High-speed router filter for blocking TCP flooding under DDoS attack

We present a hardware solution that can reliably block most of the malicious TCP traffic at the edge routers while passing, the legitimate TCP traffic during the Distributed Denial-of-Service (DDoS) attack. By allocating bandwidths separately for TCP, the TCP portion of the bandwidth can be protected In simulation study, the filter successfully blocked 99.9% of the attack traffic while legitimate traffic showed nearly identical performance as in the non-attacked condition. This filtering is transparent to the hosts or routers and a filtering device can be easily attached to router ports.