Research

With communication networks getting more and more present in our daily activities, network outages or even significant degradations of the quality of service become less and less tolerable. Network survivability and the control of the quality of service are thus critical issues that require significant methodological progresses in various scientific fields. Our contributions fall in two broad categories : performance evaluation and optimization of networks.

Our research works on the performance evaluation of networks are based on queueing and game theories. They aim at the development of analytical or simulation-based methods for the large-scale evaluation of the main performance metrics, both at the packet level (delay, loss rate and jitter) and at the flow level (number of active sessions, download times, etc). They also deal with the worst-case analysis of the performance of decentralized routing algorithms.

The second category of contributions are mainly devoted to the development of new optimization methods for the design of survivable access and backbone networks, for capacity-planning and for route optimization in OSPF and MPLS networks. Since most of these problems are NP-hard combinatorial problems, often with non-linear cost functions, we usually have to resort to dedicated heuristics. Another work in the applied optimization field deals with the strictly periodic scheduling of tasks in embedded avionic systems.