How to design a TVS protection solution for the uplink port of a data center switch?

Data center switch uplink ports, which handle backbone data transmission, require a higher level of protection. The solution employs a three-level collaborative protection: The first level uses a 3R090L-6X8 gas discharge tube (DC breakdown voltage 90V, current carrying capacity 5kA) connected in parallel between the center tap of the RJ45 transformer and the chassis ground to discharge 80% of the common-mode surge energy; the second level utilizes the transformer's isolation withstand voltage of 1500VRMS to attenuate the remaining energy by 60%; the third level uses an ESDLC3V3D3B TVS (VRWM=3.3V, junction capacitance 1.2pF) bridging between differential pairs on the PHY side to precisely clamp the differential-mode residual. This solution has passed IEC61000-4-5 6kV common-mode surge and ±8kV ESD tests, with a bit error rate of <10⁻¹⁰, and is suitable for the uplink ports of core layer switches.