A exhaustive series of lawsuits between Ribbon Communications and Metaswitch Networks is ending.

The two companies agreed to mediation to resolve six separate cases. Metaswitch will pay Ribbon $63 million over the next several years, and they will cross-license their patents. The companies bitterly battled over patent infringement during the last five years. They both create software that supports telecommunication service providers.

Ribbon and Metaswitch share a colorful history with so many lawsuits that it’s difficult to keep them all straight.

Genband, Ribbon’s predecessor, offered to buy Metaswitch in 2013. The latter refused, and the next year Genband sued it for infringing on eight patents. Metaswitch followed suit and filed infringement lawsuit of its own later that year.

Genband went on to successfully sue Metaswitch for patent infringement in 2016. The court forced Metaswitch to hand over $8.1 million for infringing upon seven VoIP-related patents. Genband later merged with Sonus Networks to form Ribbon.

Metaswitch filed an antitrust lawsuit against Ribbon last November, asserting that it was Ribbon’s last remaining rival after a series of “serial acquisitions” and “exclusionary and deceptive tactics.” It argued that Ribbon ran a “kill” campaign after Metaswitch refused its acquisition offer in 2013. The campaign allegedly included misinforming Metaswitch customers, “anticompetitive” pricing and “bad faith” use of intellectual property rights.

Metaswitch’s Martin Lund

“Blatant efforts to dominate a captive market and price gouge are exactly what the antitrust laws are designed to stop,” Metaswitch CEO Martin Lund said. “We are pursuing this case not just to protect Metaswitch, but because we believe Ribbon’s conduct is hindering customers’ ability to make fixed-line upgrades that could enhance the day-to-day lives of millions.”

Ribbon CEO Franklin Hobbs dismissed the suit as nothing more than a litigation tactic to put off paying Ribbon for the previous lawsuit.

Ribbon’s Franklin Hobbs

“It is disappointing that Metaswitch is attempting to relitigate claims that it already lost in federal court,” Hobbs said. “Ribbon will not be deterred by these actions, and we look forward to having Ribbon’s intellectual property rights vindicated and Metaswitch finally paying for its misappropriation of Ribbon technology.”

Ribbon went on to sue Metaswitch again for trying to steal trade secrets. That trial was set to begin this month.

Metaswitch will first fork over $37.5 in the second quarter of 2019 and deliver the rest of the $25.5 million through three annual payments with 4% interest.

Ribbon’s stock ticked up a little more than 2% Friday after news of the mediation agreement surfaced.