AT&T has reportedly said it has completed the first phase of a multi-phase field test program for 400 Gigabit Ethernet (400GbE) transmission.

With this first test phase, the company created a 400GbE service as well as a live traffic service between New York and Washington, D.C., using a software-defined networking (SDN) controller.

In addition to building the 400GbE link, the SDN controller rerouted the service to a second path to simulate a response to a network failure.

The communications service provider said its nationwide network is now ready for what it calls "next-generation speed. In an announcement about the test last fall, AT&T said it would use optical transport equipment from Coriant during that phase of the test.

Rick Hubbard, AT&T's senior vice president of network products, said, "The way we've rolled out next-generation Ethernet speeds is working; video-driven network data is continuing to grow."

AT&T is now ready to move into the second phase of the test, which involves running 400GbE traffic over a metro network through the Tier 1 service provider's OpenROADM program.