Does EFT testing on data center switches affect data forwarding?

During EFT testing of data center switches, common-mode transients can couple to the PHY chip, causing FIFO overflow or link renegotiation, resulting in data forwarding interruptions. The evaluation standard IEC61000-4-4 requires a functional rating of Grade A (no performance degradation during testing). The following measures were implemented: A TVS (such as the ESD5V0D3B from Etymotic, VRWM=5V, junction capacitance 45pF) was added to the PHY chip power pin to suppress transients; a PBZ1608A-102Z0T ferrite bead was added for isolation on the MAC side; and firmware optimization was implemented to achieve a link fault recovery time of <2ms. Before the rectification, the forwarding packet loss rate in the ±2kV EFT test was 3.5%, meeting Grade C; after the rectification, zero packet loss and forwarding delay jitter <1μs were achieved in the ±4kV test, meeting Grade A.