VHTD Mechanism for Secure Data Transfer in Manets.

In MANETs, nodes move freely and so the topology of the nodes is highly dynamic. The process of routing the data packets to the destination is a challenging task. Most existing ad hoc routing protocols are proposed but these protocols are susceptible to node mobility, especially for large-scale networks. In order to provide an efficient and reliable data delivery in a timely manner for these MANETs, Position-based Opportunistic Routing (POR) protocol is proposed. In POR, the data packets are sent out from the source node and some of the neighbor nodes will be elected as the forwarding candidates, if the best forwarder did not forward the packet in a particular period of time then the forwarding candidates will take turn to forward the packets. And by utilizing air backup, communication is maintained without being interrupted. The additional latency incurred by local route recovery is greatly reduced and the duplicate relaying caused by packet reroute is also decreased. In case of communication hole, that is if an intermediate node (Best forwarding candidate) fails or moves out of the coverage area of the node, then Void Handling mechanism based on Temporary Destination (VHTD) is further proposed to work together with POR to provide an efficient and reliable data delivery. This is achieved by adjusting the direction of data flow temporarily. By using Void Handling mechanism based on Temporary Destination (VHTD), the communication hole is avoided.Simulation results show that the proposed protocol achieves excellent performance even under high node mobility.