Refining the ring road-delays and path lengths in a LEO satellite message-ferry network

The so-called Ring Road approach leverages low-cost LEO satellites and delay-tolerant networking (DTN) technologies to transfer data between different ground stations and, thus, renders cost-efficient worldwide communication possible. Applying DTN protocols to LEO satellite networks is a perfect fit. Nevertheless, there are central gaps in the state of the art in the context of this type of infrastructure: Firstly, no precise systematic description of Ring Road networks is available. Secondly, to this date no detailed analysis on the specific delays and end-to-end path lengths of these networks has been conducted. Thus, the discussion about the Ring Road concept and technical solutions for realizing such networks stays very general. In this paper we close both gaps. In addition to providing a more detailed description and a classification of Ring Road networks, we present an investigation of the delay and path length characteristics based on realistic satellite trajectories. The results are intended not only to further systematize research on Ring Road networks but also to establish an argumentative basis for developing dedicated routing protocols optimized for this domain.