Topology refresh data forwarding protocol for opportunistic networks

Consider the opportunistic network application scenario in which mobile node users socialize with nearby users of common interest, but there exists no pre-established session by which users register or de-register their presence. As nodes are dynamically joining and leaving the network, how a node discovers any newly joined nodes or knows when to release conversations from nodes who have left the network. In this paper, we propose to build a complete topology of end-to-end paths and periodically refresh it, to thereby erase all the connectivity and node position history, to adapt to the dynamic changing nature of opportunistic networks. We call it Topology Refresh Protocol (TRP). TRP integrates the solution to the questions with data forwarding. It is lightweight and efficient that requires no path break detection and repair as required by on-demand routing, no complex route calculations as in probabilistic routing, and no duplication of messages as used in the class of epidemic routing. We studied the TRP performance in terms of overhead, delay, and acceptance rate by computer simulations and found that TRP outperforms the AODV and ERP protocols.