Abstract
A mobile ad hoc network (MANET) is a collection of wireless mobile nodes that communicate peer-to-peer in a self-organized manner without fixed network infrastructure or any centralized administration. Because the transmission range of each node is limited, each node needs to perform routing in order to delivery and help the neighbor nodes to forward control packets and data packets. With dynamic topology, the distributed cooperation and the constrained capability, MANET can work effectively only if the participating nodes cooperate in a proper way. Therefore, the collaboration among all nodes and normal data transmission become very important. Most of the routing protocols in MANET assume nodes are trustworthy and cooperative and thus do not consider that the intermediate nodes along a routing path can promise to forward packets but in fact fails to do so. We call this situation packet dropping behaviors. Therefore, the throughput of the whole network will be affected. In original no protected routing protocols, the influence may be mitigated only when the routing path is changed due to the mobility. In view of this, we propose a novel scheme to mitigate the influence of the packet dropping in the reasonable dense MANET. Each node constantly monitors the traffic activity of its neighbor nodes in the promiscuous mode. A node which located in the signal of the upstream node and the downstream node along a routing path will be a monitor. When any neighbor drops any data packet comes from the upstream node of it, the monitor will help to retransmit the dropped data packet. After the monitor has already helped to retransmit over certain times, it dynamically adjusts the routing path to bypass a misbehavior node Therefore, even when there are many individual or colluded attackers in MANET, the data delivery rate can be hold above certain probabilities.