TCP, PEP and DTN Performance on Disruptive Satellite Channels

Fixed GEO satellite communications are impaired by long RTTs and the possible presence of packet losses on the satellite radio channel. Moreover, when the satellite receiver is mobile, short and long disruptions due to line of sight obstructions can cause further performance deterioration. In this paper, we present a preliminary assessment of disruption impact on performance comparing different approaches, such as end-to-end TCP, PEP based on TCP splitting and DTN. Performance is evaluated on a Linux testbed, by emulating the satellite link interruptions caused by tunnels on a real railway line. Results show that good performance can be achieved by all of the approaches considered provided that on the satellite channel an efficient TCP variant, like Hybla, is adopted; however, DTN offers best performance. DTN superiority emerges when the disrupted satellite channel is the last leg of a congested path, thanks to the DTN custody transfer mechanism and store and forward capability.