This amendment includes changes to IEEE Std 802.3-2022 and adds Clause 169 through Clause 173, Annex 172A, and Annex 173A. This amendment adds MAC parameters, Physical Layers, and management parameters for the transfer of IEEE 802.3 format frames at 400 Gb/s and 800 Gb/s. Additional files can be found here: https://standards.ieee.org/wp-content/uploads/2024/03/802.3df-2024_downloads.zip. (The PDF of this standard is available at no cost compliments of the IEEE GET program https://ieeexplore.ieee.org/browse/standards/get-program/page/series?id=68)