Research On Caching Replacement And Routing Algorithm In Content Centric Network

The TCP/IP protocol is a basic feature of the traditional IP network architecture.The current Internet is the most common and typical application of IP networks.The IP network architecture emphasizes address-centricity,a simple network layer,and hands over most of the work to the upper layers.However,the structural problems of the IP network are also prominent,such as redundant transmission of data and inefficiency.The transmission path is not secure.With the rapid increase in the amount of information,the pressure on the distribution of content on the Internet is also growing.In the current era of new Internet with user experience as the core factor and service-oriented,users do not care about the source and transmission of content,but care about the speed and quality of content delivery.The superimposed upgrade improvements made on the TCP/IP architecture do not accommodate multiple network layer functions.As a kind of "revolutionary" new network structure,CCN replaces the IP address with the name of the content itself as the network transmission identifier,and shifts the focus from the original content address to the content itself,and directly transmits according to the user's needs.Since every node in the network is capable of caching,the impact of cache performance is self-evident for the entire network.With the explosive growth of video traffic,the pressure of video distribution in CCN networks is also increasing.Aiming at solving this problem,This thesis proposes a cache replacement strategy based on H.264 video coding protocol.Firstly,stratifying the video stream.Then taking the popularity of the title and the popularity of each layer into consideration for cache replacement.,Comparing the video's popularity with the node's occupancy nd caching the corresponding content size according to the popularity level.The simulation results show that the scheme improves the cache hit rate and improves the overall performance of the network.After the cache placement,we found that a reasonable routing mechanism is also an important factor to improve network performance.This thesis first proposes a cache placement scheme,in which each node caches the content items with the highest popularity value among all requests of the node.After the caching placement,each node establishes a routing find table to record the cached content items in the node and its subordinate nodes.In the subsequent route forwarding process,a node is queried to the cached neighboring nodes.If a node has the cached item,the request is forwarded directly to the node.The simulation results show that compared with othermulti-path routing strategies,this scheme reduces the content acquisition delay and improves the cache hit rate.