The 400G IEEE 802.3bs RS-FEC core implements the Reed-Solomon Forward Error Correction (RS-FEC) functions which are part of the 400GBASE-R PCS layer, as described in IEEE 802.3bs and shown shaded in the following figure.
Figure 1. Architectural Position of 400G Ethernet PCS Layer
The 400G IEEE 802.3bs RS-FEC core provides FEC encoding and decoding functions using the FPGA logic fabric. This soft logic implementation is available in all supported device families.