PRABR: Integrating Primary and Backup Routing in pLEO Satellite Networks

As Proliferated Low Earth Orbit (pLEO) satellite constellations increase in popularity for providing low latency global communications networking, their vulnerability to dis-ruptive threats to deny use is also growing. Existing routing schemes for pLEO are either centralized terrestrial schemes that typically rely on knowledge of link and node states in the entire constellation, or distributed low-complexity space-based schemes that rely on factors such as orbit geometry or geographic location of endpoints. In this paper, we propose a hybrid routing scheme called Primary Routing Aware Backup Routing (PRABR). PRABR is a framework to incorporate a centrally planned primary routing algorithm alongside a distributed backup routing algorithm and intelligently switch between them based on local observations of a router. We use the ns-3 based Hypatia simulator to show that PRABR significantly outperforms primary routing alone under satellite failures while maintaining the latency minimizing properties over the backup routing algorithm alone. We also present several example routes and discuss the effects of satellite failures and PRABR on such routes.