Fast-climbing internet security provider Duo Security Inc. has agreed to be acquired by Cisco Systems Inc. for $2.35 billion, the companies announced Thursday morning.

Under the deal Cisco, a San Jose, Calif.-based networking giant, will pay in cash and assumed equity awards for Ann Arbor-based Duo Security's outstanding shares, warrants and equity incentives, Cisco vice president of corporate development Rob Salvagno said Thursday on an investor and media call.

The acquisition is expected to close in the first quarter of Cisco's fiscal 2019. Duo Security co-founder and CEO Dug Song will continue to lead his Ann Arbor company as its general manager. The firm will become part of Cisco's networking and security unit led by David Goeckeler.

The impact on Duo Security employees is unclear. The networking giant plans to take on the "vast majority" of Duo Security's 740 employees, Cisco spokesman Jim Brady told Crain's in an email.

"The combination of our companies will help build on the promise of doing the right thing for our customers," Song said during the call.

He also touched on 8-year-old Duo Security's philosophy, rise and next steps in a published letter to employees.

"With this deal, we will realize significant value for our shareholders, while gaining the opportunity to leverage Cisco's global scale and resources to democratize security faster without compromising our vision," he wrote. "They agree with us on the past state of security, and we're going to fix it together. They've had a long and successful history of acquiring companies to support and accelerate their strategic initiatives."

Duo Security's success has come from a philosophy of respect and a streamlining of an often overly complicated industry, Song said in his letter. And it will continue that trajectory after the acquisition, with Cisco's larger scale and resources.