Experiments with Non-Cooperative Space DTN Routing

In this paper, results from an experimental study of the end-to-end bundle delivery performance of two concurrent flows transmitted over a delay-tolerant network are presented. The study compares the Contact Graph Routing algorithm, which is the foundation of the CCSDS standard Schedule Aware Bundle Routing and the Cognitive Space Gateway that has been recently introduced as a cognitive networking alternative to the problem of space bundle routing. Both algorithms make non-cooperative, dynamic routing decisions for bundles at each step based on a similar utility, which is formulated as the minimum expected bundle delivery time to the destination. The study aims to find how well each algorithm plays the routing game under different conditions. The experiments were carried out on a laboratory testbed with emulated Earth-Moon communication conditions and included evaluation cases with a permanently connected substrate and a substrate that is being affected by regular link disruptions. Also, the flows were evaluated with cases where their shortest path either overlap or not. The results indicate that both routing approaches play a coherent game achieving fair performance for both flows, but with the CSG achieving better performance than the CGR approach.