NVIDIA Mellanox MCX456A-ECAT ConnectX-4 VPI Dual-Port QSFP28 100Gb/s Adapter, PCIe 3.0 x16: This is a dual-port Virtual Protocol Interconnect (VPI) network adapter built on the ConnectX-4 ASIC, supporting 100GbE Ethernet or EDR InfiniBand 100Gb/s per port. The card uses a PCIe 3.0 x16 host interface and ships with a tall (full-height) bracket. This is a VPI dual-mode card, not an Ethernet-only or InfiniBand-only adapter. This is a refurbished unit.
Engineering Context
The MCX456A-ECAT delivers up to 100Gb/s per port simultaneously on both ports. PCIe 3.0 x16 provides 128 Gb/s of raw host bandwidth (~126 Gb/s effective after 128b/130b encoding), enough to sustain one port at full 100Gb/s line rate; dual-port simultaneous line-rate operation is host-PCIe limited. The ConnectX-4 ASIC supports RDMA over Converged Ethernet (RoCE v2), GPUDirect RDMA, NVMe over Fabrics initiator and target, hardware-offloaded VXLAN/NVGRE encapsulation, and Single Root I/O Virtualization (SR-IOV) up to 256 virtual functions. Per-port mode (Ethernet vs InfiniBand) is selected at driver load.
Deployment & Use Cases
NVIDIA GPU compute servers (DGX-class and similar) requiring 100Gb/s host connectivity. Storage targets running NVMe-oF over RoCE v2 to clients on the same fabric. AI training nodes using NCCL collectives over InfiniBand EDR. Hyperconverged infrastructure where one port runs Ethernet for VM traffic and the other runs IB for storage. OpenStack and Kubernetes clusters using SR-IOV to expose virtual NICs directly to tenants.
Technical Specifications
OEM: NVIDIA Mellanox
Part Number: MCX456A-ECAT
NVIDIA P/N: 900-9X4AC-0056-ST3
ASIC: ConnectX-4
Ports: 2 x QSFP28
Per-Port Speed: 100GbE or EDR InfiniBand 100Gb/s (VPI)
Host Interface: PCI Express 3.0 x16
Bracket: Tall (full-height)
Offloads: RoCE v2, GPUDirect RDMA, NVMe-oF, VXLAN/NVGRE, SR-IOV (up to 256 VFs)
Mode Selection: Per-port Ethernet/IB at driver load
Backward Compatibility: 40/56GbE and FDR/FDR10 InfiniBand
Condition: Refurbished — Tested by T.E.S IT-SOLUTIONS
Compatibility & Hard Constraints
Compatible with NVIDIA Spectrum (SN2000/SN3000/SN4000) and SwitchX/Quantum switches at matching speeds. Compatible with QSFP28 DAC, AOC, and SR4/LR4 transceivers. Requires PCIe 3.0 x16 slot (will run at reduced bandwidth in x8 slots, limiting throughput). Tall bracket is included; low-profile bracket is not part of this SKU. Driver support: MLNX_OFED for Linux and WinOF-2 for Windows; mainline Linux mlx5 driver also supports the card. Not compatible with HDR (200Gb/s) or NDR (400Gb/s) speeds — those require ConnectX-6 or ConnectX-7. PCIe 3.0 x16 is a hard requirement for line-rate dual-port operation.
Why Choose T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS tests every MCX456A-ECAT under both Ethernet and InfiniBand modes, validates link-up at 100Gb/s per port, runs traffic with iperf3 and ib_send_bw to confirm sustained throughput, and checks bracket and connector condition before shipment. We provide expert consultation on host-side configuration, driver matrix, and global shipping with comprehensive warranty. Visit tes-itsolutions.com. Handling time 1-3 business days.