Scalable routing in low-Earth orbit satellite constellations: Architecture and algorithms

Low-Earth orbit satellite constellations (LEO-SCs) are attractive for provisioning global, high-speed and low latency Internet access services. Due to the fast movement of satellites and the lack of inter-satellite links (ISLs), the LEO-SC topology is highly dynamic. Applying shortest path routing directly to LEO-SCs may suffer from poor scalability and frequent route changes. In this paper, a scalable two-layer routing architecture is first proposed. Based on it, two stable routing algorithms, delay-bounded routing (DBR) and delay-aware routing (DAR), are designed to minimize route changes. DBR is flow-based. It provides bounded network latency but at the cost of a larger forwarding table. DAR is destination-based. Although network latency is not bounded, we show that the further reduction in route changes is significant and the increase in average latency is minimal.