DDoS traffic re-injection method, SDN controller, and network system

The embodiment of the invention provides a DDoS traffic re-injection method, an SDN controller, and a network system, and relates to the technical field of communication. The problem that a large amount of resources investment is needed to solve the DDoS traffic re-injection across a metropolitan area network, resulting in a relatively high operation cost in the prior art is solved. The method comprises the following steps: when an ARP message reported by a cleaning device forwarded by a central SDN forwarding device is received, issuing a first Openflow flow table to the central SDN forwarding device; and issuing a second Openflow flow table to an edge SDN forwarding device. The embodiment of the invention is applied to DDoS traffic re-injection. 本发明的实施例提供了种DDoS流量回注方法、SDN控制器及网络系统，涉及通信技术领域，解决了现有技术中在解决跨城域网域的DDoS流量回注的问题时，需要大量的资源投入导致运营成本较高的问题。该方法包括，当接收到中心SDN转发设备转发的清洗设备上报的ARP报文时，下发第Openflow流表至中心SDN转发设备；下发第二Openflow流表至所述边缘SDN转发设备。本发明实施例用于DDoS流量的回注。