SDN Controller Design for LEO Satellite Networks with Three-Phase Traffic Engineering

With recent advancements in Low Earth Orbit (LEO) satellite constellation launch technology, the cost of deploying LEO satellites is rapidly decreasing. Leveraging these constellations, LEO satellite networks provide the potential for low-latency communications, enabling latency-sensitive applications such as financial trading and tele-surgeries. However, the large scale of these networks introduces significant management challenges, particularly in adapting to dynamic environments and responding to network events. Maintaining efficient operation requires continuous updates to forwarding rules in a constantly shifting topology, where frequent satellite handovers further complicate real-time decision-making.To address these challenges, we propose an SDN design for LEO satellite networks, incorporating a three-phase traffic engineering scheme to achieve optimal path assignments with minimal control-loop latency. The key idea is to take advantage of the trajectories of satellite movements and perform path assignment ahead of time. We evaluate the proposed controller design extensively through simulations. The results demonstrate that our three-phase traffic engineering scheme significantly improves network performance. Compared to a purely reactive controller, our design achieves up to twice the residual bandwidth while deriving path assignments that attain 95% of the optimal minimal residual bandwidth.