Introduction

Packet Intelligence sued NetScout in the Eastern District of Texas, alleging infringement of U.S. Patent Nos. 6,665,725, 6,839,751, and 6,954,789.  The District Court ruled that all three patents were valid under 35 U.S.C. §§ 101 and 102, and infringed.  The § 101 dispute was tried at the bench.  NetScout appealed.

The core technological aspects under dispute are described reasonably well in the '789 patent as follows:

Some prior art packet monitors classify packets into connection flows.  The term "connection flow" is commonly used to describe all the packets involved with a single connection.  A conversational flow, on the other hand, is the sequence of packets that are exchanged in any direction as a result of an activity—for instance, the running of an application on a server as requested by a client.  It is desirable to be able to identify and classify conversational flows rather than only connection flows.  The reason for this is that some conversational flows involve more than one connection, and some even involve more than one exchange of packets between a client and server.

A hypothetical example of this might be that a packet monitor examining packets only on the granularity of TCP connection flows (defined by a 5-tuple of source and destination IP address, source and destination port, and protocol) might not be able to identify two TCP connection flows involving in the same transaction as being related to one another as members of a conversational flow.  Notably, the '789 patent has a June 1999 priority date, a time frame in which this type of packet monitor typically was only able to identify flows based on static filters.  Today's packet monitors largely have the ability to dynamically identify multiple related flows.

Claim 19 of the '789 patent was agreed upon to be representative, and recites:

19.  A packet monitor for examining packets passing through a connection point on a computer network, each packet conforming to one or more protocols, the monitor comprising:
    (a) a packet acquisition device coupled to the connection point and configured to receive packets passing through the connection point;
    (b) an input buffer memory coupled to and configured to accept a packet from the packet acquisition device;
    (c) a parser subsystem coupled to the input buffer memory and including a slicer, the parsing subsystem configured to extract selected portions of the accepted packet and to output a parser record containing the selected portions;
    (d) a memory for storing a database comprising none or more flow-entries for previously encountered conversational flows, each flow-entry identified by identifying information stored in the flow-entry;
    (e) a lookup engine coupled to the output of the parser subsystem and to the flow-entry memory and configured to lookup whether the particular packet whose parser record is output by the parser subsystem has a matching flow-entry, the looking up using at least some of the selected packet portions and determining if the packet is of an existing flow; and
    (f) a flow insertion engine coupled to the flow-entry memory and to the lookup engine and configured to create a flow-entry in the flow-entry database, the flow-entry including identifying information for future packets to be identified with the new flow-entry, the lookup engine configured such that if the packet is of an existing flow, the monitor classifies the packet as belonging to the found existing flow; and if the packet is of a new flow, the flow insertion engine stores a new flow-entry for the new flow in the flow-entry database, including identifying information for future packets to be identified with the new flow-entry,
    wherein the operation of the parser subsystem de-pends on one or more of the protocols to which the packet conforms.

We will discuss the Court's § 101 analysis of this claim.

In Alice Corp. v. CLS Bank Int'l, the Supreme Court set forth a two-part test to determine whether claims are directed to patent-eligible subject matter under § 101.  One must first decide whether the claim at hand involves a judicially-excluded law of nature, a natural phenomenon, or an abstract idea.  If so, then one must further decide whether any element or combination of elements in the claim is sufficient to ensure that the claim amounts to significantly more than the judicial exclusion.  But elements or combinations of elements that are well-understood, routine, and conventional will not lift the claim over the § 101 hurdle.  While this inquiry is generally carried out as a matter of law, factual issues can come into play when determining whether something is well-understood, routine, and conventional.

Notably, procedure for the proper application of this test with the abstract idea exception has been inconsistently defined and is confusing in practice.  A potentially more workable definition of patent eligibility is that a claim is directed to an abstract idea if all of its elements are either non-specific, address a non-technical problem, or known in the art.  Thus, a claim is more likely to survive a § 101 challenge if one or more elements thereof have three qualities:  specificity, a technical problem that they solve, and some degree of novelty.

The Majority Opinion

Judge Lourie wrote for the majority, which was he and Judge Hughes.  The majority provided an overview of the District Court's § 101 analysis, of note being that the District Court made a series of factual findings with respect to the claimed invention versus the prior art and based its holding of eligibility on those findings.

In any event, the majority framed its opinion by stating that "[i]n our eligibility analysis, we consider the claim as a whole and read it in light of the specification."  The majority cited to a number of previous Federal Circuit decisions relating to the patent-eligibility of computer-implemented and networking inventions.  In this, the majority emphasized that the inquiry often turns on "whether the focus of the claims is on a specific asserted improvement in computer capabilities or, instead, on a process that qualifies as an 'abstract idea' for which computers are invoked merely as a tool."

With the § 101 framework in place, the majority agreed with the District Court that claim 19 was not directed to an abstract idea.  Particularly, "claim 19 purports to meet a challenge unique to computer networks, identifying disjointed connection flows in a network environment" and provides "detail how this is achieved in several steps."

Moreover, "[t]he asserted patents' specifications make clear that the claimed invention presented a technological solution to a technological problem."  They "explain that known network monitors were unable to identify disjointed connection flows to each other, and the focus of the claims is a specific improvement in computer technology: a more granular, nuanced, and useful classification of network traffic."

NetScout argued that Two-Way Media Ltd. v. Comcast Cable Commc'ns, LLC mandates limiting the Alice part one analysis to the specification's concrete embodiments.  But the majority observed that Two-Way Media stands for the notion that the claims, "not the specification, must include an inventive concept" under Alice part two.  Since the majority concluded that claim 19 was not abstract under part one, it did not have to reach part two.

Accordingly, the claimed invention was found to be patent-eligible.

Judge Reyna's Dissent

Judge Reyna wrote in dissent because, in his view, "the claims are directed to the abstract idea of identifying data packets as belonging to conversational flows rather than discrete connection flows."  Judge Reyna stressed that "the asserted advance over the prior art is the classification of data packets according to the flow of data associated with given activities rather than potentially disjointed exchanges transmitted over individual connections."  And, he found this distinction to be "conceptual, not technological, in the absence of specific means by which that classification is achieved."

The crux of the disagreement between Judge Reyna and the majority is that Judge Reyna limited his § 101 inquiry to the language of the claim, while the majority looked to the specification.  Judge Reyna noted that claim 19 recites "only a general method of sorting data packets according to any flow, not a specific means of sorting packets by conversational flow," and that "the claim does not recite how the individual packets are actually identified as belonging to a conversational flow beyond the functional requirement that identifying information is used."

Judge Reyna admitted that the specification provides the necessary detail, but "[n]one of these processes or components are recited in claim 19, and the claim elements have not been construed as limited to the structures and processes disclosed in the embodiments."  Thus, "the components and operations actually recited in the claims do not provide the specificity required to transform a claim from one claiming only a result to one claiming a way of achieving it."  Without this detail, Judge Reyna believes that the invention is drawn to information processing "falling within the realm of abstract ideas."

Conclusion

The majority found claim 19 to be a reasonably specific technical invention that provided an advance over the prior art.  Judge Reyna disputed this finding because he views the claim as being non-specific in terms of its technical character, thereby making any such improvement to be too abstract for patenting.  The case turned on a disagreement in fundamental principle -- when and how should one read the technical aspects of a specification into the broader language of the claims, if at all?  Until this question is answered, the appropriate level of detail to place into claims will remain an open issue.

Packet Intelligence LLC v. NetScout Systems, Inc. (Fed. Cir. 2020)
Panel: Circuit Judges Lourie, Reyna, and Hughes
Opinion by Circuit Judge Lourie; opinion concurring in part and dissenting in part by Circuit Judge Reyna