Centralized and Decentralized Routing Solutions for Present and Future Space Information Networks

Space information networks (SINs) are pushing the boundaries of networking into near-Earth orbit and beyond. Nevertheless, the harsh and costly space context forces most risk-prone missions to be designed with minimal chance of failure. The careful consideration of routing protocols used to connect the fleet is by no means the exception. Although decentralized SIN routing schemes have received the most attention of the research community, centralized approaches are captivating the industry, as these come with tighter control and enable troubleshooting of valuable space assets from a mission control center on the ground. In this article, we settle the matter by qualitatively and quantitatively comparing both SIN paradigms. We propose two novel centralized routing schemes, and evaluate their resulting performance against contact graph routing (CGR), the decentralized state of the art. In this evaluation, computational effort, memory utilization, and energy consumption are taken as figures of merit. The outcome provides compelling evidence that centralized routing schemes can safely, successfully, and efficiently connect SINs with up to 10,000 daily contacts, while CGR can be better entrusted with larger-scale SIN deployments.