Priority-based scheduling policy for a hybrid routing algorithm in a Vehicular Delay Toleant Network

Vehicular Delay Tolerant Network (VDTN) has emerged as a special type of network that is distinguished by the non-existence of end-to-end path between source nodes and destination nodes. Routing is one of the crucial issues in VDTN. To route a message, it must be scheduled from the outgoing buffer of a node. This is also an important issue considering the fact that the routing algorithm routes this message faster towards its destination based on message emergency. Scheduling policies that have been discussed in the literature schedule messages according to some known policy and some existing routing algorithm would be used to route these messages. In this paper, we propose an priority based scheduling and drop policy and also propose a hybrid routing algorithm that routes messages that have been scheduled based on priorities. The priority is based on the types of messages (e.g. Accident related messages, Traffic related messages and General purpose messages like finding a parking slot in a nearby area) to be routed through the network. The hybrid routing algorithm we design routes messages to the nodes according to the message prioritiy. Our evaluations show that, our algorithm performs better in terms of message delivery ratio, overhead ratio and average delivery latency as compared to some existing VDTN routing approaches like Epidemic, Spray-and-Wait & First Contact.