The Antipollution Cooperative Caching Scheme In Vehicular Content Centric Network

Vehicular Content Centric Network(VCCN)is a network architecture which is combined with Vehicular Ad Hoc Network(VANET)and Content Centric Networking(CCN).Nodes in VCCN not only follow the same mobility patterns and the same communications with VANET,but also have the same caching patterns and the same processing mode for request/response with CCN.Due to the fast speed of nodes in VANET,it is difficult to maintain the stable network topology,which can result in longer delay of forwarding and response.However,caching mechanism in Content Centric Networking aims at solving these problems.By using caching buffer in nodes to store content,CCN can enhance the performance of network and reduce response delay.Besides,nowadays more users are interested in content but the origin where content comes from.Thus applying Content Centric networking into Vehicular Ad Hoc Network is an effective measure.Caching nodes in CCN need to evaluate frequency and times of content being accessed,or other metrics,so malicious nodes will send Interests for unpopular contents to caching nodes,which breaks the Zipf’s law followed by users and makes unpopular contents be cached to pollute caching buffer,decay the efficiency of network.Therefore detection and defense for pollution attack are of concern.In this paper,we concern about the anti-polluted caching scheme in VCCN,and propose a mobility trajectory based cooperative caching scheme and a scheme on caching pollution attack detection and defense based on V2 I communication.In cooperative caching scheme,considering that vehicular nodes have some mobility patterns,we start with mobility trajectory,collect and train information of mobility location.After dividing map into several hot regions,the possibility of nodes moving into these regions are predicted through variable-order Markov Model.The proper nodes are then selected as caching nodes.During the caching scheme,we also propose a cache replacement based on content popularity by taking concern of both frequency and freshness of the content accessed.In pollution attack detection and defense scheme,a grey model GM(1,4)was trained to detect pollution attack by using content popularity and three other associated series.Then we protect routers from pollution attack by dynamically adjusting increment speed of content popularity through “exponential decay and linear growth” method.In our paper,we verified our caching scheme and pollution attack detection-defense scheme with ONE simulator and ndnSim simulator respectively,by evaluating success ratio,delay and other metrics.We also simulated the caching performance of different node types in VCCN and analyzed the complexity of detection-defense algorithm.According the results compared to other schemes,our scheme can improve the network performance,have faster response speed,lower delay,more accurate detection ratio and higher hit ratio.