(Reuters) - Arista Networks Inc (ANET.N) won a ruling on Thursday in its legal battle with Cisco Systems Inc (CSCO.O) over networking device technology, setting the stage for Arista to undo a U.S. agency's order blocking importation of some of its products.
Arista had asked the U.S. Patent and Trademark Office to review the validity of a patent it granted to Cisco relating to network device security. The Patent Office sided with Arista on Thursday, invalidating key claims in the patent.
A week earlier, the Patent Office invalidated claims in a different Cisco patent on a way to improve processing in network devices.
San Jose, California-based Cisco and Arista are fierce competitors in the multibillion-dollar market for ethernet switches that connect computers and servers.
Last month, the U.S. International Trade Commission concluded that Arista's switches had infringed the Cisco patents and said it would issue an order banning Arista from importing the infringing products into the United States.
Arista general counsel Marc Taxay said on Thursday that the company "will now seek complete suspension" of the ITC's import ban, which is slated to go into effect in July.
Cisco did not immediately return a request for comment.
Thursday's ruling is the latest development in a years-long legal battle between Cisco and Arista.
Cisco brought multiple lawsuits against Arista in 2014, alleging it has a "culture of copying" Cisco's intellectual property. Arista has denied the allegations and accused Cisco of a smear campaign.
The ITC ruled last year that Arista had infringed three other Cisco patents relating to managing and securing communications networks. Arista redesigned its switches, and U.S. Customs and Border Protection said in April that the company could resume importing its redesigned products.
Shares of Santa Clara, California-based Arista closed at $148.52 on Thursday, up 0.7 percent, after dropping below $145 a share earlier in the day. Cisco shares ended the day 0.9 percent higher at $31.82.
Reporting by Jan Wolfe; Editing by Noeleen Walder