Centripetal Networks holds U.S. Patent No. 10,193,917, which covers a method for rule-based network-threat detection using a packet-filtering device. The device receives network packets, applies filtering rules to determine if they match specific threat indicators, and generates log data. This data includes 'packet log' entries for individual packets and 'flow log' entries that consolidate multiple packet logs associated with a common threat identifier. Keysight Technologies petitioned for inter partes review of the patent, arguing that the claims were obvious over prior art references known as 'Sourcefire' and 'Macaulay.' The Patent Trial and Appeal Board (PTAB) agreed with Keysight for most claims, finding them obvious, but ruled that claims 4 and 14 were not obvious. Centripetal appealed the obviousness rejections, while Keysight cross-appealed the non-obviousness finding for claims 4 and 14.
The Federal Circuit addressed two primary issues: claim construction and obviousness. Regarding claim construction, the court rejected Centripetal's argument that the Board deprived it of notice by construing the term 'packet flow entry' rather than 'packet flow.' The court found that Centripetal had adequate notice and an opportunity to be heard, as the term 'packet flow entry' was central to the dispute and discussed during the Board's hearing. The court also affirmed the Board's construction of 'packet flow entry' as an entry reflecting a set of packets with a common feature, such as a common threat ID, noting that the patent specification supports this interpretation over Centripetal's narrower definition.
The decision creates a split outcome for the patent. Claims 1-3, 5-13, and 15-20 remain unpatentable as obvious, effectively invalidating the core of the patent. However, claims 4 and 14 are saved from invalidation and remanded to the PTAB for further proceedings. This means the patent owner retains a potential path to enforce these specific claims, while the broader scope of the patent is lost. The ruling reinforces the requirement that the PTAB must provide substantial evidence, specifically regarding the motivation to combine prior art references, to support an obviousness rejection.
Podcast (federal-narrative-summaries): Play in new window | Download