AJSR: an Efficient Multiple Jumps Forwarding Scheme in Software-Defined WAN

Software Defined Networks (SDN) is an emerging network architecture. It is shown that SDN can be deployed in a variety of small size networks, such as personal area networks and local area networks. Nevertheless, the deployment of SDN in large scale networks, such as wide area networks, raises a lot of concerns. In these scenarios, SDN relies on traditional hop-by-hop forwarding scheme which may lead to performance degradation due to heavy control traffic incurred and flow tables over-consumption. Source routing can be utilized to reduce control traffic and flow table consumption by installing only one flow table entry in the ingress switch and encoding complete routing path of a particular flow in the packet header. However, it will lead to severe bandwidth overhead which may also degrade network performance. In this paper, we propose an efficient forwarding scheme called Arbitrary Jump Source Routing (AJSR), which makes use of MPLS-based source routing. AJSR aims to achieve a trade-off between the control traffic overhead and the bandwidth overhead by dividing the complete routing path of a particular flow into arbitrary length sections and distributing these sections at different switches along the flow's routing path. To find the most suitable flow entry placement scheme, we formulate the flow entry placement problem as an optimization problem and present a dynamic programming solution with the objective of maximizing the overall cost saving. Through simulation experiments, we find that AJSR can effectively achieve a trade-off between the control traffic overhead and the bandwidth overhead.