CASPaR: Congestion avoidance shortest path routing for delay tolerant networks

Abstract

Unlike traditional transmission control protocol/Internet protocol–based networks, delay/disruption tolerant networks may experience connectivity disruptions and guarantee no end-to-end connectivity between source and destination. As the popularity of delay/disruption tolerant networks continues to rise, so does the need for a robust and low-latency routing protocol. A one-copy, shortest path delay/disruption tolerant network routing protocol that addresses congestion avoidance and maximizes total network bandwidth utility is crucial to efficient packet delivery in high-load networks and is the motivation behind the development of the congestion avoidance shortest path routing. Congestion avoidance shortest path routing is designed to either route undeliverable packets “closer†to their destinations or hold onto them when advantageous to do so. Congestion avoidance and bottleneck minimization are integrated into its design. Moreover, congestion avoidance shortest path routing negotiates node queue differentials between neighbors similar to backpressure algorithms and maps shortest paths without any direct knowledge of node connectivity outside of its own neighborhood. Simulation results show that congestion avoidance shortest path routing outperforms well-known protocols in terms of packet delivery probability and latency and is still quite efficient in terms of overhead requirements. Finally, we explore the effectiveness of modeling a variant of congestion avoidance shortest path routing based on the resistance to current flow of electrical circuits in an attempt to further reduce network congestion. Preliminary results indicate a noticeable performance increase when this method is used.