Research And Implementation Of Link Failure Recovery Technology For SDN Fattree

With the expansion of network and the growth of Internet traffic,traditional networks have exposed problems such as overly complex built-in protocols,internal opacity,and high network operation and maintenance costs.Therefore,software-defined networks have emerged.Under a software-defined network,failures can cause huge economic losses,and packet loss after failure can affect quality of service.Therefore,how to reduce the packet loss rate,improve the quality of service,and ensure a short failure recovery time is an important issue that needs to be solved under the new network.The paper studies the mainstream fault handling methods for the packet loss problem after link failure,and proposes the recovery strategy of link failure(RSLF).The strategy includes two phases.The first phase is based on the remaining features of the Fattree.Each link of the primary path is pre-defined with multiple backup paths.The second stage is to redistribute part of the fault traffic by combining the flow rate statistics when the fault occurs.And then based on this strategy,we design and implement a link failure recovery system of the SDN.1)Aiming at the packet loss problem occurs after the link fault occurs in SDN.Based on the redundancy features of the fattree topology,a predefined multiple backup path strategy CombinePR is proposed.This strategy can reduce the packet loss rate while ensuring a short recovery time.2)According to the flow rate statistics in the network.When the remaining bandwidth of the predefined backup path cannot meet the bandwidth requirement of the fault traffic,the controller processes some fault traffic and distributes them between different backup paths.Or,looking back for a new forwarding path,a fault handling strategy(RSLF)is proposed.Through experimental comparison,the strategy can further reduce the packet loss rate and improve the quality of service.3)This thesis designs and implements the link failure recovery system in SDN network.The Link fault recovery system includes a topology management module,a flow rate statistics module,a fault decision module,a fault detection module,and a flow table delivery module,and the effectiveness of the fault processing is verified through experiments.