A system and method for building a data structure for determining if multiple routing or forwarding tables yield the same or different forwarding behaviors. VeriTable uses a single tree/trie traversal to quickly check if multiple forwarding tables are forwarding equivalent, yield routing loops, or black holes. VeriTable also uses the Longest Prefix Matching rule for lookups, e.g., checking if route updates in control plane are consistent with the ones in forwarding plane. VeriTable can be applied to network-wide abnormality diagnosis of network problems, such as scalable and efficient forwarding loop detection and avoidance in the data plane of a network. In addition, VeriTable can be extended to handle incremental updates applied to the forwarding tables in a network.