Traffic engineering is performed by means of a set of techniques that can be used to better control the flow of packets inside an IP network. We discuss the utilization of these techniques across interdomain boundaries in the global Internet. We first analyze the characteristics of interdomain traffic on the basis of measurements from three different Internet service providers and show that a small number of sources are responsible for a large fraction of the traffic. Across interdomain boundaries, traffic engineering relies on a careful tuning of the route advertisements sent via the border gateway protocol. We explain how this tuning can be used to control the flow of incoming and outgoing traffic, and identify its limitations.