400GbE interface
For 400 Gigabit Ethernet, the IEEE 802.3bs working group has specified various physical interfaces.
In terms of transmission technology, 400GbE relies on optical fibers, both multimode fibers and single- mode fibers. The CWDM method is used for wavelength division multiplexing. The possible distance ranges are between 100 m with multimode fibers and from 2 km and 5 km with monomode fibers. The bridgeable distance with single mode fibers depends on the OS class. Transmission takes place with wavelength division multiplexing according to CWDM over 4 lanes with 100 Gbit/s, 8 lanes with 50 Gbit/s or 16 lanes with 25 Gbit/s. The corresponding interfaces have the designations 400GBase-SR8 and 400GBase-SR16.
The interfaces are implemented in transceiver modules, with CFP modules and QSFP modules being used in a wide variety of designs.