Quality of service in network communication is mainly assured by traffic management consisting in a variety of protocols and mechanisms whose role is to prevent the network from being congested. Traffic management has been a very active area of research for two decades following the conception of packet-switched integrated services networks, such as the Internet. This chapter provides samples of the state of the an in traffic management. It includes contributions on traffic theory, traffic and service models, quality monitoring, as well as traffic control and measurements. © Springer-Verlag Berlin Heidelberg 2003.