$x$eoverse: A Real-time Simulation Platform for Large LEO Satellite Mega-Constellations

In the evolving landscape of satellite communications, the deployment of Low-Earth Orbit (LEO) satellite constellations promises to revolutionize global Internet access by providing low-latency, high-bandwidth connectivity to underserved regions. However, the dynamic nature of LEO satellite networks, characterized by rapid orbital movement and frequent changes in Inter-Satellite Links (ISLs), challenges the suitability of existing Internet protocols designed for static terrestrial infrastructures. Testing and developing new solutions and protocols on actual satellite mega-constellations are either too expensive or impractical because some of these constellations are not fully deployed yet. This creates the need for a realistic simulation platform that can accurately simulate this large scale of satellites, and allow end-to-end control over all aspects of LEO constellations. This paper introduces xeoverse, a scalable and realistic network simulator designed to support comprehensive LEO satellite network research and experimentation. By modeling user terminals, satellites, and ground stations as lightweight Linux virtual machines within Mininet and implementing three key strategies - pre-computing topology and routing changes, updating only changing ISL links, and focusing on ISL links relevant to the simulation scenario - xeoverse achieves real- time simulation, where 1 simulated second equals 1 wall-clock second. Our evaluations show that xeoverse outperforms state- of-the-art simulators Hypatia and StarryNet in terms of total simulation time by being 2.9 and 40 times faster, respectively.