A DTN Approach to Satellite Communications

Satellite communications pose serious challenges to transport layer performance, mainly because of long propagation delays (especially in geosynchronous systems) and the possible presence of random errors on the satellite link. Solutions that cope with these impairments usually rely upon either the adoption of enhanced versions of transport protocols, or the insertion of intermediate agents, like PEPs (Performance Enhancing Proxy). An alternative approach is to adopt DTN (Delay/Disruption Tolerant Network) architecture, based on the introduction of the new "bundle" layer in the protocol stack. The aim of the paper is to discuss the advantages and disadvantages of the DTN approach compared to more conventional solutions. DTN performance is assessed by using a testbed based on a cluster of Linux PCs running the DTNperf application, which was developed to this end by the authors and now included in the official DTN package. Preliminary results are presented and discussed in the paper.