NVIDIA Mellanox MCX456M-ECAT ConnectX-4 VPI Multi-Host Dual-Port Adapter, EDR IB / 100GbE QSFP28: This is a Multi-Host PCIe network adapter built on the ConnectX-4 VPI ASIC (vendor P/N 900-9X4AC-0056-MT0). It exposes two QSFP28 ports, each capable of EDR InfiniBand (100 Gb/s) or 100GbE Ethernet, and uses a Socket Direct architecture with two independent PCIe 3.0 x8 host interfaces so the card can be shared by up to two CPUs / hosts. This is a Multi-Host VPI card (the M suffix), not a standard single-host ConnectX-4. This is a refurbished unit, tested by T.E.S IT-SOLUTIONS, shipped with a tall (full-height) bracket.
Engineering Context
ConnectX-4 Multi-Host enables up to two independent hosts to share the same physical NIC, each presenting its own PCIe function set, with full QoS isolation between the hosts. Socket Direct routes each PCIe x8 link to a different CPU socket, eliminating the QPI/UPI hop for NIC traffic and reducing tail latency on NUMA systems. The adapter delivers RDMA over both InfiniBand (native) and Ethernet (RoCEv1/v2), NVMe-oF target/initiator, OVS-offload, T10-DIF/CRC, and SR-IOV with up to 256 virtual functions per port.
Deployment & Use Cases
Hyperscale and OCP server designs sharing a single 100G NIC across two compute nodes. AI training clusters running RDMA over EDR InfiniBand. NVMe-oF storage targets exposing 100GbE RoCE LUNs. Telco vRAN/OAI servers needing dual-host network virtualization. Cost optimization in dense rack designs where one Multi-Host adapter replaces two single-host NICs.
Technical Specifications
OEM: NVIDIA Mellanox
Part Number: MCX456M-ECAT
Vendor P/N: 900-9X4AC-0056-MT0
ASIC: ConnectX-4 VPI (Multi-Host)
Ports: 2 × QSFP28
InfiniBand: SDR / DDR / QDR / FDR10 / FDR / EDR (up to 100 Gb/s)
Ethernet: 1 / 10 / 25 / 40 / 50 / 56 / 100 GbE
Host Bus: Dual PCIe 3.0 x8 (Socket Direct, Multi-Host)
SR-IOV: Up to 256 VFs per port
Form Factor: Half-Height, Half-Length (HHHL)
Bracket: Tall (Full-Height)
Compliance: RoHS R6
Condition: Refurbished — Tested by T.E.S IT-SOLUTIONS
Compatibility & Constraints
Requires a server platform that physically supports Socket Direct: two PCIe 3.0 x8 cabled connections to two CPU sockets (typically via an auxiliary connector and harness). Compatible with NVIDIA MLNX_OFED for Linux and WinOF-2 for Windows. The Multi-Host capability is enabled at the firmware level — single-host operation is also supported, but in single-host mode only one PCIe link is active and the second link is unused. Not interchangeable with standard MCX456A-ECAT (non-Multi-Host) firmware. EDR rate requires a switch and cable rated for EDR; lower IB rates auto-negotiate.
Why Choose T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS tests every Multi-Host adapter for both PCIe links, port LED status, and link training before shipment. We provide expert consultation on Socket Direct cabling, EDR fabric design, global shipping, and a 1–3 day handling time. Visit tes-itsolutions.com for the full enterprise networking catalog.