Cache scheduling policy for opportunistic networks based on message priority

Opportunistic Networks (ONs) are a newly emerging type of delay tolerant networks that can exploit opportunistically unplanned contacts between nodes to share information. Message delivering in ONs is characterized by store-carry-and-forward and there is no end-to-end path from the source node to the destination node, so the choice of cache management policies and message discarding strategies can have a major impact on system performance. In this paper, we first present a method of calculating number of message copies. Then we propose a new cache scheduling policy based on message priority (PCSP) by defining message priority on the basis of message properties, such as the number of messages copies, elapsed time and time to live. The simulation results also show that the PCSP policy is much better than the existing ones in terms of message delivery ratio, delay, and overhead. 2013 Binary Information Press.