How to improve the EFT immunity of data center switch communication ports?

Measures to improve EFT immunity of data center switch communication ports (network ports/management ports): A 1000pF/2kV high-voltage capacitor is connected in parallel to ground from the center tap of the transformer to provide a common-mode low-impedance discharge path. The capacitor is made of COG material with stable temperature characteristics. A PBZ1608A-102Z0T (1000Ω@100MHz) ferrite bead is connected in series with the signal line to absorb high-frequency energy. A low-capacitance TVS such as ESDLC3V3D3B (junction capacitance 1.2pF) is connected between the differential pairs of the PHY chip to clamp the residual signal. The ground spacing of the PCB differential traces is <5λ/20. The above measures improved the EFT immunity of the communication port from ±1kV to ±4kV, and the bit error rate was <10⁻⁹ with zero link interruption during the test.