Study On Routing Algorithm Based On Storage State In Delay-Tolerant Network

With the country's space technology development, the needs of deep space exploration continued to grow. However, due to the prosperities of deep-space link, such as long delay, intermittent connectivity, the Internet protocol is not suitable for deep-space environment. A new protocol is needed in order to meet the needs of deep space exploration. This, JPL propose the IPN architecture, and Kevin Fall proposed DTN Protocol Architecture based IPN.This paper introduces the system structure and the origin of the InterPlanetary Network, summarizes the protocol architecture of Delay Tolerant Network and the current research situation of routing algorithms in DTN, especially routing algorithms based on the storage state. Traditional DTN routing algorithms are suitable for the link characteristics such as intermittent connectivity, long variable delay. However, due to the restrictions without considering the storage state, the node may be congestion because of the exhausted of storage. DTN requires to confirm the information hop by hop, information can not be removed until receiving the confirmation. Because of the intermittent nature of the link, it is easy to run out of storage space if the space is not big enough. In response, researchers have proposed SR protocol and BARPIN protocol. After the node congestion occurs, SR pushes some messages to a neighbor node which have enough storage capacity, and pull them back as the congestion resolved . BARPIN take the storage state into account while making the route decision, in order to prevent selecting nodes which has the shortest delay, but lack of storage capacity. Take into account that the design ideas of these two methods are complementary, one focusing on prevention of congestion, the other one focus on processing of congestion, this paper proposes that combining these two methods, to solve congestion problems in two ways. In order to simulate deep space network scenarios accurately, this paper designed a scenario using STK, then simulate the four routing algorithms: routing protocols without storage state, SR protocol, BARPIN protocol and improved protocol, to study their transmission rate and delay. Simulation results show that, in the same storage capacity, the improved algorithms has the highest transmission rate, the lower latency than SR but higher than BARPIN and common routing.