NVIDIA Mellanox MCX353A-QCBT ConnectX-3 VPI Single-Port QSFP Adapter (IB QDR 40Gb/s, 10GbE): This is a single-port Virtual Protocol Interconnect (VPI) network adapter built on the ConnectX-3 ASIC. It auto-negotiates between InfiniBand QDR (40Gb/s) and Ethernet 10GbE on the same QSFP physical port. The host interface is PCIe 3.0 x8 at 8GT/s and the card ships with a tall PCIe bracket. This is a refurbished unit, not a new-sealed factory part.
Engineering Context
VPI lets a single adapter run InfiniBand or Ethernet without changing hardware — the protocol is selected per port via mlxconfig. The QSFP connector accepts copper DAC, AOC, and optical transceivers rated for QDR (10 Gb/s per lane, 4 lanes = 40 Gb/s aggregate). Although the QSFP cage is mechanically QSFP/QSFP+ compatible, the MCX353A-QCBT silicon does NOT support FDR (14 Gb/s lane) or FDR10. Maximum Ethernet rate on this SKU is 10GbE; it does not auto-bond to 40GbE. PCIe 3.0 x8 at 8GT/s provides 64 Gb/s of host bandwidth, well above the 40 Gb/s line rate.
Deployment & Use Cases
HPC compute nodes joining an existing InfiniBand QDR fabric where new FDR adapters are not required. Storage initiators for SRP/iSER targets over QDR. Lab and academic clusters needing low-cost VPI flexibility. 10GbE host connectivity over QSFP-to-SFP+ adapter cables. Mixed protocol pilots where a node may switch between IB and Ethernet during testing.
Technical Specifications
OEM: NVIDIA Mellanox
Part Number: MCX353A-QCBT
Controller: ConnectX-3 (VPI)
Ports: 1x QSFP
InfiniBand Rate: QDR — 40 Gb/s
Ethernet Rate: 10GbE
Host Interface: PCIe 3.0 x8 (8GT/s)
Bracket: Tall (full-height)
Form Factor: Standard PCIe HHHL
Protocols: InfiniBand, Ethernet, RoCE v1, SR-IOV
Condition: Refurbished — Tested by T.E.S IT-SOLUTIONS
Compatibility & Constraints
Requires a PCIe 3.0 x8 (or wider) slot — runs at reduced bandwidth in PCIe 2.0 slots. Compatible with Mellanox SwitchX/SwitchX-2 QDR switches and any standards-compliant InfiniBand QDR fabric. Does NOT support FDR or FDR10 — pair with an MCX353A-FCBT or newer if FDR is required. Single-port only — no port-failover within the card. Driver support: MLNX_OFED for Linux, WinOF for Windows Server, native InfiniBand drivers for VMware ESXi 6.x. The QDR optical/copper cable is sold separately.
Why Choose T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS bench-tests every ConnectX-3 VPI adapter for link training (IB QDR and 10GbE), PCIe enumeration, and firmware integrity before shipment. T.E.S IT-SOLUTIONS ships globally with 1–3 business day handling and offers expert support on VPI configuration.