ConnectX
NVIDIA's network adapter line, carrying the RDMA, hardware timestamping, and reordering features a fabric's transport depends on; its firmware is a first-class item in cluster version lockstep.
Current numbers
2x400GbEConnectX-8: the single 800 Gb/s physical port runs Ethernet as 2×400GbE (single 800GbE link unsupported; XDR IB carries 800G on the same port) — the dual-plane substrate
up to 1.6 Tb/sNVIDIA ConnectX-9 SuperNIC bandwidth (Rubin generation) — double ConnectX-8's 800 Gb/s; BlueField-4 (integrates a CX-9) ships at 800 Gb/s, double BlueField-3
< 4 nsinternal ASIC sync error (Spectrum) and ConnectX-class NIC timestamp variance