Conception et mise a jour des reseaux de telecommunication (French text)

This thesis is composed of four articles on the planning of two-level telecommunication networks. The term “two-level” refers to the fact that the network is composed of two major subnetworks: the access and the backbone network. The access network links the users to switches whereas the backbone network links the switches to one another. Moreover, we suppose that the switches used are modular, with different types of ports and bases, such as ATM switches. In fact, an important feature of our work is the consideration of modular switches in the planning models.; The first article deals with the design problem of private networks. We define a private network as a two-level network containing modular switches, OC-3 SONET links in the access networks and OC-192 SONET links in the backbone network. Moreover, in such a network, multiplexers may be used to connect several links to a single port. In the first article, we propose a literature review on the two-level network planning problems and a mathematical programming model for the design problem of private networks. This model is specialized to backbone networks having a ring or a tree topology. Next, in order to obtain a good solution, we propose a greedy heuristic that provides a starting solution and a tabu search heuristic to improve that starting solution. The solutions obtained are, on average, at 0.86% from a lower bound found by solving a relaxed version of the model.; The second article is dedicated to the design of multitechnology networks. We define a multitechnology network as a two-level network containing modular switches and several access technologies and rates in order to satisfy the specific demand of each client. Moreover, in such a network, OC-192 SONET links are used in the backbone network. In this article, we propose a mathematical programming model for the multitechnology network design problem and study three backbone topologies (tree, ring and full-mesh). Next, we propose a greedy heuristic and a more sophisticated heuristic based on the tabu search principle. The solutions obtained with the tabu-based approach are, on average, within 2.87% of the optimal solution.; The third article deals with the problem of how to expand multitechnology networks in a cost-effective way. We propose a mathematical programming model for this problem for the specific case in which the backbone has a multiple ring topology. The choice was made because many telecommunication backbones use this topology. Next, an initial heuristic is designed to provide a starting solution, and a tabu-based heuristic is proposed to improve the solution. We present an illustrative example of a multitechnology network design with its successive expansions followed by a systematic set of experiments designed to assess the performance of the proposed algorithms (using two lower bounds). The solutions obtained are, on average, at 0.59% from the best lower bound.; The last article is devoted to the update problem of private networks. Again, an initial heuristic, a tabu-based heuristic and a post-optimization algorithm are proposed. We present an illustrative example followed by a performance analysis of the proposed heuristics (using a lower bound). The solutions obtained are, on average, within 0.74% of the optimal solution.