ODCP: An On-Demand Clustering Protocol for Directed Diffusion

Directed diffusion (DD), uses mechanisms such as data aggregation and in-network processing to suppress the additional data overhead however there is no guarantee that paths from nearby sources join after a few hops. In cases where sensed event is spread geographically, the probability of such combination is reduced. Another problem arises in presence of many source nodes near a single event. In DD for path construction, each source floods a distinct exploratory data (ED) packet through the network, thus a significant amount of network energy is dissipated. The ODCP protocol is proposed to address these two problems: late-aggregation and distinct ED-flooding. In our local on-demand clustering protocol, early aggregation and limited ED-flooding can be achieved by using a virtual sink (VS) near the sources. This node plays the role of sink node and broadcasts local interest messages. Therefore the data packets are sent initially to the VS node and then routed toward destination. Although in simulations we did not consider the improvements gained by early-aggregation, the results show that using this method, connection life-time between source and sink will be increased significantly (up to three times better than directed diffusion).