FlexE, also known as Flexible Ethernet, is a communications protocol published by the Optical Internetworking Forum (OIF). It enables flexible Ethernet connectivity between routers independent of the physical line rates of the optical layer. For service providers, using FlexE gives them real traffic separation and the ability to remotely adjust service bandwidth on demand and maximize efficiency at each network layer. While it was designed to offer higher capacity and more efficient data center interconnect (DCI), the industry is now looking at deploying FlexE in the era of 5G networks.