Optimal RTO Timer for Best Transmission Efficiency of DTN Protocol in Deep Deep-Space Vehicle Communications
Abstract: The delay/disruption-tolerant tolerant network (DTN) was proposed as an end end-to-end networking architecture for file delivery service in a stressed communication environment. A typical application of DTN technology is for reliable data delivery in deep-space vehicle communications. The main protocol of DTN, i.e., bundle protocol (BP), utilizes a store store-and-forward forward mechanism and a custody transfer option for transmission reliability. However, little work has been done on the performance evaluation of DTN's BP in deep deep-space pace communications. In this paper, we present a study of the retransmission timeout (RTO) timer setting for the use of BP for reliable file (or data) transmission over a relay-based relay based deep deep-space vehicle communication infrastructure characterized by extremel extremelyy long latency, lossy data links, and highly asymmetric channel rates. Unlike most studies proposed for terrestrial Internet for which the RTO timer is set equal to or longer than the round-trip trip time (RTT), we propose to set the RTO timer shorter than the RTT and expect that it will increase delivery efficiency per unit of time. We intend to find an RTO timer setting for maximum data delivery performance of BP, which is considered to be an optimal RTO timer, for deep-space deep space missions. For the first time, analytical ytical models are built for delivery performance involving the RTO timer. Using the built models, we tune the RTO timer toward the highest data delivery performance. The models are validated by running text file transfer