Research Of Routing Protocols In Delay Tolerant Networks

The development of science and technology leads to the appearance of Delay Tolerant Network. It is not satisfied with some basic assumptions of the Internet architecture. Delay Tolerant Network is characterized with high link delay, high link error, frequent connecting breaking apart and limited node resources. Thus TCP/IP protocol can not run on it very well. Delay Tolerant Network can be widely applied in scenarios like Terrestrial Mobile Network, Exotic Media Network, Military Ad-Hoc Network, Sensor Network and etc. At present researches of Delay Tolerant Network are still in its initial stage. Routing researching is one of the most important content.This thesis makes Delay Tolerant Network routing protocol as the main researching object. We firstly describe the technical background of Delay Tolerant Network. After that we compare and classify the routing algorithms presented recent years. According to the difference of network knowledge protocols utilized and difference of delivery methods, these algorithms can be divided into Flooding-Based Routing and Forwarding-Based Routing. After summarizing the application scenarios of Delay Tolerant Network, we analyzed advantages and disadvantages of each algorithm.In the following this thesis goes into the developing trends of Delay Tolerant Network and analyzes the feasibility of combining routing strategy with some theories of Social Network. We proposed a copies limited and social based (CLASB) routing algorithm. CLASB decreases copies redundancy by restricting the maximal number of message copies. During the spray phase a node with higher rank of centrality will get larger number of message copies. By doing this CLASB improves message diffusing and delivering. We have done simulation experiments with simulator ONE. Simulation results demonstrate our method has correspondingly higher performance of delivery ratio, average latency and overhead ratio, when compared with other DTN routing protocols.Additionally this thesis studies the relationship of routing protocol performance and buffer management policy. We proposed a buffer management policy BRN which is based on message replicate number. This policy is fit for flooding-based routing protocols. We run simulations with ONE. Differences between BRN and other commonly used policies are compared and analyzed. Simulation results demonstrate that BRN achieves a relatively better performance when compared to other mechanisms. The results also show that a routing protocol with different buffer management policies will get different performance. It can be seen that buffer management policy is a very important part for a routing protocol.Finally, the thesis summarizes the researching works have been done, and provides some further interesting directions.