A US trade judge ruled that Arista used Cisco’s network device technology in its ethernet switches without permission.
Judge Mary Joan McNamara of the US International Trade Commission in Washington, said that Arista had infringed two patents owned by Cisco. The ruling could lead to an order banning the import of Arista’s products into the United States.
Cisco filed the complaint at the ITC in December 2014, alleging that Arista was infringing six of its patents, which relate to improving the speed and performance of networked computers and devices.
The products accused of infringement include Arista’s 7000 series of switches, which generate most of that company’s revenues.
Arista general counsel Marc Taxay said the company looks forward to presenting its case to the full commission as it strongly believes that its products do not infringe any of the patents under investigation.
Cisco’s general counsel, Mark Chandler, said: “Our goal has always been to protect technological innovation, and stop Arista from using our patented technology.”
In June, the ITC ordered an import ban on Arista’s products that infringed several other Cisco patents.
The US Trade Representative allowed that order to go ahead in August, but US customs officials last month ruled that Arista could resume imports of its redesigned switches because they were not within the scope of the ban.
There is a trial currently underway in California, where Arista is defending against claims of copyright and patent infringement brought by Cisco.