(September 21, 2018, 12:37 PM EDT) -- ALEXANDRIA, Va. — A patent describing a packet-filtering device would have been obvious to a person of ordinary skill in the art, Cisco Systems Inc. maintains in a Sept. 18 petition for inter partes review (IPR) filed with the Patent Trial and Appeal Board (Cisco Systems Inc. v. Centripetal Networks Inc., No. IPR2018-01760, PTAB)....