Inbound traffic engineering for multi-homed ASes using AS path prepending

Unlike outbound traffic, incoming traffic distribution to a multi-homed AS is influenced mainly by the upstream ISPs´ routing policies. Currently, only a handful of mechanisms is available for such an AS to engineer the traffic volume coming into these links. We concentrate on the problem of re-distributing the incoming traffic across the multiple links. We consider the approach of AS path prepending which artificially inflates the length of the AS path to the network reported in BGP (border gateway protocol) messages, with the hope of diverting some of the traffic from one incoming link to another. Although this approach has already been deployed by many ASes, it is often performed on a trial-and-error basis; there is also a lack of a detailed measurement study on the effectiveness of this approach. The paper attempts to fill these gaps. In particular, we have proposed a complete procedure based on the AS path prepending method to engineer incoming traffic according to some traffic control policy. The procedure includes passive measurements, active measurements, and traffic change prediction. We have deployed this approach to a noncommercial site and evaluated its effectiveness based on measurements collected over six months. Similar measurement cycles can be replicated in other multi-homed ASes by deploying the procedure and the associated software tools.