Research On Caching Strategy Of File Distribution Based On Named Data Networking

With the rapid development of Internet and information technology,the information content based on traditional media gradually takes the network as the media,and the application and popularization of content distribution are also increasing.However,the such as transmission bottleneck and network security in the system architecture with TCP/IP protocol as the core appear particularly serious.The emergence of named data network(NDN)provides the possibility to replace the TCP/IP protocol that has dominated the Internet for half a century,and changes the Internet host-host communication paradigm in its design.In order to improve the reuse of content,NDN uses cache technology on a large scale.Each routing node can cache the content passed by and achieve reliable and fast content transmission.However,due to the limited cache space,some content needs to be deleted beyond the space limit,and the cache and selection of content have become a hot research topic.Based on the named data network and combined with the application characteristics in the file distribution scenario,this paper proposes the cache strategy for optimizing NDN,hoping to promote the practical application of NDN.The main work of this paper is as follows :(1)Aiming at the cache decision strategy,this paper explores the existing cache decision strategy according to the particularity of the file distribution scene,and constructs the cache algorithm of the dynamic planning area.It obtains the number of dynamic requests of consumers by increasing the table structure,modifies the cache location of the dynamic planning content of the packet structure,and uses the identification field to avoid the redundancy of the cache content,so that the content distribution in the network topology is more reasonable,so as to reduce the transmission delay and improve the cache utilization.(2)Aiming at the the cache replacement strategy,in order to avoid the phenomenon that hot content is replaced in local time and non-hot content is stored in a static environment for a long time,this paper constructs a cache replacement function,which comprehensively considers the three factors of periodic popularity,smoothness and data request cost of content,and constructs different replacement values for cache content.When the space exceeds the upper limit,the minimum replacement value is deleted by sorting,so as to reduce the server burden and improve the reusability of content.(3)This paper uses NDN network as the network layer framework of the whole system based on the file distribution system architecture under the current IP system and the functions of each part of the architecture.On the basis of NDN network,in order to adapt to the caching strategy proposed in this paper,the network layer of file distribution system is designed in detail,and the naming mechanism,caching mechanism,routing forwarding mechanism and security mechanism of the network layer are expounded to meet the functional requirements of file distribution in NDN network.In this paper,ndn SIM is used to complete the simulation experiment of the cache strategy.Compared with the traditional cache strategy from the aspects of network delay time,network traffic and cache hit rate,the proposed cache strategy has a tradeoff between the complexity and processing ability of the routing node cache,so as to reduce the bandwidth consumption and improve the content reuse.