AlterWAN, Inc. v. Amazon.com, Inc. — Federal Circuit Upholds Narrow Network-Bandwidth Claims

Background

AlterWAN’s patent concerns wide-area networks designed to improve quality of service. Claims 18 and 51 require routing data along a path between “cooperating service providers.” After an earlier Federal Circuit appeal, the Delaware district court construed that phrase to mean a provider agreeing to supply “non-blocking bandwidth,” and refined the latter term to mean bandwidth that remains available and sufficient while the network can transmit data.

The parties then stipulated to noninfringement under those constructions. AlterWAN appealed, arguing for a broader ordinary meaning of “cooperating service provider” and challenging the revised bandwidth construction. It also contested the exclusion of part of its damages expert’s testimony.

The Court’s Holding

A divided Federal Circuit panel affirmed. The majority found that the specification and prosecution history tied the claimed providers to a special bandwidth commitment. Although “cooperating service provider” does not appear in the specification, the applicant introduced it during prosecution while distinguishing prior systems. The patent family consistently described specially selected or participating providers and non-blocking bandwidth as central to the invention.

The court also approved the district court’s qualification of “non-blocking bandwidth.” The phrase did not require the impossible when the Internet was inoperable; it required bandwidth to remain available and sufficient while the network was capable of carrying data. Because the affirmed constructions supported the stipulated judgment, the majority did not reach the damages-expert issue.

District Judge Subramanian dissented from the construction of “cooperating service provider.” He viewed the majority as importing a bandwidth limitation that was not in the claim, relying on unclear prosecution statements and equating different terminology. He agreed, however, that the district court’s construction of “non-blocking bandwidth” itself was unobjectionable.

Key Takeaways

• Prosecution statements can narrow a later-added claim term when they consistently identify a feature as the point distinguishing prior art.
• A court may use the specification’s repeated description of the invention’s core solution to constrain otherwise broad everyday words.
• A dissent highlights the risk of importing limitations from related terminology that the claims themselves do not use.

Why It Matters

The ruling shows how patent-family history can control the meaning of network and software claims years after filing. Applicants that introduce new terminology during prosecution should make clear whether the new words carry limitations from the specification. For litigants, the case illustrates how an apparently ordinary phrase can become decisive when the intrinsic record connects it to a particular technical promise.