NVIDIA Mellanox MCX4411B-ACAN ConnectX-4 Lx EN OCP 2.0 25GbE Mezzanine Adapter: This is an OCP 2.0 (Open Compute Project) form-factor mezzanine network adapter built on the ConnectX-4 Lx EN ASIC. It provides a single 25GbE SFP28 port over a PCIe 3.0 x8 host interface. This is not a standard PCIe stand-up card; it requires an OCP 2.0 Mezzanine slot in the host server. This is a refurbished unit, tested by T.E.S IT-SOLUTIONS.
Engineering Context
ConnectX-4 Lx EN is the Ethernet-only sibling of ConnectX-4 with hardware offloads for RoCEv1/v2, VXLAN/NVGRE/GENEVE tunnelling, OVS-offload, and DPDK acceleration. The single SFP28 port negotiates 25GbE / 10GbE / 1GbE depending on the link partner. The OCP 2.0 mezzanine form factor places the adapter on the server motherboard rather than a PCIe riser, freeing standard slots and reducing cabling complexity. Host management features (NC-SI / MCTP) expose adapter telemetry and lights-out manageability to the BMC. PCIe Gen3 x8 provides ~64 Gb/s of host bandwidth — comfortable headroom for a single 25GbE link.
Deployment & Use Cases
OCP 2.0 server platforms in hyperscale and cloud data centers. ToR-attached compute nodes in 25GbE Spectrum fabrics. RoCEv2-enabled storage initiators for NVMe-oF and SMB Direct. SR-IOV / DPDK-accelerated NFV workloads. Bare-metal cloud servers needing lights-out NIC management via the BMC.
Technical Specifications
OEM: NVIDIA Mellanox
Part Number: MCX4411B-ACAN
Controller: ConnectX-4 Lx EN
Ports: 1 × SFP28
Speeds: 25GbE / 10GbE / 1GbE Ethernet
Host Interface: PCIe 3.0 x8
Form Factor: OCP 2.0 Mezzanine
Bracket: No bracket (OCP form factor)
Host Management: NC-SI / MCTP supported
Offloads: RoCEv1/v2, VXLAN, NVGRE, GENEVE, SR-IOV, OVS
Compliance: RoHS
Condition: Refurbished — Tested by T.E.S IT-SOLUTIONS
Compatibility & Constraints
Requires an OCP 2.0 Mezzanine slot — not compatible with standard PCIe expansion slots and not compatible with OCP 3.0 NIC bays. Driver support: MLNX_OFED, in-kernel mlx5_core (Linux), Windows native and WinOF-2. Operates only as Ethernet — this is not a VPI adapter and cannot run InfiniBand. Pair with NVIDIA SFP28 25GbE optics or DAC/AOC cables for tested interoperability; third-party transceivers may require coding lock disable on the host. Single-port only — for dual-port OCP 2.0 see the MCX4421A-* family.
Why Choose T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS bench-tests every ConnectX adapter on a server fixture before shipment, verifying link training, host management (NC-SI), and PCIe negotiation. Visit tes-itsolutions.com for the full refurbished NIC catalog and OCP 2.0 host compatibility consultation. Orders ship in 1–3 business days with global tracking.