Azure Networkset al. v. CSR et al.

This case addresses a common question: whether an exclusive licensee has the right to sue. Generally, only the patent owner has the right to sue. But if a license grants sufficient rights to the licensee and retains sufficiently few for the licensor, the license effectively assigns the patent along with the patent owner’s right to sue.  It helps significantly when, as in this case, the license explicitly conveys a right to sue along with independent authority to decide whether to sue.

The majority concluded that the term “MAC address” should be given its customary meaning, which the majority asserted is a device identifier that can be assigned by a LAN or a permanent address set by a manufacturer. A standard MAC address includes a bit identifying the address as either one provided by a LAN or one provided by the manufacturer.  The district court, and a dissenting judge of the appeals court, would have concluded that the MAC address must be one set by LAN based on the specifications’ only describing MAC addresses set by a LAN.  The dissenting judge disputed whether the evidence established that “MAC address” has an ordinary and customary meaning that include permanent addresses.  This shows there is a risk of relying on a customary meaning without stating that meaning in the specification.