Achieving low end-to-end latency with a Handoff-based Deterministic Routing Protocol (HDRP) in Delay-Tolerant Networking

DTN is able to adapt any mobility environment where any mobile routers and terminals are combined owing to the DTN´s flexible hop-by-hop routing schemes. The existing DTN protocols like Epidemic, Prophet and Spray-and-Wait protocols rely on the message distribution mechanism where each DTN node produces one or more message copies. They can naturally adapt to the mobile situation where the destination node moves from an old connection endpoint to a new connection endpoint because any message copy may luckily be able to reach the new connection endpoint where the mobile node is newly connected. These protocols suffer from long latencies because message copies are not immediately forwarded until any suitable condition for forwarding is met. To solve these problems, we propose a Handoff-based Deterministic Routing Protocol (HDRP) that makes the best use of general handoff mechanisms intended for the IP network. This handoff mechanism includes the registration of locations by mobile nodes and backward propagation and caching of these locations over the experienced route. Our simulation results indicate that HDRP outperforms other existing protocols especially in terms of end-to-end latency.