Palo Alto Networks (PAN) filed a petition for inter partes review of Centripetal Networks’ patent—U.S. Patent No. 10,530,903—which is directed to a computing system for correlating packets in communication networks with a network device and multiple hosts. The PTAB upheld the patent claims, finding that PAN had not shown that the prior art taught or suggested transmitting an indication of the first host (the source of malicious activity) responsive to the correlation of packets across network boundaries. PAN appealed. The Federal Circuit vacated and remanded the PTAB’s decision because the PTAB (1) failed to make clear findings on motivation to combine references; and (2) improperly analyzed the prior art references in isolation rather than as a combined whole.
The Federal Circuit first addressed the PTAB’s motivation to combine analysis in which the PTAB merely stated that “the necessary bridge” was missing between the two references. The Federal Circuit could not tell whether the PTAB found no motivation to combine and held that the PTAB failed to make a clear finding on whether a person of ordinary skill in the art would have been motivated to modify one reference (Paxton) by adding another reference’s (Sutton) step of notifying a network administrator of the identity of the first host after correlating the packets. The Federal Circuit then addressed whether the PTAB correctly determined that one reference (Paxton) as modified by another reference (Sutton) would have taught the recited “transmitting responsive to the correlation” limitation. The Federal Circuit held that the PTAB’s erred when it analyzed the two references individually, as opposed to the combination.
