SENDIT: a satellite network routing digital twin solution for mega-constellations

Satellite systems are characterized by having a changing and continuously repeating network topology, requiring regular routing update operations. Each time the topology changes, a reconfiguration of the routing system is triggered. At the same time having a significantly longer routing convergence duration due to the increased link delay, results in large de- synchronization and network instability time intervals. To remove this effect, we propose a new digital twin-based approach for implementing a centralized routing mechanism appropriate for these specific network conditions. We propose to externalize the routing decision functionality from the satellite system to a properly sized software emulation environment. Thereby, we can simulate multiple topologies of the system asynchronously to their actual deployment and thus, are able to pre-define and to pre-distribute the needed routing information. The proposed approach is implemented and validated in a demonstrator using Linux OS tools, clearly underlining the advantages of pre-event, digital twin-based routing operations, outperforming other satellite-oriented routing implementations.