Françoise Sailhan

Scalable Service Discovery for MANET

Mobile Ad hoc NETworks (MANETs) conveniently complement infrastructure-based networks, allowing mobile nodes to spontaneously form a network and share their services, including bridging with other networks, either infrastructure-based or ad hoc. However, distributed service provisioning over MANETs requires adequate support for service discovery and invocation, due to the networks dynamics and resource constraints of wireless nodes. While a number of existing service discovery protocols have shown to be effective for the wireless environment, these are mainly aimed at infrastructure-based and/or 1-hop ad hoc wireless networks. Some discovery protocols for MANETs have been proposed over the last couple of years but they induce significant traffic overhead, and are thus primarily suited for small-scale MANETs with few nodes. Building upon the evaluation of existing protocols, we introduce a scalable service discovery protocol for MANETs, which is based on the homogeneous and dynamic deployment of cooperating directories within the network. Scalability of our protocol comes from the minimization of the generated traffic, and the use of compact directory summaries that enable to efficiently locate the directory that most likely caches the description of a given service

Cooperative Caching in Ad Hoc Networks

Terminals latency, connectivity, energy and memory are the main characteristics of todays mobile environments whose performance mayb e improved by caching. In this paper, we present an adaptive scheme for mobile Web data caching, which accounts for congestion of the wireless network and energylimit ation of mobile terminals. Our main design objective is to minimize the energycost of peer-to-peer communication among mobile terminals so as to allow for unexpensiveWeb access when a fixed access point is not available in the communication range of the mobile terminal. We propose a collaborative cache management strategyam ong mobile terminals interacting via an ad hoc network. We further provide evaluation of the proposed solution in terms of energy consumption on mobile devices.

Developing Ambient Intelligence Systems: A Solution based on Web Services

Enabling the ambient intelligence vision means that consumers will be provided with universal and immediate access to available content and services, together with ways of effectively exploiting them. Concentrating on the software system development aspect, this means that the actual implementation of any ambient intelligence application requested by a user can only be resolved at runtime according to the users specific situation. This paper introduces a base declarative language and associated core middleware, which supports the abstract specification of Ambient Intelligence applications together with their dynamic composition according to the environment. The proposed solution builds on the Web services architecture, whose pervasiveness enables both services availability in most environments, and specification of applications supporting automated retrieval and composition. In addition, dynamic composition of applications is dealt in a way that enforces the quality of service of deployed applications in terms of security and performance.

Group management for mobile Ad Hoc networks: design, implementation and experiment

Mobile ad hoc networks (MANET) offer a convenient basis toward realization of pervasive computing, due to its ease of deployment and inherent support for anytime, anywhere network access for mobile users. However, the development of applications over such networks is faced by the challenge of network dynamics attributed to node mobility and the scalability issue. Group management poses as a promising paradigm to ease the development of distributed applications for dynamic, mobile networks. Specifically, group management makes transparent the failures due to node mobility and assembles mobile nodes to meet target functional and non-functional properties. Various network-level grouping schemes over MANET have been investigated over the last couple of years. In this paper, we introduce the design and implementation of a generic group service for MANET, defined with respect to the various attributes of relevance. Generic group management is further demonstrated with its support of scalable service discovery in MANET.

Energy-aware Web caching for mobile terminals

A terminals latency, connectivity, energy and memory are the main characteristics of todays mobile environments whose performance may be improved by caching. We present an adaptive scheme for mobile Web data caching, which accounts for congestion of the wireless network and energy limitation of mobile terminals. Our main design objective is to minimize the energy cost of peer-to-peer communication among mobile terminals so as to allow for inexpensive Web access when a fixed access point is not available in the communication range of the mobile terminal. We propose a collaborative cache management strategy among mobile terminals interacting via an ad-hoc network. We further provide evaluation of the proposed solution in terms of energy consumption on mobile devices.

Software architecture for mobile distributed computing

Todays wireless networks and devices support the dynamic composition of mobile distributed systems, according to device connectivity. This has in particular led to the introduction of a number of supporting middleware. However, such solutions need to be complemented with adequate modeling and verification support towards enforcing the correctness of the dynamic mobile systems with respect to both functional and nonfunctional properties. Building on the elegant properties of software architecture modeling, this paper introduces base modeling of mobile software components, which integrates key features of the wireless infrastructure and allows for reasoning about the behavior of dynamically composed systems.

Wireless Mesh Network Monitoring: Design, Implementation and Experiments

Mesh networks conveniently complement infrastructure- based networks, allowing devices to spontaneously form a network and connect with other networks. However, effective service provisioning requires a network monitoring solution with adequate support for topology data dissemination and diagnosis, due to the underlying network dynamics and the absence of pre-existing network infrastructure. In addition, monitoring systems have to face a number of challenges relating to autonomy, robustness and scalability. To this end, we have created a self-organised management overlay that homogeneously and dynamically organises devices into a cluster-based hierarchy on which monitored data is dis- seminated. Scalability of the monitoring system is achieved through the minimisation of the generated traffic, as a result of the optimised design. We have implemented the proposed monitoring system and evaluated through experiments the resulting performance.

Self-configuration for radio access networks

The ongoing work presented in this paper is aimed at bringing self-configuration capabilities into next generation radio access networks. We present the main concepts and architecture of our prototype. We also introduce briefly a novel strategy for foreseeing the outcome of enforcing policies integrating behaviour discovery techniques and finite state calculus into the conflict detection and resolution process. The main objective of this approach is to avoid instability problems of a distributed rule-based system

On Lightweight Intrusion Detection: Modeling and Detecting Intrusions Dedicated to OLSR Protocol

Mobile ad hoc networks mostly operate over open, adverse, or even hostile environments and are, therefore, vulnerable to a large body of threats. Conventional ways of securing network relying on, for example, firewall and encryption, should henceforth be coupled with advanced intrusion detection. To meet this requirement, we first identify the attacks that threaten ad hoc networks, focusing on the Optimized Link State Routing Protocol. We then introduce IDAR, a signature-based Intrusion Detector dedicated to ad hoc routing protocols. Contrary to existing systems that monitor the packets going through the host, our system analyses the logs so as to identify patterns of misuse. This detector scopes with the resource-constraints of ad hoc devices by providing distributed detection; in particular, depending on the level of suspicion and gravity, in-depth cooperative diagnostic may be launched. Simulation-based evaluation shows limited resource consumption (e.g., memory and bandwidth) and high detection rate along with reduced false positives.

Trust-Enabled Link Spoofing Detection in MANET

Ad hoc networks operate over open environments and are hence vulnerable to a large body of threats. To tackle this issue, we propose a distributed, signature-based anomaly detector that evaluates the trustworthiness of others so as to secure such a distributed detection. Contrary to existing detectors that passively observe packets, our detector analyses logs so as to identify patterns of misuse and proactively collaborate with others to gather additional evidences. As a result, no change is requested in the implementation of the node. The main challenge stems from difficulty involved in stating the occurrence of an attack based on second-hands evidences that may come from colluding attacker (s). To tackle this issue, we propose an entropy-based trust system that evaluates the trustworthiness of the nodes that provide the evidences. We further introduce a novel indicator which measures the level of confidence in the detection. Preliminary evaluations of the trust system along with the confidence measure have been conducted.