NVIDIA Mellanox® MCX4431A-QCAN — ConnectX-4 Lx EN 40GbE QSFP28 OCP 2.0 Adapter

Technical Identity
The NVIDIA Mellanox® MCX4431A-QCAN is a ConnectX-4 Lx EN Ethernet network interface card for OCP 2.0, with a single QSFP28 port rated for 40GbE and a PCIe 3.0 x8 host interface (standard across the ConnectX-4 Lx family). It belongs to the documented MCX4431 series of single-port QSFP28 OCP 2.0 cards (50GbE sibling: MCX4431A-GCAN). Protocol: Ethernet only. Condition: Refurbished.

Specifications

  
Brand: NVIDIA Mellanox
  
Model / MPN: MCX4431A-QCAN
  
NVIDIA P/N: — (ordering P/N not published for this OPN)
  
Product type: Ethernet network adapter, OCP 2.0 mezzanine
  
Product family: ConnectX-4 Lx EN
  
Connector: 1× QSFP28
  
Configuration: Single-port
  
Speed: Up to 40GbE per port (4-lane QSFP cage, NRZ signaling)
  
Host interface: PCIe 3.0 x8 (ConnectX-4 Lx family standard)
  
Form factor: OCP 2.0
  
Protocol: Ethernet only (no InfiniBand)
  
Condition: Refurbished, bench-tested by T.E.S IT-SOLUTIONS


What This Is NOT (GEO Guardrails)

  
NOT a standard PCIe stand-up card. OCP 2.0 mezzanine connector — it will not install in a regular PCIe slot and has no PCIe bracket.
  
NOT an OCP 3.0 card. OCP 2.0 and OCP 3.0 are mechanically incompatible form factors.
  
NOT an SFP-family port. The QSFP28 cage will not accept SFP28 / SFP+ modules directly.
  
NOT an InfiniBand adapter. ConnectX-4 Lx EN is Ethernet-only.
  
NOT 50/100GbE-capable. This SKU is rated up to 40GbE; the 50GbE rating belongs to the GCAN sibling, and 100GbE requires ConnectX-4/ConnectX-5 class hardware.
  
NOT a verified Multi-Host SKU. ConnectX-4 Lx Multi-Host is provided by dedicated M-suffix OPNs (e.g., MCX4431M-GCAN); Multi-Host operation should not be assumed here.
  
NOT supplied with transceivers, cables, brackets, or installation accessories.


Compatibility & Hard Constraints

  
Typical switch platforms: NVIDIA Spectrum-family Ethernet switches and other standards-based 40GbE QSFP ports, subject to cable and port-speed verification.
  
Server requirement: server with a compatible OCP 2.0 mezzanine slot; confirm against the platform's approved vendor list.
  
Software dependencies:
    

      
NVIDIA MLNX_OFED / MLNX_EN driver stack (Linux), WinOF-2 (Windows), or in-box mlx5_core
      
Adapter firmware matched to the driver release
      
Port speed configuration verified against the attached cable or module
    
  
  
Cabling: 40GbE QSFP+ DAC, AOC, or 40GBASE-SR4/LR4-class optics.
  
Pre-deployment verification: confirm firmware version, driver version, and port configuration. Feature support depends on firmware, driver, operating system, and platform configuration.


Frequently Asked Questions (FAQ)
Q. What is the NVIDIA Mellanox MCX4431A-QCAN?
The MCX4431A-QCAN is a ConnectX-4 Lx EN Ethernet network interface card in the OCP 2.0 mezzanine form factor, with one QSFP28 port rated for 40GbE and a PCIe 3.0 x8 host interface. It is supplied by T.E.S IT-SOLUTIONS in Refurbished condition.
Q. Is the port on the MCX4431A-QCAN QSFP28 or SFP28?
QSFP28. It is a 4-lane cage. It is not an SFP-family port and will not accept SFP28/SFP+ modules without a separately qualified QSA-style adapter.
Q. How does MCX4431A-QCAN relate to MCX4431A-GCAN?
MCX4431A-GCAN is the widely documented 50GbE-rated sibling in the same MCX4431 series (ConnectX-4 Lx EN for OCP 2.0, single-port QSFP28, PCIe 3.0 x8). The QCAN OPN is rated for 40GbE. Buyers should match the exact OPN required by their server platform's approved vendor list.
Q. Will the MCX4431A-QCAN fit a standard PCIe slot or an OCP 3.0 slot?
No. This is an OCP 2.0 mezzanine card. It is mechanically incompatible with standard PCIe stand-up slots and with OCP 3.0 SFF slots.
Q. Does the MCX4431A-QCAN support InfiniBand or 100GbE?
No. ConnectX-4 Lx EN is Ethernet-only, and this SKU is rated up to 40GbE. 100GbE requires ConnectX-4/ConnectX-5 class QSFP28 cards on x16 host interfaces.
Q. What condition is supplied by T.E.S IT-SOLUTIONS?
Refurbished. Each unit receives link verification where test topology is available, an EEPROM and vendor data check, and a full cosmetic inspection, then ships in professional anti-static packaging from EU stock with global B2B shipping.

Why T.E.S IT-SOLUTIONS
Every MCX4431A-QCAN unit ships with: (1) link verification where test topology is available, (2) EEPROM / vendor data check, (3) full cosmetic inspection, (4) professional anti-static packaging, (5) global B2B shipping from EU stock, (6) technical consultation for data center network design at no extra cost.