Showing papers on "Optimized Link State Routing Protocol published in 2008"

Efficient routing in intermittently connected mobile networks: the multiple-copy case

Abstract: Intermittently connected mobile networks are wireless networks where most of the time there does not exist a complete path from the source to the destination. There are many real networks that follow this model, for example, wildlife tracking sensor networks, military networks, vehicular ad hoc networks, etc. In this context, conventional routing schemes fail, because they try to establish complete end-to-end paths, before any data is sent. To deal with such networks researchers have suggested to use flooding-based routing schemes. While flooding-based schemes have a high probability of delivery, they waste a lot of energy and suffer from severe contention which can significantly degrade their performance. Furthermore, proposed efforts to reduce the overhead of flooding-based schemes have often been plagued by large delays. With this in mind, we introduce a new family of routing schemes that "spray" a few message copies into the network, and then route each copy independently towards the destination. We show that, if carefully designed, spray routing not only performs significantly fewer transmissions per message, but also has lower average delivery delays than existing schemes; furthermore, it is highly scalable and retains good performance under a large range of scenarios. Finally, we use our theoretical framework proposed in our 2004 paper to analyze the performance of spray routing. We also use this theory to show how to choose the number of copies to be sprayed and how to optimally distribute these copies to relays.

A survey of secure mobile Ad Hoc routing protocols

Abstract: Several routing protocols have been proposed in recent years for possible deployment of mobile ad hoc networks (MANETs) in military, government and commercial applications. In this paper, we review these protocols with a particular focus on security aspects. The protocols differ in terms of routing methodologies and the information used to make routing decisions. Four representative routing protocols are chosen for analysis and evaluation including: Ad Hoc on demand Distance Vector routing (AODV), Dynamic Source Routing (DSR), Optimized Link State Routing (OLSR) and Temporally Ordered Routing Algorithm (TORA). Secure ad hoc networks have to meet five security requirements: confidentiality, integrity, authentication, non-repudiation and availability. The analyses of the secure versions of the proposed protocols are discussed with respect to the above security requirements.

A Power Control MAC Protocol for Ad hoc Networks

Abstract: The mobile Nodes in wireless Ad hoc networks are fed by batteries,so the energy limitation has become a performance bottleneck for mobile ad hoc networks.IEEE 802.11 has been used as the current standard MAC protocol for ad hoc networks.However,it has not the ability of adjusting power level dynamically,which reduces the performance of network.Power control can enhance the power efficiency of nodes,reduce the interferer of neighbor nodes and improve the performance of network.A novel power controlled MAC protocol based on SNR in mobile Ad hoc networks is presented in this paper.Simulation results demonstrate that compared to the IEEE 802.11 MAC protocol,the proposed protocol can decrease the power consumption greatly,and improve the energy utilization of mobile terminals while maintaining the throughput performance.

Minimizing broadcast latency and redundancy in ad hoc networks

Abstract: Network wide broadcasting is a fundamental operation in ad hoc networks. In broadcasting, a source node sends a message to all the other nodes in the network. In this paper, we consider the problem of collision-free broadcasting in ad hoc networks. Our objective is to minimize the latency and the number of transmissions in the broadcast. We show that minimum latency broadcasting is NP-complete for ad hoc networks. We also present a simple distributed collision-free broadcasting algorithm for broadcasting a message. For networks with bounded node transmission ranges, our algorithm simultaneously guarantees that the latency and the number of transmissions are within O(1) times their re spective optimal values. Our algorithm and analysis extend to the case when multiple messages are broadcast from multiple sources. Experimental studies indicate that our algorithms perform much better in practice than the analytical guarantees provided for the worst case.

ODSBR: An on-demand secure Byzantine resilient routing protocol for wireless ad hoc networks

Abstract: Ah hoc networks offer increased coverage by using multihop communication. This architecture makes services more vulnerable to internal attacks coming from compromised nodes that behave arbitrarily to disrupt the network, also referred to as Byzantine attacks. In this work, we examine the impact of several Byzantine attacks performed by individual or colluding attackers. We propose ODSBR, the first on-demand routing protocol for ad hoc wireless networks that provides resilience to Byzantine attacks caused by individual or colluding nodes. The protocol uses an adaptive probing technique that detects a malicious link after log n faults have occurred, where n is the length of the path. Problematic links are avoided by using a route discovery mechanism that relies on a new metric that captures adversarial behavior. Our protocol never partitions the network and bounds the amount of damage caused by attackers. We demonstrate through simulations ODSBR's effectiveness in mitigating Byzantine attacks. Our analysis of the impact of these attacks versus the adversary's effort gives insights into their relative strengths, their interaction, and their importance when designing multihop wireless routing protocols.

Ad-hoc Networks: Fundamental Properties and Network Topologies

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Delay-bounded routing in vehicular ad-hoc networks

Abstract: Ad hoc networks formed by traveling vehicles are envisaged to become a common platform that will support a wide variety of applications, ranging from road safety to advertising and entertainment. The multitude of vehicular applications calls for routing schemes that satisfy user-defined delay requirements while at the same time maintaining a low level of channel utilization to allow their coexistence. This paper focuses on the development of carry-and-forward schemes that attempt to deliver data from vehicles to fixed infrastructure nodes in an urban setting. The proposed algorithms leverage local or global knowledge of traffic statistics to carefully alternate between the Data Muling and Multihop Forwarding strategies, in order to minimize communication overhead while adhering to delay constraints imposed by the application. We provide an extensive evaluation of our schemes using realistic vehicular traces on a real city map.

Prevention of Co-operative Black Hole Attack in MANET

Abstract: A mobile ad hoc network (MANET) is an autonomous network that consists of mobile nodes that communicate with each other over wireless links. In the absence of a fixed infrastructure, nodes have to cooperate in order to provide the necessary network functionality. One of the principal routing protocols used in Ad hoc networks is AODV (Ad hoc On demand Distance Vector) protocol. The security of the AODV protocol is compromised by a particular type of attack called ‘Black Hole’ attack In this attack a malicious node advertises itself as having the shortest path to the node whose packets it wants to intercept. To reduce the probability it is proposed to wait and check the replies from all the neighboring nodes to find a safe route. Our approach to combat the Black hole attack is to make use of a ‘Fidelity Table’ wherein every participating node will be assigned a fidelity level that acts as a measure of reliability of that node. In case the level of any node drops to 0, it is considered to be a malicious node, termed as a ‘Black hole’ and is eliminated. Computer simulation using GLOMOSIM shows that our protocol provides better security and also better performance in terms of packet delivery than the conventional AODV in the presence of Black holes with minimal additional delay and Overhead.

Ad hoc networks beyond unit disk graphs

Abstract: In this paper, we study an algorithmic model for wireless ad hoc and sensor networks that aims to be sufficiently close to reality as to represent practical real-world networks while at the same time being concise enough to promote strong theoretical results The quasi unit disk graph model contains all edges shorter than a parameter d between 0 and 1 and no edges longer than 1 We show that--in comparison to the cost known for unit disk graphs--the complexity results of geographic routing in this model contain the additional factor 1/d2 We prove that in quasi unit disk graphs flooding is an asymptotically message-optimal routing technique, we provide a geographic routing algorithm being most efficient in dense networks, and we show that classic geographic routing is possible with the same asymptotic performance guarantees as for unit disk graphs if d ≥ 1/√2

Robust content dissemination in disrupted environments

Abstract: Content dissemination in disrupted networks poses a big challenge, given that the current routing architectures of ad hoc networks require establishing routes from sources to destinations before content can disseminated between them. In ad hoc networks subject to disruption, lack of reliable connectivity between producers and consumers of information makes most routing protocols perform very poorly or not work at all. We present DIRECT (DIsruption REsilient Content Transport), which is a content dissemination approach for ad hoc networks that exploits in-network storage and the hop-by-hop dissemination of named information objects. Simulation experiments illustrate that DIRECT provides a high degree of reliability while maintaining low levels of delivery latencies and signaling and data overhead compared to traditional on-demand routing and epidemic routing.

EE-OLSR: Energy Efficient OLSR routing protocol for Mobile ad-hoc Networks

Abstract: This paper presents two novel mechanisms for the OLSR routing protocol, aiming to improve its energy performance in Mobile ah-hoc Networks. Routing protocols over MANET are an important issue and many proposals have been addressed to efficiently manage topology information, to offer network scalability and to prolong network lifetime. However, few papers consider a proactive protocol (like OLSR) to better manage the energy consumption. OLSR presents the advantage of finding a route between two nodes in the network in a very short time, thanks to its proactive scheme, but it can expend a lot of resources selecting the MultiPoint Relays (MPRs) and exchanging Topology Control information. We propose a modification in the MPR selection mechanism of OLSR protocol, based on the Willingness concept, in order to prolong the network lifetime without losses of performance (in terms of throughput, end-to-end delay or overhead). Additionally, we prove that the exclusion of the energy consumption due to the overhearing can extend the lifetime of the nodes without compromising the OLSR functioning at all. A comparison of an Energy-Efficient OLSR (EE-OLSR) and the classical OLSR protocol is performed, testing some different well-known energy aware metrics such as MTPR, CMMBCR and MDR. We notice how EE-OLSR outperforms classical OLSR, and MDR confirms to be the most performing metric to save battery energy in a dense mobile network with high traffic loads.

Detecting and avoiding wormhole attacks in wireless ad hoc networks

Abstract: A particularly severe attack on routing protocols in ad hoc networks is the so-called worm- hole attack in which two or more colluding attackers record packets at one location, and tunnel them to another location for replay at that remote location. When this attack targets specifically routing control packets, the nodes that are close to the attackers are shielded from any alternative routes with more than one or two hops to the remote location. All routes are thus directed to the wormhole established by the attackers. In the optimized link state routing protocol, if a wormhole attack is launched during the propagation of link state packets, the wrong link information percolates throughout the network, leading to routing disruption. In this article we devise an efficient method to detect and avoid wormhole attacks in the OLSR protocOLSR protocolol. This method first attempts to pinpoint links that may potentially be part of a wormhole tunnel. Then a proper wormhole detection mechanism is applied to suspicious links by means of an exchange of encrypted probing packets between the two supposed neighbors (endpoints of the wormhole). The proposed solution exhibits several advantages, among which are its nonreliance on any time synchronization or location information, and its high detection rate under various scenarios.

Multi-metric routing calculations

Abstract: In a Mobile Ad Hoc Network (MANET), multi-metric information is gathered and applied to a cost-based route calculation. In particular, each node gathers resource metrics from neighboring of nodes, along with data rate and reliability information for data links to and from the node. This information is applied to a costing algorithm such as Dykstra' Open Shortest Path First algorithm to obtain routes through the network. This approach may be adapted with suitable modifications to use with unicast traffic or with a multicast forwarding group.

An O(log n) dominating set protocol for wireless ad-hoc networks under the physical interference model

Abstract: Dealing with interference is one of the primary challenges to solve in the design of protocols for wireless ad-hoc networks. Most of the work in the literature assumes localized or hop-based interference models in which the effect of interference is neglected beyond a certain range from the transmitter. However, interference is a more complex phenomenon that cannot, in general, be captured by localized models, implying that protocols based on such models are not guaranteed to work in practice. This paper is the first to present and rigorously analyze a distributed dominating set protocol for wireless ad-hoc networks with O(1) approximation bound based on the physical interference model, which accounts for interference generated by all nodes in the network. The proposed protocol is fully distributed, randomized, and extensively uses physical carrier sensing to reduce message overhead. It does not need node identifiers or any kind of prior information about the system, and all messages are of constant size (in bits). We prove that, by appropriately choosing the threshold for physical carrier sensing, the protocol stabilizes within a logarithmic number of communication rounds, w.h.p., which is faster than the runtime of any known distributed protocol without prior knowledge about the system under any wireless model that does not abstract away collisions.

Randomized 3D Geographic Routing

Abstract: We reconsider the problem of geographic routing in wireless ad hoc networks. We are interested in local, memoryless routing algorithms, i.e. each network node bases its routing decision solely on its local view of the network, nodes do not store any message state, and the message itself can only carry information about O(1) nodes. In geographic routing schemes, each network node is assumed to know the coordinates of itself and all adjacent nodes, and each message carries the coordinates of its target. Whereas many of the aspects of geographic routing have already been solved for 2D networks, little is known about higher-dimensional networks. It has been shown only recently that there is in fact no local memoryless routing algorithm for 3D networks that delivers messages deterministically. In this paper, we show that a cubic routing stretch constitutes a lower bound for any local memoryless routing algorithm, and propose and analyze several randomized geographic routing algorithms which work well for 3D network topologies. For unit ball graphs, we present a technique to locally capture the surface of holes in the network, which leads to 3D routing algorithms similar to the greedy-face-greedy approach for 2D networks.

Performance Comparison of Wireless Mobile Ad-Hoc Network Routing Protocols

Abstract: Summary The Efficient routing protocols can provide significant benefits to mobile ad hoc networks, in terms of both performance and reliability. Many routing protocols for such networks have been proposed so far. Amongst the most popular ones are Ad hoc Ondemand Distance Vector (AODV), Destination-Sequenced Distance-Vector Routing protocol (DSDV), Dynamic Source Routing Protocol (DSR), and Optimum Link State Routing (OLSR). Despite the popularity of those protocols, research efforts have not focused much in evaluating their performance when applied to variable bit rate (VBR). In this paper we present our observations regarding the performance comparison of the above protocols for VBR in mobile ad hoc networks (MANETs). We perform extensive simulations, using NS-2 simulator. Our studies have shown that reactive protocols perform better than proactive protocols. Further DSR has performed well for the performance parameters namely delivery ratio and routing overload while AODV performed better in terms of average delay.

(p,q)-Epidemic routing for sparsely populated mobile ad hoc networks

Abstract: This paper considers (p, q )-Epidemic Routing, a class of store-carry-forward routing schemes, for sparsely populated mobile ad hoc networks. Our forwarding scheme includes Two-Hop Forwarding and the conventional Epidemic Routing as special cases. In such forwarding schemes, the original packet is copied many times and its packet copies spread over the network. Therefore those packet copies should be deleted after a packet reaches the destination. We analyze the performance of (p, q)-Epidemic Routing with VACCINE recovery scheme. Unlike most of the existing studies, we discuss the performance of (p, q)-Epidemic Routing in depth, taking account of the recovery process that deletes unnecessary packets from the network.

Enhancing AODV routing protocol using mobility parameters in VANET

Abstract: VANET is new generation of ad hoc networks that implement between vehicles on a road. Because of high mobility, routing in VANET has more problems than MANET. Thereby, in this paper we propose a modification on AODV as MANET routing protocol to make it adaptive for VANET. When a node is mobile, it has three mobility parameters: position, direction and speed. In our method, we have used direction as most important parameter to select next hop during a route discovery phase. With respect to mobility model, if nodes has same direction with source and/or destination nodes, our solution might selects them as a next hop. Position is another parameter that we used for next hop selection.

Cooperative black and gray hole attacks in mobile ad hoc networks

Abstract: In this paper, we propose a complete protocol to detect a chain of cooperating malicious nodes in an ad hoc network that disrupts transmission of data by feeding wrong routing information. Our technique is based on sending data in equal but small sized blocks instead of sending whole of data in one continuous stream. The flow of traffic is monitored independently at the neighborhoods of both source and destination. The results of monitoring are gathered by a backbone network of trusted nodes. With assumption that a neighborhood of any node in the ad hoc network has more trusted nodes than malicious nodes, our protocol can not only detect but also remove a chain of cooperating malicious nodes (gray/black hole) by ensuring an end-to-end checking between the transmission of two blocks of data. The protocol takes O(mdBN) time for detection and removal of gray/black holes chain which betters an earlier O(n2) time bound [4] for detecting a single black hole in the network. Here, m is the number of malicious nodes in the network, dBN is the diameter of a backbone network formed out of the flat ad hoc network, and n is the total number of nodes in the ad hoc network.

An algorithmic approach to geographic routing in ad hoc and sensor networks

Abstract: The one type of routing in ad hoc and sensor networks that currently appears to be most amenable to algorithmic analysis is geographic routing. This paper contains an introduction to the problem field of geographic routing, presents a specific routing algorithm based on a synthesis of the greedy forwarding and face routing approaches, and provides an algorithmic analysis of the presented algorithm from both a worst-case and an average-case perspective.

An energy efficient routing scheme for mobile wireless sensor networks

Abstract: Research on wireless sensor networks has recently received much attention as they offer an advantage of monitoring various kinds of environment by sensing physical phenomenon. Among various issues, energy consumption is one of the most important criteria for routing protocol in wireless sensor networks (WSNs). This paper introduces an energy efficient clustering algorithm for mobile sensor network based on the LEACH protocol. The proposed protocol adds feature to LEACH to support for mobile nodes and also reduces the consumption of the network resource in each round. The proposed protocol is simulated and the results show a significant reduction in network energy consumption compared to LEACH.

Survey of Energy Efficient Strategies in Wireless Ad Hoc and Sensor Networks

Abstract: The diversity of the applications supported by wireless ad hoc and sensor networks explain the success of these networks. However, their energy constrained nature requires the use of energy efficient strategies to maximize network lifetime. We can classify these strategies in four categories: 1. energy efficient routing, 2. scheduling the nodes sleeping state, 3. topology control by tuning node transmission power and 4. reducing the volume of information transferred. For each category, a state of the art is given and new protocols are presented. The best energy efficiency will be obtained by combining all the four categories of strategies. A cross-layering approach is a promising tradeoff between generic solutions and solutions optimized for a specific application.

CASCADE: Cluster-Based Accurate Syntactic Compression of Aggregated Data in VANETs

Abstract: We present a method for accurate aggregation of highway traffic information in vehicular ad hoc networks (VANETs). Highway congestion notification applications need to disseminate information about traffic conditions to distant vehicles. In dense traffic, aggregation is needed to allow a single frame to carry information about a large number of vehicles. Our technique, CASCADE, uses compression to provide aggregation without losing accuracy. We show that CASCADE makes efficient use of the wireless channel while providing each vehicle with data that is highly accurate, represents a large area in front of the vehicle, and can be combined with aggregated data from other vehicles to further extend the covered area.

Reference point group mobility and random waypoint models in performance evaluation of MANET routing protocols

Abstract: Ad hoc networks are characterized by multihop wireless connectivity, frequently changing network topology and the need for efficient dynamic routing protocols plays an important role. We compare the performance of two prominent on-demand routing protocols for mobile ad hoc networks: dynamic source routing (DSR), ad hoc on-demand distance vector routing (AODV). A detailed simulation model with medium access control (MAC) and physical layer models is used to study the interlayer interactions and their performance implications. We demonstrate that even though DSR and AODV share similar on-demand behavior, the differences in the protocol mechanisms can lead to significant performance differentials. In this paper, we examine both on-demand routing protocols AODV and DSR based on packet delivery ratio, normalized routing load, normalized MAC load, average end-to-end delay by varying the node density, network loading, and mobility variations for reference point group mobility and random waypoint models. This framework aims to evaluate the effect of mobility models on the performance of mobile ad hoc networks (MANETs) routing protocols. Our results show that the protocol performance may vary drastically across mobility models and performance rankings of protocols may vary with the mobility models used. This effect can be explained by the interaction of the mobility characteristics with the connectivity graph properties.

Distributed ad hoc network protocol using synchronous shared beacon signaling

Abstract: A method for forming a protocol structure for use in an ad hoc, distributed, scaleable wireless sensor node network which enables nodes to join the network autonomously without there being a designated, permanent central time reference and for enabling such nodes to synchronize timing with each other and with other nodes in the network. The method involves discovering the active channel changing sequence used by the network, synchronizing communications of a new node with the remainder of the nodes in the network and scanning communications channels to detect merging clusters of nodes.

Performance Comparison of Two On-demand Routing Protocols for Ad-hoc Networks based on Random Way Point Mobility Model

Abstract: Ad hoc networks are characterized by multihop wireless connectivity, frequently changing network topology and the need for efficient dynamic routing protocols plays an important role. We compare the performance of two prominent on-demand routing protocols for mobile ad hoc networks: Dynamic Source Routing (DSR), Ad Hoc On-demand distance Vector Routing (AODV). A detailed simulation model with MAC and physical layer models is used to study the interlayer interactions and their performance implications. We demonstrate that even though DSR and AODV share similar on-demand behavior, the differences in the protocol mechanisms can lead to significant performance differentials. In this paper we examine two on demand routing protocols AODV and DSR based on packet delivery ratio, normalized routing load, normalized MAC load, average end to end delay by varying the number of sources, speed and pause time.

Robust cooperative routing protocol in mobile wireless sensor networks

Abstract: In wireless sensor networks, path breakage occurs frequently due to node mobility, node failure, and channel impairments It is challenging to combat path breakage with minimal control overhead, while adapting to rapid topological changes Due to the Wireless Broadcast Advantage (WBA), all nodes inside the transmission range of a single transmitting node may receive the packet, hence naturally they can serve as cooperative caching and backup nodes if the intended receiver fails to receive the packet In this paper, we present a distributed robust routing protocol in which nodes work cooperatively to enhance the robustness of routing against path breakage We compare the energy efficiency of cooperative routing with noncooperative routing and show that our robust routing protocol can significantly improve robustness while achieving considerable energy efficiency

Bandwidth and cost management for ad hoc networks

Abstract: A system and method is described herein for managing bandwidth and cost in connection with a plurality of sensors in an ad hoc network. The system and method receives sensor data that is provided from a plurality of sensors and constructs an ad hoc network among the plurality of sensors based on the sensor data. The system and method also receives and analyzes bandwidth information from each sensor in a group of sensors in the ad hoc network. Based on the analysis, the system and method then modifies a manner in which at least one sensor in the group exchanges data, including sensor data and multimedia content.