2002 Reports

Analysis of Routing Algorithms for Secure Overlay Service

Cook, Debra L.

The routing of packets through an overlay network designed to limit DDoS attacks is analyzed. The overlay network structure includes special purpose nodes which affect the routes taken through the overlay. Two main factors are considered: the routing algorithm utilized for the overlay and the method for selecting the special purpose nodes. The routing algorithms considered are based on methods originally defined for peer-to-peer services. A model was developed for the overlay network which allowed altering the routing algorithm, method for selection of special purpose nodes and the underlying ISP structure. The model was used to assess the impact of specific routing algorithms and selection methods on latency and path length. The implications of utilizing a specific method for node selection on the probability of a successful DDoS attack is briefly discussed.