Khaled Boussetta

Aggregated Multicast—A Comparative Study

Abstract Though IP multicast is resource efficient in delivering data to a group of members simultaneously, it suffers from scalability problem with the number of concurrently active multicast groups because it requires a router to keep forwarding state for every multicast tree passing through it. To solve this state scalability problem, we proposed a scheme, called aggregated multicast. The key idea is that multiple groups are forced to share a single delivery tree. In our earlier work, we introduced the basic concept of aggregated multicast and presented some initial results to show that multicast state can be reduced. In this paper, we develop a more quantitative assessment of the cost/benefit trade-offs. We propose an algorithm to assign multicast groups to delivery trees with controllable cost and introduce metrics to measure multicast state and tree management overhead for multicast schemes. We then compare aggregated multicast with conventional multicast schemes, such as source specific tree scheme and shared tree scheme. Our extensive simulations show that aggregated multicast can achieve significant routing state and tree management overhead reduction while containing the expense of extra resources (bandwidth waste and tunnelling overhead). We conclude that aggregated multicast is a very cost-effective and promising direction for scalable transit domain multicast provisioning.

A Tabu Search WSN Deployment Method for Monitoring Geographically Irregular Distributed Events

In this paper, we address the Wireless Sensor Network (WSN) deployment issue. We assume that the observed area is characterized by the geographical irregularity of the sensed events. Formally, we consider that each point in the deployment area is associated a differentiated detection probability threshold, which must be satisfied by our deployment method. Our resulting WSN deployment problem is formulated as a Multi-Objectives Optimization problem, which seeks to reduce the gap between the generated events detection probabilities and the required thresholds while minimizing the number of deployed sensors. To overcome the computational complexity of an exact resolution, we propose an original pseudo-random approach based on the Tabu Search heuristic. Simulations show that our proposal achieves better performances than several other approaches proposed in the literature. In the last part of this paper, we generalize the deployment problem by including the wireless communication network connectivity constraint. Thus, we extend our proposal to ensure that the resulting WSN topology is connected even if a sensor communication range takes small values.

Differentiated Underwater Sensor Network Deployment

Underwater sensors technology has experienced a tremendous development over the last decade. They have generated considerable community enthusiasm, which applied them to a wide range of cases that could enhance human and animal habitat conditions e.g. climate changes prediction or pollution surveillance. In this paper, we address the issue of deploying a UWSN in an area characterized by the geographical irregularity of the sensed event. Our specific application context regards the monitoring of the water quality in a small closed area (e.g. a lake). For this purpose, we propose a differentiated deployment algorithm (DDA) based on a mesh representation method inspired from the image processing and 3D modeling field.

A protocol to improve the state scalability of source specific multicast

Source specific multicast (SSM) is a viable solution for current multicast applications, since the driving applications to date are one to many, including Internet TV, distance learning, file distribution, streaming media, etc. It brings many benefits in billing, address allocation, and security. However, SSM still confronts the serious state scalability problem when there are a large number of simultaneous on-going multicast groups in the network. We propose a protocol to improve the state scalability of source specific multicast, which is called aggregated source specific multicast (ASSM). We design the detailed ASSM protocol and show that our solution can obtain significant multicast state and tree management overhead reduction while achieving transparency to end-users, compatibility with existing multicast technologies and low overhead.

Artificial potential field approach in WSN deployment: Cost, QoM, connectivity, and lifetime constraints

In this paper, we address a wireless sensor network deployment problem. It is considered when the deployment field is characterized by a geographical irregularity of the monitored event. Each point in the deployment area requires a specific minimum guarantee of event detection probability. Our objective is to generate the best network topology while minimizing cost of deployment, ensuring quality of monitoring and network connectivity, and optimizing network lifetime. The problem is formulated as combinatorial optimization problem, which is NP-complete. Unfortunately, due to the large solution state space and the exponential computational complexity, the exact methods can be applied only in the case of small-scale problem. To overcome the complexity of an optimal resolution, we propose new scalable deployment heuristics based on artificial potential field and Tabu search metaheuristic, namely potential field deployment algorithm (PFDA) and multi-objective deployment algorithm (MODA). We compare our proposal to the related deployment strategies, the obtained results show that PFDA and MODA obtain the best performances.

Aggregated Multicast - A Comparative Study

Multicast state scalability is among the critical issues which delay the deployment of IP multicast. In our previous work, we proposed a scheme, called aggregated multicast to reduce multicast state. The key idea is that multiple groups are forced to share a single delivery tree. We presented some initial results to show that multicast state can be reduced. In this paper, we develop a more quantitative assessment of the cost/benefit trade-offs. We introduce metrics to measure multicast state and tree management overhead for multicast schemes. We then compare aggregated multicast with conventional multicast schemes, such as source specific tree scheme and shared tree scheme. Our extensive simulations show that aggregated multicast can achieve significant routing state and tree management overhead reduction while containing the expense of extra resources (bandwidth waste and tunnelling overhead, etc.). We conclude that aggregated multicast is a very cost-effective and promising direction for scalable transit domain multicast provisioning.

Multi-Objective WSN Deployment: Quality of Monitoring, Connectivity and Lifetime

In this paper, we will address a WSN deployment problem. The main objectives are i) reduce the cost of deployment, ii) ensure the requested event detection probabilities, iii) guarantee the network connectivity, and iv) maximize the lifetime of the network. We will formalize the problem as multi-objective combinatorial optimization problem. To resolve the problem, we will propose a new deployment algorithm named \texttt{MODA}. It will be based on evolutionary and neighborhood search algorithms. The obtained results are better than the deployment strategies found in the literature.

Capillary networks: a novel networking paradigm for urban environments

In this paper, we present our vision of the networking challenges that are yielded by the rise of Smart Cities. Smart Cities leverage massive data collected by sensors, connected devices, social applications,... for proving a whole set a new services to the citizens. However, there is a lack of reflexion on the networking solutions that enable these services, from the gathering of sensed data to the dissemination of digital services. We identify the emerging needs of Smart Cities, focus on the capillary networks paradigm which unify the wealth of wireless connectivity available in urban environment, and present the research issues it yields.

Multirate resource sharing for unicast and multicast connections

Recent advances in network equipment and the important progress in video, audio and data compression techniques has given rise to new multimedia group applications, such as Video-conferencing or Webcasting. These applications need guarantees on the QoS (Quality of Service) and require group communication services. ATM seems to be well adapted to support these applications, since it provides several service classes and QoS guarantees. However, these guarantees are possible only if the network is able to allow efficient resource sharing. Therefore, resource sharing for multirate traffic is a fundamental issue, specially for multicast connections with a huge number of recipients. In this paper, we generalize the mathematical model of Kaufman [6] to compute the exact values of call blocking probability for unicast and multicast multirate multiclass traffics sharing a single link. We show that the model has a product form solution. Moreover, we give a recursive algorithm to obtain the normalization constant and the call blocking probability.

Potential Field Approach to Ensure Connectivity and Differentiated Detection in WSN Deployment

This paper addresses the issue of Wireless Sensor Network (WSN) deployment. We investigate this problem in the case where the monitored area is characterized by a geographical irregularity of the sensed events. Precisely, we consider that each point of the deployment area requires a minimum threshold guarantee on the event detection probability. Our proposed scalable deployment method, named Potential Field-based Deployment Algorithm (PFDA), is based on the Potential Field and the Virtual Force approaches. Our proposal is able to (1) satisfy the required event detection probability threshold for each point, in a large-scale area, while minimizing the number of deployed sensors and (2) to ensure the network connectivity. The results and evaluation analysis show that PFDA outperforms the other strategies proposed in literature.