Houssein Hallani

Wireless Ad-hoc networks: Using fuzzy trust approach to improve security between nodes

A wireless Ad-hoc network is a collection of mobile nodes that can be deployed without the need for any centralized management infrastructure. The operation of Ad-hoc networks depends on the cooperation among nodes to provide connectivity and communication routes. However, such an ideal situation may not always be achievable in practice. Some nodes may behave maliciously, resulting in degradation of the performance of the network or even disruption of its operation altogether. To mitigate the effect of such nodes and to achieve higher levels of security and reliability, this paper expands on relevant fuzzy logic concepts to propose an algorithm to establish quantifiable trust levels between the nodes of Ad-hoc networks. These trust levels are then used in the routing decision making process. Using OPNET simulator, the proposed algorithm is validated and further studied. The findings show that when the proposed algorithm is utilised, the overall performance of the Ad-hoc network is significantly improved.

Wireless Ad-Hoc Networking: Analysis and Validation of Simulation Results

A wireless Ad-hoc network consists of wireless nodes communicating without the need for a centralized administration, in which all nodes potentially contribute to the routing process. In this paper the experimental results obtained from establishing a small physical network are reported. Using Optimised NETwork (OPNET) software simulator, physical results are then compared with those obtained from simulations. Correlation between the two sets of results is found to be satisfactory enough to validate the simulation technique and process. Given this validation, similar simulation techniques are used to perform an investigation of a larger scale Ad-hoc. The simulation results of the larger scale network confirm our previously obtained results. An important aspect of which is that the nature of the drop in throughput with respect to the number of nodes trying to communicate simultaneously with a single node, is linear.

Improving the Performance of Wireless Ad-hoc Networks: Accounting for the Behavior of Selfish Nodes

Modern Wireless Local Area Networks (WLANs) with relatively high data rates have become an attractive technology for providing Internet connectivity for mobile users. Ad-hoc networks are a collection of mobile nodes that can be deployed without the need for any centralized management infrastructure. In such a set-up, to establish the required communication paths, each node must be willing to act as a potential router. In practice though, some nodes may act selfishly and refuse to forward packets. In Ad-hoc networks, a node may be considered as misbehaving for different reasons, for instance when it acts selfishly, refusing to forward packets. In some circumstances, the node can be overloaded, or they simply want to save their resources by not forwarding packets unless they are of direct interest to the node itself. Conversely, these nodes may still be expecting others to forward packets on their behalf. In this paper, we report the experimental results obtained from a typical Ad-hoc networks that contain selfish nodes. We also analyze the behavior of the nodes, to establish some quantifiable measure of their reliability. Such measures, based on the behavior history of the nodes, are then utilized to improve the performance and reliability of the widely used Ad-hoc On Demand Distance Vector routing protocol. We also report the results of simulations of large Ad-hoc networks in the presence of malicious or selfish nodes. These results clearly indicate the capabilities of the proposed approach in discovering communication paths with a minimal number of malicious or selfish nodes.

Trust assessment in wireless ad-hoc networks

Wireless ad-hoc networks consist of devices communicating with each other without the need for a management infrastructure. As such, the very basic operation of ad-hoc networks is dependent on the cooperation of their nodes to provide connectivity and communication routes. In practice though, such cooperation may not always be achieved. Cases where some nodes behave in a selfish manner or maliciously are of particular interest and consequence. Such cases normally result in degradation of the performance of the network or even disruption of its operation altogether. To mitigate the effect of such nodes and to achieve higher levels of reliability, the communication rout should be based on utilization of reliable and trustworthy nodes. This clearly depends on evaluation of trust and trustworthiness of the nodes. This paper proposes an approach that is based on soft computing to establish quantifiable trust levels between the nodes of an ad-hoc network. The information on trust levels are then used in the routing decision making process. Extensive simulator studies that utilize the proposed approach are carried out, analyzed, and reported in this paper. The resulting relatively significant improvements in the performance of typical ad-hoc networks are also reported.

Improving security between nodes in wireless Ad-hoc networks

The operation of Ad-hoc networks depends on the cooperation among nodes to provide connectivity and communication routes. However, such an ideal situation may not always be achievable in practice. Some nodes may behave maliciously, resulting in degradation of the performance of the network or even disruption of its operation altogether. To mitigate the effect of such nodes and to achieve higher levels of security and reliability, this paper expands on relevant fuzzy logic concepts to propose an algorithm to establish quantifiable trust levels between the nodes of Ad-hoc networks. These trust levels are then used in the routing decision making process. Using OPNET simulator, the proposed algorithm is validated and further studied. The findings show that when the proposed algorithm is utilised, the overall performance of the Ad-hoc network is significantly improved.