In an IP network during a DDoS attack on a website or other internet
entity having an IP address, selective black-holing of attack traffic is
performed such that some of the traffic destined for the IP address under
attack continues to go to the IP address under attack while other
traffic, destined for the same IP address is, rerouted via BGP sessions
to a black-hole router. Such a selective black-holing scheme can be used
to allow some traffic to continue in route to the IP address under
attack, while other traffic is diverted.