30 resultados para AODV
Resumo:
在AODV路由算法的基础上,综合考虑节点剩余能量和跳数,提出了一种新的节能路由策略.该策略同时对数据包和路由控制包进行功率控制,改进了Hello机制.仿真结果显示该策略显著地提高了节能效果,延长了网络的生存时间.
Resumo:
作为一种无需预设设备支持的无线移动网络,移动自组网的研究越来越多地得到人们的关注,特别是对网络性能有重要影响的路由协议的研究。由于移动自组网中的节点采用电池一类的可耗尽能源来提供电源,而且每个节点既是主机又是路由器,很容易因某个节点能量耗完而导致网络分裂。同时由于移动自组网中的节点可以任意的运动,导致网络中传输路径的频繁断裂,大量的重路由操作降低了网络的运行性能。本文在AODV路由算法的基础上,综合考虑节点的运动特性和能量受限特性,提出了三种新的节能路由策略。本文首先总结了目前移动自组网中网络层的一些节能路由协议,并比较分析了它们的优缺点。接着本文在AODV路由算法的基础上,综合考虑节点剩余电池能量和跳数,提出了一种新的节能路由策略。仿真结果显示该策略改善了网络性能,延长了网络的生存时间。然后本文基于按需路由协议AODV,通过预测链路保持连接的时间和节点的生存时间,提出了一种在路由发现和路由维护两个阶段都带移动预测的路由策略。并通过模拟结果说明了该策略能有效的提高数据传送率,减少链路断裂个数。最后针对第二种改进中的不足之处,本文对其进行了进一步的改进与优化,设计了一种基于路径稳定度预测的AODV路由协议。该协议首先基于链路保持连接时间的预测,然后通过路径稳定度的预测,选择一条在t0时刻存在并可保持至t0+ 时刻的最稳定路径进行数据传输。我们也通过模拟结果论证了该算法的有效性。
Resumo:
Mobile Ad-hoc Networks (MANETS) consists of a collection of mobile nodes without having a central coordination. In MANET, node mobility and dynamic topology play an important role in the performance. MANET provide a solution for network connection at anywhere and at any time. The major features of MANET are quick set up, self organization and self maintenance. Routing is a major challenge in MANET due to it’s dynamic topology and high mobility. Several routing algorithms have been developed for routing. This paper studies the AODV protocol and how AODV is performed under multiple connections in the network. Several issues have been identified. The bandwidth is recognized as the prominent factor reducing the performance of the network. This paper gives an improvement of normal AODV for simultaneous multiple connections under the consideration of bandwidth of node.
Resumo:
Providing QoS in the context of Ad Hoc networks includes a very wide field of application from the perspective of every level of the architecture in the network. Saying It in another way, It is possible to speak about QoS when a network is capable of guaranteeing a trustworthy communication in both extremes, between any couple of the network nodes by means of an efficient Management and administration of the resources that allows a suitable differentiation of services in agreement with the characteristics and demands of every single application.The principal objective of this article is the analysis of the quality parameters of service that protocols of routering reagents such as AODV and DSR give in the Ad Hoc mobile Networks; all of this is supported by the simulator ns-2. Here were going to analyze the behavior of some other parameters like effective channel, loss of packages and latency in the protocols of routering. Were going to show you which protocol presents better characteristics of Quality of Service (QoS) in the MANET networks.
Resumo:
Wireless Mesh Networks (WMNs), based on commodity hardware, present a promising technology for a wide range of applications due to their self-configuring and self-healing capabilities, as well as their low equipment and deployment costs. One of the key challenges that WMN technology faces is the limited capacity and scalability due to co-channel interference, which is typical for multi-hop wireless networks. A simple and relatively low-cost approach to address this problem is the use of multiple wireless network interfaces (radios) per node. Operating the radios on distinct orthogonal channels permits effective use of the frequency spectrum, thereby, reducing interference and contention. In this paper, we evaluate the performance of the multi-radio Ad-hoc On-demand Distance Vector (AODV) routing protocol with a specific focus on hybrid WMNs. Our simulation results show that under high mobility and traffic load conditions, multi-radio AODV offers superior performance as compared to its single-radio counterpart. We believe that multi-radio AODV is a promising candidate for WMNs, which need to service a large number of mobile clients with low latency and high bandwidth requirements.
Resumo:
For industrial wireless sensor networks, maintaining the routing path for a high packet delivery ratio is one of the key objectives in network operations. It is important to both provide the high data delivery rate at the sink node and guarantee a timely delivery of the data packet at the sink node. Most proactive routing protocols for sensor networks are based on simple periodic updates to distribute the routing information. A faulty link causes packet loss and retransmission at the source until periodic route update packets are issued and the link has been identified as broken. We propose a new proactive route maintenance process where periodic update is backed-up with a secondary layer of local updates repeating with shorter periods for timely discovery of broken links. Proposed route maintenance scheme improves reliability of the network by decreasing the packet loss due to delayed identification of broken links. We show by simulation that proposed mechanism behaves better than the existing popular routing protocols (AODV, AOMDV and DSDV) in terms of end-to-end delay, routing overhead, packet reception ratio.
Resumo:
Sensor network applications such as environmental monitoring demand that the data collection process be carried out for the longest possible time. Our paper addresses this problem by presenting a routing scheme that ensures that the monitoring network remains connected and hence the live sensor nodes deliver data for a longer duration. We analyze the role of relay nodes (neighbours of the base-station) in maintaining network connectivity and present a routing strategy that, for a particular class of networks, approaches the optimal as the set of relay nodes becomes larger. We then use these findings to develop an appropriate distributed routing protocol using potential-based routing. The basic idea of potential-based routing is to define a (scalar) potential value at each node in the network and forward data to the neighbor with the highest potential. We propose a potential function and evaluate its performance through simulations. The results show that our approach performs better than the well known lifetime maximization policy proposed by Chang and Tassiulas (2004), as well as AODV [Adhoc on demand distance vector routing] proposed by Perkins (1997).
Resumo:
We consider a Delay Tolerant Network (DTN) whose users (nodes) are connected by an underlying Mobile Ad hoc Network (MANET) substrate. Users can declaratively express high-level policy constraints on how "content" should be routed. For example, content may be diverted through an intermediary DTN node for the purposes of preprocessing, authentication, etc. To support such capability, we implement Predicate Routing [7] where high-level constraints of DTN nodes are mapped into low-level routing predicates at the MANET level. Our testbed uses a Linux system architecture and leverages User Mode Linux [2] to emulate every node running a DTN Reference Implementation code [5]. In our initial prototype, we use the On Demand Distance Vector (AODV) MANET routing protocol. We use the network simulator ns-2 (ns-emulation version) to simulate the mobility and wireless connectivity of both DTN and MANET nodes. We show preliminary throughput results showing the efficient and correct operation of propagating routing predicates, and as a side effect, the performance benefit of content re-routing that dynamically (on-demand) breaks the underlying end-to-end TCP connection into shorter-length TCP connections.
Resumo:
We consider a Delay Tolerant Network (DTN) whose users (nodes) are connected by an underlying Mobile Ad hoc Network (MANET) substrate. Users can declaratively express high-level policy constraints on how “content” should be routed. For example, content can be directed through an intermediary DTN node for the purposes of preprocessing, authentication, etc., or content from a malicious MANET node can be dropped. To support such content routing at the DTN level, we implement Predicate Routing [1] where high-level constraints of DTN nodes are mapped into low-level routing predicates within the MANET nodes. Our testbed [2] uses a Linux system architecture with User Mode Linux [3] to emulate every DTN node with a DTN Reference Implementation code [4]. In our initial architecture prototype, we use the On Demand Distance Vector (AODV) routing protocol at the MANET level. We use the network simulator ns-2 (ns-emulation version) to simulate the wireless connectivity of both DTN and MANET nodes. Preliminary results show the efficient and correct operation of propagating routing predicates. For the application of content re-routing through an intermediary, as a side effect, results demonstrate the performance benefit of content re-routing that dynamically (on-demand) breaks the underlying end-to-end TCP connections into shorter-length TCP connections.
Resumo:
Les réseaux véhiculaires mobiles, ou Vehicular Ad-hoc NETworks (VANETs), existent depuis les années 80, mais sont de plus en plus développés depuis quelques années dans différentes villes à travers le monde. Ils constituent un apport d’informations aux réseaux routiers grâce à la mise en place de communications entre ses constituants : principalement les véhicules, mais aussi certaines infrastructures de bords de routes liées directement aux automobilistes (feux de circulation, parcomètres, infrastructures spécialisées pour les VANETs et bien d’autres). L’ajout des infrastructures apporte un support fixe à la dissémination des informations dans le réseau. Le principal objectif de ce type de réseau est d’améliorer la sécurité routière, les conditions de circulations, et d’apporter aux conducteurs et aux passagers quelques applications publicitaires ou de divertissement. Pour cela, il est important de faire circuler l’information de la manière la plus efficace possible entre les différents véhicules. L’utilisation des infrastructures pour la simulation de ces réseaux est bien souvent négligée. En effet, une grande partie des protocoles présentés dans la littérature simulent un réseau ad-hoc avec des noeuds se déplaçant plus rapidement et selon une carte définie. Cependant, ils ne prennent pas en compte les spécificités même d’un réseau véhiculaire mobile. Le routage de l’information dans les réseaux véhiculaires mobiles utilise les infrastructures de façon certes opportuniste, mais à terme, les infrastructures seront très présentes dans les villes et sur les autoroutes. C’est pourquoi nous nous sommes concentrés dans ce mémoire à l’étude des variations des différentes métriques du routage de l’information lors de l’ajout d’infrastructures sur une autoroute avec l’utilisation du protocole de routage AODV. De plus, nous avons modifié le protocole AODV afin d’obliger les messages à emprunter le chemin passant par les infrastructures si celles-ci sont disponibles. Les résultats présentés sont encourageants, et nous montrent qu’il est important de simuler les réseaux VANETs de manière complète, en considérant les infrastructures.