Software defined routing algorithm in LEO satellite networks

Abstract

In the next generation network, Low Earth Orbit (LEO) satellite networks are indispensable due to global seamless coverage and lower orbit altitude to maintain low- latency communication. However, the time-variant topologies of satellite networks bring great challenges to network management and robust routing algorithms design. Furthermore, non-uniform distribution of users will cause load unbalance among intersatellite links (ISL). In this paper, we embrace the idea of software-defined networking (SDN) to divide the satellite network into control and data plane. The satellites as switches only forward the data so that the on-board processing capacity is minimized. To realize flexible centralized management of the satellite network, we design a master controller and several slave controllers around the earth. Based on this, we propose a software defined routing algorithm (SDRA) which can obtain the optimal routing path by centralized routing strategy. With collecting congestion status of the satellites in real time, the controllers can bypass the congested ISLs when calculating routing paths. Compared with other routing algorithms, the proposed SDRA reduces the queueing delay by a nearly half, achieves a better traffic distribution and has better performance in terms of end-to- end delay, packet dropping probability and network throughput.