Research And Implementation Of Software Defined Network Topology Discovery Technology

Software Defined Networking(SDN)separates the control plane and the data plane.The control plane of the SDN is responsible for the logical control of the entire network and maintaining global network topology information,and the data plane is responsible for the forwarding of data packets.In order to establish global network visibility,the controller of the control plane needs to discover the network topology of the entire SDN network.During the operation of SDN,a safe and efficient topology discovery strategy is essential to the calculation of forwarding paths and the application of security rules in the network.In this paper,in the SDN topology discovery process of the data center network,The calculation cost of controller is high.The problem of SDN link discovery is researched,and the SDN topology discovery strategy(Minimum Switch Coverage,MSC)based on the minimum switch coverage is proposed,designed and implemented the SDN topology discovery system.The main research contents of this paper are as follows:This paper proposes an SDN topology discovery strategy based on minimal switch coverage.First,calculate a set of minimally covered switches based on the initial network topology state,and the switches in this set can connect to all the links in the network.Traverse all the switches in the set,and generate an active port list for each switch according to the switch port situation.Determine whether any two switches in the set are adjacent switches.If they are adjacent switches,delete the active port of one of the switches connected to this link.The controller pre-installs flow rules to specify the switch's behavior of forwarding detection packets.For switches in the collection,it issues a rule for duplicating detection data packets based on active ports,and for switches that are not in the collection,it sends an original backhaul detection.The rules of the data packet.When the controller sends and forwards link detection data packets according to the set,the MSC can reduce the number of data packets sent and processed by the controller,and reduce the calculation load of the controller.The MSC independently verifies the unidirectional link,and verifies the link disconnection event from the ingress and egress of each link port.When a link disconnection event occurs in the network,the controller will respectively send a detection data packet from both ends of the link to verify the packet receiving and sending functions of the ports at both ends of the link.In this way,it is determined whether the link disconnection event is unidirectional disconnection or bidirectional disconnection.MSC conducted experiments on the data center network topology and compared it with other topology discovery strategies.The experimental results show that MSC can accurately collect network topology information,and can effectively reduce the controller's calculation overhead and discovery traffic overhead.Based on the SDN topology discovery strategy with minimal switch coverage,a software-defined network topology discovery system was designed and implemented.Including coverage switch module,flow rule issuing module,topology management module,disconnected link detection module,and controller load monitoring module.The function,performance and reliability of the system have been verified through experiments and tests.