An adaptive routing protocol with congestion avoidance for opportunistic networks

Routing and forwarding of messages towards destinations in opportunistic networks is a challenging task due to the topological uncertainty caused by node mobility and frequent disconnections between node pairs. One of the recently proposed adaptive routing protocol [1] for opportunistic networks makes informed forwarding decisions based on the expected level of connectedness and the predictability of nodes as determined heuristically on the past history of contacts [1], [2]. Though this kind of forwarding in adaptive routing increases the final delivery probability, some nodes in the network will have to devote more of their resources than others as popular nodes often get congested with too many messages to store and carry, and be forced to drop incoming messages. In opportunistic networks, when congestion occurs at intermediate nodes messages get dropped and will not be forwarded towards their destination. In this paper we propose, implement and evaluate the performance of an enhanced congestion aware adaptive routing protocol for opportunistic networks and show that the proposed routing protocol outperforms many of the well-known routing protocols in the field.