Application of Contact Graph Routing to LEO Satellite DTN Communications

Delay-/Disruption- Tolerant Networking, which originated from research on deep space communications, has enlarged its scope to encompass all challenged networks, including LEO satellite communications. Focusing on single satellite or incomplete constellation cases, the advantages of DTN mainly relate to its ability to cope with disruption and intermittent connectivity, typical of LEOs. This, however, requires the adoption of routing solutions specifically designed for DTNs. Among the many proposals, Contact Graph Routing, designed by NASA for deep space, seems particularly appealing, as it takes advantage of the a priori knowledge of “contacts” between DTN nodes, a characteristic peculiar to both deep space and LEO environments. This paper aims to investigate the suitability of CGR in LEO satellite DTN communications, by focusing on two practical application scenarios: Earth observation and data mule. Results, obtained through a Linux testbed running ION, the DTN Bundle protocol and CGR implementation developed by NASA, highlight the advantages of CGR when applied to LEO satellite communications.