Multicent: A multifunctional incentive scheme adaptive to diverse performance objectives for DTN routing

Due to intermittent connection and limited communication opportunity, routing in Delay Tolerant Networks (DTNs) is usually conducted in a store-carry-forward manner. Consequently, different packet forwarding or storage strategies can lead to different performance objectives, such as minimal average delay, maximal hit rate, and minimal maximal delay, which are desired by applications with different purposes. However, nodes may not be willing to follow these strategies. Further, selfish nodes may even refuse to carry or forward packets for others if they cannot obtain benefits in return. Though many incentive systems have been proposed to encourage packet forwarding, none of them aim to encourage nodes to realize the aforementioned performance objectives. In this paper, we first discuss the strategies that can realize different performance objectives and then propose Multicent, a game theoretical incentive scheme that not only provides cooperative incentives but also encourages nodes to follow defined rules to realize the desired performance objective. Multicent also makes the Quality of Service (QoS) of packet routing adjustable for specific sources, destinations, or source-destination pairs. Extensive trace-driven experimental results verify the effectiveness of Multicent.