In a move that could lead to a ban on selling its products in the United States, the US International Trade Commission has ruled that Arista does in fact infringe on a number of Cisco’s technology patents.

Arista now must decide if it wants to ask the US government to overturn a so-called “import ban” or ask that an appeals court toss the decision, observers say. It could also decide to build products in the US – a move that Cisco says would “not only would violate the ITC orders, but the federal court has the authority to enjoin local manufacturing of infringing products.”

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Cisco’s reaction to the ruling was tenacious: “This marks the end of Arista’s ability to mislead its shareholders and customers about the infringing nature of their products. The ITC remedies include an exclusion order, which would ban all Arista switches and their components from importation into the U.S. and a cease and desist blocking the use to build infringing products in the US comprised any imported components,” said Mark Chandler, General Counsel for Cisco in his blog.

“Arista has as much as acknowledged the infringement of the Private VLAN patents, announcing that they will discontinue the private VLAN feature “for now,” belying their claim that they had developed workarounds. The remedies also include a cease and desist order prohibiting the marketing, sale, and distribution of infringing Arista switches in the U.S. These orders are scheduled to go into effect at the end of the Presidential Review Period on August 23, 2016. Arista made much of the fact that it had challenged the validity of Cisco’s patents. Arista did not challenge the validity of the Private VLAN patents, however, and the Patent and Trademark Office declined to institute review proceedings on six claims in the SysDB patent which the ITC found infringed,” Chandler stated.

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For its part Arista was just as unyielding and said the next step is for the “U.S. Trade Representative to review the matter and decide whether to disapprove the limited exclusion order and cease and desist order. The U.S. Patent and Trademark Appeal Board (PTAB) has also recently instituted an Inter Partes Review of certain claims of U.S. Patent Nos. 7,162,537 [a Cisco patent having to do with database management in a router] to determine their validity.”

“Arista respects the Commission’s decision and intends to fully comply with the orders,” said Marc Taxay, Senior Vice President, General Counsel for Arista. “Despite Cisco’s rhetoric claiming that the lawsuits are a defensive move to protect its intellectual property, these actions are clearly part of a broader effort to use litigation to preserve Cisco’s market position. If allowed to succeed, Cisco’s scheme would have a chilling effect on innovation. While we will defend our rights in these actions, our primary focus remains on the continued supply of products to our customers.”

Arista also added that it had released a new version of its “EOS software containing design-arounds that it believes address the ITC’s findings with respect to the features implicated in the Final Determination. Arista intends to seek appropriate regulatory approvals for these design-arounds.”

The work-arounds could end up being a key point in this case, experts added.

"The ITC is barring Arista products that violate the Cisco patents from the US market. However, Arista had stated previously that they have developed workarounds for any products that may be in question. Therefore, it would be surprising if Arista did not anticipate and is already prepared for this ruling," said Jim Duffy, a senior analyst with 451 Research.

Cisco began its legal proceedings on December 19, 2014 by filing two lawsuits against Arista. One suit is for patent infringement, which charges Arista with violating 14 Cisco patents for 12 features in the Arista EOS operating system. The second suit is for extensive copying of Cisco’s user manuals and command line structures, right down to the grammatical errors within them, Network World wrote at the time.

The complaint alleged violations of section 337 of the Tariff Act of 1930 in the importation into the United States and sale of certain network devices, related software, and components thereof that infringe patents asserted by Cisco Systems. Cisco wants the ITC to issue a limited exclusion order and a cease and desist order.

Arista in January filed a counterclaim to Cisco’s copyright infringement suit in the U.S. District Court, Northern District of California, for antitrust and unfair competition. Arista alleges Cisco conducts a “bait and switch” with its command line interface in which it claims it is an industry standard and then attempts to penalize competitors for emulating it. The claim in February became a lstandalone lawsuit.

The ITC in April granted a full review of certain patents in the now 15-month old patent suit between Cisco and Arista.

Specifically the ITC granted full review of the three patents that Arista is allegedly infringing under the initial determination issued by the presiding judge on Feb 2. In February the ITC made an initial determination that Arista Networks infringed on three Cisco patents in its switches -- patents associated with a central database for managing configuration data (SysDB) and private VLANs.

At the time of that ruling Cisco said, “none of the patents have been proposed for or adopted as industry standards. And all patents we asserted against Arista were invented either by Cisco employees who became Arista executives, or by engineers who worked for Arista executives when employed at Cisco.”