A SYN packet bandwidth Distributed Denial-of-Service (DDoS) attack is
defended against by intercepting and identifying SYN packets in a "DDoS
gateway" advantageously positioned at the edge of the network to be
protected (e.g., one hop upstream from the protected link), and by
queuing these intercepted SYN packets in a separate queue from other TCP
packet queues. Edge per-flow queuing is employed to provide isolation
among individual TCP connections sharing the link. A fair scheduling
algorithm such as round robin scheduling is used to ensure that SYN
packets (such as those generated as part of a SYN bandwidth attack)
cannot overwhelm the egress link in the presence of other TCP packets.