The IEEE 802.3cm working group is concerned with the standardization of 400 Gbit/s Ethernet over eight channels with 50 Gbit/s
per channel. Standardization variants are available for the transmission of 400 Gbit/s, whose 400GbE interfaces are designated 400GBase-SR8 and 400GBase-SR16. 400GBase-SR8 operates with eight transmission channels at 50 Gbit/s each. The connector is an MPO connector with 16 fibres, eight for the home channels and a further eight for the return channels. Optionally, the 802.3cm standard also provides single fiber connectors such as the CS connector and the MDC connector, both VSFF connectors, Very Small Form Factor (VSFF).