可靠路径剩余生存期（RPL, residual path lifetime）估计的MANET路由发现算法（RLE-RPLP）,该算法充分考虑相邻链路剩余生存期相关性,建立优化的多跳路径RPL统计特性分析,提供了更可靠的路由稳定性评估。通过仿真分别与忽略链路RLL相关性的源路由协议及已有稳定性路由协议进行对比。仿真结果表明,RLE-RPLP算法能有效提高网络吞吐量并减少路由重建次数;当节点移动度较高或网络负载较大时,在吞吐量、路由开销等方面均优于已有的稳定性路由对比算法。     

Survey of Secure Routing Protocols for Wireless Ad Hoc Networks

The mobile ad hoc network is a type of wireless network characterized by mobile nodes without a centralized administration. Frequent variations of the topology and the nature of the radio links have a negative impact on the stability of the links. Indeed, the link quality deteriorates rapidly and link breaks become frequent. To overcome these problems, new forms of routing protocols are used as the MultiPath routing. In addition, routing protocols require the knowledge of the nodes neighborhood to build and manage routes. The neighbor discovery process is performed by a Hello protocol. The Hello protocol typically involves several parameters such as the packet’s period; node’s transmit power, node’s position and node’s battery level. The purpose of this paper is to change the behavior of ad hoc On demand Multi-path Distance Vector (AOMDV) routing protocol by considering the density of the nodes as well as the interference of the neighboring nodes. This selection of paths goes through two stages. In the first step, we study the impact of the neighbor discovery process to select a set of paths having a minimum number of neighboring nodes to diminish contention problems and interference rate. In the second step, the Interference Ratio (IR) metric is used to select the paths in which the nodes are surrounded by a minimum of interference. We choose for our study two proposed approaches based on AOMDV routing protocol. The first is called AOMDV_neighbor and considers the density parameter as a path metric. The second is called AOMDV_neighbor_IR which considers the interference rate (IR) between each node and its neighborhood as a path metric. We evaluate the proposed routing protocols performance under various NS2 simulation scenarios in a shadowing environment.

     

Energy Efficient Routing Technique for Wireless Sensor Networks Using Ant-Colony Optimization

Wireless sensor networks (WSN) consists of numerous number of nodes fitted with energy reserves to collect large amount of data from the environment on which it is deployed. Energy conservation has huge importance in wsn since it is virtually impossible to recharge the nodes in their remote deployment. Forwarding the collected data from nodes to the base station requires considerable amount of energy. Hence efficient routing protocols should be used in forwarding the data to the base station in order to minimize the energy consumption thereby increasing the life-time of the network. In this proposed routing protocol, we consider a hierarchical routing architecture in which nodes in the outer-level forwards data to the inner-level nodes. Here we optimized the routing path using ant-colonies where data moves along minimal congested path. Further, when ant-colony optimization is used, certain cluster-head nodes may get overloaded with data forwarding resulting in early death due to lack of energy. To overcome this anomaly, we estimated the amount of data a neighboring Cluster-head can forward based on their residual energy. We compared the energy consumption results of this proposed Routing using Ant Colony Optimization (RACO) with other existing clustering protocols and found that this system conserves more energy thereby increasing lifetime of the network.