Cheetah sued AT&T along with Ciena Corporation alleging infringement of U.S. Pat. 7,522,836 which is a grandchild of U.S. Pat. 6,943,925. U.S. Pat. 7,339,714 is a continuation-in-part of the '925 patent based on which Cheetah had previously sued and settled with Ciena.
The Federal Circuit, citing General Protecht Group, Inc. v. Leviton Manufacturing Co., Inc., dismissed the infringement suit because the settlement agreement between Cheetah and Ciena clearly indicated that 'all parents' of the '714 patent (e.g., the '925 patent) are covered by the agreement. The court in General Protecht held that continuations of patents that were licensed by a settlement agreement are covered by an implied license of the settlement agreement.
Read the case here.