Evaluating contact volume in DTN networks

In a Delay Tolerant Network (DTN), a contact is the opportunity to transfer data between DTN nodes. A contact occurs when at least one of the nodes is in movement. The duration time of a contact, termed dwell time, can vary from few seconds up to several hours. This period must be seized to transfer as many bundles, a basic data unit of DTN, as possible. DTN approaches are key solution to transmit data in rural and isolated areas, such as forests. This work is part of Amazon Regatão project, whose goal is to provide Internet access to riparian communities of Amazon Rivers based on DTN schemes. We have developed a novel technique to predict the amount of bundles to be transferred during a DTN contact. Measuring campaigns were carried out to evaluate propagation and bundle throughput in different locations in the core of the Amazon region. The results can be used to design a queue bundle strategy and bundle proactive fragmentation to optimize the delivery ratio in DTNs. Real experiments were conduct at the Experimental Farm and at the Campus of Federal University of Amazonas, using IEEE 802.11n interface routers and a DTN Reference Implementation.