Haut PDF Non-cooperative Forwarding in Ad-hoc Networks

Non-cooperative Forwarding in Ad-hoc Networks

Non-cooperative Forwarding in Ad-hoc Networks

Unité de recherche INRIA Sophia Antipolis 2004, route des Lucioles - BP 93 - 06902 Sophia Antipolis Cedex France Unité de recherche INRIA Futurs : Parc Club Orsay Université - ZAC des Vi[r]

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Authentication and consensus overhead in vehicular ad hoc networks

Authentication and consensus overhead in vehicular ad hoc networks

9 Conclusion and future work VANETs deployment has the potential to greatly increase vehicular safety and improve driving experience. But, ve- hicular communications need to be secured. Therefore, the DSRC standard for vehicular ad hoc networks is based on the ECDSA algorithm for supporting authentication mecha- nism. But, security mechanisms come with overheads that affect the performance of the V2V communications, and hence that of the safety applications. In this paper, we inves- tigate the total overhead of ECDSA, combining the packet size, processing and communication overheads. We focus on safety applications, and analyze the impact of the au- thentication on the braking distance. We conduct simulation study in order to evaluate the performance of secured beacon safety message dissemination in vehicular ad hoc networks. We pay special attention to safety requirements while study- ing networking performance issues.
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Authentication and consensus overhead in vehicular ad hoc networks

Authentication and consensus overhead in vehicular ad hoc networks

Authentication and consensus overhead in vehicular ad hoc networks Jonathan Petit · Zoubir Mammeri Abstract Vehicular ad hoc networks aim at increasing pas- senger safety by exchanging warning messages between ve- hicles wirelessly. A main challenge is to resist to various malicious abuses and security attacks. However, any secu- rity mechanism comes with overhead. We analyze how the authentication algorithm ECDSA and the consensus mech- anism impact the vehicular network performance and the braking distance. Processing and communication overheads, decision methods for consensus, are analyzed by analytical models and intensive simulations. We propose a formula to assess the total time overhead of the authentication. Results conclude that the authentication key size should be chosen carefully, and the decision method should be adapted to the context.
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Proximity aware routing in ad hoc networks

Proximity aware routing in ad hoc networks

Abstract: Most of the existing routing protocols for ad hoc networks are designed to scale in networks of a few hundred nodes. They rely on state concerning all links of the network or links on the route between a source and a destination. This may result in poor scaling properties in larger mobile networks or when node mobility is high. Using location information to guide the routing process is one of the most often proposed means to achieve scalability in large mobile networks. However, location- based routing is difficult when there are holes in the network topology. We propose a novel position- based routing protocol called Proximity Aware Routing for Ad-hoc networks (PARA) to address these issues. PARA selects the next hop of a packet based on 2-hops neighborhood information. We introduce the concept of “proximity discovery”. The knowledge of a node’s 2-hops neighborhood enables the protocol to anticipate concave nodes and helps reduce the risks that the routing protocol will reach a concave node in the network. Our simulation results show that PARA’s performance is better in sparse networks with little congestion. Moreover, PARA significantly outperforms GPSR for delivery ratio, transmission delay and path length. Our results also indicate that PARA delivers more packets than AODV under the same conditions.
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Scalability and Quality of Service in Mobile Ad Hoc Networks

Scalability and Quality of Service in Mobile Ad Hoc Networks

in MANETs. Due to node movement and unstable radio channel, the network topology may change frequently. These changes will cost bandwidth to transmit a great amount of control messages to update the routing table in every cluster head. SESTP focus on providing stable cluster structures, specifically for highly mobile ad hoc networks. Thus, the stability of available wireless communication connections is one of the most important concerns in this scheme. SESTP based on two algorithms that a relative speed estimation algorithm and a stay time prediction algorithm. The Doppler shifts associated with periodically exchanged Hello packets between neighboring nodes are used to estimate the relative speed between cluster head and cluster members. With the estimated speed, a node can predict its stay time in every nearby cluster. A node may only play one of the following three roles at any moment: cluster head, cluster member or undecided. This clustering scheme divided into two stages. Initially, all nodes have an unde- cided status. In the initial clustering stage a node joins a cluster that can provide it with the longest stay time in order to reduce the number of re-affiliations and the procedure of cluster formation as following:
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Opportunistic Software Deployment in Disconnected Mobile Ad Hoc Networks

Opportunistic Software Deployment in Disconnected Mobile Ad Hoc Networks

deployment of component-based applications in disconnected MANETs. These specific problems have however been addressed in many projects and following dif- ferent lines in the past few years. For example Java Web Start [Sun Microsystems, 2004] sup- ports the deployment and the update of Java- based application programs. It relies on a client-server model: a server (or a collection of servers in the case of Maven) maintains a repository where applications can be stored, and clients can download new applications— or new versions of applications they have al- ready downloaded—from this server. We be- lieve that the client-server model is hardly ap- plicable for deploying and updating software in an autonomous ad hoc network, although it usually performs satisfactorily in an infrastruc- ture network. The approach we propose thus aims at achieving software deployment based on opportunistic peer-to-peer interactions be- tween mobile devices, as we think that this ap- proach is better suited to ad hoc networks.
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Routing in Large Scale tactical mobile ad hoc Networks

Routing in Large Scale tactical mobile ad hoc Networks

7.1 Conclusion The Transformation of the military networks that is currently occurring with the ad- vent of the Network Centric Warfare adopts the concept of “Mobile Ad Hoc Network” (MANET) as a central component of the tactical network environment. Military networks are typically transportable networks made of multiple components among which the tactical network which refers to the nodes responsible for the operations on-the-field. In the future, the tactical network is expected to be made of nodes that are mobile, self-managing, self-configuring without relaying on any infrastructure. Thereby, the concept of Mobile Ad hoc Networks appears as the ideal candidate so- lution for supporting the fully mobile and dynamic tactical communication networks. Since the 1980’s, the Mobile Ad Hoc Networks have known a substantial at- tention. MANETs are often considered as “wireless access network” solutions to connect mobile users to a fixed infrastructure. Their use in the military environment is different from the commercial employment. Whereas in the commercial use of mobile ad hoc network the wireless network is seen as an extension of a wired IP network i.e. operating as a stub, its use within the tactical network structure places it as a transit network carrying traffic entering and then leaving the network (and not sinked or generated by MANET nodes). The first chapter of this manuscript presents the tactical network architecture and the role of the tactical MANET as a transit network within the architecture. The Tactical Internet is made of a variety of heterogeneous networks such as LANs, satellite networks, commercial networks that are interconnected through the Tactical Communications Nodes. These Tac- tical Communications Nodes integrate radio equipments to form together a highly dynamic radio network, the tactical MANET. Thereby, the tactical MANET is a transit network that must inter-operate different networks (LANs, commercial Inter- net...). The context of employment of the tactical MANET engenders challenges to solve as well as the ones inherent to this type of network. We can mention among others the scalability (tactical networks can be made of several hundreds of nodes), the importance of multicast communications and the interoperability with wired net- works. Through this thesis, we endeavours to define how multicast communications can be settled between actors that are spread among different types of networks interconnected thanks to the MANET network.
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CoopGeo : a beaconless geographic cross-layer protocol for cooperative wireless ad hoc networks

CoopGeo : a beaconless geographic cross-layer protocol for cooperative wireless ad hoc networks

on [14], with MAC-physical cross-layer design. Likewise, in view of the interaction between the MAC and network layers, we also incorporate routing issues in this paper as a properly designed MAC protocol can fa- cilitate routing process at the network layer, in particular the beaconless geographic routing 1 (BLGR) [28]–[33]. BLGR is one of the most efficient and scalable routing solutions for wireless ad hoc and sensor networks. The key advantage of BLGR is that it needs neither prior knowledge of network topology for making a route deci- sion nor the periodic exchange of control messages (i.e., beacons) for acquiring neighbors’ geographic locations. A current node can make its own routing decisions by using local information. In general, a BLGR protocol comprises two operating phases: forwarding phase and recovery phase. In the forwarding phase, routing deci- sions are made according to the greedy mechanism, a neighbor closest to the destination is chosen as the next hop of a current node. Greedy forwarding, however, fails when reaching a local minimum, i.e., a current node that has no neighbor closer to the destination. In this case, the recovery mode based on the well-known face routing algorithm is triggered to find another path to the destination.
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A cross-layer protocol for cooperative content discovery over mobile ad-hoc networks

A cross-layer protocol for cooperative content discovery over mobile ad-hoc networks

and flooding), similar topologies (i.e., flat, changing topologies with a high churn rate), and a low reliability of single nodes. Nevertheless, there are several important parameters of ad-hoc networks that are usually not taken into account by wired peer-to-peer protocols, such as node mobility, link quality, and node density. On the Internet, a P2P network is an overlay justified by the need for specialised functions not possible at IP level, e.g., multicast support (not provided by most IP routers). Unstructured P2P overlays offer a logic network through which queries are flooded when a peer looks for piece of data to find as many peers as possible sharing the data. Structured P2P overlays offer a content addressable networks that permit efficient content-based routing, which is otherwise not possible in the IP layer.
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Routing and Broadcasting in Hybrid Ad Hoc Networks

Routing and Broadcasting in Hybrid Ad Hoc Networks

Projet POPS Rapport technique n° 0291 — Février 2004 — 14 pages Abstract: Hybrid ad hoc networks consist of two kinds of nodes, regular nodes and nodes with additional capabilities. For example, multi-hop cellular and wireless Internet networks consist of static or mobile nodes and access points to a fixed infrastructure. Each node may access fixed infrastructure either directly or via other nodes in multi-hop fashion. Another example is heterogeneous sensor networks, which consists of regular tiny sensors, and spe- cial nodes capable of communicating between themselves and to monitoring station using their own backbone network. In this paper, we propose some protocols for broadcasting and routing in hybrid ad hoc networks. Hybrid blind flooding uses backbone of access nodes to spread the message, otherwise blind flooding is applied. Component neighbor elimination based flooding applies neighbor elimination based broadcasting separately within each com- ponent, consisting of all nodes with the same closest access point. In adaptive flooding, each node additionally estimates whether each of its neighbor from a different component already received the packet via its own access point in the neighbor elimination process. Multipoint relaying, and dominating set based broadcasting are generalized from existing ad hoc net- work protocols, utilizing the capabilities of access points. These broadcasting protocols can be applied for route discovery in proactive or reactive routing protocols for hybrid ad hoc networks. Hybrid routing protocol for hybrid ad hoc networks applies proactive routing to maintain the link to the closest access point, and reactive routing to find route between two ad hoc nodes. Access points cooperate to reduce the hop count of later route discovery.
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Authentication services in mobile ad hoc networks

Authentication services in mobile ad hoc networks

Another possibility that have not been widely exploited is to generate autonomous wireless networks using the ad hoc connection capabilities of the wireless cards. In such environments all the nodes are connected together and if the number of nodes and the area it covers increases them a routing protocol is needed. Usually, these ad hoc networks are mainly used to share files and internet connections because there are not still business models that could take advantage of this kind of networks, and one of the main reasons is the lack of AAA services due to the distributed nature of these networks. However there is a possibility of having these services inside the ad hoc network, where an operator could pre-configure some nodes with AAA services and use them to deploy an ad hoc network and make business. The potential users have to be authenticated before having access to services and their operations will be registered for charging purposes. Then the challenge is how to deploy this kind of networks.
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Ad Hoc Mobility Notification in Wireless Infrastructure Networks

Ad Hoc Mobility Notification in Wireless Infrastructure Networks

Research efforts aiming at merging cellular wireless and ad hoc networking have been recently increasing [ 5 , 26 , 6 , 13 , 2 , 23 , 7 ]. Hybrid networks, the extension of cellular network using ad hoc connectivity, offer obvious benefits. On one hand, they allow an extension cellular networks range using ad hoc connectivity and on the other hand they provide a global Internet connectivity to ad hoc nodes. However, deployment of a wired cellular infrastructure still represents a high cost as well as a lot of constraints. Both costs and constraints can be reduced if we replace the wired infrastructure network by a fully wireless one. The infrastructure network becomes a collection of static wireless nodes acting both as base stations and infrastructure routers. Infrastructure communications become wireless multi- hop communications. As the wireless medium really differs from the wired one (pervasive medium, non isolated links, higher latency and lower bandwidth), the design of classical micro-mobility protocols must be rethought and if necessary altered. As it seems hard to achieve as good performances in a wireless hybrid network as in a wired one, a deeper attention must be given to each layer of the networking stack in order to design protocols in adequation with the wireless medium characteristics.
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Global visualization of experiments in ad hoc networks

Global visualization of experiments in ad hoc networks

To our knowledge, few works deal with such experiments. The works of [8, 9, 13] aim at depicting the behaviour of some particular routing (DSR for [8, 9] and ABR for [13]). Only APE [6] and Forwarding [2] are completely dedicated to experiments. Their goal is to ease the deployment of scenarios on real ad hoc network. APE concerns essentially the evaluation of routing protocols whereas the aim of Forwarding is to test the MAC protocols. As mentioned in [7], the studied metrics during experiments are essentially packet loss, jitter, end-to-end delay, throughput. All these metrics can be obtained with local log files collected during the experiment. No global visualization of the the run of the experiments is provided in the previously mentionned works. But it can be very useful to get a global log of the experiments. Such kinds of logs can give information on the schedule of the packets during the experiments, the possible spatial re-use, the possible collisions, etc. Such informations help in a better understanding of the protocols under evaluation.
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Towards End-to-End QoS in Ad Hoc Networks

Towards End-to-End QoS in Ad Hoc Networks

118 Route de Narbonne - 31062 Toulouse Cedex 04 - France Email: {benzekri, osman}@irit.fr Abstract— In this paper, we address the problem of supporting adaptive QoS resource management in mobile ad hoc networks, by proposing an efficient model for providing proportional end- to-end QoS between classes. The effectiveness of our proposed solution in meeting desired QoS differentiation at a specific node and from end-to-end are assessed by simulation using a queueing network model implemented in QNAP. The experiments results show that the proposed solution provides consistent proportional differentiation for any service class and validates our claim even under bursty traffic and fading channel conditions.
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Service Provision in Disconnected Mobile Ad Hoc Networks

Service Provision in Disconnected Mobile Ad Hoc Networks

4. Related work Existing middleware solutions, such as DEAPspace [6], Konark [5], ReMMoC [4] and INDISS [2], have inves- tigated the service provision issues in ad hoc networks. DEAPspace provides a support for the discovery and the delivery of services in wireless single-hop ad hoc networks. The middleware Konark targets environment and goal sim- ilar to DEAPspace, but considers multi-hop wireless ad hoc networks. Like in DEAPspace, each device in Konark maintains in a directory a vision of services available in the network, and acts both as client and provider of ser- vices. Konark makes some assumptions regarding the net- work by considering that a transmission route can be es- tablished between a client and a service provider whenever needed. Thus it does not support the service provision in in- termittently connected mobile ad hoc networks. ReMMoC and INDISS have investigated the dynamic discovery and interaction in pervasive environments, particularly focusing on configuring and using the appropriate discovery protocol to find services in the current environment. These systems have so far only considered infrastructure-based wireless networks in which standardised discovery protocols such as Jini, Service Location Protocol, and Universal Plug and Play are used.
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CONNECTION TIMES IN LARGE AD-HOC MOBILE NETWORKS

CONNECTION TIMES IN LARGE AD-HOC MOBILE NETWORKS

Keywords and phrases. ad-hoc networks, connectivity, random waypoint model, dynamic continuum percolation, large deviations 1. Introduction and main results 1.1. Background and goals. Ad-hoc networks consist of individuals in a given domain that com- municate with each other via a relay principle: messages are forwarded from individual to individual as long as this transmission is local, until the message finally arrives at the recipient. This requires of course that the sender is connected with the recipient, i.e., that there is a chain of individuals connecting them such that all links are not larger than a given radius, the transmission radius or com- munication radius. This principle of message transmission within the system of participants, rather than via antennas or fixed wires, has a number of advantages over a firmly installed communication system; e.g., its installation is cheap, it does not require much maintaining, it can accommodate more information etc. A disadvantage is of course that the connectivity is not always fulfilled, i.e., it may be that two given individuals are not connected with each other and are therefore not able to exchange messages.
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Broadcast-based Directional Routing in Vehicular Ad-Hoc Networks

Broadcast-based Directional Routing in Vehicular Ad-Hoc Networks

Vehicular ad hoc networks have been essentially developed to enhance driver safety. We believe that to efficiently implement this kind of systems a major problem needs to be solved: ”how to rapidly disseminate the information among the vehicles?”. At the wireless link level, a step has been already made in the 802.11 standard [15] by accelerating the link setup (the IEEE 802.11p removes the need of association between stations before communicating). At the network level, one method that is considered to be very effective is broadcast. It is a technique that does not require a prior end-to-end connection establishment or maintenance. It is cheap and simple in terms of deployment and gives good performance thus its popularity.
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Congestion Control in Vehicular Ad Hoc Networks

Congestion Control in Vehicular Ad Hoc Networks

Mobile Computing and Networking Research Laboratory (LARIM), Department of Computer Engineering, Polytechnique de Montréal, Montreal, Canada Abstract To provide reliable communications in Vehicular Ad hoc Networks (VANets), it is vital to take into account Quality of Services (QoS). Delay and packet loss are two main QoS parameters considered by congestion control strategies. In this paper, a Multi-Objective Tabu Search (MOTabu) strategy is proposed to control congestion in VANets. The proposed strategy is dynamic and distributed; it consists of two components: congestion detection and congestion control. In the congestion detection component, congestion situation is detected by measuring the channel usage level. In congestion control component, a MOTabu algorithm is used to tune transmission range and rate for both safety and non-safety messages by minimizing delay and jitter. The performance of the proposed strategy is then evaluated with highway and urban scenarios using five performance metrics including the number of packet loss, packet loss ratio, number of retransmissions, average delay, and throughput. Simulation results show that MOTabu strategy significantly outperforms in comparison with other strategies like CSMA/CA, D-FPAV, CABS, and so on. Conducting congestion control using our strategy can help provide more reliable environments in VANets.
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Maximal Group Membership in Ad Hoc Networks

Maximal Group Membership in Ad Hoc Networks

5 Conclusion In this paper, we have been mainly concerned by group membership protocols in ad hoc networks. After specifying its basic safety properties and a maximality criterion about the installed views, we have proposed a group membership al- gorithm. Lastly, with respect to this criterion, we have compared our algorithm with two group membership algorithms. We have also specified the properties of the algorithm as well as its description in the TLA+ formalism. Currently, we have performed model-checking experiments with the TLC tool [5]. On small size graphs (6 nodes), we have been able to automatically check the correctness of our algorithm. We are now working on its formal correctness (any number of nodes) through theorem proving techniques.
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S-TGDH, secure enhanced group management protocol in ad hoc networks

S-TGDH, secure enhanced group management protocol in ad hoc networks

that these protocols were not formally specified. So, we are currently investigating formal modeling and proofs of our current proposition. Finally, the current implementation of S-TGDH is a java simulator, which simulates the algorithm behaviour. An important dimension in ad hoc network is the mobility [Dav00]. Thus, implementing our protocol using the well known simulator NS-2 will help us to test our solution in mobile networks, using adequate mobility models, and to analyze the interaction with the underlying layers (for instance, OLSR or AODV).

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