Abstract: In some scenarios, Epidemic algorithm has high delivery ratio, small delivery delay, but the adaptability of the algorithm is poor. However, the performance of the algorithm will be significantly reduced in other scenarios. On the basis of an analysis of the factors affecting the algorithm performance,Crowding-Out effect is considered as the main reason leading to decreased performance. Self-adaptive mechanism was put forward so that the nodes can adjust the number of packets joining the network, according to the buffer of the nodes nearby, and inhibit the Crowding-Out effect actively and then the performance of epidemic algorithm can be improved. The simulation results show that the proposed algorithm has greatly improved the delivery ratio and has considerably dropped the routing overhead under various scenarios.

Key words: Opportunistic network, Routing algorithm, Epidemic, Crowding-out effect, Self-adaptive mechanism