Virtualization Technologies for DTN Testbeds

At present, Internet is based on the availability of a continuous path from the source to the sink node and on limited delays. These assumptions do not hold in “challenged networks”, which comprise a wide variety of different environments, from sensor networks to space communications (including satellite systems). These networks are the preferred target of Delay/Disruption Tolerant Networking (DTN), an innovative networking architecture able to cope with long delays, channel disruptions and limited or intermittent connectivity. Given the increasing interest in DTN, there is urgent need for suitable tools for DTN performance evaluation. In general, there are two approaches to performance evaluation in networking: simulation and real testbeds. In this paper, after an in-depth discussion of advantages and disadvantages of both, a third way based on a virtualization is proposed and tested for DTN environments, for which it seems particularly suitable. To validate this assumption, a virtual counterpart of a real testbed is set-up using Virtual Testbed Toolkit (VTT) components. A series of tests is then performed by considering DTN transmission on a heterogeneous network including a GEO satellite link. The close match between real and virtual testbed results confirms the validity of the virtual approach for accurate performance evaluations in DTN environments.