The Senate hearings are scheduled to start at 7am and 11am Portland time and can be streamed live at c-span.org. Key witnesses to be called include former National Security Agency director Keith Alexander, who now heads a private contractor, IronNet Cybersecurity, as well as Kevin Mandia, the chief executive of another contractor called FireEye that published some of the key digital forensic analyses attempting to connect the Russian government to last year's hack of the Democratic National Committee.