On the Performance of Delay–Tolerant Routing Protocols in Underwater Networks

The underwater acoustic channel features long and variable propagation delay, high bit error rate and limited bandwidth. Moreover, underwater mobile networks consisting of Autonomous Underwater Vehicles (AUVs) for surveillance and monitoring applications often suffer from intermittent connectivity as nodes move around the area of operations. Therefore, this scenario is appropriately modeled as a Delay-Tolerant Network (DTN). In this paper, we investigate two classes of DTN routing protocols: Spray-and-Wait (SNW) and the Resource Allocation Protocol for Intentional DTN (RAPID), together with a standard flooding protocol for underwater mobile networks, and their performance is analyzed in terms of packet delivery ratio, average end-to-end delivery delay and throughput, in different load conditions across various node mobility scenarios. Our results show that RAPID performs better than other DTN routing protocols in terms of packet delivery ratio at higher load conditions irrespective of node mobility, whereas the Binary version of SNW has the best performance in terms of average delivery delay.