OpenSesame v. GO1 — Court Adopts Topological Network Architecture in E-Learning Patent Claim Construction

Background

OpenSesame and GO1 are competitors in the e-learning technology market — both develop software that makes digital coursework possible. At the center of their dispute is U.S. Patent No. 8,784,113, which OpenSesame obtained in 2014 for a “unique system architecture” that addressed two longstanding limitations in e-learning: the difficulty of modifying course content in real time, and the fragility of courses when platform standards like SCORM or AICC were updated.

The patent describes SESAMESEED, a proxy system that lets course providers store content remotely rather than uploading static files directly to a Learning Management System (LMS). The proxy bridges the “network-side” (OpenSesame’s servers) and the “client-side” (the user’s LMS and devices), enabling live updates and interactive features.

OpenSesame sued GO1 for infringement in 2021. After GO1 survived a motion to dismiss and the PTAB upheld the patent’s validity in inter partes review, the case reached the Markman stage. Four claim terms were disputed: “user,” “network-side,” “client-side,” and “content player.”

The Court’s Holding

“Network-side” and “client-side” — topology, not management. The central dispute turned on whether these terms describe positions in a network topology (GO1’s view) or components “managed” by different entities (OpenSesame’s view). Judge Simon adopted GO1’s topological reading, using a memorable analogy: network topology is like a subway map — it shows the relative positions of nodes, not their physical locations. Under this construction, “network-side” means “the provider’s (that is, the server’s) end of a client/server connection,” and “client-side” means “the user’s (that is, the client machine’s) end.”

The court found that OpenSesame itself had used precisely this topological framework — both during inter partes review at the PTAB, where it argued a prior art component could not be “client-side” because it was “in the server,” and in earlier briefing before the Magistrate Judge, where OpenSesame had manually annotated the patent’s figures with “network-side” and “client-side” labels corresponding to the server and user sides of the network connection. Under Federal Circuit precedent, statements made during IPR constitute prosecution disclaimer and bind the patent holder.

“Content player” — what the claims actually say. The court rejected OpenSesame’s proposed construction (“software comprising one or more sets of instructions, configured when executed to play content”) in favor of GO1’s simpler definition: “Software that plays content provided by the e-learning system.” The court noted that the patent uses the phrase “configured when executed” explicitly for other components — its absence from the “content player” language indicated the patentee intentionally omitted it. Adding it back would create ambiguity about whether the software must be configured before execution to play content, or becomes configured by execution.

“User” — resolved by agreement. At the April 6, 2026 hearing, the parties agreed to construe “user” as “a person who uses the e-learning system, such as an author, instructor, training manager, learner, or student.”

Key Takeaways

• IPR positions create binding claim construction commitments. OpenSesame’s topological arguments at the PTAB locked it into a construction it later tried to escape at trial. Patent holders should assume that every statement made during IPR will be used against them in district court proceedings.
• Annotated patent figures can constitute disclaimer. OpenSesame’s decision to add “network-side” and “client-side” labels to figures in earlier briefing gave the court concrete evidence of the patentee’s own understanding — and undermined its later attempt to broaden the terms.
• Claim differentiation doctrine cuts both ways. The court’s analysis of “configured when executed” — present for other elements but absent for “content player” — shows how careful claim drafting (or the lack thereof) can determine construction outcomes years later.

Why It Matters

This ruling has immediate consequences for the OpenSesame-GO1 infringement case: GO1’s topological construction could make it easier to argue that its architecture positions components differently in the client/server chain, potentially avoiding infringement. But the broader lesson resonates for any patent holder litigating after surviving IPR. The Federal Circuit has made clear that IPR statements can serve as prosecution disclaimer — and Judge Simon’s opinion demonstrates how courts will enforce that principle. In an era when patent holders routinely defend validity at the PTAB before asserting infringement in district court, the positions taken in one forum will inevitably shape the outcome in the other.

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