Research On Distributed Routing Method For SDN Central Control

Traditional networking usually uses distributed routing protocols such as IGP to choose the routes while software-defined networking(SDN)uses a centralized control method.The distributed routing protocols of traditional networking have strong stability,but its utilization efficiency is low and it is difficult to meet the requirements of users.SDN directly control the network forwarding centrally and improve network manageability significantly.Yet,on one hand,most routers or switches of traditional network do not support the SDN protocol,on the other hand,the scalability and robustness of SDN are difficult to guarantee.Fibbing,an architecture that enables central control over distributed routing,operates Open Shortest Paths First(OSPF)through some lies,performing well in flexibility,manageability,and robustness.Fibbing introduces fake nodes and links to the underlying link-state routing protocol so that the protocol computes forwarding tables based on the augmented topology.However,Fibbing has some shortcomings in the aspect of efficient deployment and cross-domain routing.This article makes some improvements to Fibbing.The main work includes the following three parts:1.Increased network routing efficiency through coordinated Fibbing.The algorithm Farsighted Coordinated Fibbing(FCF)is proposed.FCF considers the effect of routing on the addition of fake nodes and fake links when computing routes and perform linear programming on the data transmitted on the links to minimize the sum of link cost and fake node cost.The results of our experiments show that compared with random algorithm and shortest path algorithm,the numbers of fake nodes added in random networks topologies and classical network topologies are significantly reduced,and the sums of link cost and fake node cost are significantly reduced.2.Processing multi-source and multi-sink requests through coordinated Fibbing.The algorithm Multi-source and Multi-sink Fibbing(MAMF)improves FCF,performing the linear programming based on the paths rather than the links.The linear programming is performed to the data on the paths between the source node and the sink node.MAMF makes up for the lack of FCF about multi-source and multi-sink requests.In addition,MAMF also optimizes the routing strategy when multiple flow requests share one fake node.The results of the experiments show that,when dealing with multi-source and multi-sink requests,compared with random algorithm and shortest path algorithm MAMF reduces the number of fake nodes and the total cost about links and fake nodes significantly.3.Fibbing-based flexible cross-domain routing.The scheme Fibbing Cross-Domain(FCD)and the algorithm Fibbing Cross-Domain Routing(FCDR)are proposed.In FCD,Fibbing is used in the intra-domain and inter-domain of the network.Through the dual ways of routing redistribution and the interaction of controller,intra-domain routing process and inter-domain routing processes can obtain the information each other.FCDR considers intra-domain routing information when computing inter-domain routing,minimizing the total cost of intra-domain and inter-domain.The results of experiments show that when FCD is used in cross-domain routing,compared to shortest path algorithm the FCDR reduces the total cost about intra-domain routing and inter-domain routing.