US Patent 9379956 Identifying a network topology between two endpoints

Some embodiments provide a method that identifies a network topology that is involved in routing of the network traffic between the endpoints in a pair of endpoints. The identified topology covers (1) all the routing paths (e.g., hardware and software-defined paths) between the endpoints and (2) all the forwarding elements (e.g., hardware and software-defined non-edge forwarding elements) along each path that forwards the network traffic (e.g., network packets). The method identifies, and groups together, the receiving interfaces as well as the forwarding interfaces of each forwarding element along different paths between the endpoints. By doing so, the method can identify a real link between a pair of forwarding elements when a set of forwarding interfaces of each one of the forwarding elements in the pair points to the other forwarding element.