Hybrid scheme to enable DTN routing protocols to efficiently exploit stable MANET contacts

Disaster communication is still challenging due to the unpredictable nature and high variance in possible scenarios. Hybrid networking solutions that integrate principles from mobile ad hoc networks (MANETs) and delay tolerant networks (DTN) have been suggested to guarantee a certain robustness for the communication service in case of partial or complete failure of infrastructure. Real-time communication remains however challenging and the goal of any system is to minimize the message delay. One common approach is to provide better connectivity by including additional nodes and exploit the resulting contacts as efficiently as possible. Well-known DTN protocols are however not able to guarantee that, because they are unaware of connections that last for a relatively long time and thus provide stable connectivity. This results from general design assumptions of the DTN protocols and is crucial for the performance of hybrid MANET-DTN solutions. In this paper, we provide a review to this situation and suggest a hybrid solution concept based on layer 3 service discovery and a contact-aware utility scoring mechanism for DTN protocols and implement our concept as an example in one DTN protocol. Using simulations, we are able to show that this combination of mechanisms is able to provide better overall performance in the presence of long-lasting stable contacts