N-Drop

Abstract

Delay-Tolerant Networks are wireless networks where disconnections may occur frequently due to node mobility, power outages and propagation phenomena. In order to achieve date delivery, store-and-forward protocols are used in DTN and routing protocols based on epidemic message dissemination has been proposed, such as Epidemic routing. Under Epidemic routing, packets can be delivered completely between every tow nodes if every node buffer is big enough and the communication time is long enough after one node contacts another one. But congestion will occur easily at a node if the buffer of this node is limited under Epidemic routing in DTN. In order to solve this problem, a congestion control strategy was introduced. If a node buffer is full and it needs to store a new packet, every packet in the node buffer will be checked, in order to find out the packets whose numbers of forwarding are over N and then erase them. If there is no packet whose number of forwarding is over N, the last packet will be erased. The strategy is called N-Drop. Using simulations based on a random waypoint model, the simulation results proved the improvement of our strategy.