IMS is the next generation network (NGN) architecture which enables the convergence of fixed and mobile networks. It provides voice, data and multimedia services all over IP, even for traditional circuit and packet switched systems. Videoconferencing and social media platforms are applications. Alassane Bâ studies the traffic in the core of these networks and its optimization. His work explains how to manage a load distribution by a traffic class and define a threshold of tolerated connections. From theory and calculations, he gives useful indications for dimensioning IMS traffic. An experimental platform is implemented thanks to the efficiency, the engineering and the availability of open sources systems.