Exploiting the potential of DTN for energy-efficient internetworking

Since its original conception as a space-oriented communications architecture, Delay Tolerant Networking (DTN) has been generalized to address issues in terrestrial networks as well. In this work we employ DTN to form an internetworking overlay that exploits the surplus capacity of last hop wireless channels in order to prolong battery life for mobile networking devices. We propose a novel rendezvous mechanism and show experimentally that the DTN overlay can shape traffic, allowing the wireless interface of the mobile device to switch to the sleep state during idle intervals without degrading performance. The simulation experiments are based on a comprehensive DTN agent that incorporates the rendezvous mechanism and facilitates quantifying energy conservation. The DTN agent, implemented in ns-2, enables the study of additional Bundle Protocol design issues, such as route selection, bundle sizing, retransmission strategies, and highlights the need for cross-layer interaction between DTN and the underlying transport protocol.