Load Balancing Routing Algorithm Based On Software Defined Network

Software Defined Network(SDN)is proposed to provides new ideas for network traffic engineering problems because the traditional network forwarding control tightly coupled architecture cannot meet the current business traffic diversification and highperformance transmission requirements.Its forwarding and control decoupling architecture makes the control layer have a global view of the infrastructure layer,dynamic and fine-grained routing calculations can be performed through software programming.Based on the software-defined network architecture,this thesis studies network routing issues.The main contents are as follows:1.In view of the low flow table utilization rate caused by the current SDN network in dealing with a large number of data flows,the slow forwarding response and the current routing algorithm is likely to cause local network congestion and load imbalance,a multipath scheduling algorithm based on segment routing is proposed.First,the SDN controller issues the initial flow entries according to the network topology link;then,integrates the path hop count,link bandwith load,and path bandwith load fluctuation function to calculate the optimal path for the newly generated large bandwidth data flow;finally,according to the path information construct an SR(Segment Routing)flow entry and modify it to the edge switch to complete flow forwarding.Experimental results show that the proposed algorithm has certain advantages in terms of average network throughput,average end-to-end delay,and packet loss rate compared with ECMP and Hedera algorithms.The performance of the algorithm with and without SR technology is compared.It is proved that SR saves the flow entry overhead significantly while almost no loss in transmission performance.2.Aiming at the local congestion in the network,a load balancing routing algorithm based on link state prediction and congestion control.First,the algorithm uses a quadratic exponential smoothing prediction algorithm to predict whether the link will exceed the congestion threshold at the next moment to determine whether the newly generated large bandwith data flows avoid the link.For the observed congested link,the controller obtains the data flow information on the link,and then finds the path satisfying the constraint conditions on the backup path set for shunting;finally,the SR flow entry is constructed according to the path information and install on the edge switch to complete the switching of the data flow to the new path.Experimental results show that the algorithm compared with Nimble and ECMP algorithm reduces the congestion link and the network bandwidth utilization is improved.