Study On Caching Mechanism Of Content Centric Networks

In parallel to the Internet's growth,an unprecedented number of innovations,in both the applications and services running on top of it have emerged,such as the streaming media,cloud computing,Internet of things,and social networking services.The most applications in the Internet are to fetch the mass contents driven by receivers instead of the end-to-end communication services.The current TCP/IP based Internet is facing more and more challenges such as scalability,mobility,security and so on.Information-Centric Networking has emerged as a promising candidate for the architecture of the Future Internet to resolve these problems.Content-Centric Networking was proposed as an alternative Internet paradigm to solve the problems of current host-centric Internet.Content Center Network treats content as basic entity.Each content chunk has a globally unique naming identifier.CCN fundamentally changes the encapsulation structure and addressing mode of the packet by locating,routing,and transmitting the content identifier.The focus moves from the address and the host to the content itself.In-network caching is a key technology of CCN and it can improve the utilization of network resource and decrease the request delay.CCN employs Leave Copy Everywhere caching strategy now,which leads to serious content redundancy and reduce the content diversity.We proposed the node Centrality Metric based Caching mechanism(CMC).CMC utilizes controllers to obtain the topology of the whole network and cache space idle rate,and calculates the degree centrality,closeness centrality and betweenness centrality.When CMC chooses the caching node,take the three metrics and cache space idle rate into account.Simulation results show that CMC can effectively increase the cache hit ratios and reduce the content acquired hops and average request delay compared with the traditional routing algorithm in CCN.We proposed the K-means algorithm utilized Caching Mechanism(KCache)mechanism.KCache utilizes controllers to obtain the number of content request of each router and collect network status.Then the controller will calculate several caching nodes according to the upload information and issues a proactive caching content instruction to these nodes.Simulation results show that KCache can effectively increase the cache hit ratios,reduce the content acquired hops and reduce the average request delay compared with the traditional routing algorithm in CCN.In summary,the paper proposes two kinds of cache mechanisms from two aspects: the inherent characteristics of nodes and the network states.It has great significance to improve the performance of cache system and make reasonable use of bandwidth resources.It also has important scientific significance to the development of content network and even future network.