An Underwater Convergence Layer for Disruption Tolerant Networking

Delay and Disruption tolerant networking (DTN) embraces the concepts of occasionally-connected networks that may suffer from frequent partitions and that may be comprised of more than one divergent set of protocols or protocol families. Since DTN was conceived to relax most of the assumptions associated with Internet protocols, the most important of which is the availability of an end-to-end path between source and destination for the duration of a communication session, it is possible to envision the application of DTN concepts to under-water acoustic networks, where the bandwidth-limited acoustic channel suffers frequent disruptions due to environmental factors. This paper presents the design and implementation of an Underwater Convergence Layer (UCL) for the DTN2 Reference Implementation, which provides DTN support for the WHOI Micro-Modem. UCL was tested in the field during the Acommsnet10 sea trial, in a heterogeneous context comprising underwater nodes communicating acoustically and surface nodes communicating with radio frequency. Initial results and lessons learned from field testing are also presented. The principal value of this development resides in the delivery of new capabilities towards the application of DTN concepts to the maritime domain, to enable functionalities like multi-hop acoustic communication, data mule using autonomous vehicles and gateways between different transmission media (e.g. between underwater acoustic communications and above water radio/satellite).