Design And Implementation Of Content Routers With Centralized Cache Management

Named Data Networking(NDN)is a futuristic network architecture.The architecture takes content as the core and gives the content router used a certain cache capability.Although this innovative architecture has gained the advantage of data transmission,it adds extra states to the intermediate nodes of network.This additional state brings performance burden.In NDN,the lookup and forwarding of the router is implemented by three modules:Content Store,Pending Interest Table and Forwarding Information Table.At present,researches have proved that the performance bottleneck of the content router is in Content Store.When Content Storage faces extremely heavy loads,the overall performance of the router is limited.In order to improve the performance of the entire network,this paper proposes a content router scheme based on centralized cache management.The main contributions of this paper are as follows:1.Based on the performance bottleneck of the traditional NDN content router,this paper not only analyzes the limitations of existing solutions,but proposes a content router architecture based on centralized cache management.Firstly,this scheme decouples the content router and its local Content Store,and adds a Remote CS to the traditional NDN.The Remote CS with large storage capacity and fast access speed can centrally cache and manage the frequently requested resources in the network.Thus,when the CS is overloaded,the congested traffic will be forwarded to Remote CS to process.This operation can compensate for the performance deficiency of Content Store.At the same time,in order to realize shunting and forwarding,the data plane of the content router is modified,the forwarding processing of interest packet is designed according to the shunting rules.This "decoupling before centralization"approach can effectively alleviate the performance bottleneck of the content router,and at the same time forward the diverted interest requests purposefully to ensure a relatively stable access delay.2.In order to further facilitate effective interaction between content routers and Remote CS,and to achieve the shunting forwarding of interest overloaded traffic by the content routers,the design of the routing protocol must be considered in the content router design scheme based on centralized cache management.With this in mind,a dual-path routing protocol is proposed in this article.By maintaining the synchronization of the link state database,the protocol helps the router obtain the distribution of network resources and routing information.Then by running the extended Dijkstra algorithm,two forwarding paths can be generated for each interest request,thereby achieving efficient forwarding processing of interest requests and facilitating the interaction between devices in the network.In this paper,a content router simulation system based on centralized cache management is built by C++language.At the same time,the system was tested for the performance.Experimental data shows that,compared with the traditional distributed NDN,the centralized cache management scheme proposed in this paper can effectively improve the performance of the router.This improvement is mainly reflected in two aspects.On the one hand,the solution can reduce the average round-trip delay by 13.79%,and on the other hand,it can increase the throughput by 17.28%.Combined with experimental data,it is not difficult to know that the centralized caching scheme can alleviate the performance bottleneck of the CS module,thereby improve the overall performance of router data plane.At the same time,it also reduces the dependence of content router on fast but expensive memory,ultimately achieving cost savings.