Does 200G QSFP56 to 4xSFP56 Breakout DAC need FEC enabled on the host?
200G QSFP56 to 4xSFP56 Breakout DAC is a passive Twinax assembly with no retimer, so FEC and lane mode are decided entirely by the source and branch QSFP56 host ports. Confirm the FEC mode the target platform expects before ordering, because a passive cable cannot compensate for a host that assumes a retimed link.