Research On Routing And Caching Mechanism Based On SDN In Content Centric Network

At the beginning of the rise of the Internet,it was designed to solve the problem of sharing information among computers.Time flies,the use of the Internet has also changed a lot.For example,the scale of the Internet has increased,business has been more abundant and the number of users has increased dramatically.Therefore,the original network architecture which based on TCP/IP protocol has been difficult to meet the changing needs of users.Different from the traditional network,Information centric networking is a new network architecture whose center is information rather than hosts.It is connected by the name of the information,not hosts.Content centric networking is a relatively mature architecture in the information centric networking.Although the content centric networking can solve some problems of traditional networking based on TCP/IP,there are still some problems to be solved in routing and caching mechanisms.Software defined networking can help the content centric networking because of its forwarding separation,centralized control and programmable features.In this paper,a cooperative caching strategy is proposed based on software defined networking.With the help of global control of the software defined networking,the proposed strategy considers the node betweenness and content popularity to select optimal nodes to cache different contents.The controller calculates the cache related decision according to the information of contents sent by switches.Then,it determines which contents should give priority to cache and how many copies should be cache and which nodes should be cached.Apart from caching strategy,this paper also proposes a centralized routing mechanism which combines the software defined networking with content centric networking.In this mechanism,two data structures--cache list and request list are added.And raw data packet and interest packet structure are also modified.In this way,fully knowing network topology and cache location information according to controller,the controller has the right to determine the forwarding strategy.The proposed routing mechanism can effectively reduce unnecessary flooding and improve the efficiency of data transmission.Finally,through building a reasonable simulation environment,this paper did quantitative analysis on the performance of the cache and the routing strategy proposed in this paper.The results show that the caching strategy can effectively improve the hit ratio,allocate resource rationally,use cache space effectively and increase the diversity of cache.The routing mechanism proposed in this paper can effectively reduce request delay,reduce the network load and improve the efficiency of content transmission.