The Improvement Of Spray And Wait Routing Method In DTN

With the wide application of the Internet network, communication technology based onTCP/IP is mature day after day. In the world, each country and each region with Internetaccess network form can make reliable communication and interaction. The defaultrequirement of the TCP/IP protocol in the Internet is that in the duration of thecommunication, network has the end-to-end path in existence between data source anddestination, the maximum round-trip time between any pair of nodes will not be too long, thepacket loss rate is smaller. However, with the military field, the expedition zebra networkneeds, such a kind of network emerges as the times require, node mobility of this kind ofnetwork structure is strong, the topological structure changes sharply, end-to-end doesn’t havestable link, connection interrupt frequently. In2003, this kind of network was named the delaytolerant network (DTN) by FALL.Traditional DTN routing algorithm is mainly divided into two kinds of routing methods:single copy routing method and multiple copy routing method. Single copy routing methodonly keeps one copy of specific message in the network. The transfer success rate of suchkind of routing method is not high due to the network interruption or no accurate selectionstrategy of the next-hop. But single copy routing method saves network overhead, and canavoid network problems such as congestion, especially in network environment with largenumber of nodes, multiple copy routing protocol is difficult to apply, including the twoclassical routing method DirectDeliveryRouter and FirstContactRouter. The multiple copyrouting method is mainly through increasing the number of copies in the network and spreadas far as possible to the destination node to improve the success rate of delivery, but resourcesconsumption of this kind of routing method is larger, and network congestion easily happened,which leads to the reduction of routing performance, including the two classical routingmethod Spray and wait and Epidemic.Due to the high mobility of DTN nodes, the network topological structure changesconstantly, connection interrupt frequently, end-to-end link is sporadic. Putting forward a kindof efficient routing protocol on it becomes the main subject to research in the field. Accordingto the characteristics of the mobility of the nodes, this article puts forward a DTN routingalgorithm based on the perception of the nodes mobile information called BMI, the algorithm is improved on the basis of the classic routing protocol spray and wait. First, the wait stage ischanged to active routing stage, and then we will take the mobile information of the meetnodes and the destination nodes into account, in the two separate stage, we will choose thenodes which are more likely to meet with the destination nodes to be the delivery informationof nodes. At the same time, the congestion control strategy based on markov meet timeinterval is introduced in the node local cache, which improves the queue and discard principleof the cache. The simulation results show that the algorithm can more obviously improve thesuccess of rate of delivery, and reduce the delay.