Providing QoS as a Means for Defending DoS Attacks in Active Networks

Protecting legitimate traffic from the effects of denial of service attack traffic is desirable not only for availability of legitimate services but also for effective network utilization. Both can be achieved by means of ensuring effective QoS to users based on their actual needs. This paper deals with QoS management issue and is based on the proposed work of Michael Welzl for effective QoS provision. Active networks seem to be particularly useful in the context of QoS support and the active QoS routing (AQR), an on-demand routing, algorithm is used to detect DoS attacks by comparing the QoS parameters in the presence and absence of attack traffic with that provided by shortest path routing. In this paper a variant of AQR using the product of available bit rate and delay for finding the best path is proposed to improve the attack detection and is demonstrated to be much efficient in reducing the jitter with heavy traffic in the network and hence suits detection of flooding type DoS attacks effectively based on the heavy delay variations.