首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
A mobile ad hoc network (MANET) is an open wireless network that comprises a set of mobile, decentralized, and self‐organized nodes. Its properties render its environment susceptible to different types of attacks, which can paralyze the mobile nodes in MANET. A particularly dangerous type of attack is run primarily under flooding bogus packet mechanisms, such as hello floods, routing table overflows, exploitation of node penalizing schemes, and resource consumption attack (RCA). Flooding‐based attacks impose severe effects because they are intended to consume MANET resources, such as bandwidth, node memory, and battery power. Therefore, identifying such effects facilitates the development of countermeasures against the intrusions. In this paper, we introduce a simulation‐based study on the effects of RCA on MANET. Qual Net v5.0.2 is used to examine the severity of the effects on MANET performance metrics in terms of throughput, end‐to‐end delay, energy consumption, and routing overhead. The effects of RCA are also monitored under two combinations of four factors: we first vary the number of attackers and attackers' positions, and then modify the attackers' radio range and flooding rate. We also examine the effect of flooding mechanism on the energy consumed by resource consumption attackers. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

2.
Nodes in a computer network often require a copy of a message to be delivered to every node in the network. The network layer can provide such a service, referred to as network‐wide broadcast routing or simply ‘broadcasting’. Broadcasting has many applications, including its role as a service to many routing protocols. In a mobile ad hoc network (MANET), simplistic broadcast schemes (such as flooding) inundate the network with redundancy, contention, collision, and unnecessary use of energy resources. This can prevent broadcasts from achieving their primary objective of maximizing delivery ratio, while also considering secondary objectives, such as balancing energy resources or reducing the network's burden on congested or busy nodes. As a solution, we propose multiple‐criteria broadcasting (MCB). In MCB, the source of each broadcast specifies the importance assigned to broadcast objectives. Network nodes use these priorities, along with local and neighbor knowledge of distributed factors, to broadcast in accordance with the objective priorities attributed to the message. Using ns2, the performance of MCB is evaluated and compared to that of other broadcast protocols. To present knowledge, MCB constitutes the first reconfigurable, multi‐objective approach to broadcasting. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

3.
This paper studies dynamic resource allocation in a decentralized communication network. The temporal aspect in the decentralized resource allocation problem presents new challenges, e.g., in optimizing the delay-throughput trade-off under user-specific delay costs. A dynamic bandwidth allocation game modelling an agent-based network is presented. The dynamic noncooperative game achieves Pareto-efficient bandwidth allocation that can be implemented by a greedy algorithm with pricing. Optimal dynamic pricing is discussed for the efficient sharing of network resources. An ad hoc wireless network is an example of such self-organizing decentralized system: the mobile nodes need not be directly connected to a base station. Another application of the model is to consider distributed uplink scheduling, based on local information, in a WCDMA network. The discretized control variable of a mobile node is either the received power/QoS-level or the binary decision on packet transmission.  相似文献   

4.
Ad hoc wireless networks are composed of mobile nodes communicating through wireless links, without any fixed backbone infrastructure. Frequent topology changes due to node mobility make routing in such dynamic networks a challenging problem. Moreover, successful message routing implies every mobile node is potentially capable of acting as a router, thus supporting store-and-forward mechanisms. However, resource limitations on these nodes also require a control on congestion due to message forwarding. In this paper, we consider our recently proposed randomized version of the well-known Destination-Sequenced Distance Vector (DSDV) routing protocol, referred to as R-DSDV, and validate its performance through extensive simulation experiments. Our results demonstrate that a probabilistic control on message traffic based on local tuning of protocol parameters is feasible, and that R-DSDV outperforms the basic DSDV protocol by significantly reducing the average queue size associated with each mobile node and hence the average packet delay.  相似文献   

5.
Accuracy of sensed data and reliable delivery are the key concerns in addition to several other network‐related issues in wireless sensor networks (WSNs). Early detection of outliers reduces subsequent unwanted transmissions, thus preserving network resources. Recent techniques on outlier detection in WSNs are computationally expensive and based on message exchange. Message exchange‐based techniques incur communication overhead and are less preferred in WSNs. On the other hand, machine learning‐based outlier detection techniques are computationally expensive for resource constraint sensor nodes. The novelty of this paper is that it proposes a simple, non message exchange based, in‐network, real‐time outlier detection algorithm based on Newton's law of gravity. The mechanism is evaluated for its accuracy in detecting outliers, computational cost, and its influence on the network traffic and delay. The outlier detection mechanism resulted in almost 100% detection accuracy. Because the mechanism involves no message exchanges, there is a significant reduction in network traffic, energy consumption and end‐to‐end delay. An extension of the proposed algorithm for transient data sets is proposed, and analytic evaluation justifies that the mechanism is reactive to time series data. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

6.
Delay tolerant networks are a class of ad hoc networks that enable data delivery even in the absence of end‐to‐end connectivity between nodes, which is the basic assumption for routing in ad hoc networks. Nodes in these networks work on store‐carry and forward paradigm. In addition, such networks make use of message replication as a strategy to increase the possibility of messages reaching their destination. As contact opportunities are usually of short duration, it is important to prioritize scheduling of messages. Message replication may also lead to buffer congestion. Hence, buffer management is an important issue that greatly affects the performance of routing protocols in delay tolerant networks. In this paper, Spray and Wait routing protocol, which is a popular controlled replication‐based protocol for delay tolerant networks, has been enhanced using a new fuzzy‐based buffer management strategy Enhanced Fuzzy Spray and Wait Routing, with the aim to achieve increased delivery ratio and reduced overhead ratio. It aggregates three important message properties namely number of replicas of a message, its size, and remaining time‐to‐live, using fuzzy logic to determine the message priority, which denotes its importance with respect to other messages stored in a node's buffer. It then intelligently selects messages to schedule when a contact opportunity occurs. Because determination of number of replicas of a message in the network is a difficult task, a new method for estimation of the same has been proposed. Simulation results show improved performance of enhanced fuzzy spray and wait routing in terms of delivery ratio and resource consumption. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

7.
With the prevalence of mobile devices, it is of much interest to study the properties of mobile ad hoc networks. In this paper, we extend the concept of diameter from static ad hoc network to mobile ad hoc network, which is the expected number of rounds for one node to transmit a message to all other nodes in the network, reflecting the worst end‐to‐end delay between any two node. Specifically, we investigate the diameter of identically and independently mobility model in cell‐partitioned network and random walk mobility model in two‐dimensional torus network, achieving the boundary , when (k=Ω(n)), and O(k log2k), respectively, where n is the number of nodes and k is the number of cells of network and especially under random walk mobility model . A comparison is made among the diameter of mobile ad hoc networks under identically and independently mobility model, random walk mobility model and static ad hoc network, showing that mobility dramatically decreases the diameter of the network and speed is an essential and decisive factor of diameter. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

8.
蒋凌云  孙力娟  王汝传  肖甫  徐佳 《电子学报》2012,40(12):2495-2500
 针对间歇性连通的移动无线传感网提出一种能量时延约束的自适应路由协议(EDCA),EDCA由初始化阶段、转发决策阶段、转发阶段和等待阶段组成,传感器节点根据目标时延实时判断是否转发副本,并选择剩余能量多的节点进行副本转发.EDCA对平均时延和网络负载具有控制力,对网络环境变化具有自适应能力,能够有效延长网络生命周期.  相似文献   

9.
Zhenchuan  Zhenfu  Rongxing   《Ad hoc Networks》2007,5(7):1046-1054
Password authentication has been accepted as one of the commonly used solutions in network environment to protect resources from unauthorized access. The emerging mobile Ad hoc network, however, has called for new requirements for designing authentication schemes due to its dynamic nature and vulnerable-to-attack structure, which the traditional schemes overlooked, such as availability and strong security against off line guessing attacks in face of node compromise. In this paper, we propose a threshold password authentication scheme, which meets both availability and strong security requirements in the mobile Ad hoc networks. In our scheme, t out of n server nodes can jointly achieve mutual authentication with a registered user within only two rounds of message exchanges. Our scheme allows users to choose and change their memorable password without subjecting to guessing attacks. Moreover, there is no password table in the server nodes end, which is preferable since mobile nodes are usually memory-restricted devices. We also show that our scheme is efficient to be implemented in mobile devices.  相似文献   

10.
Anycast is a one‐to‐any bidirectional transmission scheme that can be used to provide various service‐oriented applications. However, traditional anycast cannot support some distributed applications that need to locate multiple servers such as network time protocols and threshold cryptography. Although there are some extended anycast schemes that can support the discovery of k services, they may cause high control overhead, low satisfaction ratio, or high searching latency when there are more service requesters and providers. The main reasons for these shortcomings are unknown service information and limited hierarchical structure. This work proposes an efficient anycast scheme, called AnyKast, for discovering k services in cluster‐based mobile ad hoc networks. In the AnyKast scheme, an anycast tree based on the clustering and virtual backbone is established to reduce unnecessary message transmission. In the anycast tree, anycast clusterheads disseminate their information to certain specific nodes that take the service information and perform the service selection task instead of blindly searching. Furthermore, to decrease the cost of service information collection and maintenance, scope flooding is used to limit the information transmission, and information piggybacking and periodical inquiry mechanism are used to increase the service information accuracy. The experimental results demonstrate that our scheme can effectively discover services, reduce request and reply message control overhead, and lower the searching latency. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

11.
With their proliferation and increasing capabilities, mobile devices with local wireless interfaces can be organized into delay‐tolerant networks (DTNs) that exploit communication opportunities arising out of the movement of their users. As the mobile devices are usually carried by people, these DTNs can also be viewed as social networks. Unfortunately, most existing routing algorithms for DTNs rely on relatively simple mobility models that rarely consider these social network characteristics, and therefore, the mobility models in these algorithms cannot accurately describe users’ real mobility traces. In this paper, we propose two predict and spread (PreS) message routing algorithms for DTNs. We employ an adapted Markov chain to model a node's mobility pattern and capture its social characteristics. A comparison with state‐of‐the‐art algorithms demonstrates that PreS can yield better performance in terms of delivery ratio and delivery latency, and it can provide a comparable performance with the epidemic routing algorithm with lower resource consumption. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

12.
In this paper, we propose a Load‐Balancing and Coding‐Aware Multicast (LCM) protocol for mobile ad hoc networks. In LCM protocol, a new route metric named Expected Transmission Time with Coding and Load Balancing (ETTCL) is presented at first, aiming at effectively selecting the path not only that has the possible coding opportunity but also where overflow due to network overload can be prevented. Then, we describe the route discovery phase by constructing the node‐disjoint multicast tree on the basis of ETTCL and employ network coding to encode the data flows for route maintenance. The effectiveness of LCM protocol is simulated and analyzed by NS‐2, which shows that this protocol has good performance in reducing average end‐to‐end delay and control overhead and can improve packet delivery ratio compared with the existing protocol. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

13.
This article puts forward a new scheme to control message redundancy efficiently in delay tolerant mobile Ad-hoc networks(MANET).The class of networks generally lacks end-to-end connectivity.In order to improve the efficiency that messages are delivered successfully,multiple message copies routing protocols are usually used,but the network load is increased due to a large number of message redundancies.In the study,by using counter method,every node adds an encounter counter based on epidemic routing scheme...  相似文献   

14.
With the advent of the Internet of Things (IoT), more and more devices can establish a connection with local area networks and use routing protocols to forward all information to the sink. But these devices may not have enough resources to execute a complex routing protocol or to memorize all information about the network. With proactive routing protocols, each node calculates the best path, and it needs enough resources to memorize the network topology. With reactive routing protocols, each node has to broadcast the message to learn the right path that the packets must follow. In all cases, in large networks such as IoT, this is not an appropriate mechanism. This paper presents a new software‐defined network (SDN)–based network architecture to optimize the resource consumption of each IoT object while securing the exchange of messages between the embedded devices. In this architecture, the controller is in charge of all decisions, and objects only exchange messages and forward packets among themselves. In the case of large networks, the network is organized into clusters. Our proposed network architectures are tested with 1000 things grouped in five clusters and managed by one SDN controller. The tests using OpenDayLight and IoT embedded applications have been implemented on several scenarios providing the ability and the scalability from dynamic reorganization of the end‐devices. This approach explores the network performance issues using a virtualized SDN‐clustered environment which contributes to a new model for future network architectures.  相似文献   

15.
In this paper, we present a routing algorithm for a class of networks where a contemporaneous end‐to‐end path may not exist at the time of data transfer due to intermittent links. Several examples of such networks exist in the context of sensor networks, mobile ad hoc networks and delay tolerant networks. The proposed routing algorithms follow a priori routing similar to source routing. Link state changes are assumed to be known ahead of time, for instance, due to planned duty cycling resulting in scheduled connectivity. The basic idea behind the proposed routing algorithms is to modify the breadth first search (BFS) algorithm to take into account link state changes and find the quickest route between source and destination nodes. We introduce the idea of time‐varying storage domains where all nodes connected for a length of time act as a single storage unit by sharing the aggregated storage capacity of the nodes. This will help situations where storage is a limited resource. We evaluate the routing algorithm with and without storage domain in an extensive simulation. The delay performance of the proposed algorithms is conceptually the same as flooding‐based algorithms but without the penalty of multiple copies. More significantly, we show that the Quickest Storage Domain (Quickest SD) algorithm distributes the storage demand across many nodes in the network topology, enabling balanced load and higher network utilization. In fact, we show that for the same level of performance, we can actually cut the storage requirement in half using the Quickest SD algorithm. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

16.
Sensor nodes are powered by battery and have severe energy constraints. The typical many‐to‐one traffic pattern causes uneven energy consumption among sensor nodes, that is, sensor nodes near the base station or a cluster head have much heavier traffic burden and run out of power much faster than other nodes. The uneven node energy dissipation dramatically reduces sensor network lifetime. In a previous work, we presented the chessboard clustering scheme to increase network lifetime by balancing node energy consumption. To achieve good performance and scalability, we propose to form a heterogeneous sensor network by deploying a few powerful high‐end sensors in addition to a large number of low‐end sensors. In this paper, we design an efficient routing protocol based on the chessboard clustering scheme, and we compute the minimum node density for satisfying a given lifetime constraint. Simulation experiments show that the chessboard clustering‐based routing protocol balances node energy consumption very well and dramatically increases network lifetime, and it performs much better than two other clustering‐based schemes. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

17.
Wireless sensor networks (WSN) are event‐based systems that rely on the collective effort of several sensor nodes. Reliable event detection at the sink is based on collective information provided by the sensor nodes and not on any individual sensor data. Hence, conventional end‐to‐end reliability definitions and solutions are inapplicable in the WSN regime and would only lead to a waste of scarce sensor resources. Moreover, the reliability objective of WSN must be achieved within a certain real‐time delay bound posed by the application. Therefore, the WSN paradigm necessitates a collective delay‐constrained event‐to‐sink reliability notion rather than the traditional end‐to‐end reliability approaches. To the best of our knowledge, there is no transport protocol solution which addresses both reliability and real‐time delay bound requirements of WSN simultaneously. In this paper, the delay aware reliable transport (DART) protocol is presented for WSN. The objective of the DART protocol is to timely and reliably transport event features from the sensor field to the sink with minimum energy consumption. In this regard, the DART protocol simultaneously addresses congestion control and timely event transport reliability objectives in WSN. In addition to its efficient congestion detection and control algorithms, it incorporates the time critical event first (TCEF) scheduling mechanism to meet the application‐specific delay bounds at the sink node. Importantly, the algorithms of the DART protocol mainly run on resource rich sink node, with minimal functionality required at resource constrained sensor nodes. Furthermore, the DART protocol can accommodate multiple concurrent event occurrences in a wireless sensor field. Performance evaluation via simulation experiments show that the DART protocol achieves high performance in terms of real‐time communication requirements, reliable event detection and energy consumption in WSN. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

18.
In opportunistic networks (OppNets), which are characterized by intermittent end‐to‐end connections, the messages are routed in a store‐carry‐and‐forward fashion using the locally inferred knowledge about the behavior of nodes. As such, most OppNets routing protocols use social metrics that are dependent on the nodes' past information. But the participation of nodes in the message forwarding process is not guaranteed without incentivizing them because most nodes are reluctant in sharing their private resources for public uses. In this paper, some socially derived psychological attributes of a node are introduced to ensure their trustworthy participation in the message forwarding process, leading to the design of an altruism‐dependent trust‐based data forwarding mechanism for OppNets (called ATDTN). In this protocol, each node is associated with a dynamically changing altruism value representing its trust in the network, which is used to determine its status with regard to its participation in message forwarding. Through trace‐driven simulations using the ONE simulator, it is shown that ATDTN outperforms IronMan and SimBet protocols for routing in OppNets (respectively, 18% and 48% improvement), in terms of delivery ratio, end‐to‐end delay, overhead count, and average number of hops, under varying buffer size and time‐to‐live.  相似文献   

19.
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.  相似文献   

20.
Mobility management (MM) in Long‐Term Evolution (LTE) networks is a vital process to keep an individual User Equipment (UE) connected while moving within the network coverage area. MM Entity (MME) is the LTE component responsible for tracking and paging procedures and controlling the corresponding signaling between the UE and its serving cell, which is necessary for data‐packet exchange. Because of the massive increase in the density of mobile UEs, MME is burdened by the high volume signaling load, especially because most of that load comes from Tracking Area Update (TAU) and Paging messages, which are essential to exchange UE‐specific information with the network. To achieve cost‐efficient resource provisioning, many solutions have been proposed for TAU and Paging management to optimize not only UE experience (ie, battery power consumption) but also network resources (ie, bandwidth). In this paper, we discuss various solution schemes for TAU and Paging in terms of complexity, latency, and computation costs. Also, this review discusses the adverse effects of these solutions on the LTE Key Performance Indicators (KPIs). Furthermore, we present a new trend of MM solutions in LTE networks, called software‐defined network (SDN) and software‐defined virtualization (SDNV). To this end, we examine the existing schemes and challenges in the literature toward next‐generation wireless networks (eg, 5G, Internet‐of‐Things [IoT], and machine to machine [M2M] communications), and we describe user mobility models that are used to analyze the network performance.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号