K.Mizra v. Nokia — E.D. Tex. Markman Order Rejects Nokia’s Narrow Construction of “Preemption” in Pseudowire Networking Patents

Background

K.Mizra LLC, a patent assertion entity, sued Nokia of America Corporation for infringing claims from three networking patents: U.S. Patent 8,018,880 (Layer 2 Virtual Private Network over Ethernet, with fast recovery after link failure), U.S. Patent 9,749,249 (data traffic protection and redundancy for pseudowires), and U.S. Patent 10,735,320 (managing application traffic over a carrier network). The parties presented three disputed claim terms to the court for construction, and Judge Gilstrap held a Markman hearing on March 31, 2026.

The Court’s Holding

The court resolved the three disputes largely in K.Mizra’s favor.

Preemption of data traffic on the standby pseudowire (’249 Patent, claims 1, 7, 12). Nokia tried to narrow the term two ways: it argued that “preemption” requires existing traffic on the standby wire (so a pure switchover wouldn’t qualify), and also that the term is limited to “dropping” existing traffic. The court split the difference. Agreeing with Nokia, Judge Gilstrap held that “preemption” is different from “switchover” and requires traffic already on the standby pseudowire — the patent’s own Figure 5 shows two alternate paths, one with preemption and one without, confirming they aren’t synonyms. But the court rejected Nokia’s further attempt to limit “preemption” to “dropping,” finding neither clear lexicography nor clear disavowal in the prosecution history. The court gave the term its plain and ordinary meaning.

Virtual Switch Instances, or VSIs (’880 Patent, claims 1, 14, 26, 39). Nokia asked the court to adopt the specification’s description — “a bridge used to construct a VPLS service over an MPLS network” — as a binding definition. K.Mizra opposed. The court sided with K.Mizra, finding no clear lexicography. Figure 4 of the patent shows VSIs connected to a PBB metro network, not MPLS, which undercuts any definitional reading of the statement Nokia relied on. The court construed VSI as “a learning bridge and can be used to bridge Ethernet traffic from any source.”

Control plane that is external to the plurality of sites (’880 Patent, claims 1, 14, 26, 39). Nokia argued the term excludes instrumentalities that use both an external control plane and an in-band control plane to provision the VSIs, citing prosecution-history disparagement. The court rejected the exclusion. The claims use the open-ended transition “comprising,” which presumptively allows unclaimed additional elements. Nokia’s disparagement argument could not overcome that presumption because the claims already require an external control plane, and nothing in the specification says only an external control plane can perform the provisioning step. The term got a plain-and-ordinary-meaning construction, with the court noting that presence of an in-band control plane on top of an external one does not avoid infringement.

Key Takeaways

• Mostly a K.Mizra win. Two of three disputed terms came out with plain-meaning or broad constructions that favor the patentee’s infringement theory. The one slight narrowing (“preemption” requires actual standby traffic) cuts against a pure switchover-only product, but K.Mizra defeated Nokia’s attempt to limit it further to “dropping.”
• Lexicography requires precision. The court’s refusal to treat the “VSI” specification statement as definitional, and its refusal to read “dropping” into “preemption,” both track Federal Circuit case law requiring “reasonable clarity, deliberateness, and precision” (In re Paulsen) before a court will find a patentee acted as its own lexicographer.
• “Comprising” presumption is hard to overcome. Nokia’s argument that an in-band control plane reads out of the claim ran squarely into MagSil v. Hitachi and In re Varma — additional unclaimed elements are only excluded when they make the claimed elements “no longer satisfied,” and Nokia didn’t show that.
• Stakes. Nokia now faces infringement theory on three networking patents under constructions that will be materially harder to design around than the ones Nokia proposed. The case moves toward expert reports and infringement contentions under these constructions.

Why It Matters

K.Mizra is typical of a growing class of non-practicing entities asserting networking patents against incumbent telecom and data-center vendors. The ruling is a reminder that at Markman, narrow constructions rarely arrive for free — the specification and prosecution history have to do the work. For Nokia, the loss on “VSI” and “control plane” narrows its design-around options and strengthens K.Mizra’s infringement case going into expert discovery. For other defendants facing similar pseudowire or VPLS patents, the opinion’s discussion of when a specification statement becomes lexicography — and when it does not — is worth close study.