IEEE publishes IEEE 802.3bz for 2.5 and 5 Gigabit Ethernet
IEEE and the IEEE Standards Association (IEEE-SA) have published IEEE 802.3bz-2016, "Standard for Ethernet Amendment: Media Access Control Parameters, Physical Layers and Management Parameters for 2.5 Gb/s and 5 Gb/s Operation." The specifications support Ethernet transmission at those rates over Category 5e and Category 6 twisted-pair copper cabling.