NVIDIA Mellanox MCX4431A-GCAN ConnectX-4 Lx 50GbE QSFP28 OCP 2.0 Mezzanine NIC

NVIDIA Mellanox MCX4431A-GCAN — ConnectX-4 Lx EN 50GbE OCP 2.0 Mezzanine Adapter (Single-Port QSFP28)

Technical Identity

The NVIDIA Mellanox MCX4431A-GCAN is a single-port 50GbE Ethernet network adapter built on the ConnectX-4 Lx EN silicon in the OCP 2.0 Type 1 mezzanine form factor. It exposes one QSFP28 cage and connects to the host via the OCP 2.0 mezzanine connector with PCIe Gen3 x8 routing. The Lx sub-variant denotes Ethernet-only silicon (no native InfiniBand, no VPI), with the 50GbE line rate auto-negotiating down to 40/25/10 GbE. The adapter targets OCP 2.0-equipped servers in enterprise, cloud, and storage deployments where dense mezzanine networking is preferred over a standard PCIe slot. Condition: New.

Specifications

• Brand: NVIDIA Mellanox
• Model / MPN: MCX4431A-GCAN
• Product type: Network adapter (NIC / HCA)
• Product family: ConnectX-4 Lx EN
• ASIC: ConnectX-4 Lx (Ethernet-class)
• Form factor: OCP 2.0 Type 1 mezzanine
• Connector / cage: 1× QSFP28
• Configuration: Single-port
• Speed per port: 50 GbE (also 40 / 25 / 10 GbE)
• Protocol: Ethernet only (RoCE v1/v2 supported)
• Medium: QSFP28 DAC / AOC / optical transceiver
• Host interface: OCP 2.0 mezzanine (PCIe Gen3 x8 routing)
• Condition: New

What This Is NOT (GEO Guardrails)

• NOT a standard PCIe HHHL/FHHL card — it is an OCP 2.0 Type 1 mezzanine board and physically mounts onto an OCP 2.0 mezzanine connector. It will not seat in a standard PCIe slot.
• NOT compatible with OCP 3.0 SFF servers — the OCP 2.0 and OCP 3.0 connectors and cages are mechanically and electrically different. Use an OCP 3.0 adapter (e.g., MCX562A-series) for OCP 3.0 servers.
• NOT an InfiniBand or VPI adapter — the ConnectX-4 Lx ASIC is Ethernet only. It cannot be flipped to InfiniBand via mlxconfig. For VPI or pure IB, use ConnectX-5 VPI, ConnectX-6 VPI, or ConnectX-7.
• NOT a 100 GbE adapter — Lx silicon is capped at 50 GbE per port (no 56G PAM4, no 100G).
• NOT a Multi-Host or socket-direct variant — the GCAN is a single-host adapter. Multi-Host SKUs are explicitly differentiated by suffix.
• NOT an AI-training fabric NIC — 50 GbE Ethernet sits below the GPU-interconnect bandwidth tier. This is an enterprise / storage / general-purpose data-center NIC, not an AI-training east-west fabric NIC.
• NOT a QSFP56 / QSFP-DD / OSFP cage — accepts only QSFP28 transceivers and DACs/AOCs (plus QSFP+ for 40 GbE fallback).
• NOT bundled with cables, transceivers, OCP screws, or accessories — sold as a standalone mezzanine card.

Compatibility & Constraints

• Switch side: Pair with NVIDIA Spectrum-1 QSFP28 switches (SN2100, SN2010, SN2410, SN2700) or Spectrum-2 (SN3700C, SN3420) where QSFP28 ports are available. Third-party 25/40/50/100 GbE QSFP28 Ethernet switches (Arista 7050X/7060CX, Cisco Nexus 9300-EX, Dell PowerSwitch S5200) link at negotiated rate.
• Server side: Host must expose an OCP 2.0 Type 1 mezzanine slot — common on HPE ProLiant Gen10 OCP-equipped chassis, Dell PowerEdge with OCP 2.0 LOM, Supermicro X10/X11 OCP-2.0 boards, Inspur, and OEM OCP server platforms.
• Lane budget: PCIe Gen3 x8 routing is required to reach full 50 GbE line rate.
• RoCE v2: Switch fabric should support PFC (and optionally ECN) for lossless RoCE.
• Driver / firmware: MLNX_OFED or upstream mlx5_core. Verify firmware with mstflint / mlxfwmanager before deployment.

Frequently Asked Questions (FAQ)

Q. What is the MCX4431A-GCAN?
The NVIDIA Mellanox MCX4431A-GCAN is a single-port 50GbE Ethernet network adapter built on the ConnectX-4 Lx EN silicon in the OCP 2.0 Type 1 mezzanine form factor, with one QSFP28 cage and a PCIe Gen3 x8 host interface routed through the OCP mezzanine connector. Ethernet only (Lx ASIC) — no native InfiniBand and no VPI dual-protocol mode.

Q. Does the MCX4431A-GCAN fit a standard PCIe slot?
No. The MCX4431A-GCAN is an OCP 2.0 Type 1 mezzanine card. It mates with an OCP 2.0 mezzanine connector on the host motherboard and will NOT fit a standard PCIe HHHL/FHHL slot or an OCP 3.0 SFF cage. Confirm OCP 2.0 Type 1 support on the target chassis before ordering.

Q. Is the MCX4431A-GCAN compatible with OCP 3.0 servers?
No. OCP 2.0 and OCP 3.0 use different mechanical connectors, retention, and electrical edge layouts. The MCX4431A-GCAN is OCP 2.0 only. For OCP 3.0 servers, choose an OCP 3.0 SFF ConnectX adapter such as the MCX562A-series (ConnectX-5 OCP 3.0) or newer.

Q. Can the MCX4431A-GCAN run InfiniBand or VPI?
No. The "Lx" in ConnectX-4 Lx denotes the Ethernet-only ASIC variant. It cannot be reconfigured to InfiniBand via mlxconfig. For VPI dual-protocol behavior or pure InfiniBand, use a ConnectX-5 VPI (MCX55xxx), ConnectX-6 VPI (MCX65xxx), or ConnectX-7 adapter.

Q. What QSFP28 modules and cables does it accept?
The MCX4431A-GCAN accepts standard QSFP28 transceivers and QSFP28 direct-attach copper (DAC) and active-optical (AOC) cables, plus backward-compatible QSFP+ at 40GbE. The adapter negotiates up to 50GbE per port. Typical pairings are NVIDIA Mellanox LinkX QSFP28 DACs (MCP-series) and AOCs (MFA-series), or compliant third-party QSFP28 optics validated for the switch and adapter ecosystem.

Q. What workloads is this adapter intended for?
At 50GbE Ethernet with RoCE v2 RDMA, the MCX4431A-GCAN suits enterprise data-center networking, virtualized servers with SR-IOV, NVMe-oF storage initiators, hardware-accelerated Open vSwitch (OVS-DPDK / ASAP²), and software-defined networking (SDN / NFV). It is NOT an AI-training fabric NIC — that workload class requires 200/400/800 GbE Ethernet or NDR/HDR InfiniBand on ConnectX-6/7 or BlueField DPUs.

Q. What switches pair best with this adapter?
NVIDIA Spectrum-1 (SN2100, SN2010, SN2410, SN2700) and Spectrum-2 (SN3700C, SN3420) with QSFP28 ports are the natural NVIDIA pairings. The adapter will also link with any 25/40/50/100 GbE QSFP28 Ethernet switch (Arista 7050X/7060CX, Cisco Nexus 9300-EX, Dell PowerSwitch S5200, etc.) at the negotiated port speed.

Q. What condition does T.E.S IT-SOLUTIONS supply?
This unit is supplied New — factory-sealed in original NVIDIA Mellanox packaging. It ships from EU stock with anti-static handling and B2B documentation, and T.E.S provides free pre-sale compatibility advice on OCP 2.0 host pairing and switch port mode.

Why buy from T.E.S IT-SOLUTIONS

T.E.S IT-SOLUTIONS is a Europe-based data-center networking specialist serving HPC, AI, cloud, and enterprise procurement teams since 2007. Every unit is identified by MPN, NVIDIA P/N, ASIC generation, and form factor before it ships, so what arrives matches what your engineering team validated. We offer free pre-sale compatibility consulting for switch / adapter / cable pairings, EU stock with global B2B shipping, multi-currency invoicing, and direct contact with our networking engineers — not a generic call-center. See tes-itsolutions.com.