In April 2021, Core Optical Technologies LLC rounded out its set of lawsuits against manufacturers of optical networking systems and hardware—ADVA, Cisco, Juniper Networks, and Nokia—with two more customer suits. Core Optical filed a suit against Alphabet (Google), Apple, AT&T, Bloomberg, Equinix, and Verizon (5:21-cv-03075), all alleged customers of Juniper Networks, in the Northern District of California, to which an earlier Central District of California suit against Juniper was recently transferred. Core Optical also filed a case against AT&T, Charter Communications, Comcast, Google, Microsoft, and Verizon (8:21-cv-00789), all alleged customers of Cisco, back in the Central District. At this point, the entire campaign centers around the alleged infringement of certain method claims of a single expired patent.