Research On Multipath Load Balancing Of Data Center Network Based On SDN

With the rapid development of the Internet,the network traffic presents explosive growth,the data center as its important infrastructure is also facing great challenges.Software defined network(SDN)is a major reform for the traditional network architecture.Its main idea is to separate the data layer and the control layer.In this paper,mainly research on SDN-based data center network multipath load balancing.According to the feature of flow concentration in data center network,and the advantage of centralized control and software programmable for SDN,we use the multipath load sharing method to improve the utilization ratio of network link and reduce congestion.In this paper,Ryu controller is selected as the research platform,and five modules are defined in the application layer through REST API to implement the multipath load balancing strategy.The modules are:global topology sensing module,network state measurement module,k short path calculation module,road state evaluation module,congestion handling and flow table forwarding module.Ryu controller periodically calls global sensing module and network status measurement module to obtain information such as global topology,bandwidth,and delay to realize dynamic monitoring.Through the k shortest path calculation module,link state evaluation module,congestion handling and flow table forwarding module to achieve the current traffic load distribution function.Ryu controller can periodically send LLDP packets to obtain global network topology information,it can use software methods to prevent network loops and learn MAC address,and it can use OpenFlow protocol to complete real-time monitoring for network bandwidth,delay and other parameters.In this paper,Yen algorithm is chosen as the KSP algorithm to calculate k candidate paths.And then the controller establishes an evaluation model to evaluate the priority of current each link,selects the link with the highest priority to packet-out flow table in OpenFlow switch,periodically monitors the current link congestion,and selects the optimal route except the current path to implement rerouting when the current forwarding path bandwidth reaches the threshold.This paper uses the Mininet simulation platform to simulate the fat-tree topology of the data center network,and implements the multipath load balancing scheme on the Ryu controller.The paper uses Iperf tool to simulate flow occurs.Two groups of test experiment show that the proposed scheme has good performance in improving network link utilization,reducing delay and reducing congestion.