Effectiveness of close-loop congestion controls for DDoS attacks

High-bandwidth traffic aggregates may occur during times of flooding-based distributed denial-of-service (DDoS) attacks which are also known as flash crowds problems. Congestion control of these traffic aggregates is important to avoid congestion collapse of network services. We perform fundamental researches to minimize the effect using existing congestion controls. We simulate DDoS attacks in different Internet topologies (Tiers model, Transit-Stub model, Scale-free model). We try to improve network resistance against DDoS attacks and similar overflow problems by using open-loop and close-loop congestion controls such as Droptail, RED and CHOKe. Furthermore we propose a new congestion contorl method based on protocol type of flow and compare the performance with existing methods