NVIDIA Mellanox MCX516A-CCAT ConnectX-5 EN Dual-Port 100GbE QSFP28 Adapter, PCIe Gen3 x16: This is a server-class network adapter card built on the ConnectX-5 ASIC, not a switch, transceiver, or passive interconnect. The card provides two QSFP28 ports operating at 100GbE per port and seats in a PCIe 3.0 x16 host slot. The card ships with a tall (full-height) bracket. This is a refurbished unit.
Engineering Context
The ConnectX-5 EN ASIC is engineered for low-latency, high-message-rate Ethernet workloads. The MCX516A-CCAT is the dual-port 100GbE EN-only variant: it does not run native InfiniBand. The PCIe 3.0 x16 host interface supplies the bandwidth required to drive both 100GbE ports concurrently in server-class deployments, though sustained line-rate on both ports under heavy small-packet loads is bottlenecked by host PCIe limits when fewer than 16 PCIe 3.0 lanes are negotiated. ConnectX-5 introduces Tunnel Offloads (VXLAN, NVGRE, Geneve), embedded virtual switch acceleration (ASAP^2), and hardware offloads for RoCEv2 and NVMe-over-Fabrics, which together reduce CPU overhead in virtualized and storage-heavy hosts.
Deployment & Use Cases
Hypervisor hosts (VMware ESXi, KVM, Hyper-V) running ASAP^2 / SR-IOV virtual switching with 100GbE uplinks. NVMe-over-Fabrics initiator and target nodes using RoCEv2 transport. AI/ML training nodes where GPU-direct RDMA over Ethernet is required. Hyperconverged compute nodes in vSAN, Nutanix, or Ceph clusters that need RDMA acceleration. Storage gateways and software-defined networking appliances needing tunnel offload and connection tracking in hardware.
Technical Specifications
OEM: NVIDIA Mellanox
Part Number: MCX516A-CCAT (NVIDIA reference 900-9X5AD-0056-ST1)
ASIC: ConnectX-5 EN
Port Configuration: Dual-port QSFP28
Per-Port Speed: 100GbE (also supports 50/40/25/10/1GbE)
Protocol: Ethernet only (no native InfiniBand on the CCAT SKU)
Host Bus: PCIe 3.0 x16
Bracket: Tall / Full-Height (standard)
RDMA: RoCEv1 and RoCEv2 hardware offload
Tunnel Offload: VXLAN, NVGRE, Geneve in hardware
Storage Acceleration: NVMe-oF target/initiator offload, T10-DIF/PI
Condition: Refurbished — Tested by T.E.S IT-SOLUTIONS
Compatibility & Constraints
Compatible with PCIe 3.0 (and electrically compatible with PCIe 4.0/5.0) x16 host slots; running in a narrower slot will reduce achievable bandwidth and may not sustain dual-port line rate. Driver support covers Linux (MLNX_OFED, in-tree mlx5), Windows Server (WinOF-2), VMware ESXi (native nmlx5), and FreeBSD. Accepts MSA-compliant 100GbE QSFP28 transceivers, AOCs, and DAC cables. The CCAT variant is Ethernet-only and cannot be flashed to run native InfiniBand; for VPI (IB+EN) operation, the MCX516A-CDAT or MCX556A-EDAT variants are required. Tall-bracket only — for low-profile chassis a low-profile bracket replacement is required.
Why Choose T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS bench-tests every adapter for PCIe link width, per-port link, and firmware integrity before shipment. Visit https://www.tes-itsolutions.com for inventory updates. Handling time is 1-3 business days with international shipping and a comprehensive warranty.