FlexE stands for Flexible Ethernet. It is a technology that allows network operators to create and manage multiple logical Ethernet links on top of a single physical Ethernet link. FlexE can provide flexible bandwidth allocation, network slicing, and improved performance and reliability for Ethernet-based services.
FlexE works by using a shim layer between the Ethernet MAC layer and the PHY layer, which can multiplex and demultiplex multiple sub-rate Ethernet MAC flows over a single higher-rate Ethernet PHY. FlexE can also use a calendar mechanism to schedule the transmission and reception of the sub-rate MAC flows over the PHY.