NVIDIA Mellanox MCX345A-BCPN ConnectX-3 Pro EN, 40GbE Single-Port QSFP+ OCP Mezzanine Adapter: This is an OCP form-factor mezzanine network interface card based on the ConnectX-3 Pro EN ASIC, providing one QSFP+ port at up to 40 Gigabit Ethernet over a PCIe Gen3 x8 host interface. The QSFP+ cage is a 40GbE-class connector — it accepts QSFP+ DAC, AOC, and optical transceivers, but is not a QSFP28 100GbE cage and will not negotiate above 40GbE. This is a refurbished unit.
Engineering Context
The ConnectX-3 Pro silicon adds hardware-based VXLAN and NVGRE encapsulation and decapsulation offload over the original ConnectX-3, which removes the encap/decap CPU tax in overlay-heavy data center fabrics. The card supports RoCE v1 and v2 for kernel-bypass RDMA, SR-IOV, and stateless TCP/UDP/IP offloads. PCIe Gen3 x8 provides approximately 63 Gb/s of bus bandwidth, comfortably above the 40GbE line rate. The card ships in OCP form factor without a standard PCIe-slot bracket.
Deployment & Use Cases
OCP-compliant compute racks running OpenStack Neutron with VXLAN tunneling. Legacy 40GbE storage fabrics and clustered file systems (Lustre, BeeGFS). Migration projects upgrading 10GbE infrastructure to 40GbE without going to a 100GbE TCO step. Cost-sensitive 40GbE rebuilds where ConnectX-4 is over-spec.
Technical Specifications
- OEM: NVIDIA Mellanox
- Part Number: MCX345A-BCPN
- ASIC: ConnectX-3 Pro EN
- Form Factor: OCP Mezzanine
- Ports: 1 x QSFP+
- Max Speed: 40GbE (also 10GbE)
- Host Interface: PCIe Gen3 x8
- RDMA: RoCE v1 / v2
- Overlay Offloads: Hardware VXLAN, NVGRE encap/decap
- Virtualization: SR-IOV
- Stateless Offloads: TCP/UDP/IP checksum, TSO, LRO
- Condition: Refurbished — Tested by T.E.S IT-SOLUTIONS
Compatibility & Hard Constraints
Requires an OCP-compatible mezzanine slot. No PCIe slot bracket is included. The QSFP+ cage is 40GbE — does NOT auto-negotiate to 100GbE and is not pin-compatible with QSFP28-only modules at 100Gb/s. Will not run in QDR/FDR InfiniBand mode — this is the EN (Ethernet-only) SKU. Driver support: MLNX_OFED-3.x and 4.x branches for Linux, WinOF for Windows Server 2012R2+, ESXi inbox driver from 6.0 onward.
Why Choose T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS link-tests every ConnectX-3 Pro adapter at 40GbE, validates firmware integrity, and verifies PCIe Gen3 x8 negotiation before shipment. EU and worldwide shipping with 1–3 business day handling. Visit T.E.S IT-SOLUTIONS for the full Mellanox catalog.