The issue of providing Quality of Service (QoS) in the Internet is becoming more and more important because of two phenomena: (1) the growth of value added services that require QoS (e.g., IPTV) and (2) network convergence towards a unified IP-based architecture, for voice, image and data services. In this context, the limitations of existing QoS technologies emerge: it is currently difficult for an operator to guarantee that its network can offer a specific level of service. Furthermore, it is very difficult to ensure a consistent treatment of end-to-end QoS-sensitive flow that cross networks controlled by several operators. Indeed, the control on such traffic flows is shared between all the traversed operators. In the thesis, we have studied these issues and, more specifically, routing and dynamic traffic engineering at inter-domain level. We have proposed several algorithms to compute paths subject to multiple performance constraints. Analytical studies and simulations show that our algorithms are efficient. Our work represents an important step towards more effective inter-domain traffic management in traffic engineered networks. ??