Flooding-based distributed denial-of-service (DDoS) attack presents a very serious threat to the stability of the Internet. In this paper, we propose a novel global defense architecture to protect the entire Internet from DDoS attacks. This architecture includes all the three parts of defense during the DDoS attack: detection, filtering and traceback, and we use different agents distributed in routers or hosts to fulfill these tasks. The superiority of the architecture that makes it more effective includes: (
) the attack detection algorithm as well as attack filtering and traceback algorithm are both network traffic-based algorithms; (
) our traceback algorithm itself also can mitigate the effects of the attacks. Our proposed scheme is implemented through simulations of detecting and defending SYN Flooding attack, which is an example of DDoS attack. The results show that such architecture is much effective because the performance of detection algorithm and traceback algorithm are both better.