Traffic engineering is a set of actions whose goal is to evaluate and optimize the performance of operational networks. The performance of an operational network is enhanced by addressing traffic-oriented performance measures, such as delay, delay variation, packet loss, and throughput, while utilizing network resources economically and reliably. One of the most important traffic engineering actions is the control of the routing function in the network so that traffic can be steered through it as effectively as possible. This book is based on a work which introduces novel and practical algorithms that optimize traffic routing within operational IP and MPLS networks.