Research On Caching And Routing Strategy In Named Data Networking

In recent years,with the rapid development of Internet technology,the traditional Internet architecture has shown various drawbacks such as poor scalability,low security performance,limited mobile support and so on.The academic community has begun to study new future network that can completely get rid of the limitations of TCP/IP system architecture.With the continuous increase of network traffic,information acquisition has gradually become the core requirement of users.Researchers proposed a new network architecture called Information Centric Networking(ICN).It can change the original end-to-end communication mechanism of the Internet,focusing only on the content itself rather than the specific location of the content and centering on information.Named Data Networking(NDN)is one of the representative new network architectures.The built-in caching in the network is one of the important features of NDN.Users can obtain content directly from the routers without needing to obtain them from the server.It can greatly improve the user experience and transmission efficiency,and reduce the pressure on the server.However,the storage space of the router is limited.How to deploy cached content reasonably and obtain content quickly have become the focus of NDN research.An excellent caching strategy and routing strategy can greatly improve the network performance of NDN and the quality of service.NDN adopts caching everywhere and blind routing by default,which leads to serious cache redundancy,low utilization of cached content,low efficiency of route search and so on.To solve the above problems,this paper designs strategies from two aspects:caching and routing.The specific research work is as follows:1.In order to effectively utilize the central nodes and improve the cache profit,a caching strategy based on community division and content popularity is proposed.Firstly,the strategy analyzes the importance of nodes by synthesizing four node centrality indicators and then divides topology into different communities,finds the global core nodes in the whole topology and selects a regional core node in each community.Finally,different caching methods are adopted according to whether interest packet passes through the core nodes and division of popularity is combined to reasonably cache different content on nodes of different importance.Simulation results show that the content cached in the core nodes can not only serve the requests of global users and regional users greatly,the regional core nodes can also better reduce latency and improve user experience.2.In order to solve the problem that the selection of core nodes depends too much on the static network topology and the node's state changes dynamically with time,an optimal location caching strategy based on improved firefly algorithm is proposed.It converts the cache placement problem into an optimization problem and takes the path as the optimization unit.0-1 binary code is used to combine with the cache problem,various factors are integrated to formulate the corresponding objective function.Node idle rate is added to represent the dynamic of the node either.Finally,the improved firefly algorithm is used to solve the problem,each solution corresponds to an optimized cache scheme.Simulation results show that the strategy can be applied to complex topologies and reflects the dynamics of nodes.It has better performance in terms of cache hit ratio,latency,link load and path stretch ratio.3.In order to effectively improve the efficiency of route search and user experience,a routing strategy based on intra-community ant colony algorithm is proposed.This strategy analyzes the rationality of ant colony algorithm from the perspective of local area,and divides the routing process into intra-community routing and inter-community routing.The two parts of route are used for exploration and forwarding.The improvement of the ant colony algorithm and node patency are added to the intra-community routing,and the community similarity and the selection of the initial node are considered in the inter-community routing.The simulation results show that,compared with other classical routing strategies,this strategy can effectively improve the route hit ratio,reduce the route hops and request delay.