Reported / Citable
Background
K.Mizra LLC accused Nokia of America Corporation of infringing claims from three networking patents. The court’s claim-construction order addressed disputes involving U.S. Patent Nos. 9,749,249 and 8,018,880. The ’249 Patent concerns protection and redundancy for Layer 2 traffic carried over pseudowires, while the ’880 Patent addresses traffic restoration and forwarding in Layer 2 virtual private networks.
The parties disputed three sets of terms: language requiring a determination whether to initiate “preemption” of traffic on a standby pseudowire; “Virtual Switch Instances (VSIs)”; and a “control plane that is external to the plurality of sites.” The court considered the parties’ briefing and arguments presented at a March 31, 2026 hearing.
The Court’s Holding
The court gave the ’249 Patent’s “preemption” phrases their plain and ordinary meaning. It held that preemption requires existing traffic on the standby pseudowire and means more than merely switching traffic from a primary pseudowire to the standby pseudowire. But the court rejected Nokia’s proposed construction limiting preemption to “dropping” existing traffic because neither the specification nor the prosecution history clearly and precisely imposed that restriction.
For the ’880 Patent, the court construed “Virtual Switch Instances (VSIs)” as “a learning bridge and can be used to bridge Ethernet traffic from any source,” rejecting Nokia’s proposal to limit a VSI to a bridge used to construct a VPLS service over an MPLS network. The court gave the external-control-plane phrase its plain and ordinary meaning and corrected “control plan” in Claim 14 to “control plane.” Although an external control plane does not itself include an in-band control plane, the presence of both external and in-band provisioning in an accused system does not necessarily place that system outside the claims.
Key Takeaways
- “Preemption” requires traffic already present on the standby pseudowire, but it is not limited to dropping that traffic.
- A VSI is not confined to constructing a VPLS service over an MPLS network; the court adopted the broader learning-bridge construction.
- A system may remain within the external-control-plane claims even if it also uses an in-band control plane for provisioning.
Why It Matters
The constructions define the claim scope that will govern the parties’ infringement and validity arguments. The preemption ruling preserves a meaningful distinction between preemption and ordinary switchover without adopting Nokia’s narrower dropping-only interpretation.
The VSI and control-plane rulings also reject categorical limitations sought by Nokia. In particular, the court’s treatment of the claims’ open-ended “comprising” language leaves room for accused systems containing additional control-plane functionality, so long as the required external control plane is present and performs the claimed provisioning.