Research On CCN Routing And Caching Algorithm Based On Improved DBSCAN

As a new network architecture,content centric network(CCN)separates the content and location of data,uses hierarchical data content names instead of IP addresses to transmit data,makes the data content itself become the core element in the Internet architecture,and effectively solves the disadvantages of IP communication.Each router node in CCN has cache characteristics.How to design a reasonable route forwarding method and cache technology is very important.The default routing forwarding method adopted in CCN is to forward the user’s request to the content source server,which can make good use of the cached content on this path.However,it can not make full use of the nodes that cache the relevant content close to the user outside this path.Aiming at the problem of low utilization of cache content outside the path node,which makes the transmission delay longer,this thesis proposes an improved density based spatial clustering of applications with noise routing(IDBR).This algorithm divides the nodes in the network into different autonomous regions by clustering,and then determines the way of routing and forwarding through the core nodes in each autonomous region.Simulation results show that this algorithm can reduce the content acquisition delay and improve the cache hit rate,so as to improve the overall performance of the network.The default cache placement algorithm and cache replacement algorithm adopted in CCN are leave copy everywhere and least recently used,respectively.LCE algorithm will lead to a lot of redundancy in the content in the network,while LRU algorithm will lead to the replacement of high popularity content copies by low popularity content copies.Aiming at the problems of a large amount of content redundancy and high popularity content replacement in the network,this thesis proposes a cache replacement based on comprehensive content popularity and hash calculation(NCPHC).The algorithm determines the placement node of the cache by hashing the content name,and determines the replacement node of the cache by synthesizing the popularity of the content.Simulation results show that this algorithm has a good improvement in reducing user content request delay,reducing cache content redundancy between nodes and improving cache hit rate.