US Patent 7376154 Non-intrusive method for routing policy discovery

Discovering routing policies in information networks. Large networks such as Autonomous Systems are abstracted as a single network element. A plurality of taps on the borders of the abstracted element filter ingress/egress data which is forwarded for collection and correlation. By correlating information from different taps, routing policies are discovered. These discovered policies may be compared with published policies. Access control makes discovered policies and the comparisons with published policies selectively available depending on predefined access classes.